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Old 01-22-2008, 12:00 PM
jackellis jackellis is offline
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Crosscut Sled Tolerance

I built a "temporary" crosscut sled for stock that can't be cut safely using the miter gauge (small parts). It uses only one of the saw's miter slots rather than both of them or the edge of the saw table.

A test cut results in an error of about 1/32 inch over the 7 inch metal leg of a try square which works out to about 1/4 degree. Not good enough for cutting miters but I'm wondering how well others have done getting their sleds dead on and whether you consider 1/4 degree good enough for most woodworking. Is it unrealistic to expect dead-on accuracy using a single slot?

Note. I've checked my measuring tools independently and against one another. They seem to be fine, though I'll check again in the light of day.

I'm eventually going to build a panel cutting sled that uses two guideways (both miter slots or a miter slot and the edge of the saw table) in order to avoid this problem.
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Old 01-22-2008, 12:19 PM
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Garasaki Garasaki is offline
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Google "five cut method"

you can awwwwwwwwwwwwwwwwwwwwwfffuuuulllllllyyyyyy close to perfect aligning the fence on your crosscut sled that way.

IMO your silly to build a crosscut sled for "odd ball" use. Build one to use all the time. You'll fall in love with it. Best jig ever.
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Old 01-22-2008, 12:31 PM
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Not long ago, I cut a panel that was approximately 24" x 28" using my single-slot panel-cutting sled. The amount by which it was out of square was essentially unmeasurable -- less than 1/64".

This was using my PM2000. I'm not trying to boast about its accuracy, just saying that I think you can do a lot better. A 32nd off over 7" is a lot, IMO.
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Old 01-22-2008, 01:22 PM
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You might want to read this guys method for making a sled.
http://www.ridgidforum.com/forum/showthread.php?t=14120

and here:
http://www.ridgidforum.com/forum/showthread.php?t=13945
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Old 01-22-2008, 09:23 PM
drumpriest drumpriest is offline
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My sled isn't that big on capacity, can only cut about 13-14", uses both slots, and is easily better than 1/64" over the full distance. They are pretty easy to tune up, so I've been very happy with my sled, even compared to the SMT of my good ole 3100.
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Old 01-22-2008, 09:35 PM
JimD JimD is offline
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I've been trying to figure out a good way to attach my fences to a couple sleds. Thanks for the post, pecker, this looks like what I was looking for.

One change I made that I think is a good idea is I cut a dado 1/8 thick and 2 inches wide centered where the blade will come through the sled. That way I can attach 1/8 hardboard and have a zero clearance sled with replaceable zero clearance insert.

My sleds are a small one for 13 inch crosscuts and a big one for 25 inch crosscuts. They use the miter slots I just added to my BT3100. I cut dados into the 1/2 MDF base of the big one and liked the result. Maybe I lucked out but I got the dados lined up well with the miter slots.

Jim
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Old 01-25-2008, 03:23 PM
lakkdainen lakkdainen is offline
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Excuse the possibly ignorant question, but what is the benefit of having the sled register on two slots instead of one? If it's straight, it's straight, right?
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Old 01-25-2008, 03:34 PM
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RodKirby RodKirby is offline
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Quote:
Originally Posted by lakkdainen View Post
Excuse the possibly ignorant question, but what is the benefit of having the sled register on two slots instead of one? If it's straight, it's straight, right?
Excellent question!

"Less chance to wobble" - I think it's more in the mind than anything else.

Mine only has a miter bar on the left and it doesn't move!


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Old 01-26-2008, 07:55 PM
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I think it is fully possible to have a sled work fine with only one runner. Norm on New Yankee woodshop (? is that the name) uses one. I don't like them, however. They do not feel balanced to me. I like two runners so I have runners on both sides of the blades. Two runner sleds also support both sides of the wood you are cutting.

I agree with Rod, largely a personal preference kind of thing. I'm sure the bT3100 SMT works well for some too but I just got my sleds done and I already like them better than the SMT. I used the little one to make most of the cross cuts for the big one. I have a radial arm saw and a CMS but the sled is zero clearance. I will still use the other tools for long pieces within their capabilities but I like the sleds (both dual runner).

Jim
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