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Nearly accurate miters at last!

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Nearly accurate miters at last!

#1

Nearly accurate miters at last!

Stephen Kirk in Quakertown PA


>After much swearing at the table saw, and even some harsh language for the LV LA Jack, I think I finally solved my 45 deg miter problem. I already had a workable shooting board for 90 deg cuts, but I couldn't seem to get anything to work right at 45 deg, and a donkey's ear is a bit tricky to build (at least I thought so on my first try). I finally did use the table saw to but a very accurate right triangle, doing a little shimming to get it perfect. Then, I fix that against the fence of my shooting (or chuteing) board with some double stick tape, such that the miter to trim lays on the ramp and presents the mitered face at 90 deg to the plane. I also added another block to up the fence height so I have something to hold the board against. A few passes with the plane, and they are pretty darn close.

One thing I'm still seeing, which puzzles me, is that when I assemble the joint, it's closed, and square, but I often have a slight gap running down the inside of the joint. For reference, I am putting 45 deg bevels on the sides of boxes (not miters like you'd use on a picture frame). It's not a big deal, but I can't figure out why it's happening.

Re: Nearly accurate miters at last!

#2

If I understand this correctly...

Scott Burr in Ben Lomond CA


>It sounds like your using a cambered blade to shoot your miters. My miter planes blade is sharpened flat across the blade.

Re: Nearly accurate miters at last!

#3

Dale Lenz

Re: Nearly accurate miters at last!

Dale Lenz


>I use a donkey's ear to shoot miters. The first time I did this I got the inside bevel as I believe you are referring to. The problems was I was shooting a correct 45* but I was not shooting straight across the miter. Check the width of your miter with a square, should be 90*

Hope this makes sense, that was one of my problems...Dale

Re: Nearly accurate miters at last!

#4

Re: Nearly accurate miters at last!

Stephen Kirk in Quakertown PA


>I think I see what you are saying. Most likely, my workpiece is not square against the fence, or on the ramp. So I'm getting an accurate 45 deg, but not a square 45.

Re: Nearly accurate miters at last!

#5

Dale Lenz

Re: Nearly accurate miters at last!

Dale Lenz


>Lets say you are mitering 3/4" x 3" miters for your box. The slightly >3/4" 45* miter is right on. But your 3" length miter might be out of square some what.

Hope this helps..Dale

Re: Nearly accurate miters at last!

#6

Re: Nearly accurate miters at last!

Stephen Kirk in Quakertown, PA


>I also noticed that after I sharpened my iron, I was just a fraction off on the miters again, which probably means a slight adjustment of the plane - it sure looks square, though. Little things can really make a difference.

Re: Nearly accurate miters at last!

#7

Errors are doubled

David Charlesworth


>Errors are doubled here.

If there is going to be a minute gap, the best place is the inside corner, as mitre tips are very slightly flexible, and might well close with good clamping pressure.

Godd clamping pressure is best done with glued on clamping blocks, windlasses or web clamps might bow the sides in length.

Minute adjustments of angle, can be made when shooting, by shimming the work with card or paper on the shooting board, in either plane.

David

Re: Nearly accurate miters at last!

#8

Re: Not just the angled...

paul womack


>For a mitred frame (or box in your case) to meet "true", not only must the angles be very close to 45 degrees, but the opposite side must be very near to the same length.

The length thing is just as important, which is why picture framing mitre saw have fancy length stops.

BugBear

Re: Nearly accurate miters at last!

#9

Re: Errors are doubled

Stephen Kirk in Quakertown PA


>Thanks David, that was going to be my next try. I'm glad this is not a rush project for me, so I can take the time to figure this technique out, and then hopefully have it down pat when I do need to work quickly.

Re: Nearly accurate miters at last!

#10

Re: Not just the angled...

Stephen Kirk in Quakertown PA


>Yeah, I've already realized that. I was getting good 45 miters, but yet still seeing some gaps. Then I started to compare the inside lengths of the adjacent sides, and sure enough, one was off a little. A few swipes bring it into nice alignment.

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