Metrology For the Cabinermaker - II

[Brian Holcombe]

This thread is a continuation of Metrology for the cabinetmaker.

Please don't mistake the level of detail and effort as dissatisfaction, I'm very happy with this machine, it cuts a good mortise and does so very well. The reason I'm doing this is because I'm putting a mini-pallet and sine plate on this machine to handle angled mortises and everything must be tip-top for that to work out properly.

I find it highly important to be able to reliably dial in my machine tools, check parts (of the tools) and inspect to find errors in their machined surfaces or tune. I recently purchased a Wadkin DM mortiser. Upon inspection I found some parts out of tram. My initial thought was to shim the column to bring it into tram, however I decided to inspect the table first.

Prior to inspecting the table I setup an indicator to run across X, Y and Z across various parts of the main table. Z provided out by .007" over the length of the fence, the fence out of parallel to the travel by .012". I then ran X and Y on the main table itself, the table provided out of tram at the ends by an amount I don't recall (not zero, lol) and .005" across the major part of the table. Presumably more but I ran out of Y before I ran out of table.

First point of inspection was the table itself, I sat my camelback straight edge on it and the straight edge revealed a bow in the center of the table. So, table must be re-ground. The table is bigger than I want to machine myself so it's off to the machine shop. What they plan to do is bring everything square to the fence and grind the bottom of the ways to remove the slight concavity there. Without recutting the ways nothing will bring the fence back to parallel but Wadkin ways are 55 degrees rather than a standard 60, so i'm debating my approach there.

Next I decided to inspect the saddle. It's in fine shape with exception to a .002" bow in the center of the ways. I'm debating wether to mill this.

Finally I got the machine down to the fixed ways. I inspected these ways and found the head out of tram to the ways. I worked them lightly with a hone to remove burrs and take out a very slight out of parallel situation, then sat a shop standard square on the ways in multiple places.

I'm traveling the head the entire length of the machine's travel, which is a lot.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4683-414516509-1571089113582.jpg

.0035" tilted along the side, I was able to manage .000" along one way front to back and .001" along the other.

I ultimately decided it would be best to shim the column, I stuck two round shims front and back along the offending side.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4687-534298884-1571089286386.jpg

The back remained slightly out still, but something I can live with

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4689-4167101443-1571089380215.jpg

I reinstalled the saddle after deburring everything, an important part of inspecting.

The outer gib screw was out of proper adjustment, bringing it into adjustment allowed smooth travel and brought the surface into tram, almost. That .001" bump in the center is showing itself here. Inspection grade blocks are used to raise the square.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4682-1873950091-1571089392967.jpg

Before adjustment above:

After:

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4690-2561107430-1571090255141.jpg

While the table is out I will check the chisel holder to see if it is centered to the spindle and parallel to travel. I will also inspect the collet holder for runout both inside and outside.

[David Eisenhauer]

The German blood in me loves this stuff Brian. I have the desire for "exactness" in a machine, but not the skills/training to make it so. This is one of the things that pushed me to a more hand tool approach after retiring.

[andy bessette]

Well done Brian.

[Brian Holcombe]

Thank you, both! David, that’s it for me as well I’ve been chasing the idea of ‘machine perfection’. I’d like to pursue scraping, so I’ve been adding stuff for that as opportunity allows. I’ve been contemplating learning to flake just for this machine.

[Mark Hennebury]

Hi Brian, Nice work!
It's fun to chase down the demons in the search for absolute. I am also hoping to get some practice at scraping in surfaces soon.

[Michael Todrin]

I always enjoy your posts Brian and learn something every time. Thank you for sharing your methods.

Michael

[Brian Holcombe]

Thanks gents! My pleasure!

Mark, very interesting that you’re heading this way as well, what do you plan to scrape up first?

[Mark Hennebury]

Hi Brian, I don't know where to begin... Everything needs tuning up. I may start with the cross-slide on my lathe.
I did some work on my table-saw top with a disc- grinder and a die-grinder.( not as crude as you might think) the sliding top was about twenty thou out, its now within 0.002" I have since purchased a large granite, grade A surface plate, so i may get around to finishing it at some point.I have a few camel-backs up to 6'. I have been doing a bit of research on it, and its all pretty fascinating. I have to get some scrapers soon.

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Thanks gents! My pleasure!

Mark, very interesting that you’re heading this way as well, what do you plan to scrape up first?

[Brian Holcombe]

Interesting, wow .020” is a lot! That would be pretty sweet to see that big table scraped in flat, but I’d imagine that’s a pretty time consuming start.

[Mark Hennebury]

Brian,
the problem is, it's all connected once you start you petty much have to do everything.
And really to start you need to get a verified reference surface. But without going to far down the rabbit hole, i could assume that my surface plate is more than good enough for my use, and scrape in my camel-backs. And work from that.
It get pretty intoxicating when you start looking into it, and hard to know when to stop.

[Brian Holcombe]

Exactly, it’s very hard not to dig deeper once you start looking closely at things, I mean that in a general sense since I have no experience scraping.

I thought I might be able to just sweep and indicator over the table and then live with the results....yeah right.

[Mark Hennebury]

Yeah, good luck with that.


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Exactly, it’s very hard not to dig deeper once you start looking closely at things, I mean that in a general sense since I have no experience scraping.

I thought I might be able to just sweep and indicator over the table and then live with the results....yeah right.

[Brian Holcombe]

This machine job was too big for the Bridgeport so I brought it to a local shop which did a fabulous job in my opinion. They inspected the part on a 4x8 granite with cert, moved it to a gantry style Haas then started taking measurements. The table top was like a landscape, highs and lows all over. The fence was out of square to the table and out of parallel to the ways. I was happy to see numbers very similar to what I got measuring on the machine. .007” out if square and .012” out of parallel.

They brought it to dead on square (no change in the indicator) and parallel to .001”.

I have more work to do to this for installing the mini-pallet. So when I setup to do that work I will reapply the main grooves in the table for posterity.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4713.jpg

If you’re wondering the time involved, about 5-6 hrs of setup and a few hours to cut and that doesn’t count my inspection time.

This shop is fantastic, really care about the work they are doing and did not mind my nosing in and putting my two cents in here and there as the part was setup and measured

[Mark Hennebury]

Hi Brian, Nice work!
Glad that you have found a great shop to do that quality of work.

[Brian Holcombe]

Thanks, Mark! They will be handy to have access to, for certain, and great to work with people interested in unique work and who take pride in quality of results.

[Joe Calhoon]

Your posts are always interesting Brian! I’ll have to check my DM a little closer when I get home. For door work it’s accurate enough but can see your quest for furniture making.
did they re- machine the back fence? Mine is planed with deep ridges that help keep the workpiece from wanting to pull up when chisel is retracted. Would hate to loose this.

Can you recommend a good magnetic indicator base? I want to upgrade mine. I see the Mitutoyo digital indicator. Do you prefer that to the dial type?

[Brian Holcombe]

Thanks, Joe! Loosing the grooves was the lesser of two evils. Option B was to re-grind the table ways parallel and square to the fence which required scraping in the saddle. Being that the ways were accurate I hated to do that.

I am looking at ways to reapply the grooves, currently. I plan to do so when I drill for holes to locate the mini-pallet.

Fisso is a really nice Swiss made indicator base. Probably as good as it gets.

In the middle range I would consider Mitutoyo.

I don’t mind dial or digital, for an indicator in fact dial is sometimes better. I like Mitutoyo Japan made but plenty of guys prefer Mahr which are made in Germany.

[Jared Sankovich]

Re: the indicator mag base. Im partial to Noga or like, and prefer dial to digital.

[Joe Calhoon]

Thanks for the info guys.
Very helpful

[Brian Holcombe]

Dialing in the chisel holder was surprisingly difficult. I did not expect perfect alignment but I was surprised at the reasons why it was out.

There are many reasons for wanting this square, primarily I do not want the chisel to deflect under load, approaching the piece with the chisel cocked is going to apply a horizontal force to the chisel, bending it.

I checked the pin for straightness on my surface plate.

At first glance it appears that the chisel holder is bolted up tight, but further inspection provided that one could see light between the mating parts. I decided to indicate it first to see where I stood.

I work to set everything in alignment to travel, which is why I first make the effort to set the column square to the base's dovetails utilizing the travel of the head as my basis. That allows us to align parts to travel, rather than to each other. In theory, the limit of accuracy would be the machine ways themselves.

First step was to chamfer all holes and deburr the surfaces at hand. There were some pretty offensive burrs, but they were easily removed with a hand burring tool and a light india stone.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4717-3487043706-1571537078646.jpg

Next, I started to dig in. First thing I found was a sleeve in the bottom of the motor that was proud of the surface by quite a bit.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4718-1600589291-1571537124202.jpg

I filed that back and expected the parts to mate, but they did not still. So I got some marking compound and applied it to the motor.

At this point I also decided to indicate the spindle to make sure it was actually aligned with the ways. Normally I would use a test indicator here instead of this dumb approach, but it worked and saved me from driving to pickup my test indicator.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4720-2056377882-1571537197376.jpg

This was followed by a sweep around the mating surface. I found this pretty decent, a thousandth showing here and there.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4721-227993228-1571537093236.jpg

Next, returning to the part to take a print. I came to find that the step was actually mating with the spindle bearing and preventing the part from seating. I can't imagine this was intentional. I spent some time cutting this by hand to the point where the part contacted the bearing lightly when bolted up and contacting the mating surface well.

This resolved the issue and it checked mainly square afterward.

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4723-3818424224-1571537166221.jpg

https://brianholcombewoodworker.com/wp-content/uploads/2019/10/img_4724-2113671683-1571537183423.jpg

[Mark Hennebury]

Brian, Your home planet called and said that you have blown your cover and must return immediately.

[Brian Holcombe]

Hah! Thanks, Mark.

It is revealing when you start digging into parts, I found a nice big curve in the rack (and pinion) so I plan to resolve that before putting it back on the machine. I’m assuming it was deflecting the table at least a little bit.

This process reminds me of ‘engine blueprinting’ which was the process of bringing a motor from how it actually leaves the factory into an ideal spec and how it should alter performance. I haven’t cut a mortise after having the table done and attending to these few problems but I expect it will be slightly easier than before. Quite frankly it worked beautifully even as I first received it so I’m solving very minor issues.

[Jim Becker]

Brian, Your home planet called and said that you have blown your cover and must return immediately.

https://sqepwq.bn.files.1drv.com/y4mBGf5R-0uPkaUaeT6LmqGRycGHHhZsv2HHth7hVzw7D42iJZ9YmRepfMW Cwp5HhlpCiQiqOB3CjuMH0jL9OsqUTh107mnscQa-E_6nOw_cktlgS2B60MbsqRvetue1MjcO3TqxfaI6zqwWpdAM4n bfpD_HucF9bpY392xukOulIpBLq4SCgFyRfm0fnerAWYb-l20hi_JarYhuGaIcyjH4g?width=381&height=400&cropmode=none

[Brian Holcombe]

Sponge Bob is from Bikini Atoll, known in his fictional world as 'Bikini Bottom'.

[Jim Becker]

True dat!!!!!!!

[Joe Calhoon]

Checking my DM the fence is out of square to the base by quite a bit. Almost 1mm in the height of the back fence. I do not see this as a problem as the clamp pushes the workpiece agains the back fence. I did check to see if the chisel is parallel to the back fence and it’s out about 0.3mm in the height of the fence. ( I’m sure my measuring technology is not as accurate as yours)

I would like to correct this and thinking it might be in the chisel holder. I had 2 originals with the machine that were cracked in the bolt area but still functional. I ordered a replacement from AMS but I thought the fit was poor and the finish rough. I’ll put one of the originals back and see what that does.

[Brian Holcombe]

I’d be curious to see if your chisel holders also gap between the mating surfaces. I assume this is why the originals cracked. Your mention of that situation is actually what caused me to dig in here, when I bolted it up it didn’t seat as it normally should and so I wanted to find out why.

If you put some gear marking compound on the top ring I would bet that the ring contacts the bearing. I would imagine this to be a common error in these machines of a similar vintage.

[Joe Calhoon]

I’ll check the flatness tomorrow Brian. I think the holder may have cracked from wrenching the holding bolt too tight or undersize chisel. Machine originally came from a school shop so who knows. The one on the machine had a unsightly support added. I may clean it up and use it.
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I was way off base when I checked fence squareness last night. Under better light and a rested brain it is only 0.3 mm off which would correspond to the chisel being off. I chopped a mortise today and cut it in half. It’s only 0.1 mm off parallel in 3”. I can live with that. Especially given chisel mortising is fairly crude.

Also, I was looking at my table sideways stop rods that are original to my machine. They have a flat on the bottom and were held by square head bolts that made adjustments unhandy. I think they were BSW thread so I drilled them slightly bigger and put metric kip levers in. I noticed yours are round and must be aftermarket.

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[Joe Calhoon]

Be interesting to see one of the hollow chisel mortisers from Japan that Chris talked about. I bet they are nice.

[Brian Holcombe]

I linked you to a post of someone using a Japanese HCM. They’re actually very similar to the DM in my opinion.

My table rods were missing so the ones in the machine now are from McMaster, they are also flat on the bottom but I didn’t replace the bolts with kip levers yet. I may do that pretty soon, I’m sure wrenching will get old quickly.

Did the original supports have a washer in the split to limit how far the split would close? Mine does and it just barely grips tight, I used a spacer for some chisels and it added enough slack that they would not tighten and required me to swap bushings. I ended up buying another set of chisels so that they all have the same shank.

I added a 5/8” chisel which Axminster lists as .500” shank, but I’m suspicious of that number and hoping it is larger than .500” so I can have it cut down to size.

.004” (.1mm) is fine for most mortises I would imagine, in fact that is smaller than PVA’s gap tolerance of .005” so it should be perfectly alright. My machine produced a similar result. My reason for doing most of this is more about making certain that they chisel force is all going straight down. To me it seemed like the machine needed a tad more force than necessary to cut with the 1/2” chisel and having both parts very slightly out of alignment would certainly cause that.

[Joe Calhoon]

The Japanese one is very similar, thanks.
the originals have washers same thickness as the new one I bought. When using the chisels with bushings it seems like I have to tighten more than necessary. I have thought about changing washer thickness but worried that might be what causes cracking. It must have been a common problem with the DMs because they offer that replacement part.

[Chris Pyle]

I had to bring this back because i just saw this thread, thanks for sharing this Brian. I have a HCM that needs a going over, very generous of you to share the process! I hope you'll post more of these in the future, time permitting.

[Brian Holcombe]

Thanks, Chris! Good to hear fro you.