Miter sled done, a drastic improvement!

[Phil Thien]

A week ago I needed to make a frame w/ mitered corners (to be used as a door on a medicine cabinet for a bathroom I'm redoing). I used my Incra miter gauge. The gauge always cross-cut at 90-degrees perfectly. So, I adjusted the gauge to 45-degrees and cut the frame members. But when I dry fit the frame I had small gaps. I checked one of the cuts with my Starrett and (sure enough) it was a little off (probably less than 1/2-degree, but still...).

Instead of using the Incra gauge I coulda used my old adjustable sled, but it was too time consuming to turn all the knobs required to make the adjustments to the fence.

I decided to build a better miter sled. This is the thread where I started (and got stuck):
http://www.sawmillcreek.org/showthread.php?t=80131

Doug was instrumental in providing some advice to help me figure out how to attach the pivot side of the fence.

Everything is put together using t-bolts riding in t-slots cut using a Rockler t-slot bit. The pivot is actually just a t-slot bolt with the slot cut in the BOTTOM of the sled, and the bolt extending through a 5/16" hole (the original 1/4" hole that was used as the pivot to cut the t-slot arc, widened to 5/16").

The runner is an Incra 18" that can be fine-tuned for fit (slop) through holes on top of the sled. I just used countersunk maching screws to mount it because I don't need to adjust it for square (after all, the fence is adjustable).

To adjust the angle of the fence I simply use a plastic triangle or protractor using the line on top of the fence that was used to establish the screw line for the Incra runner. Someday I may mark the left edge of the sled at .5-degree increments, but I will probably just mark common angles as I need/find/use them.

The fence is just 1/8" thick aluminum angle, with a 3/4" sacrificial fence with t-slots routed on the front and back. A stop block rides in the front t-slot.

I made another frame using the new sled and the joints fit perfectly. I've cut FF biscuit slots (two) into each corner and now all I have to do is glue it together.

Now I just have to figure out how to clamp it. I have fiberglass tape (always a favorite) and a band clamp in my miter clamping arsenal. I once had one of these (http://www.rockler.com/product.cfm?page=725&filter=miter%20clamp) but I found it bulky and that it was better for square frames but that rectangles weren't tensioned evenly.

Looks like a trip to Rockler/Woodcraft tomorrow to get either this:

http://www.rockler.com/product.cfm?page=10401&filter=miter%20clamp

or this:

http://www.rockler.com/product.cfm?page=11060&filter=miter%20clamp

[J. Z. Guest]

Oh Phil. A photo of one nice-looking miter joint doesn't prove anything. You'll have to show all four of them. Not that I would know from experience. No-siree. :rolleyes:

[Phil Thien]

Oh Phil. A photo of one nice-looking miter joint doesn't prove anything. You'll have to show all four of them. Not that I would know from experience. No-siree. :rolleyes:

Excellent point. I'll try to get a photo showing all four corners of the assembled frame, but I might need a better camera. :D

[Tim Sgrazzutti]

Phil, I always use and highly recommend spring clamps for this. I like these http://www.collinstool.com/base.php?page=collins_miter_clamps.htm better than the ones Rockler sells. They have a huge range, so one size fits all, and they take up very little storage space compared to other "miter" clamps. They will not influence the angle of your joinery, which is good IMHO, because it makes them useful for clamping any angle. I use them a lot in the shop, and they are great for holding outside corners together when installing trim in the house.

[Phil Thien]

Phil, I always use and highly recommend spring clamps for this. I like these http://www.collinstool.com/base.php?page=collins_miter_clamps.htm better than the ones Rockler sells.

Thanks Tim!

I went ahead this morning and used my fiberglass tape and a web clamp I already had (like this one: http://www.woodcraft.com/family.aspx?FamilyID=3719&cs=317&pcs=fam).

So I dodged another tool purchase (whew!). But I do like the Collins spring clamps you linked. I can see the advantage over the ones at Rockler and Woodcraft. Plus, Collins has a local dealer.

The question I have is, do these leave much of a mark in the wood? And does the Collins design provide as much tension as the other designs? That is, does the wider range of the Collins mean that it isn't as tight as the other brands that don't have the "loop?"

I can see using them for trim projects around the house, and I may want to make more frames in the future.

[Tim Sgrazzutti]

I don't know how much force the other ones apply, but these are in the neighborhood of 20 lbs when the points are 1" apart. It's been enough clamping pressure for everything I've used them on. I frequently use biscuits to reinforce miters like you did, and so in that case, you only need enough pressure to keep the joint closed while the biscuits swell.

Yes, they will leave a small mark in the wood. How much depends on how hard the wood is, and how much you spread them apart. In hard porous woods like oak you can't even tell, and even in soft pine they're usually not deep enough to bother me.

[glenn bradley]

Very nice job Phil. Thanks for sharing.

[Jim Dunn]

Real nice Phil. I have to ask, how square is that aluminum that you used? Square enough or did you have to bend it into square?

[Phil Thien]

Real nice Phil. I have to ask, how square is that aluminum that you used? Square enough or did you have to bend it into square?

That is an interesting question, because it implies that aluminum angle isn't normally all that square. I don't use a lot of the stuff but I've use it for fences and have always found it to be straight and square.

In the way I'm using it, it doesn't have to be perfectly square, but I imagine (and like I said I'm gonna check it) that it is pretty darn square.

I'll check it when I get home and let you know.

So, have you had problems sourcing square aluminum angle?