Need Help Cutting 22.5 Deg Angle (for Flag Display Case)

[Lee Schierer]

Here's another solution. Build your flag case like this one.
flagcase2.jpg
Your angles to the base are 45 degrees. I cut a groove in the base for the glass using a router table with a 1/8" diameter bit. I set the fence so the groove is where I want it on the base to align with the grooves in the two top pieces and set stops so that the groove is the correct length without coming out past the edges of the two top pieces. I can lower the base down onto the moving router bit. I use feather boards to insure the base stays tight to the fence. Screws up through the base hold the top in place and allow glass replacement if ever needed.

[Mike Trent]

...I can't use the blade tilt to get the 22.5 deg.

I'm currently making a case for Dad's flag, and it's been a pretty steep learning curve for this relative newbie. Below is what has worked for me.

First: YouTube is your friend. Search on “flag case,” and you’ll find more than a few videos of flag case construction. Specifically, search for a show called Rough Cut (believe this airs or aired on PBS), and watch RC105 Flagbox. He shows how to cut the angles using a shop-made jig. I copied his design, and it has worked well (and no need to spring for a tenoning jig).

The jist is that the 22.5’s must be cut while the board is standing on end, and the board must be 90* to the table. I use a digital angle finder and shim the workpiece as necessary with post-it notes or paper scraps.

Once the workpiece is perpendicular to the table saw, tilt the blade to 67.5* (90* - 67.5* = 22.5*). Use a relative-angle gauge (red thing in pic below) to ensure that the blade is tilted to exactly 67.5*

Some fine folks have made cases for fallen heroes; I’m using their design with some mods:

http://www.diablowoodworkers.com/flagcases.html

I’m glad to be able to reply to a question here, for once; I’ve lurked for a long time, and most questions posed are best left to others! DM me if you have any questions about this process.
AngleJig.jpg

[Mike Cutler]

Clark


You've been given a lot of good alternatives here, but one think I'm not understanding is how thick is the material?
Your Rockler jig is a clone of the Delta 181-183 series tenon jigs.
If it is a faithful clone, turn it over and you may find two threaded holes on the opposite side of the base from the current miter bar. The entire jig can be "flipped" to work in the right miter slot. You may have to attach a sacrificial spacer to make up the distance from the miter slot to the blade. (Usually miter slots are not equidistant from the blade) I use MDF. It's a good idea to always have a sacrificial face on that jig anyway. You will only ever once let the blade hit that jig doing a bevel cut. BTDT. Se if your jig can be swapped.

One thing about that jig. You may find that you have a very slight "slop" of the miter bar in the miter slot. According to Delta that was a designed feature. The material was supposed to go through the blade twice, with the final pass taking off the few thousandth's for a nice smooth tenon.
I say baloney. I use a page from a cheap magazine to tighten up that "engineered" gap.

A second thing to look for with the jig is that the material is not passing through the blade at an angle. In other words, the face of the jig is parallel to the face of the blade. Don't assume that just because your miter slot is parallel to the blade, the face of the jig is.

With what you're trying to accomplish, any deviation from a straight parallel pass is going to give you fits. The jig has to be tuned, and they don't really provide a mechanism. It takes a dial indicator and shims to accomplish this.

It's a nice jig ,truly it is, but you need to take a morning or afternoon to get it tuned up for your saw. I would also advise that the beveled angle be controlled with the blade and the tenon jig set to 90 degrees. Your blade tilt mechanism is much more robust than the flimsy tilt lock on the tenon jig.

I have a Delta 183 Tenon jig that I use a lot, but at one time I was ready to throw it in a scrap metal dumpster until I realized that I had to tune it up to work properly. Now I wouldn't want to be without it.

[Jim Becker]

For this, I would construct a dedicated sled to cut the angles safely and provide support right to the ends to eliminate tear-out.

[Lee Schierer]

There are absolutely no adjustments on the guide bar that rides int he miter slot, and there is a LOT of slop in mine.

You can buy self adhesive UHMW polyethylene tape in various thicknesses. I have eliminated the "slop" on several miter gauge bars by sticking a strip of this tape on the side of the miter bar and trimming it to fit. It not only removes the slop, but makes it slide more smoothly in the miter slot. A big plus for this method is that the tape lasts for a long time as compared to putting dimples in the side of the miter bar.

[Jim Morgan]

For this, I would construct a dedicated sled to cut the angles safely and provide support right to the ends to eliminate tear-out.

In the jig that I described above (#13), the vertical cleat serves as a backer preventing tear-out.

[Clark Harbaugh]

Thanks, guys. I think the shop made jig to run on my fence is what I'll try.