22.5 degree cut

[Steven Wallace]

I need some help. I am starting to build shadow boxes for burial flags that have the tradition triangular fold for an American Flag. The top of the triangle is a 90 deg joint made up of 2-45deg cuts. However at the base they are 45deg joints with 22.5 deg cuts. Can any of you suggest how to set this up on a miter saw that does not have a 22.5 setting. I am probably way over thinking this issue. I am also wondering what would be the way to join these pieces together for the cleanest finished look. Steve

[Lance Norris]

Steve... they arent 22.5, they are actually 67.5 if I remember correctly. Miter saws wont have or be able to cut an angle this severe. There are at least 2 ways to cut this angle. Miter gauge on your table saw, set to 22.5(all after market miter gauges have this setting, factory miter gauges may not) or you can use the head of a combination square held against the fence of your miter saw(to give you 45 degrees) and the blade set to 22.5 degrees to give you 67.5 degrees(I know you said you dont have 22.5, but you can experiment with scrap until you get it right).

[Ken Higginbotham]

I think if you cut a 45 out of say 2x material, then place it on the saw as the guide and position your 22.5 cut pc on the 45 cut you should get it. Hope that made sense. If not I'll dabble up a sketch...

Eidt: Do you have a table saw?

[Jeff Wille]

I agree with Ken. You'll basically have to build out the fence of the saw to get that extreme angle (67.5 is correct). The table saw is a good option too - miter guage or tapering jig.

As for joining them together... Id cut the angles a tad shy so that the 3 corners contact tightly. Then, Id use glue, ratchet straps, and brad nails.

Jeff Wille

[M Toupin]

While you can get away with jut using 45deg miters and leaving the bottom piece flat, I like the look of the 22.5deg miter. I use a tenoning jig on the TS. Hold the piece edge and tilt the fence on the jig back.

I've made many like this. It works very well, but does take a bit of setup the first time to get it right. Be sure to use a backing strip on the back side. The very fine edge will blow out every time if you don't.

Mike

[Ken Higginbotham]

If you have a table saw I was thinking something like this:



Heck, I suppose you could rig this type jig on a miter saw - ?

[Casey Carr]

Isn't 67.5 degrees the same thing as 22.5? Just depends on what corner you're looking at. Add up all angles of a triangle and you get 180, so 90 for the corner, 22.5 for another corner and 67.5 for the last. So, it really depends on what side you're measuring from. But the tip will be 22.5. That is if you put a protractor on the part cetered at the tip, the hypotenuse side of the triangle will be 22.5. Just didn't want Mr. Wallace confused on that.

I'm thinking the bigger problem is that a miter saw won't make a 22.5 cut along the length. Instead of referencing the side of the wood against the miter fence, turn it 90 degrees and reference the end of the stick off the miter fence.

One way I can think of getting this accomplished is with a sliding bevel. Set the bevel to the angle you need and reference your miter saw off it.

[Kendall Stokke]

i think if you build a jig to use on one side of your blade and set it up for a 45 degree slope and then tilt your blade to 22.5 and you should get it accomplished.


kendall

[Lance Norris]

Instead of referencing the side of the wood against the miter fence, turn it 90 degrees and reference the end of the stick off the miter fence.

Thats a good way to cut your hand off

[Jeff Wille]

Thats a good way to cut your hand off

Exactly, you'd be cutting off the edge that is against the fence. This would cause the board to be pulled into the blade and your hand with it.

You really do need to push the long edge against a fence/jig - either tablesaw or mitersaw. The tablesaw sled is a great idea. Just make one for the 45's and one for the 22.5/67.5's.

Jeff Wille

[Casey Carr]

Thats a good way to cut your hand off

Depending on how long the piece is, I could see it happening. If it's long enough though, and with some type of hold-down, I don't think I would rule it out. I do agree that the tablesaw setup is much better for it though.

[Chris Padilla]

The miter box could work fine with extra set-up, hold-down, and much care. I've done it before. You need to make a fence 90* to the current fence and then fiddle with hold-downs (double stick tape can help) and such. Be sure to do some practice cuts first so you see how things are going to react.

For the table saw, some miter gauges go beyond 45* (my Incra one goes 0-90, both swings) so that is likely to be my choice for cutting such an acute angle.

[David Christopher]

Isn't 67.5 degrees the same thing as 22.5? Just depends on what corner you're looking at. Add up all angles of a triangle and you get 180, so 90 for the corner, 22.5 for another corner and 67.5 for the last. So, it really depends on what side you're measuring from. But the tip will be 22.5. That is if you put a protractor on the part cetered at the tip, the hypotenuse side of the triangle will be 22.5. Just didn't want Mr. Wallace confused on that.

I'm thinking the bigger problem is that a miter saw won't make a 22.5 cut along the length. Instead of referencing the side of the wood against the miter fence, turn it 90 degrees and reference the end of the stick off the miter fence.

One way I can think of getting this accomplished is with a sliding bevel. Set the bevel to the angle you need and reference your miter saw off it.

Yes it is the same...if your miter saw moves but dont have a setting at 22.5 you can use a miter gauge or wixley to set it then lock it down and cut

[Jack Porter]

I've made a few of these and like to use a tenoning jig on the TS to cut the 22.5 deg bottom corners of the case. The other option is to cut the bottom corners at 45 deg, you'll have more of a butt joint than an true miter joint. Just remember, if you go this route you'll want to cut any inside corner details after you assemble the sides and bottom.

Reinforce with biscuits or splines.

I've attached an example of both types of joints.

[David DeCristoforo]

These are difficult to make because there are few tools with enough "swing" or "tilt". My preferred method involves making an approximate cut on the band saw. Then the cut is trued up using a disk sander with a guide fence. My "disk sander" is a wood disk mounted to the faceplate of my lathe with a shop made "table" clamped to the lathe bed. The "fence" is a simple guide block screwed or clamped to the "table". It's easy, very accurate and very safe.

PS You can also attach a "fence" to a stationary belt sander if you have one....