Calipers, Digital Dial?

[Mike Holbrook]

The chair making classes I have taken so far have tested round straight and tapered tenons for correct size with a ruler or simple mechanical calipers. I had a hard time telling how much more needed to be removed by trying to fit a mechanical caliper over the tenons I was turning on a lathe. There is quite a large selection of digital dial calipers available for around $30. The Starrett model is about 3x the cost and seems to have the exact same scales. The time savings and peace of mind one of these devices could provide seems to suggest one would be more than worth the cost. I imagine these calipers provide at least as accurate a measurement as I can come up with trying to measure the distances with a ruler or ruler and mechanical caliper? I believe it would be handy to be able to check outside stock dimensions, mortise dimensions, tenon dimensions, inside groove dimensions....I'm sure the measurements would be much easier, faster and less strain on the brain.

Peter Galbert came up with a caliper design that Benchmade now makes for turners. I believe this devise is specifically made to work in the groove made in turnings with a parting tool. For twice the money and a fraction of the uses though I think a digital caliper would provide a great deal more general woodworking utility?

[Derek Cohen]

Hi Mike

A calliper for me is a general purpose tool, not just for turning. For the past number of years I have sworn by the Mitutoyo Absolute range of digital calipers. The model I use is #500-197-20

I managed to find a couple on eBay quite cheaply, as these are expensive (more so than Starrett? I am not sure). The important features are that they have a long battery life and always return to the zero position on closing. They are reliable - which is all-important when measuring small numbers.

You must take care with these on eBay since there are a number of fakes around, made in China. I suspect one I purchased was as it has stopped working. The other soldiers on.

Anyway, I decided to buy a second digital calliper, and in my searchings discovered that Wexey make one. This has the additional feature of having imperial fractions, which is very useful. And cheap! http://wixey.com/calipers/index.html

I've been using the Wexey for some months now and it have been very reliable and easy to use.

Regards from Perth

Derek

[Jim Koepke]

This is only my opinion…

The Galbert caliper is a great design. My turning has not gotten to the point of needing such a device at this time, but maybe someday.

Having a caliper that reads to .001" has many uses in a shop. My preference is a dial as opposed to a digital readout. Another option is a vernier readout.

Outside stock dimensions are usually checked with my metal bench caliper that reads to 1/32".

For mortise, tenons, grooves and such it is easier/faster to check against the mating part or to make a go no go gauge from a piece of scrap.

For measuring tenons on a lathe SAE or metric wrenches can be used. For making bench dogs a 3/4" (19mm) wrench or 18mm for some European benches.

jtk

[John Huds0n]

Mitutoyo are pretty much the 'gold standard' when it comes to digital calipers, and they are definitely not cheap. I have the 6" 500-7680-10 and they were over $160. They cost so much it seems that sometimes I am afraid to use them....

I also have the Wixey - but they give me problems every now and then and I find them hard to turn on. In that price range ($30-$40) I like my IGaging set better. The display is bigger and they will also do fractions. (They also got much better reviews on Amazon compared to the Wixey)
http://www.amazon.com/gp/product/B001AQEZ2W/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

[Hilton Ralphs]

Digital vs Dial.

I have both varieties in Vernier Callipers and Dial Indicators. Some old school people swear by the dial callipers as the batteries in the Digital versions can often die just when you need the device the most. With ageing eyes, the Digital Callipers are infinitely easier to use but the accuracy on some of the cheaper ones may not be up to scratch for machinists but for woodworking they are perfect.

You can't go wrong with the iGaging Digital Vernier Calliper sold on Amazon. It's probably only $40.

For turning you get those inside and outside callipers in Digital too and again, I doubt you need 6 digit after the zero accuracy for wood.

iGaging even has a nice set comprising of a Digital Vernier Calliper plus a Digital Micrometer.

[Marko Milisavljevic]

All you need to know is here:


https://www.youtube.com/watch?v=1yqZx_FNbSs

[Dave Anderson NH]

I have several which I've collected over the years. 6" Starrett bought in 1970, 6" long jaw Fowlers, 12" Mitotoyo, and one of the cheap $30 digitals. All except the cheapos are dial type. I actually use the digitals the most for a single simple reason. It is easier for me to remember the reading when it is graphically displayed in almost 1/2" high digits than it is to remember the location/reading of the dial type. What that really says is that I am a visually oriented person. As for any caliper returning to zero, I've always found that when it doesn't happen it is the result of dust or small debris left on the inside of the jaws.

[george wilson]

I have only ever used DIAL calipers. It is easy to interpolate to a 1/4 thousandth with them. On a dial caliper you are stuck with a 1/2 thou reading. Plus,batteries go bad. The Starretts were,at least,bad battery eaters. I hope they have improved them.

The Mitutoyo are likely the most reliable of the commonly available types. Certainly their dial calipers have held up very well.

Unless you have a very good sense of touch,and your calipers are properly adjusted, they are not all that accurate anyway. In things like fitting bearings,better use micrometers. Most of the time I use my dial calipers,though.I'm not rebuilding engines.

I have an excellent Peacock dial caliper. When Enco,several years ago,started selling the Peacock brand again,I got all excited and ordered one. It turned out to be complete junk,though. The grinding was very rough. I sent it back. Too bad this nice brand must have been bought out by junk peddlers. Worse than anything Harbor Freight ever offered.

My Starrett DIAL calipers are good also. But,I'll warn you that the first Starrett I had was way off on the internal measurement side. I had to send it back for repair. When I got it back,it was STILL way off. Finally,they sent me a new one. I have no idea how those calipers got out of their factory TWICE(even after special attention). Brown and Sharpe have been made by a variety of makers over the years. I think they are French made now. Used to be Swiss made,I think. They are o.k..

[glenn bradley]

I abandoned my digital calipers or turned them into other tools:

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They're just too fussy for me for a lot of woodworking tasks. I find an easy to read dial quicker and easier as I rarely try to machine wood to 1/128"; I do that by hand. I do deal in imperial in the shop for therapeutic reasons and use the 1/64" tick mark dials with good success.

[Mike Null]

I've used a Mitutoyo 500-196 for more than 10 years. I frequently use the metric scale so the digital option is perfect for me. Back then I believe I paid about $130.

[ian maybury]

It's very tough without a lot of practice to get accurate measurement with the classic outside mechanical/contact callipers.

Another with Mitutoyo here, digital in this case out of circumstances (and it's been rock solid reliable and given fabulous battery life) for years. I was brought up on and feel a vernier type is the most reliable of all - very little scope to go wrong. A nifty accessory was a simple clamp on aluminium cross bar that attaches to the end of the scale that turns it into a much more useable depth gauge: http://www.axminster.co.uk/axminster-vernier-caliper-depth-gauge-attachment (some of the budget ones don't have the central sliding bar that enables this)

Wary of the various cheap brands, but some seem OK. I have a Wixey branded one that gets used for rough knock about (and to be fair it seems perfectly reliable for woodworking type dimensions), but as above it's much harder on batteries.

This may sound a bit daft, but feeling the need for an easy means of getting accurate much larger measurements at times i took a chance and bought an Indian made 600mm verner callipers off EBay for about €80 (more now) plus postage - thinking it'd probably be rubbish. http://tiny.cc/5ph9vx It turned out to be a great buy, although who knows if they are all like that or not.

Spent months trying to buy a used Mitutoyo in the UK, but kept on getting beaten out by tool dealers. The Indian model seems to be spot on. It's actually quite well made, and while the screws securing the bronze strips in the back of the head that control the fit on the scale needed minor filing to sort a fit issue it's otherwise been fine. It doesn't have quite the silky feel of a Mitutoyo, and the box wasn't up to much - but it's fine in use and perfectly functional...

[george wilson]

It doesn't have the silky feeling of the Mitutoyo,but you don't notice". Sounds like you DID notice!!!:):):)

[ian maybury]

:o Errm, well… yes George. Just not the $600 or whatever a Mitutoyo in that size would cost worth of notice i guess. :)

There seem to be some large size electronic models about at reasonable money too, i never got to check one out...

[Brian Holcombe]

As with George when I worked in the machine shop we almost never used digital calipers, but rather used micrometers for everything. So I have one in my shop now for tool related purpose, the digital calipers seem quite fine for woodworking.

I have an iGaging from Lee Valley that works well. I am transferring measurements using the same gauge, so slight inconsistency compared to absolute measurements is not so important, this was a practice I picked up at the machine shop as well, we always used the same gauge to measure parts that were going to work as an assembly or use one gauge as the standard. Not super critical for woodwork, but good practice is good practice.

[Jim Koepke]

I am transferring measurements using the same gauge, so slight inconsistency compared to absolute measurements is not so important, this was a practice I picked up at the machine shop as well, we always used the same gauge to measure parts that were going to work as an assembly or use one gauge as the standard. Not super critical for woodwork, but good practice is good practice.


When I worked in a print shop we would do this with layouts and the tape measures or yardsticks we used. They all had disagreements at some point or another.

jtk

[Mike Holbrook]

Wow, this is why I keep posting here year after year. Everything I could want to know about a tool from people I trust, who use the tools in real life much as I do. Great post guys, different view points and opinions with the logic behind users choices.

iGaging got me thinking about all the devices they offer in package deals on Amazon. I went to their web site and was amazed to see all the measuring devices: iGaging Digital 3-in-1 Marking/Mortising Gauge, iGaging 6" Digital Multi Gauge 3-in-1 (height gauge)...I could immediately see that the marking/mortise gauge would not have the feel or solid registering area of the popular Japanese mortise marking gauges but it might have other advantages. The iGaging Multi Gauge got me thinking about the similarities between it and the Galbert Caliper.

Checking Galbert's Blog re his Caliper, apparently it has to be calibrated on a known diameter round object and it only measures diameters from 1/2" to 2 3/4". I began to realize the advantage of moving the Galbert Caliper onto a spinning spindle and having real time feed back on the current diameter as one worked. Still I'm not sure I would be comfortable holding any caliper against spinning wood. In the class I took at Country Workshops Drew Langsner was checking his work with a caliper on spinning spindles but as he was doing it he was questioning his own IQ for doing it.

I am leaning toward ordering the iGaging EZCal Digital caliper. My eyes have been changing significantly about every year for the last 3-4 years, plus I have those floating squiggly deals inside my eyes that can cloud visual acuity at close distances. Progressive lenses are expensive and I tend to put off the dreaded trip to get rechecked and buy new lenses. As a result I tend to face some significant visual challenges seeing at common woodworking distances. I'm pretty sure I want have a problem reading the large digital display on the EZCal. I don't understand how anyone reads the fine print on many labels these days. I often wonder if that is the point of manufacturers continuing to make the print smaller and smaller and smaller....

The $30 expenditure will allow me to do further research and calculating concerning whether or not an iGaging 6" Digital Multi Gauge can be used in conjunction with a flat surface to produce the same or better results vs the Galbert Caliper....If I want to get real accurate for some reason I am hearing micrometer is the answer. Right now, working green wood, I am guessing the change in the wood after it spends a day in the kiln may be greater than the error in a digital devise.

[Judson Green]

For my purposes the veneer calipers are used mostly to visually compare thicknesses, meaning I don't really look at the numbers on it. Of course some times its used for measuring. I've neither the dial or digital but the old school type.

[Shawn Pixley]

I use both a digital and dial caliper. For the digital, I have the Mitutoyo and love it. But my go to ,have knocking around caliper was a cheap General Tool caliper (<20$ -maybe much less - I don't remember). The dial ring got banged enough that it became inaccurate (the needle will move the dial). So I'll get another cheap one. I guess I actually prefer the dial type. For more accuaracy I go to my micrometer.

[george wilson]

IIRC,the acceptable accuracy of tape measures in 3/16" out at 6' of length! No wonder there were disagreements. I have not yet found a METAL tape measure that inaccurate. Maybe the old cloth types?

[Bruce Page]

Dial calipers, and not just any dial calipers, Brown & Sharp dial calipers. I have owned several name brand calipers from Helios to TESA, to Starrett digital. I have never found any that has a better feel than the Brown & Sharp 6" caliper. The Starrett digital had the worst feel and you always had to worry about the danged battery.
JMHO, but I made a living using them.

[ian maybury]

For sure callipers can (depending on the maker and spec) flatter to deceive on accuracy - in that just because they read to 0.01mm doesn't mean they are necessarily accurate to that. There's mutterings about of inacuracies coming in in some as batteries discharge too - don't know what the reality is. It's not going to be much of an issue in woodworking, but as the guys micrometer based stuff is normal in engineering in most situations where e.g. parts are being machined to deliver a particular fit and a thou can make a lot of difference.

Rules depending on the type and standard are not aways very trustworty either as you surely know George. I've started checking standards before I buy. Dieter Schmid in Germany does Shinwa which are very nice, very clear and certified: http://www.fine-tools.com/shinwa-ruler.html No doubt avilable in the US too. The rule stops offered with them can be very useful too, they enable hooking it over an edge..

Must say that with my eye sight i find when marking out with a rule that I often do better with one graduated in just mm - that i can quite accurately eyeball whatever proportion of a mm i want. That finer graduations just confuse my eyes.

[Mike Holbrook]

I think I may fall into the same visually oriented category Dave Anderson mentions and I think Ian refers to above. My eyes can get lost in all the little marks on a ruler or dial, forgetting exactly which length line, reversing the image....I have to study the marks and double or triple check myself and I may still cross them up when I try to transfer the information. I find mm's easier to follow and use too, if so many things were not imperial I would use metric all the time.

[Marko Milisavljevic]

I have an iGaging from Lee Valley that works well.

I would be careful getting this item from Lee Valley. Notice how whenever an item is Made in China their website doesn't tell you the brand name? I wonder if they are just some locally made knock-offs.

[Hilton Ralphs]

I would be careful getting this item from Lee Valley. Notice how whenever an item is Made in China their website doesn't tell you the brand name? I wonder if they are just some locally made knock-offs.

That hasn't been my experience. I think they just prefer to mention Brands that they have official distribution rights with. If you email customer services and ask, they will confirm the OEM part number and Brand so you can verify.

[Mike Henderson]

I'm in the mechanical camp. I like to be able to see exactly where the reading is. With a digital, the result is rounded.

I also like that I don't have to depend on a battery.

Mike

[Brian Holcombe]

I would be careful getting this item from Lee Valley. Notice how whenever an item is Made in China their website doesn't tell you the brand name? I wonder if they are just some locally made knock-offs.


The brand is on the gauge itself....

As much as I like to fall down the 'better is better' rabbit hole of quality, this has served me quite well in the way of woodwork and I have a Mitutoyo micrometer for accurate work.

[Hilton Ralphs]

I'm in the mechanical camp. I like to be able to see exactly where the reading is. With a digital, the result is rounded.

My $46 iGaging rounds up to the next ten thousands of an inch (1/10000). I really hate that, puts all my work out.

[Marko Milisavljevic]

It was a joke about Canadian-made knock-offs of Chinese items, which seems absurd currently, but I guess I didn't word it well. Not for too long, though, if Chinese keep increasing quality of their items as is evident with these iGaging callipers.

iGaging has mostly been miss for me so far.

I just bought 4" LV-branded PEC-made square, and rather enjoyed throwing into garbage my 4" and 6" iGaging squares. They worked, but I just grew to dislike them more and more for their sticky screw, not square ends, and roughly milled channel in the ruler that made sliding not smooth.

I also took the opportunity at the same time to throw away iGaging 6" rule which is a nasty piece of junk when compared to inexpensive thing of beauty that is Shinwa 6"

I have iGaging digital protractor, and arms are cheaply made stamped steel but ok - I rarely use it so for that it works.

I also have their digital marking gauge, which seems like a great idea but I regret buying it because if feels extremely clumsy to use and I will probably never use it again.

I have their 24" straight edge. It seems straight enough - I don't have a suitable reference to compare it to - but not machined very nicely.

I had iGaging 6" divider which fell apart in my hands while using it. I have LV "french" dividers, which are also pretty rough and prone to rusting. I guess it is Starrett-time on these.

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I also have iGaging sliding bevel which is Starrett knockoff and it isn't too bad. Not beautifully made, but good enough.

I wish I could see more Shinwa items. They seem universally good quality and inexpensive.

[Pat Barry]

It was a joke about Canadian-made knock-offs of Chinese items, which seems absurd currently, but I guess I didn't word it well. Not for too long, though, if Chinese keep increasing quality of their items as is evident with these iGaging callipers.

iGaging has mostly been miss for me so far.

I just bought 4" LV-branded PEC-made square, and rather enjoyed throwing into garbage my 4" and 6" iGaging squares. They worked, but I just grew to dislike them more and more for their sticky screw, not square ends, and roughly milled channel in the ruler that made sliding not smooth.

I also took the opportunity at the same time to throw away iGaging 6" rule which is a nasty piece of junk when compared to inexpensive thing of beauty that is Shinwa 6"

I have iGaging digital protractor, and arms are cheaply made stamped steel but ok - I rarely use it so for that it works.

I also have their digital marking gauge, which seems like a great idea but I regret buying it because if feels extremely clumsy to use and I will probably never use it again.

I have their 24" straight edge. It seems straight enough - I don't have a suitable reference to compare it to - but not machined very nicely.

I had iGaging 6" divider which fell apart in my hands while using it. I have LV "french" dividers, which are also pretty rough and prone to rusting. I guess it is Starrett-time on these.

310345

I wish I could see more Shinwa items. They seem universally good quality and inexpensive.
I'm a bit curious why you would have purchased so many crappy tools from the same brand name if you had such poor results

[Marko Milisavljevic]

Haha, excellent question Pat. When I started woodworking I needed a lot of items quickly and I couldn't stomach prices of quality tools. That was before I knew this was an endless pit. I don't completely regret it, they served a purpose for a while.

At first I thought they were pretty good tools. I mean, it is square. I can mark with it. It slides up and down, etc. I used them and learned with them and wondered why someone would pay 5 times more for a fancy tool. Over time you get more sophisticated and demand more. The same reason we eat steak if we can afford it and not spam.

[Mike Henderson]

My $46 iGaging rounds up to the next ten thousands of an inch (1/10000). I really hate that, puts all my work out.
And if you're working to ten thousands of an inch, that's good. But I mostly work in units that I can see on a rule, which is about a sixteenth. I use a fractional caliper so I like to be able to see that something is, for example, a bit shy of 3/16, or a fat 3/16. If I set a digital to read fractions, and set it for sixteenths, I lose the ability to see the difference.

Mike

[I don't want to set the caliper to 128th, for example, and then have to try to convert those readings into something I can see on a rule.]

[Brian Holcombe]

Haha, excellent question Pat. When I started woodworking I needed a lot of items quickly and I couldn't stomach prices of quality tools. That was before I knew this was an endless pit. I don't completely regret it, they served a purpose for a while.

At first I thought they were pretty good tools. I mean, it is square. I can mark with it. It slides up and down, etc. I used them and learned with them and wondered why someone would pay 5 times more for a fancy tool. Over time you get more sophisticated and demand more. The same reason we eat steak if we can afford it and not spam.

Agreed, of all of my tools some of the ones I thought I was going over-board on are the ones I enjoy the most.

[Marko Milisavljevic]

And if you're working to ten thousands of an inch, that's good. But I mostly work in units that I can see on a rule, which is about a sixteenth. I use a fractional caliper so I like to be able to see that something is, for example, a bit shy of 3/16, or a fat 3/16. If I set a digital to read fractions, and set it for sixteenths, I lose the ability to see the difference.

Mike

[I don't want to set the caliper to 128th, for example, and then have to try to convert those readings into something I can see on a rule.]

Mike, this is exactly what I'm struggling with while deciding on what calliper to buy. I have some no-name digital calliper that has served me well enough, but I keep wishing for fractions. On the other hand, digital fractions are a pain because of the issue you mention - it is hard to tell if you are above or below a fraction, and if you are aiming for 3/16 and your digital caliper tells you that you are at 23/128 can you quickly tell me if you are above or below your target?

I am reluctant to buy $30-40 Chinese dial calliper, because of hit-and-miss nature of those products, but don't want to spend $100 for Starrett without being sure that Starrett is really good, and iGaging or similar is not quite good enough. Decisions, decisions...

(edit: Starrett dial caliper is also made in China)

[Mike Henderson]

Marko, I bought a Starrett fractional some years ago and it's been a good tool. You might look on eBay and see if you can find one - if you're not excited about the one they're selling now.

Mike

[Winton Applegate]

What the heck . . . I may as well add to the over abundance here and make it even "more".
I just bought this (http://www.amazon.com/gp/product/B000TGF82A/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1) for my main birthday extravagance.
I checked it for accuracy with one of these (http://www.amazon.com/Mitutoyo-293-344-Micrometer-0-25-4mm-Graduation/dp/B001C0XY4G/ref=pd_sbs_indust_7?ie=UTF8&refRID=1CVKH5N5SPDEM2C4ARPD) which comes with a 25 mm carbide tipped precision test standard.
Then I used those to check this guy which I use at work (http://www.amazon.com/Stainless-Digital-Fractions-Conversion-446/dp/B000YFT0A2/ref=sr_1_2?s=industrial&ie=UTF8&qid=1427668092&sr=1-2&keywords=calliper+digital+fraction) for quick checks to sort drill bits and to determine wrench size/bolt head sizes . . . whether what I am working with is a fractional inch or metric. It shows the size in fractions of an inch and has a very large display.
The last caliper is surprisingly accurate (both inside and outside measurement jaws) for the price and I am very pleased; especially since I have been using it hard every day for years so it has held up. I went through a few batteries in that time. It lets you know well in advance when the battery is going dead and has never let me down flat. In other words even though the display is flashing I can use it all day before I replacing the battery.

For home use I bought the dial because of the battery issues Hilton referred to and my particular situation : not near as frequent of use and cold shop temps. Also use mostly metric in my home projects . . . I have coveted an all metric dial my whole life so now was the time to pounce.

I can't tell you how many times I have reached for my battery powered food thermometer that I use in the hide glue and it has had a dead battery. The micrometer I listed above is not so happy with a low battery and cold temps. All of my other micrometers are mechanical (not battery). I just wanted one ultra precise one and I sure am happy with the Mitutoyo in that respect.

So there you have it.

[Winton Applegate]

As far as buying on eBay that can get dicy with precision tools.
There is an old saying among machinists . . .
. . . when the newb asks the old guy if he can borrow a caliper or micrometer . . . and the old guy just grunts but doesn't answer.
The young guy asks one of the other guys "is he hard of hearing?"
Answer : no . . . it's just that you would have better luck asking to borrow his wife than one of his precision measuring tools.

the good ones are hung onto and the dropped ones get unloaded.

[ian maybury]

Zingy colour scheme apart Winton, did you go for the 100mm version for any particular reason?

[Winton Applegate]

Hi Ian,

Yes, I wanted a more compact version. I really didn't need the more precise, .01mm, calibration but that was a bonus.
Mostly I wanted one that did not stick up as far out of , or across, my shop apron.
Turns out the depth of the jaws is a bit less to. I'm perfectly pleased with that.

The draw back I discovered is, while using the caliper one handed, there is less bar length to grip with the smaller fingers side of one's hand while moving the slide with the index finger and thumb. I have small hands so not much of a problem for me but some may find it a two handed tool only.

[Hilton Ralphs]

digital fractions are a pain because of the issue you mention - it is hard to tell if you are above or below a fraction, and if you are aiming for 3/16 and your digital caliper tells you that you are at 23/128 can you quickly tell me if you are above or below your target?


That's why Decimal should be used in that situation as it will give you the nearest 1/10000. Fractions are designed only for dividing up the chocolate bar with your siblings.

When you guys finally enter the 21st century and use a proper measuring system all this trouble will magically vanish and all you'll have to worry about is remember tens (10s). Dead simple.

[Lee Reep]

Digital calipers make great Imperial to metric converters, and vice-versa. Try to do that on a dial caliper. :D

[Marko Milisavljevic]

That's why Decimal should be used in that situation as it will give you the nearest 1/10000. Fractions are designed only for dividing up the chocolate bar with your siblings.

When you guys finally enter the 21st century and use a proper measuring system all this trouble will magically vanish and all you'll have to worry about is remember tens (10s). Dead simple.

It is not as easy as you make it sound. There are 10ths, 100ths, 1000ths, and then you also have to worry x10, x100 etc. That's a lot of numbers.

Kidding aside, I lived my whole life in metric+decimal, until I took up woodworking a few years ago. Imperial is default for woodworking in north america so I went along. It is simultaneously really stupid (21/64 is... what?) and liberating because it is easy to fractions of 2, 4 or 8 and pretty easy to calculate if you keep it in 16ths.

[Pat Barry]

That's why Decimal should be used in that situation as it will give you the nearest 1/10000. Fractions are designed only for dividing up the chocolate bar with your siblings.

When you guys finally enter the 21st century and use a proper measuring system all this trouble will magically vanish and all you'll have to worry about is remember tens (10s). Dead simple.
I love the 10's aspect Hilton, its just those hard to understand cm, mm, kg, km, C that are all foreign to me. Yes foreign. Not saying anything bad about that of course, just that for us in the inch world, the benefit has gone to the tool makers and not really evident to the consumer. Listen, I work in both unit styles everyday in my day job and have for longer than you folks care to hear about. My first metric exposure in the real world was my Honda 350 finding out I needed an 8mm wrench and that's why I was stripping the heads of my bolts with my closest inch size socket wrench. Even then I thought "made in Japan ...". Now though, even my Chevy's have kinda converted - enough that I need two complete tool sets. That ain't helping me a bit. So when I do woodworking, I use what I prefer and that's inches. As Jim K says, YMMV.

[ian maybury]

I was brought up on both systems, and even worked for a couple of years way back as a machinist using both. There's situations where i'm much happier with mm (as in drawing/laying out work), and others where i'm more intuitive with inches.(household sized measurements and believe it or not thou based fits etc in engineering) Inch fractions i understand, but they really cause me problems in that other than very simple addition or whatever requires a pencil and paper.

What i'm maybe saying is that there's no definitive answer - that it's mostly a matetr of what we learn and become proficient enough in that it's intuitive. Trouble is as we get older it's harder to change/learn new stuff in the deeply embedded way we do when younger...

[Trevor Walsh]

I use mechanical both mechanical calipers (mostly for turning) and dial or vernier for all other tight tolerance work, I have a 1" micrometer that sees little and specific use.

Like George, I dislike the digital because they all seem to go through batteries too quickly, and I never seem to have a spare around. When I buy most tools, I don't want a recurring cost to allow it to function.

[Hilton Ralphs]

So Mike Holbrook, why not get both the Dial and Digital Callipers and see which one you prefer? Then sell off the other or keep it as a spare. Some of the digitals eat batteries like there's no tomorrow and then some don't. I guess you could invest in some of the rechargeable LIR2032s and then a suitable charger but it all depends on how quickly you go through batteries.

[Bruce Haugen]

Mario, I have the LV 6" fractional and have been very happy with it.

[Robert Engel]

No offense intended but there's always a few "wood machinists" around when talking about this stuff, isn't there? :)

I agree with Hilton. First of all the tolerances in ww'ing are to the 1/64th or 20 thou which is a gaping hole for a machinist.

Remember we're dealing with wood, which moves around, not steel so you don't need an expensive machinists type tool for woodworking, which is what Starrett, Mitituyo, etc. are for.

An Igaging digital caliper is fine. I've compared it to an expensive dial indicator and its very accurate.
In fact, its too accurate going all the way to 128'ths of an inch.
So most of the time I use the digital scale. It also does mm's which is handy sometimes.

Matter of fact, most of the time I don't care about the number I just want something that I can set for OD and ID for fitting purposes .... like tenons!

[Robert Hazelwood]

I prefer a dial caliper in decimal inches. It's so easy to read that I don't see the point of having a digital readout.

Now vernier calipers are a different story. My first caliper was a fractional vernier and you needed pen and paper to take a measurement. It didn't last long.

I also don't care to use fractions smaller than 1/16 - if I need a more precise measurement I would rather switch to decimals.

[Art Mann]

I use my calipers quite often on CNC router projects where the thickness of a piece needs to be consistent within 0.005" and that is waaaay more accuracy than what is needed for most woodworking projects. I have 3 sets of calipers. I have a 6" dial caliper from Brown and Sharpe which would cost in excess of $100 to replace, I have a 6" vernier caliper made by Starrett which was given to me by a technician who acquired new digital calipers and I have 8" digital calipers which I obtained from Harbor Freight for the princely sum of $16. I have had all three calipers for more than 5 years. By far, my favorite caliper is the Harbor Freight. If I use a Whiteside precision milled 1/2" brass setup block as a reference, I get better than 0.001" consistency between all three instruments. The vernier requires better eyesight than I have without my glasses to read. The dial caliper is easier to read but, as someone else already said, the number I get is harder to remember than in digital form. Especially considering that 1/64" (0.016") is an accuracy level that exceeds what most people need, I can't see spending a premium for a name brand set of digital calipers for woodworking purposes.

By the way, I have a cheapo iGaging brand digital height/depth gauge that reads the thickness of the setup block within 0.001" of the calipers. The reason it may be off by a thousandth is probably because I am not referencing off a precision ground granite plate.

[Marko Milisavljevic]

Digital calipers make great Imperial to metric converters, and vice-versa. Try to do that on a dial caliper. :D

You mean like this? http://www.amazon.com/Anytime-Tools-Caliper-Reading-Standard/dp/B00B5XJW7I/ref=pd_sim_hi_1?ie=UTF8&refRID=0E7ZDRPK5MNYVGXF647B

[Brian Holcombe]

No offense intended but there's always a few "wood machinists" around when talking about this stuff, isn't there? :)

I agree with Hilton. First of all the tolerances in ww'ing are to the 1/64th or 20 thou which is a gaping hole for a machinist.

Remember we're dealing with wood, which moves around, not steel so you don't need an expensive machinists type tool for woodworking, which is what Starrett, Mitituyo, etc. are for.

An Igaging digital caliper is fine. I've compared it to an expensive dial indicator and its very accurate.
In fact, its too accurate going all the way to 128'ths of an inch.
So most of the time I use the digital scale. It also does mm's which is handy sometimes.

Matter of fact, most of the time I don't care about the number I just want something that I can set for OD and ID for fitting purposes .... like tenons!


Hah, there is a lot that we don't 'need'.

IMO, there are often times when I prefer to be more accurate than .020". A sliding dovetail with .020" clearance is practically so loose it will come out of the receiver with a good pull.

[Kent A Bathurst]

Just my take:

I have had Mito digital decimal - high quality tool. Sold it, in favor of my....

Starrett fractional analog dial caliper. Here's why:

I don't understand the whole "round stuff" you lathe guys do. My stuff is flat - more or less.

The rule on the TS, and the rule on the CMS infeed table [Biese], and the depth gauges on my fleet of PC 690 routers all have these little lines - "ticks" marking length, depth, whatever. Same with my Starrett combo and double squares.

Those ticks [ 1/32"] correspond directly to the little marks on the Starrett dial face.

So - I can think in terms of "one tick above 2-7/16", or "one-half tick below 4-4/16". I don't [generally] have to sweat out 32ds, 64ths, etc - it is sixteenths and ticks.

I don't have to translate decimals to fractions, my mind is trained to always think in 16ths [notice I did not say 4-1/4" above] and the ticks are an analog visual representation of the teensy fractions used in wood stuff. My notes for the above dimensions would say "2-7 +", or "4-4 -1/2",

The ability to visually recognize and transfer dimensions is something I find very efficient.

[ian maybury]

:) It'snot just woodworking that this arises in, i remember way back being bemused at fractional inch engineering drawings (with tolerances added in thou) issuing from the design office of a US corporate i worked for at the time. Down to /64ths which while i could sort out by maths and convert to decimal were on first sight meaningless. As before it's all a matter of what you are used to.

I don't think woodworking and engineering are as different as many perceive. It's for example common enough to see fabrications and castings for example quite loosely dimensioned (possibly covered by a general tolerance), but the tight tolerances emerge immediately in situations where parts have to fit closely together.

Woodworking (as Brian) is little different - a properly fitting dovetail, or a mortise and tenon, or even two faces forming a plane surface are likely fitted to within a thou. Try a 0.010in gap at one end of a joint, or as clearance in a joint...

The change to working from dimensions came when the need for parts made in differing locations, or at different times to fit together. Especially volume produced standard parts made in multiple locations over extended time periods. Traditional custom production for example permits a story stick to be used to manage the dimensions of a single cabinet (to be silly - you'd have to mail the stick to China to get cheap drawers made), but even in the case of this single custom product the joints are typically very tightly fitted. To each other though by craft means, as opposed to cut to specified dimensions.

This actually was the way that engineering worked too until the advent of mass production. Early cars from a single factory certainly looked the same, but the parts were in fact generally custom fitted to each other (hence the term 'fitter' used over here for a mechanic) and not interchangeable between individual examples of the same car...

[Tom Vanzant]

Pat Barry, ah the joys of mixed fastener systems in the same vehicle. My 1972 (?) Ford Pinto...USA vehicle, assembled in Canada with the German-made 2.0L SOHC engine and Northern Ireland-made carb. Virtually everything under the hood was metric, and the rest Imperial.

[Winton Applegate]

Don't want 1/128ths . . . don't need 1/64ths . . . 1/32nds rarely used ?

Have you seen . . . are you aware of . . . this ? (http://www.amazon.com/Sliding-Vernier-Jewelry-Measuring-Caliper/dp/B00R5U8A46/ref=sr_1_13?ie=UTF8&qid=1427775881&sr=8-13&keywords=mini+caliper)
Increments of 1/16th.
There are a few different ones.
Personally I need more of a friction thumb brake or locking screw to prevent the setting from changing . . . I have never really made friends with this little caliper but it may be all you need from what I am reading here.
Shallow jaws though.

[Marko Milisavljevic]

If someone could make a fractional digital caliper that had a line on bottom or top of display, taking full width of LCD, with 128 pixels, representing an inch, and tick marks in 1/16 increments, then you could have a visual cue where your measurement is in relation to importation fractions of an inch rather than doing all the juggling with 1/128.

[Hilton Ralphs]

Have you seen . . . are you aware of . . . this ? (http://www.amazon.com/Sliding-Vernier-Jewelry-Measuring-Caliper/dp/B00R5U8A46/ref=sr_1_13?ie=UTF8&qid=1427775881&sr=8-13&keywords=mini+caliper)
Increments of 1/16th.


Reminds me of this one I bought from Lee Valley. I keep it in my pocket when out shopping for hardware.

No locking mechanism or other fancy tricks but will quickly tell you the size of a drill bit, masonry plug or bolt, be it Imperial or Metric. Less than $6.

310468

[William Adams]

If someone could make a fractional digital caliper that had a line on bottom or top of display, taking full width of LCD, with 128 pixels, representing an inch, and tick marks in 1/16 increments, then you could have a visual cue where your measurement is in relation to importation fractions of an inch rather than doing all the juggling with 1/128.

That’s a very cool idea.

The open hardware folks have been doing some neat stuff --- apparently the digital calipers can communicate w/ other tools: http://concifederico.blogspot.com/2013/05/digital-caliper-to-bluetooth-interface.html#!

So it should be possible to add a new display and firmware so as to make that happen.

[Dennis Aspö]

I have a metric mitutoyo vernier caliper. It's superb and reliable, I have a digital one that goes between metric and imperial (in decimals, I don't understand fractions) which is also useful, and its battery doesn't run out when not in use, or at least it takes a while, 2 years or more between battery swaps. Brand is toolmate and it was a birthay gift I remember many years ago.

I'd like a dial caliper because they look nifty and I think the dial comes in handy sometimes. I have a real dial indicator though which also works.

[Robert Engel]

Hah, there is a lot that we don't 'need'.

IMO, there are often times when I prefer to be more accurate than .020". A sliding dovetail with .020" clearance is practically so loose it will come out of the receiver with a good pull.Really? If there's a 1/64th gap I submit you will have a snug fit, so how can .020 be that sloppy?

1/64th = .016, so for the sake of argument, permit me to revise the .020 figure.
I mean, you have to have some room for the glue, don't you?

My point is, we are woodworkers, not machinists.
Our building material is alive and moves and shrinks and expands, so cutting and fitting beyond 1/64 is a waste of effort.

As to your example, you wouldn't have the issue with a tapered sliding dovetail. :)

[Curt Harms]

I was brought up on both systems, and even worked for a couple of years way back as a machinist using both. There's situations where i'm much happier with mm (as in drawing/laying out work), and others where i'm more intuitive with inches.(household sized measurements and believe it or not thou based fits etc in engineering) Inch fractions i understand, but they really cause me problems in that other than very simple addition or whatever requires a pencil and paper.

What i'm maybe saying is that there's no definitive answer - that it's mostly a matetr of what we learn and become proficient enough in that it's intuitive. Trouble is as we get older it's harder to change/learn new stuff in the deeply embedded way we do when younger...

And that's the crux of the matter. As far as digital calipers, I do wish manufacturers would forego 1/128ths. I just have to move the head until I see a figure that is usable.

[Dave Anderson NH]

Robert, I find caliper accuracy quite necessary in a few woodworking operations. My most common example is when turning the open end of my tool handles where a blade goes into a hole and a brass ferrule goes over the outside. I test every handle OD for a +.001" -.005" fit so that the ferrule slides on and with a slight bit of epoxy fits firmly without play. Experience has told me that undersizing the OD by anything more than -.010" is both detrimental and poor workmanship. There are occasional other situations where super tight tolerances are necessary but are fit tested rather than measured. Generally, a properly fit mortise and tenon joint is within .005" and if you go as loose as .010-.015" the fit is noticeably sloppy. As much as possible in furniture work I avoid measurements altogether and use a story stick.

[Mike Holbrook]

Interesting Dave. Brian is running a post discussing the handle he is working on for his new Gennou head, similar to the one Derek made for his. Dave mentions "turning the open end of my tool handles", which sounds like he is turning tool handles on a lathe?

I am interested as I am thinking about some sort of lathe to help with chair parts and tool handles. I prefer to do as much of this work as possible with hand tools, still working to the tolerances Dave mentions probably isn't going to happen with just hand tools. In the class I took a couple weeks ago at Country Workshops we made short wide spindles for Welsh Stick chairs from splits out of red oak. We made roughly square pieces from the splits, then octagons with spokeshaves. We roughed out tapered spindle shapes on a lathe as we formed the tenons on each end. We finished the bodies with spokeshaves to leave them a little rough but finished the tenons on the lathe to get a more precise fit.

I have been wondering about the precision we make tapered tenons to. In the class I took recently with Chris Schwarz he explained that the reason tapered tenons driven into corresponding mortises in the seat of a chair or bench are strong but do not split the wood they are being driven into has to do with the different woods used for the various parts. The chair legs are typically very hard wood (tenon) where the wood used in the seat (mortise) is typically a softer wood. The idea being that the harder wood tends to embed in the softer wood rather than split it. If the hard piece can compress the wood in the softer piece, might the precision of the fit be less significant?

[Dave Anderson NH]

You and CS are correct in the sense that with either a round tapered tenon or a faceted tapered tenon the softer wood of the seat deforms when the harder legs are driven into the tapered mortise. What I meant on precision fitting is that we work to very tight precision tolerances most of the time when making furniture with either hand or power tools but often don't measure, but rather adjust to fit. In most things we can actually get a better fit and work to a tighter tolerance with hand tools than with power tools. An easy example is the absurd notion of trying to remove .001-.003" from the edge of a board with a table saw, planer, or power jointer. A hand plane of almost any type would do the job quickly, easily, and without setups and adjustments to the machines.

[Winton Applegate]

Dave,

I find caliper accuracy quite necessary in a few woodworking operations. My most common example is when turning the open end of my tool handles where a blade goes into a hole and a brass ferrule goes over the outside. I test every handle OD for a +.001" -.005" fit so that the ferrule slides on and with a slight bit of epoxy fits firmly without play. Experience has told me that undersizing the OD by anything more than -.010" is both detrimental and poor workmanship. There are occasional other situations where super tight tolerances are necessary but are fit tested rather than measured. Generally, a properly fit mortise and tenon joint is within .005" and if you go as loose as .010-.015" the fit is noticeably sloppy. As much as possible in furniture work I avoid measurements altogether and use a story stick.
THANK YOU
I am sick to the teeth of arguing that one so I kept quiet.
+ 1 on the usefulness of story sticks . . . also go/no go "gauges" ; self made or otherwise.
PS: the Mitutoyos I spoke of way earlier on are for my metal working but find use in the wood shop, just not for their ultra precision obviously.

[Winton Applegate]

Hilton,
Your plastic one is no doubt easier to read than my brass one.
There is a brass one with a white strip with black graduations I almost bought hoping it would be easier to read but I don't really need it right now.
I am adverse to plastic calipers (just a personal phobia; I'm in counceling for it making great progress . . . in a controlled environment where I feel safe I can hold one in my hands now for almost a minute) :) . . . but they have their place especially if fiber reinforced.

PS: obviously the plastic caliper is perfectly useful for the purpose you use it for.
Allow me to give an example of why I am ascared of plastic in semi precision situations :
We had a batch of assemblies that used to be made for decades and decades out of aluminum ; they had hardened steel shafts and adjustable hardened bearings. From the factory the bearings were always just put together but not adjusted. Every mechanic was expected to adjust the bearings to a zero play setting with only a very small or zero amount of binding (after all they were going to break in some). Play was unacceptable though.

There was a big blow up. I was in charge of inspection. There were a lot of assemblies (plastic ones only) that had a fair amount of play upon final inspection. Here I am going around telling some of the best people in the business that they didn't know what they were doing and that they were lying to me when they said they had adjusted the assemblies for zero play.

Long story short. I put several of the dambed things on the roof in the sun. All had zero play when I put them up there (adjusted at shop ambient about 70°F or lower) It was only 90° to 100°F on the roof. Every one of them had very significant play.

Plastic machine parts peeesses me off.

PPS: the adjustments were often done early in the day when the shop was cool and beings there was no air conditioning (swamp cooler) by after noon the shop was around 90°F so the bearings developed play from the plastic moving. Only 20 or 30 degrees. The difference between inside a trouser pocket and room temp.

[Pat Barry]

There was a big blow up. I was in charge of inspection...
LOL, Somehow, I can picture this.








Edit = you know I'm just kidding Winton, I couldn't resist

[Steve Voigt]

Really? If there's a 1/64th gap I submit you will have a snug fit, so how can .020 be that sloppy?

1/64th = .016, so for the sake of argument, permit me to revise the .020 figure.
I mean, you have to have some room for the glue, don't you?

My point is, we are woodworkers, not machinists.
Our building material is alive and moves and shrinks and expands, so cutting and fitting beyond 1/64 is a waste of effort.



If I make a tenon that is 1/64 undersized, it is going in the burn pile or getting a shim glued to it.

If your dovetails have gaps of more than about .005, they will look pretty sloppy (and that's a generous number).

An edge joint that has an .015 gap in the middle is a recipe for failure, even if you manage to pull it together with clamps.

A door stile that is twisted by .015 will throw off the flatness of the whole door.

My point is, we work to tolerances of much closer than .015 all the time. Whether we need calipers for that is a different question--only one of the situations I listed above would involve calipers, and it certainly doesn't require them. I use calipers because I used to be a machinist and they're practically surgically attached to my hand, but in most cases you can achieve the necessary precision without them. But the precision is definitely necessary if you are trying to do fine work.

[Daniel Rode]

I couldn't agree more. For general carpentry, a 1/64 gap seems small, dead on even. For furniture and other fine wood working, 1/64 is a HUGE gap.

I use variety of methods to insure accuracy. One of them is a dial caliper with 1/64" increments. However, it's pretty easy to judge 1/2 and 1/4 of that on the dial without dedicated marks.

If I make a tenon that is 1/64 undersized, it is going in the burn pile or getting a shim glued to it.
...
My point is, we work to tolerances of much closer than .015 all the time.

[Pat Barry]

...For furniture and other fine wood working, 1/64 is a HUGE gap.

I use variety of methods to insure accuracy. One of them is a dial caliper with 1/64" increments. However, it's pretty easy to judge 1/2 and 1/4 of that on the dial without dedicated marks.
I tend to agree in principle with this sentiment about wanting your fine work to be well fitted, however, I suspect that we achieve tighter results through a practice of check and trim rather than using a fine caliper. I may be the oddball here but I rarely use my caliper. In fact, I only recall using it in the past year to verify the size of a bolt I cut off my truck in order to find a metric replacement. I have never used one of my calipers for woodworking, not even for setting my power tools (ie depth adjustment , etc). Even for the job Dave described above you don't need a fancy caliper.

[Brian Holcombe]

I don't measure everything I'm building with calipers, but yes it's very likely that a great deal of it is much closer than 1/64


Really? If there's a 1/64th gap I submit you will have a snug fit, so how can .020 be that sloppy?

1/64th = .016, so for the sake of argument, permit me to revise the .020 figure.
I mean, you have to have some room for the glue, don't you?

My point is, we are woodworkers, not machinists.
Our building material is alive and moves and shrinks and expands, so cutting and fitting beyond 1/64 is a waste of effort.

As to your example, you wouldn't have the issue with a tapered sliding dovetail. :)

Not everything I make is glued and tapered sliding dovetails are not always feasible....but even then they will be friction fit when they are much tighter than .020" clearance.

A very strong glue joint relies on a tight fit, not bridging a gap.

.020" is the thickness of a commercially cut veneer, how often can you fit that in with one of your mortise and tenons?

Point still stands at .016"

[Mike Holbrook]

I think it is important to recall the original context of the OP. At least in my young experience turning, it is very hard to judge the size of a round object on a lathe. I understand that normally we might test the fit and adjust by hand with hand tools. Unfortunately when the tenon being worked is in a lathe it gets a little complicated to pull it out and check it in the mortise. I have ten 9-10" spindles lying on a chair seat. I tried to get them close to the right size on the lathe using an open ended wrench and mechanical calipers. They are all significantly oversized. Once the wrench slides over the tenon being worked the tenon being worked is too small, a very hard problem to fix. With a dial or digital caliper I can tell exactly how much over sized the piece I am working is. It may even be possible with some devices to check size on the tenon turning in the lathe.

Actually I find multiple types of tenons in Windsor chairs which require differing degrees of precision. The tapered tenons on chair legs that fit in open ended tapered mortises in the chair seat need to make contact with most of the sides of the mortises. The wedge placed in these joints helps but the joint still requires consistent pressure throughout. Driving the tenon into the mortise too firmly will crack the seat, which that late in the game is a real bummer. The straight mortises in the outside of the chair seat and in the arm/back can be much less precise as the spindles these mortises hold in place are designed to flex and move anyway. As long as the spindles do not pop out of the bottom joint, unlikely if the mortises are deep enough, close is good enough. The top joint on each spindle needs to stay put in the bow/arm but, a wedge in this joint usually assures this.

The number of objects being fitted to mortises also comes into play here. With two tenons on rungs and spindles and tricky tapered tenons on the chair legs the extra time to fit all those pieces can become a larger factor. My issue is getting each tenon as close as possible to the correct size as early in the work as I can.

[Jim Koepke]

I tried to get them close to the right size on the lathe using an open ended wrench and mechanical calipers. They are all significantly oversized. Once the wrench slides over the tenon being worked the tenon being worked is too small, a very hard problem to fix.

Your gonna need a bigger wrench.

There are locking jaw Crescent wrenches that can be set to any size within their range.

Sometimes I make a gauge by drilling a hole in a piece of scrap then cut it in half.

Here is something Junior Strasil posted that can be modified to check tapered holes:

http://www.sawmillcreek.org/showthread.php?112339-Chisel-Handle-Socket-Taper-Jig

jtk

[Daniel Rode]

I used to have a digital caliper that read in decimal. I used it, but not often. A couple years ago, I picked up a fractional dial caliper and I use it all the time. For tenons, I'm likely to use it to measure the thickness of the rough cut or to compare left to right top to bottom to see if I'm staying square. It's just a fast and convenient way to measure a variety of things.

The final fit is achieved by sneaking up on the cut, not by working to a specific measurement. Each tenon is custom fit to it's mortise. I think most hand tool woodworkers do this.

[Winton Applegate]

I know what you mean though.


Your gonna need a bigger wrench.

There are locking jaw Crescent wrenches that can be set to any size within their range.


Newbie comment here so take it as such but . . .
and I do zero turning on a wood lathe but . . .
and if I wanted to make round things the right size I would put it in my metal lathe and with very little concentration make it to the right size but . . .
and I have watched enough Norm to think I know but . . .

couldn’t/ wouldn’t a guy just set one of these things (http://www.amazon.com/Big-Horn-19052C-Outside-Caliper/dp/B0015YHDUU/ref=sr_1_1?ie=UTF8&qid=1427850165&sr=8-1&keywords=turning+calipers) to the close to done size and another one to the done size and turn to that ? ? ? ?
Set it with a measuring caliper of some kind that is close enough even if you just put the inside measuring jaws in the hole and lock the screw and use it to set the things above without looking at the little gradgeeeations.

[Jim Koepke]

A metal lathe has a tool holder. It is very controlled.

A wood lathe has a tool rest, as in it will keep the tool from flying to the floor, but the operator does the rest.

My mind still isn't quite settled on how in heck a caliper is going to help on making a taper. Most likely something is eluding me.

jtk

[Bruce Haugen]

My mind still isn't quite settled on how in heck a caliper is going to help on making a taper. Most likely something is eluding me.

jtk

For me, the caliper is only used to set the major diameter of the taper. I use a trick that Jack Guzman on WC taught me.. I drill a proper sized hole in a scrap block and then ream it out with a taper reamer. Then cut that socket in half and use it to turn the matching tenon to the matching taper.

[Jim Koepke]

I use a trick that Jack Guzman on WC taught me.. I drill a proper sized hole in a scrap block and then ream it out with a taper reamer. Then cut that socket in half and use it to turn the matching tenon to the matching taper.

My first response to the OP included making a go - no go gauge. That was a few days ago.

Maybe some folks just do not like doing things the easy way.

jtk

[Steve Voigt]

My mind still isn't quite settled on how in heck a caliper is going to help on making a taper. Most likely something is eluding me.



If you know that the diameter of your reamer tapers, say, .1" for every inch of length, then you just make two marks on your tenon, 2 inches apart, and and measure with the calipers. When the two measurements differ by .2", you are there. I like to make the marks while the lathe is still spinning, so when I measure, if I keep both blades of the calipers centered on the pencil lines, I will get an accurate measurement.

At least, that is how I do it. I don't know how it was traditionally done; I don't imagine the bodgers in the forest had Starretts. I guess if you know your tool rest is truly parallel to the long axis of the work, you could use a bevel gauge or something similar.

Edit: I just saw Bruce Haugen's response--that is a good trick, Bruce, I may try that. Thanks!

[Mike Holbrook]

Apparently there is a considerable variety of opinion regarding "the easy way" to make tenons for chairs as the methods used in the three classes I have taken have all been substantially different. I have been considering buying a Galbert Caliper, which would be my choice as the easiest way I know of to check round tenon dimensions. The Galbert device is designed to provide real time feed back as an object is being turned along the entire length of the work. Being new at turning I am not comfortable (yet) with the idea of holding a Galbert Caliper against a spinning work piece. If I plan to stop the lathe to check progress the Galbert devices advantage over a digital or dial caliper seems negligible. Since I do not own a digital or dial caliper I decided to order one for several reasons. Once I garner more experience turning and making round tenons I may revisit the Galbert Caliper idea.

There is no single dimension on a tapered chair tenon. The method I was taught for turning tapered tenons involves making two cuts on the opposite ends of the tenon area with a parting tool and then removing the waste area between the two grooves. The chair plans I have provide a chart of the smaller and larger dimensions required to make the parting tool cuts for various leg angles and tapers. The groove made by a parting tool is too small to fit a wrench into without additional work and there are two grooves. The Galbert device is made to fit into a parting tool groove. I also think most dial or digital calipers will fit in a parting tool groove with little or no additional work. Checking with the guys on the Turning Forum this seems to be the standard practice for turners making tenons, particularly tapered tenons.

Winton, regular mechanical calipers tend to move with all the back and forth between multiple tenons on a large number of spindles, especially if the user holds one against a spinning work piece or attempts to measure an irregular surface. I think mechanical calipers are designed more to fit to a fixed workpiece size than move between various measurements. I found the one I had and the ones at Country Workshop tedious to set at multiple given distances on a ruler. Without any scale to let me know I had the correct setting, I found myself rechecking to make sure I had the correct setting.

[bridger berdel]

I have one like that. Small, quick and light. I like it a lot. It gets a lot of use in my shop. It has metric and imperial scales on it with no vernier scales. It's great for sorting drill bits and the like.

If I need more accuracy I go for a larger, stainless hardened vernier caliper. It's what I learned on and use the most for work where tolerances approach .001



Don't want 1/128ths . . . don't need 1/64ths . . . 1/32nds rarely used ?

Have you seen . . . are you aware of . . . this ? (http://www.amazon.com/Sliding-Vernier-Jewelry-Measuring-Caliper/dp/B00R5U8A46/ref=sr_1_13?ie=UTF8&qid=1427775881&sr=8-13&keywords=mini+caliper)
Increments of 1/16th.
There are a few different ones.
Personally I need more of a friction thumb brake or locking screw to prevent the setting from changing . . . I have never really made friends with this little caliper but it may be all you need from what I am reading here.
Shallow jaws though.

[Winton Applegate]

There is no single dimension on a tapered chair tenon
Again I am speaking from outside the fence but . . . and "dimension" may not be the term but there is one number/angle you can go by and that is the angle of the taper.
So . . . set up the lathe how ever you have to to turn an angle equal to the taper of the hole.
On the metal lathe that is a brainlessly easy thing to do. There is a protractor right on the "compound" and then when the feed is turned the bit has to travel at that angle in relation to the axis of the turning part.

As far as how to use the adjustable turning calipers I spoke of, the slots made with the cut off tool while holding the caliper to the work until it passes over the work was what I had in mind.

There is this (http://www.leevalley.com/US/wood/page.aspx?p=54835&cat=1,180,42288,54835) and this set of tools (http://www.leevalley.com/US/wood/page.aspx?p=63795&cat=1,180,42288,63795) I suppose they are not really what is needed for a nice gradual full length taper on the tenon.
Right ?

[Winton Applegate]

There is one other thing that came to mind.
Picture in your mind a whole stack of pop sickle sticks. drill a hole through the stack and put a rod through the hole to keep them indexed and to use as a pivot for them later when you put them to use.
Then
cut the stack of sticks off at an angle to the rod same as the angle of the tenon you want to turn.
Set up the stack on the back side of the lathe so that the axis of the rod is parallel to the axis of the work.
The work is pre turned round and smooth.
Put the ends of the sticks so they are on top of the work and rubbing.
As the required size to the tenon is reached the sticks drop down past the work indicating to stop turning in the area of each stick that drops.
I have seen Norm use this when turning exact duplicates of posts with common necked dimensions.
PS: you will probably need to round the ends of the sticks or point them or other wise refine this method but you get the idea.

[Mike Holbrook]

Winton, In the Schwarz class we used the first Lee Valley tenon cutter you link to above. It worked much like an old style pencil sharpener. When very sharp, much sharper that when they arrive, they work well. I sharpened my brand new LV tenon cutter before the class but ended up sharpening it even more during the class to get it to cut as well as the ones Schwarz sharpened. I suspect it would work better locked in a vise with the work piece turned into it. I have been wondering if the second "set of tools" you mention might work well with a brace, but I have not tried it yet.

[Myk Rian]

I have only ever used DIAL calipers. It is easy to interpolate to a 1/4 thousandth with them. On a dial caliper you are stuck with a 1/2 thou reading..
What? So, which is it? Dials are good for 1/4 thou, or 1/2 thou?
I think 1/4 thou is a little hard to get on a dial caliper, unless the dial is 6" diameter.

[Jeff Ranck]

Well, I guess I can jump in. I have the dial gauge, fractions with lines in-between. Not sure what brand I bought it so long ago. However, I hardly ever use the actual measurements, so probably most anything would work for me. I almost always use it to transfer measurements by setting it on one piece, locking it at that setting, and then using it to define the other piece. I guess it is sort of a glorified "story stick" to me.

[Jim Koepke]

What? So, which is it? Dials are good for 1/4 thou, or 1/2 thou?
I think 1/4 thou is a little hard to get on a dial caliper, unless the dial is 6" diameter.

Most likely George typed dial, in the second use, when he meant to type digital.

In olden days some of us learned to use a slide rule. Part of slide rule usage is knowing how to interpolate/extrapolate digits between the lines. I do this all the time with my "old school" (non-digital) calipers.

My most used caliper is a 3" Lufkin. It has a 1/32" scale and a 1/64" scale. The 1/64" scale is never used. It is easier for me to just read where the line is on the 1/32" scale. If it is being used to determine a twit drill size needed, the number is then converted to decimal in my head as I take the walk over to where my drill indexes are stored.

In my last job my supervisor wanted me to write a manual before my retirement. We used precision spacer washers that were always getting mixed together. Here is an "eye calibration" exercise using a caliper included in the manual:


The Calibrated Eye

The purpose of this exercise is to train your eye to recognize small sizes for what they are.
To do this exercise one needs a lot of mixed spacing washers. The sizes found on our TTMs
are .001, .005, .010, .016, .030 and .040 with occasionally some other odd sizes.
A dial or digital caliper is also needed. Small containers or pieces of paper to separate the
washers into different piles are also needed.

With all the washers mixed in a pile, start measuring with the caliper. Look at the edge of each
one during the measuring process. Separate the washers into piles of washers that measure the
same. After a short time, look at the washer before measuring it and see if you know what it
will measure before it is put in to the caliper. Keep doing this until you get good.

Congratulations you now have calibrated your eyes. Recalibration may be needed if not used
on a regular basis.

In our own shops this could be done with shavings or even drill bits. Empty your drill index into a box and then check each one with your calipers.

It is amazing what one can see with just a little eye tune up and training.

jtk

[Winton Applegate]

My most used caliper is a 3" Lufkin. It has a 1/32" scale and a 1/64" scale.
Sounds cool. Any chance of a photo. Or come to think of it is it one of the brass ones we have been talking about ?

[Jim Koepke]

Sounds cool. Any chance of a photo. Or come to think of it is it one of the brass ones we have been talking about ?

My camera will have to go out to the shop tomorrow.

The only brass ones in my shop are ones that are seldom used. I do not recall their being mentioned. Maybe someone else has them.

jtk

[Jim Davenport]

For lathe work, I use a Harbor Freight fractional dial caliper.
http://www.harborfreight.com/6-inch-fractional-dial-caliper-92437.html
I don't like digitals due to battery consumption.

[george wilson]

So what???? It takes a bit of skill to develop a proper touch,but I get 1/4 thou. measurements on small diameter things with my dial caliper. Been doing it for many years.

If you think it's hard,I recommend getting magnifier reading glasses!:)

The trouble with ANY caliper is they are not as rigid as a mike,and take more skill to use.

If you really need a more serious measurement,of course use a mike. Preferably one with a ratcheting thimble as it removes the human touch factor.

[Jim Koepke]

Winton asked for pictures when my Lufkin Caliper was mentioned. I thought it was a 3" but it is 4".

311178

Here is an image of the backside:

311179

The wooden Rabone has inches on the other side but it wasn't flipped for the picture of all of them:

311180

The slide rule was given to me by my father.

jtk