Straightedge for alignment?

[Greg Urwiller]

Every so often I've needed a straightedge for alignment purposes. So far, my 4' aluminum ruler has been sufficient for those needs. But a while back I picked up a Powermatic 60 jointer that I'll need to go through and obviously, I need something a little more precise for checking the bed alignment. They really aren't too cheap, but I figured I'd just have to bite the bullet and order one. Today I was killing some time at my local gun/pawn shop and was walking through the tools. Couldn't figure out what the 6' piece of flat steel was leaning against the wall. It was a Crain 113 6' straightedge. About 3" wide, a little floppy at only about 1/8" to 3/16" thick. All I can find on the net is that it was "guaranteed to be within .005" at the factory". Don't know whether that's .005" per foot or 6' total. So, does anybody know anything about this straightedge?? While the edge isn't nicked at all, it doesn't seem like it's a real smooth, ground surface. Looking at it, I had the impression that it was a rough alignment tool rather than a precision instrument. But, at a .005" (if per 6') tolerance it shouldn't too bad. If it was .005"/foot, I would think you would be able to see that much, but sighting down the edge, it looked good. Anyway, just wondered if someone had one of these or knew anything about them. Thanks. Greg

[Bill Huber]

I don't know anything about the one you are looking at but I will say you want a thick one. I broke down a while back and get a steel Lee Valley 36". It is 3/8" wide and 36" long, the thing that I really like is the fact that when you set it down on the surface you stays put.

When I set may table saw up with it, it was so nice to have it set there and not move so I could put a feeler gauge under it and it did not move or fall over.

Just my thoughts, if you can get it for a good price I guess you can't go wrong, but it is really long.

[Kevin Presutti]

I am not sure what your budget is but here is a few links, and the other thing was you didn't mention what you were looking for as far as length. I hope this helps.
http://getmachinetools.com/pro1325616.html

http://www.calibex.com/Starrett-385-48-Steel-512908140/cb2/prices-html?nxtg=769b0a280502-5F4BD9FDF0F3A336

[glenn bradley]

So, does anybody know anything about this straightedge??

I know it is used and I would have no way of confirming the spec on a used straight edge and so would consider it as reliable as the one you already have unless I could be proved wrong. Wow, the coffee must've just kicked in :). A ruler is a ruler and a straight edge is a straight edge. If you want to know the item you are comparing against is what you think it is (as opposed to "good enough") you will want something that is a 'known' item. These come in varying qualities with the price tag reflecting what it takes to guarantee and certify a level of accuracy. I have the 36" steel Lee Valley which at the time I bought it landed in the middle to lower end of the pack price-wise without breaking the bank. True, I do not use it every day or even every month. It has been invaluable in aligning my machines and directly contributes to my satisfaction with their performance. If I dropped it, I would buy another. Avoiding the frustration of aligning to something that is 'almost straight' and then re-aligning several times to try to get things right . . . . well, I have better things to do with my shop time.

[Matt Meiser]

The Crain straightedge is a carpet tool. If you want to at least roughly check its straightness, bring a roll of paper and roll it out on the floor. Draw a line using the straight edge, then flip the edge along the line (as opposed to end-to-end) and draw a second line. Any error will be doubled. To me, the 1/8" thickness would be a drawback because it wouldn't stand on edge real well.

I put the Lee Valley 50" on my wish list after borrowing a friend's several times. A lot of people say you can make do with a 4' level or even a jointed board (not sure you you set up your jointer with a jointed board but...) and to some extent you can but a proper straight edge is much nicer. For one, the corners of the LV straight edge are crisp where the edges of a level are usually rounded making it harder to see what is going on.

I've found you can make a nice protective case for a few bucks using 2" PVC pipe, a fixed cap, a female threaded end, and a male threaded cap.

[Greg Urwiller]

One thing I didn't like about this one is the thickness, I don't think it would stand on edge very well. I think ideally that a 4' length, at least, would be nice. The 6' is a little long, but it could be cut down. The $59 for the 3' one in the first link isn't bad (but I'd like 4' better), but I'm sure not going to spend as much as those in the second link. Too cheap for that LOL! Greg

By the way, they've got $45 on the Crain. We get along pretty well, I think I could get $10 knocked off that price.

[Matt Meiser]

Then you'll like the LV 38" better at $39.50 with free shipping through 1/3/12. The 50" is $85.

http://www.leevalley.com/US/wood/page.aspx?p=50074&cat=1,240,45313

[Joe Bradshaw]

I have the 50" Veritas from LV that was a Christmas almost 10 years ago. It has worked out great. I keep it hanging from a screw behind a door. Out of sight, out of mind, except when needed.

[John Brennaman]

When I align my jointer I place a laser level on the infeed table. I then lower the infeed table until the beam just barely touches the front edge of the outfeed table. I get a perfect alignment every time. You just have to make sure that the beam leaves the laser perfectly parallel to the surface of the level that sits on the infeed table.

[Jeff Monson]

I'll throw in my vote for the Lee Valley, I have the 36" steel one also. It's an invaluable tool in my shop.

[David Kumm]

I found a Pinske edge on CL 100" long. It needs a wooden clamp to stand on edge but once I had it as a reference I found my 72" level was straight enough for machine use. It now mainly serves to reference other stuff. Dave

[Van Huskey]

A rule of thumb you can pretty much take to the bank is if a straight edge says "guaranteed to be within .005" at the factory" that "never" means over the length, it means per foot or per inch etc. If it is over the length then they will almost certainly include that in large letters. Personally, I don't buy reference tools used. I suggest you do as others have mentioned, get a LV or Woodpecker (or the Woodcraft Pinnacle version) straight edge and feel comfortable you have a true reference edge. Even if the straight edge in question was new thin and long do not a easy to use straight adge make.

[david brum]

I'm surprised that no one mentioned shop made straight edges. They are pretty much free, super accurate and you can make them as long as you want. I made up some to align the 6'+ tables on my jointer. They worked just like advertised. Here's some instsructions that I pilfered:


You need to build a straightedge

Actually three. In order to accurately reset jointer tables properly you need an accurate way of gauging the tables for proper alignment. I am not speaking of a level (sorta close like a hand grenade) or a very expensive straight edge. What you need to do is build a set of parallel bars. These are are shop built and are highly accurate over a great distance. (they are used in machine shops for critical setups so you can be assured that properly set up they will be every bit as accurate as a very long very expensive straight edge you cannot afford, or need. The key is to create the three straight edges to prove straight on any two edges in any combination, then using one or two of these shop built bars to set the in feed table up correctly.
The set up is pretty easy but takes some time to adjust. Once more this is an exercise in learning to do something methodically try to analyze what you just did before you do the tweak to adjust the last step
You take three pieces of stock ( MDF 3/4" x 4" wide by the length of your jointer works well)
then on the edges you drill and countersink three holes in each piece (one set about 1" from the end on the left then one set at 1" in from the jointer knives on the outfeed table the last set 2" in from the end on the in feed table.
they should look like this with the screws installed when you are done.
http://www.arbolloco.com/bcs/drawings/images/gobars.jpg


The next pic shows what you need to do to make the bars straight

http://www.arbolloco.com/bcs/drawings/images/detail_view_go_bars.jpgyou set two edges (1 and 2) together and locate the gaps and the ones touching then adjust each screw until they all touch.
Once they all touch, take bar 1 and 3 and repeat the process, then go to bar 2 and 3 check again.
keep doing this until you have it so that each screw head matches the heads on each stick no matter the combination. Near the end of this process you may require a feeler gauge to check the process. be critical in your adjustments the more accurate the bars are the easier the tables will be to set properly.
Once you have the go bars built you can determine whether the tables are out of plane very easily

[Jeff Duncan]

FWIW Starrett precision straight edges are also quite thin, so it's not unusual. I bought the 4' version several years back and it is not cheap, and probably 1/4" thick or less IIRC. I'm not sure what the quality of the on your looking at is, but for the price you could take it to a machine shop and have them check the flatness for you. Can't imagine they would charge you much for that. And I always would go for the longer if given the chance.....it's like hp, better to have it and not need it than the other way around;)

good luck,
JeffD

[Van Huskey]

Shop made "straight edges" are useful for somethings but worthless for others as they only give a finite number (usually three) points of reference. They are great for long bed jointers as you can make a set to fit your aircraft carrier then use a shorter (less expensive) "store bought" straight edge for most of your other tasks.

[Greg Urwiller]

I figure if the tolerance stated isn't specific, then it's usually at the high end, or in this case, per foot. Looking down it, I don't know if I could pick out .030 or not. That's a good trick to remember tho...draw a line and flip. I check my squares that way all the time....wouldn't have to if I'd quit dropping them on the floor. I might have to make an offer anyway, it would be handy to have around for other uses that didn't need high precision of a machined edge.

Actually, I was going to use David's method and make one when I did check out the jointer. Might do it yet, but I still want a good machined straightedge. I really don't have any problem with spending $85 for the Veritas 50". Now if it was only a steel one, I'd jump on it. Really rather have steel over aluminum, although I'm sure the aluminum one is a quality product. Thanks for all the replies. Greg

[Myk Rian]

This is woodworking. Use a good 4' level.

[Van Huskey]

This is woodworking. Use a good 4' level.

Good try but ultimately a fail IMHO. The problem with that approach (never mind 4' levels can be horribly poor) is when a machine is out it tends to multiply and duplicate the error over and over, such is the case with a jointer. Certainly there is a point of diminishing returns but spending 40-80 bucks on a reference to set up thousands of dollars of machines only makes good sense when you figure you will be running tens of thousands of dollars in wood over/through the machine over the life of the machine.

[Chris Parks]

A length of string and some really heavy weights each end hanging from the string. Don't laugh, it will beat any straight edge in accuracy and is cheap. What is better is some very thin wire like piano wire but it is hard to store so it remains undamaged with no kinks. The trick with the string is it must be really tight like near breaking point.

[Lee Schierer]

To me, the 1/8" thickness would be a drawback because it wouldn't stand on edge real well.

A couple rare earth magnets will stick to the straight edge and the jointer top and hold the straight edge in a vertical orientation.

[Alan Wright]

I'm fortunate that I have a brother-in-law who works in a sheet metal shop doing stainless kitchen work. The "break" they use to cut up stock is about 3 ton and is extremely accurate. I have a bunch of "scrap metal" pieces that are between 3" and 4" wide and from 3' to 7' long. I use them constantly. I have a jointer that tends to collect dust. I usually use on of the metal pieces as a straight edge guide , clamp it to the wood, and run a straight cutting bit along the length to get one straight edge to use as a reference for my glue line ripping blade in the table saw.


In any event, my suggestion is for you to look in your yellow pages, find a local sheet metal shop and stop in. You want one that does stainless steel work. The pieces you are looking for are scrap to these people and they may give it to you. However, the price of scrap stainless is high, so they may just charge you by the pound for the scrap value. In any event, it will be much cheaper than retail, and it you are nice to the shop guy, you might get a a buch of different lengths. Alan

[joe milana]

A length of string and some really heavy weights each end hanging from the string. Don't laugh, it will beat any straight edge in accuracy and is cheap. What is better is some very thin wire like piano wire but it is hard to store so it remains undamaged with no kinks. The trick with the string is it must be really tight like near breaking point.

+1 I used this method, suspending the piano wires with pulley key stock then using another piece of key stock as a "feeler gauge". It was so accurate, it showed how poor the machining was on my new PM jointer, and left me a bit discouraged.

[steven c newman]

Yep, I just use my 4' level, from Bluegrass. Since it IS longer then the bed of my jointer, only the metal balde sits on the tables. Sometimes, a piece of 3x5 card is placed under each end, and a third as a feeler gauge. Been used in the shop since the 80s....