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

[Clark Harbaugh]

I need to cut the 22.5 deg miters for the bottom side of a flag display case. I've searched forums and see where many say to use a tenon jig, so I ran out and bought one at Rockler but am still stumped. The jig runs in the left miter slot, and the blade tilts to the left, so I can't use the blade tilt to get the 22.5 deg. The bevel adjustment on the tenon jig is only 20 deg. I'm guessing I'm in a proverbial 'forest for the trees' scenario and it's probably something simple I'm missing. Any help would be appreciated.

[Bill Adamsen]

Rip cut or crosscut? What machine (assuming TS)?

[Clark Harbaugh]

Crosscut on a TS is what I'm attempting. I looked at possibly using my miter saw, but my thought would be at that angle, even if I built an auxiliary fence, I would be worried about the wood being 'pulled' into the blade.

Right now the only thing I see is to get a reamer bit and extend the curved slot on the bevel adjustment plate to allow for it to tilt further.

On a side note, for anyone wanting a review of the Rockler "Heavy Duty Tenon Jig" - it has one huge flaw. There are absolutely no adjustments on the guide bar that rides int he miter slot, and there is a LOT of slop in mine. I had to take one off an extra miter gauge I had and modify it to fit the tenon jig. More than a little disappointing.

[Bill Adamsen]

Compound miter? Which way is the crosscut? Either way I'd be inclined to do it on the miter chopsaw with a good blade. You'll likely need an auxiliary fence to set a stop for the lengths. Get some scrap wood and cut enough (typically eight with 22-1/2°) equal length pieces to see if your miter is set correctly.

[Matt Day]

TS and miter gauge with the blade tilted to 22.5? What am I missing?

[Bill Dindner]

If you flip the workpiece upside down won't you get your desired angle?

[Clark Harbaugh]

To do that, the piece would be laying flat on the table, so the blade would have to be set at 67.5 from vertical (22.5 off the table), which isn't possible. Blade at 22.5 with a tenon jig would work and was my intent, but my blade tilts left - into the tenon jig.


TS and miter gauge with the blade tilted to 22.5? What am I missing?

[Clark Harbaugh]

Just to provide clarity, here is a sketch of what I'm basically building. I'm in need of cutting the miters for the bottom two corners of the triangle. The total angle is 45, making my cuts at 22.5. Miter gauge and TS would work with my piece on the edge, but unfortunately my blade height is not sufficient for the pieces I'm cutting. An aux fence on the miter saw is a consideration, but again my concern is a) getting an aux fence built that is tapered at exactly 22.5 deg, and b) the safety factor of a very steep angle in relation to the blade. Just afraid of the piece being 'pulled' into blade.

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[Marc Jeske]

I would think - Use power miter box.. w a jig based on link below.. clamp work if "pulling" is a concern, or contact cement medium sandpaper to avoid workpiece sliding. Marc

http://www.woodworkingtalk.com/attachments/f27/8496d1239658889-angles-setting-miter-saw-100_0991.jpg

[Bill Dufour]

Any reason you can not use the jig backwards since your saw is backwards? I have a delta tenoning jig and I moved the miter slot bar over to one side by about two inches? I think this was to let me angle cut 2x stock or maybe it was to get it closer to the blade for thin stock.
I did this when my saw was a old delta contractor saw with tilt table not a tilting blade. I know my crosscut sled did not line up when I switched to a unisaw.
Bill

[Marc Jeske]

TS and miter gauge with the blade tilted to 22.5? What am I missing?

I have way less experience than the average here, but how do you do the above?

Blade only goes to 45 max... unless you mean the workpiece is run through saw vertically oriented, as in a tenon jig (Not a miter gauge) w blade at 22 1/2 off of vertical ?
Marc

[Matt Day]

To do that, the piece would be laying flat on the table, so the blade would have to be set at 67.5 from vertical (22.5 off the table), which isn't possible. Blade at 22.5 with a tenon jig would work and was my intent, but my blade tilts left - into the tenon jig.

That’s what in was missing! Lol, didn’t think it through. I’d probably use my RAS.

[Jim Morgan]

I made a high fence/tenoning jig that runs along my Bies fence. An outrigger straddles the fence so the jig cannot move laterally. A little blue tape on the back adjusts it to be perfectly vertical. It has a vertical cleat to keep the workpiece square to the table front-to-back and a couple of toggle clamps to secure the workpiece. Tilt the blade to 22.5, adjust your fence, and you've got the cut. The jig is made from mdf or the like so it doesn't matter if the blade cuts into it a bit.

[Marc Jeske]

Yup, Just like James sed .... Images here, and other similar ideas. Marc

https://www.google.com/search?q=diy+tenon+jig&source=lnms&tbm=isch&sa=X&ved=0ahUKEwji58n8o-LWAhUJYiYKHSUqA7wQ_AUIDCgD&biw=1229&bih=608

[Marc Jeske]

If this is a one time project, and you don't have a toggle clamp, configure yer jig to use a c clamp or two. Marc

[Lee Schierer]

Here's another solution. Build your flag case like this one.
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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.
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[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.