Miter bars for jigs and fixtures

[George Hoppen]

I've made a jig for cutting panels between than 10" and 18" or so for my table saw. However, I cannot get a miter bar attached to it so the jig doesn't wiggle at all. I've tried an Incra miter bar and a Kreg miter bar. The jig is 24" "long", and the miter bars are the same length. The jig either wiggles, or it is nearly impossible to push the jig through the slot.

I have a Jet table saw and have checked that the miter slot is extremely straight. I have a couple other jigs I would like to build, but until I learn the trick of successfully attaching the miter bar, I'm dead in the water.

Any advice on how to make the miter bars work?

Thanks in advance for any tips!!

[Bruce Wrenn]

Did you use a set of dial calipers to check width of miter slot? I find that the commercial miter bars that use screws to expand the bar every so often, aren't snug enough. My choices are either shop made quarter sawn oak, HDPE sized in planer to exact size, and then scraped after screwing in place (it will expand at screws), cold rolled steel, or some 3/8 X 3/4 aluminum I buy through Enco. I have some blue miter track (not Kreg) that fits snugly into miter slot, but it's over 3/8" high, so jig has to be dadoed to accept it. After measuring miter slot width, check your miter bar at each screw location, both adjusting screws and mounting screws. Also if bar isn't installed straight, it's never going to get straight.

[Jon Nuckles]

If your jig runs in both slots at once, have you checked to be sure that the miter slots are parallel? Have a friend with a saw on which they are slightly off. That would cause the problem you are seeing.

[Alan Schaffter]

I always use 3/8" X 3/4" cold rolled steel. It is straight (dimensions are precise, too), smooth, durable, and slides better than UMHW, HDPE, hardwood, and aluminum (I hate how aluminum slides or doesn't slide on cast iron). I haven't purchased any lately, but you used be able to get 20' (yes, 20 feet!) of cold rolled steel from a metal supplier (sometimes welding shops) for about what it cost for 24" of fancy miter bar from the usual WW suppliers! Online Metals (https://www.onlinemetals.com/merchant.cfm?pid=7484&step=4&showunits=inches&id=199&top_cat=197) has 8' of 3/8" X 3/4" cold rolled 1018 steel for $21.37 but you should be able to get it cheaper locally.

[George Hoppen]

It's been a while since I checked the width (over a year - been a little busy!), and I don't recall how I did it. I will check it again. Thanks!

[George Hoppen]

If your jig runs in both slots at once, have you checked to be sure that the miter slots are parallel?

I only have it riding in one slot, to the right of the blade so the jig is supported well. Thanks!!

[George Hoppen]

Thanks for the tip on the cold rolled steel! I like that idea a lot. How do you attach it to the jig? Flat head screws countersunk? If yes, what tricks do you use to ensure the alignment of the holes is straight? I could see drill them on drill press, but I don't think my DP's throat is deep enough.

[Bruce Wrenn]

First drill the steel, then use it as a guide to drill jig. The last 1218 I bought came in a 12' length for a little over $36 locally. You can either counter sink holes in steel. or use holes sized for tapping and threading. Use as a guide to drill fixture, then counter sink holes in top side of fixture, and finally tap threads in bar.

[Phil Thien]

It has been six plus years and my UHMW runners still fits the slot perfectly:

http://www.sawmillcreek.org/showthread.php?82788-Finally-a-better-sled-runner&highlight=RUNNER

[Alan Schaffter]

Thanks for the tip on the cold rolled steel! I like that idea a lot. How do you attach it to the jig? Flat head screws countersunk? If yes, what tricks do you use to ensure the alignment of the holes is straight? I could see drill them on drill press, but I don't think my DP's throat is deep enough.

I drill and tap the steel for flathead machine screws. Although I usually only use one bar, I have successfully used two in the past it is just a lot harder to get them parallel and aligned, and IMHO really not worth the hassle.

But here is a great tip- no matter what material I use for the bar, before I add the fence or do anything to the jig platform, I cut a shallow, 1/8" or so, dado in its bottom just wide enough to hold the bar snugly. That way the screw holes in the wood don't need to be perfect and I don't need to worry about them getting sloppy. And if I make the bar from material that will wear or if it gets damaged, I can easily replace it. Since it will sit in the same dado, the new bar will be automatically aligned.

[George Hoppen]

First drill the steel, then use it as a guide to drill jig. The last 1218 I bought came in a 12' length for a little over $36 locally. You can either counter sink holes in steel. or use holes sized for tapping and threading. Use as a guide to drill fixture, then counter sink holes in top side of fixture, and finally tap threads in bar.

Yeah - duh on my part!! Counterbore holes in jig - thread bolts into bar! I've done that before! Thanks for the noggin joggin!!

[George Hoppen]

I always use 3/8" X 3/4" cold rolled steel. It is straight (dimensions are precise, too), smooth, durable, and slides better than UMHW, HDPE, hardwood, and aluminum (I hate how aluminum slides or doesn't slide on cast iron). I haven't purchased any lately, but you used be able to get 20' (yes, 20 feet!) of cold rolled steel from a metal supplier (sometimes welding shops) for about what it cost for 24" of fancy miter bar from the usual WW suppliers! Online Metals (https://www.onlinemetals.com/merchant.cfm?pid=7484&step=4&showunits=inches&id=199&top_cat=197) has 8' of 3/8" X 3/4" cold rolled 1018 steel for $21.37 but you should be able to get it cheaper locally.

Thanks Alan - I checked out website and they have some good stuff. Also - for those not familiar, cold rolled steel is dimensionally much more precise than hot rolled. Also like the idea of routing dado in bottom of jig to accept the bar.

[George Hoppen]

Terrific and quick feedback all!! Thanks a bunch! Happy new year!!!

[Larry Copas]

If your miter bar is too loose you can center punch dimples on one side to make it bigger. Start with small dimples until it starts to fit snug through out the length. If it is too snug it might be a good time to meet a friendly machinist.

[allan kuntz]

check out the video on building the sled at about the 15 minute mark. he has a great idea for making an adjustable one
http://www.segeasy.com/wedgies.htm
Al

[Dave Lehnert]

I just got the new issue of WOOD Magazine today in the mail. The front cover shows "5 Must have Jigs from Plywood". One project is a sled. Sure they will have tips to help you out if you are a subscriber.
I have not looked at that issue yet so can't say what info is in it.

[Brian Henderson]

It has been six plus years and my UHMW runners still fits the slot perfectly:

http://www.sawmillcreek.org/showthread.php?82788-Finally-a-better-sled-runner&highlight=RUNNER

That's what I typically use for mine, I ended up making some hardwood runners for a crosscut sled, it works fantastic in the summer but in the winter, the runners swell and won't fit into the miter slots. I need to go grab some more UHMW stock and replace them, what I have on hand isn't long enough.

[Lornie McCullough]

Another vote for cold rolled steel..... bought a 20 foot piece locally, and now I never hesitate to make a custom jig for whatever.

Lornie

[Lee Schierer]

If your miter bar is too loose you can center punch dimples on one side to make it bigger. Start with small dimples until it starts to fit snug through out the length. If it is too snug it might be a good time to meet a friendly machinist.

The dimple method works, but tends to wear quickly. I purchased some UHMW tape that is a few thousandths of an inch thick and I apply a layer of that to the side of my miter bar and get a perfect friction free fit with no side play. The advantage is the entire length of the miter gauge bar gets slightly thicker, not just random spots. It lasts for years and is easily replaced if damaged.

[Justin Ludwig]

I make mine out of plywood. I rip,plane, and drum sand them to a perfect fit, then wax the bajezus out of them. Then I wax them some more.

[Joe Vogler]

Thanks for the tip. For the benefit of anyone interested, that would be the March 2015 Issue, #231.