Squaring a DeWalt SCMS

[Randy Rizzo]

Prior to this I've spent a lot of time trying to square up the blade to fence on my DeWalt 12" SCMS. Using a square against the fence has never yielded satisfactory results for me. With this rig I can see how much I'm moving the table, if it moves after I tighten it down, and I can make test cuts without removing the test equipment. After a five sided cut I have been able to get the error down to .001/.002 in 12 inches. I think I'm going to call that good. I have made several test cuts after removal of the test equipment, I have moved the table over to some of the miter locks and back to the 90° crosscut and I'm still cutting .001/.002. Just thought I'd share FWIW.


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[Andrew Hughes]

Thats very cleaver Randy,I like it.

[Jerry Thompson]

What is the bolt for in pic #1 at the top of the angle iron?

[Randy Rizzo]

What is the bolt for in pic #1 at the top of the angle iron?

adjusting the bolt in/out, and keep the saw pushed up tight against the bolt. Depends on which way the blade needs to go. Watch the dial indicator to get the estimated amount of correction, tighten down the miter table (black bolts on miter scale). Make a 5 sided cut to begin with, measure front and rear of the last slice. It does not make any difference how big the last slice is, you just need something to measure. If the front (fence side) measured say .678 and the rear measured .650, a difference of .028, the blade needs to go left, .028/5, or about .005. Zero the indicator, loosen table bolts, turn the bolt in the angle iron in until you see the table move .005, lock it down, make another test cut. There's probably a mathematical formula to get the exact amount to move, it took me 3 tries to dial it in. A lot faster than anything else I've done in the past and easier.

[Mark Leu]

The mathematical formula for knowing the exact amount to move and dialing it in correctly the first try instead of the third try is not that complicated. Using your example, the difference in widths on either end of your offcut was 0.005. You then divide that number by the length of your offcut. Let's assume your offcut length was 5". That means your cut angle is off 0.001" (0.005/5) per inch. You then measure the distance that your adjustment bolt is away from the miter saw fence. Let's say your adjustment bolt is 10" away from the fence. 10" x 0.001" per inch means you need to move your bolt in/out by 0.01" to get a cut that is exactly 90 degrees. HTH

[Jeff Bartley]

Randy--
How is the table for flatness on yours? And are the fences exactly 90 degrees? I have the same saw and the first time I cut crown standing up I wasn't getting good results....then I checked the aforementioned surfaces....the biggest issue with my saw is the fence extension wings. Word on the street is that the Kapex is the only saw with a perfectly flat table and perfectly square fences.
All that being said I can still make the dewalt work just fine for trim work.
Thanks for sharing your method of squaring the cut Randy!

[Randy Rizzo]

Randy--
How is the table for flatness on yours? And are the fences exactly 90 degrees? I have the same saw and the first time I cut crown standing up I wasn't getting good results....then I checked the aforementioned surfaces....the biggest issue with my saw is the fence extension wings. Word on the street is that the Kapex is the only saw with a perfectly flat table and perfectly square fences.
All that being said I can still make the dewalt work just fine for trim work.
Thanks for sharing your method of squaring the cut Randy!

I did check the fence to deck angle with a machinist square. For the most part it checked good. There was one spot where the fence was just a tad more than 90°, I mean you could see just a little daylight at the base of the square. I have trimmed out a couple of houses with this saw, I've owned it for more than 10 years and overall I've been pleased with its performance. I have seen the reviews on the Kapex and for the most they are good, everything else seems to be a mixed bag. My brother has a Bosch, model 5412 L, I think, that has been giving him fits. He finally took it into a Bosch service center to get it fixed and it came back in worse shape than when it went in. Fence to deck angle not square by a few degrees overall, they sent him a new fence, same thing. He managed to get it close to square by shimming the back edge of the fence. The miter table was proud on one end and to Bosch's credit they did manage to get that fixed. Blade wobble, apparently no fix for that. And I've seen lots of reviews on the 5412L that complain of this malady. For the $ these things cost any of them ought to be more than just a framing saw. He has spent the last couple of days trying to align the blade and get it perpendicular to the fence. I think he has finally managed to get .005/.006 difference on a five sided cut and is going to leave it at that. If I ever get to the point that I have to replace this particular saw I think I would be at a loss to pick one from what I've read. Kapex would be nice, but for a retired guy, a little pricey!

[Randy Rizzo]

The mathematical formula for knowing the exact amount to move and dialing it in correctly the first try instead of the third try is not that complicated. Using your example, the difference in widths on either end of your offcut was 0.005. You then divide that number by the length of your offcut. Let's assume your offcut length was 5". That means your cut angle is off 0.001" (0.005/5) per inch. You then measure the distance that your adjustment bolt is away from the miter saw fence. Let's say your adjustment bolt is 10" away from the fence. 10" x 0.001" per inch means you need to move your bolt in/out by 0.01" to get a cut that is exactly 90 degrees. HTH

Thanks Mark

[Mark Roderick]

The way to square a saw is not with a gauge. Take two pieces of MDF, each about nine inches square. Set the blade to what you think is 90 degrees, cut both pieces, then flip one of them over and try to snug them together against a flat surface. If there is daylight between them the cut is not square. Adjust and try again until there is no daylight.

[Randy Rizzo]

The way to square a saw is not with a gauge. Take two pieces of MDF, each about nine inches square. Set the blade to what you think is 90 degrees, cut both pieces, then flip one of them over and try to snug them together against a flat surface. If there is daylight between them the cut is not square. Adjust and try again until there is no daylight.

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Been there done that. The problem is when you're bumping the miter handle over you have no way of knowing exactly how far it's moving. You also have no way of knowing if it's moved slightly as you tighten down the miter table, the gauge set up the way I have it you can see immediately if it has moved at all and you know how much you are moving it. There is always more than one way to do a job, I just threw that out there as an alternate means.