Homemade Shopsmith Miter Bars

[dusty]

I am about to cut wood to make some miter bars for use on the Shopsmith.

Ideally, these miter bars will be .735" in width (a long 47/64"). I want these to slide smoothly in the miter track while at the same time exhibit no discernible sideways movement.

However, that is not my question at the moment.

I will be cutting these from rough cut 1" oak cutoffs. Should I mill the stock to the appropriate thickness (.308) to fit down into the track and then mill it to a 47/64" width. OR Should I mill the stock to the appropriate width (47/64") and then mill it to fit down into the track (.308")?

The best orientation of the grain is my question. Grain running the width of the track or grain running the depth of the track.

Maybe it doesn't matter one way or the other. I'm just trying to minimize the likelihood of the milled miter bars from warping.

[algale]

I've never thought about that. But since wood expansion is mostly across the grain, if the goal is no slop, shouldn't the grain be oriented to go in the direction of the depth? You can leave them a little less deep than the full depth of the track and leave room for expansion.

My $0.02.

[Gene Howe]

Dusty, mine are white oak. I milled a wide piece to the 47/64 then ripped pieces to close to the depth. Then, planed to a hair thinner than depth needed.
The stock was bone dry to begin with and no warping has happened.

I thought about using Delrin til I saw the prices.

[mountainbreeze]

I made several miter bars from hard maple for use in a sled. They have performed well for me.

What I did was plane a wide (8 to 10 inches) board to a thickness that matched the width of the slot. This allowed me to test the fit in the slot as I approached the exact fit. Then I cut the board to the depth of the slot. I think this approach is best since the depth dimension is less critical than the width. And yes, the grain should run vertically to minimize expansion in the horizontal direction. I read that somewhere but i don't recall exactly where.

[dusty]

This brings up another question. Is one species better than another for this application?

No, bad question. I know the answer to that question is YES. Which species of wood would be best for this application? What I was planning to use (rough cut oak) is in the shop.

[mountainbreeze]

Hard wood with the least expansion would be the best choice. I know there are charts for that out there for that information but I can't find them.

[Gene Howe]

I'd think maple or white oak would be the best of the readily available domestics. If you mill it ln the order Mountainbreeze and I did, red oak or most any hardwood would be fine, too.

[Gene Howe]

Another thought. Wal-Mart sells plastic cutting boards that are .40 thick. If you plan to permanently fix the runners to a jig, that might be an option.

[masonsailor2]

Dusty I have used maple over the years and they work well. I use the aforementioned method of cutting or planing to the appropriate width of the miter slot and then slice them off at the appropriate depth. I usually mill them to fit very snugly in the miter slot and then use a cabinet scraper after assembly to adjust the width a little at a time to get the proper fit.
Paul

[roy_okc]

I second Gene's idea, or get a piece of UHMW plastic, such as this: http://www.woodcraft.com/product/124228 ... thick.aspx. Some cutting boards are made of UHMW, and could save you a few bucks. This would eliminate any expansion/contraction plus slide very nicely when you get it sized right.

edit: I wonder how Corian (countertop material) might work as a miter bar.