Table Saw Miter Jig design

[Randall Kline]

I've seen a lot of miter jigs for table saws, and most of them look the same. One commonality is that they always only allow for one piece to be cut at a time. What I was wondering is, why not cut both rail and stile at the same time?? That would guarantee that those two pieces would fit together at 45 deg. every time. It would also increase productivity. Below is a picture of the overall concept design, and the second picture shows how the rail and stile would overlap to allow the simultaneous cut.

I'm open to ideas and suggestions on this design before I build it.

[Mike Cutler]

Randall. I've seen similar jigs before, not sure if I've seen one that cuts both miters simultaneously.
I think the reason that folks cut one side at a time is primarily a control issue. If the jig you have designed can control both pieces of material and eliminate "creep" you may have yourself a winner.
From your drawing I would try to have both pieces up on zero clearance risers, so that the material is being clamped against the riser and not leveraged off the table. I'd also add more clamps. I say go ahead and build it, and let us know how it works out. It looks like it should work if the clamps are strong enough, and the material stable enough. Good luck.

[Mark Singer]

Randall,

That should work fine if you know the exact lenght of both sides. Sometimes you cut one and the measure for the second cut. The jig should be made exactly at 45 degrees and accuracy needs to be the same either way. Even if you cut them at the same time they could be off and one diagnol will be longer than the other...You will need to support under rhe elevated piece also

[Dan Forman]

You will also have to take into account that all materials you want to cut will not be the same thickness, and that various moldings will have different profiles, making it very difficult to stack them in such a way. It is a very interesting idea however.

Dan

[Scott Parks]

I have built a similar jig. Except mine doesn't have a riser to cut both sides at once. Works great for all the miters I've cut. You just have to cut each side separatley. The issue for me with using the riser was the blade hieght. I built mine on a 3/4" thick base. I was using it to cut 2" tall moldings. The riser idea would work for OK for 3/4 material, but anything thicker, and you have issues. What about using one on a bandsaw for tall moldings?

[Jim Becker]

Randall, your design is similar to the one I use for all my framing and "corner" work, even for moldings that are going in the house. And I always cut opposing pieces mirrored to eliminate any slight variation (read: builder's mistake) in the jig.

[Randall Kline]

Thanks!! You have all given me a lot to consider in the design. My original design was for a miter saw (which would get around the thickness issue a little), but over all I like this idea a little better for stability. Most of my stock isn't >3/4".

One problem that occured to me is that if I cut both at the same time for all four corners, will the overall frame end up too small by the size of the kerf??

[Rick Lizek]

Make the yellow pieces in your diagram into the fences and make the left one longer to allow you to clamp a stop and you can cut repeatable lengths. You are on the right track but haven't taken it far enough. I've been using such a set up for many years with perfect results everytime. Make your first cut on the left side, then move the piece over to the right side and set the stop and repeat four times and you will get a perfect mitered square. I would get rid of the riser. If you can find Woodshop Jig and fixtures by Sandor Nagyszalanczy (Taunton press but out of print) you will find all your jigs already designed. I can't recommend this book enough. I did see it on www.alibris.com
Check out the Frame Master at www.woodhaven.com It's exactly what I was describing. It's under tablesaw fixtures. For some reason I can't paste the exact page.

Actually, looking back at Sandor's sled, Woodhaven has the miter sled perfected.

[Dan Forman]

There are several copies of Sandor's book on Amazon right now.

Dan

[Randall Kline]

Thanks. I've seen several of those designs. My thinking was that if both pieces are cut together, as long as they're held at 45 degrees, even if the cut is a hair off the pieces will still fit together at 45 degrees. If I cut the pieces individually there's a chance they could be off 45 degrees when mated (no matter how careful I am). Also, if the pieces are cut at the same time that would reduce cut time. I may try building one and just see how it does. I'll let the forum know what happens.

[Jim Dannels]

Pappy over at BT3 Central posted pictures last week and a scrap practice he cut with it. He got a perfect tight miter with it.

[Randall Kline]

Good to know Jim. That's encouraging. Thanks!