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Failed Miter Jig

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Blog entry by Jeremy Greiner posted 840 days ago 4374 reads 0 times favorited 7 comments Add to Favorites Watch

I’ve been having trouble with the 45 degree miters for my walnut veneered box, and I thought I had this very clever idea for a box miter jig on the table saw. It works the same principle as a picture frame type miter jig works. As long as your total angle is 90 degrees, the rest of the alignment isn’t as critical, so if you have a 44 degree and a 46 degree miter it will all work out in the end.

Here is a picture of the jig, the idea is the wood can sit on the left or right side (depending which part of the angle needed to be cut). I had thought I’d be able to just hold the wood onto the jig but I couldn’t get a good grip on it and that was before I even tried to make a cut.

I tried to figure out a clamping solution to clamp the work piece down, the only clamps that I had with a deep enough was a spring clamp. I was cutting through some 1/2’’ plywood test pieces when I heard the wood get caught into the blade, I immediately stopped the saw and stopped the jig.

I think the problem is that the sawblade, and gravity are pulling the piece into the blade, which causes it to pinch and could cause a huge kickback problem worse case scenereo, but it also negatively effects the mitered cuts, they are extremely inaccurate.

Unfortunatly the way it was built I can’t really get any good clamping pressure on the piece, it should be an easy fix, I can cut down the sides of the V to allow the clamp to reach the piece being cut, but in all true irony fashion. A few days before I finished the jig, I saw a tip about using a 45 degree chamfer bit to cut perfect miter corners for boxes and I just smacked my forehead and said well duh! .. (it was either in woodsmith magazine, shop notes, or one of the woodworking tv shows I don’t remember).

I finished the jig anyways, because I don’t have a chamfer bit large enough to handle a 1/2’’ miter and plus I had thought I created some brilliant jig (I was wrong).

I doubt I’ll be working to fix the jig, I haven’t thrown it away yet, who knows but it seems more likely I’m going to get a bigger chamfer bit and use my router table it seems to be a much better approach to the situation.

-jeremy

-- Easy to use end grain cutting board designer: http://www.1024studios.com/cuttingboard.html



7 comments so far

View FirehouseWoodworking's profile

FirehouseWoodworking

622 posts in 1868 days


#1 posted 840 days ago

Jeremy,

If you have some short F-clamps, you can cut or route a slot into each wing that the clamp would slip down into and then you can clamp short pieces with the F-clamp. Long pieces are no problem since you can use the F-clamp on the ends of the jig.

If you use a 45-degree bit to make the champhers, you’ll need to use a router table with a fence or you’ll never get a square miter.

Just a thought. Good luck.

Cheers!

-- Dave; Lansing, Kansas

View TopamaxSurvivor's profile

TopamaxSurvivor

14575 posts in 2271 days


#2 posted 840 days ago

That jig might work with a good sharp hand saw?

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View tsdahc's profile

tsdahc

75 posts in 946 days


#3 posted 839 days ago

if you can take the miter runners off and put them on 90 deg to what they are now you have yourself a spline jig. Im still struggling with miters corners as well, they are passible but not perfect. I picked up a digital angle guage so in conjuction with my osborne or maybe a cross cut sled Im hoping for improvements. Good luck and keep us posted on the jig if you get it working correctly. It would be interesting if one could make this jig work for both cutting the 45 walls and splines.

View Radu's profile

Radu

299 posts in 1638 days


#4 posted 839 days ago

Here is something that might work.

View Freakazoid's profile (online now)

Freakazoid

40 posts in 1373 days


#5 posted 839 days ago

You could probably use a rotated version of this spline jig:

http://lumberjocks.com/projects/59266

-- I can complicate anything

View oluf's profile

oluf

256 posts in 1634 days


#6 posted 839 days ago

I have struggled with box corner miters for years. I now am having excelent luck and making boxes with four perfect tight mitered corners. Top to bottem. they fit so well that I do not use clamps for glue up. I just run masking tape over the outside of the corners and fold the box up. I made a dedicated crosscut sled for miter cuts. It is made just like my regular crosscut sled, but I set my blade at 45 degrees when I made my cross cut through the sled. I use a Harbor Freight digital miter gauge ( $24.95) to set my saw at 45 degrees, Lay the stock flat in the sled and make my cuts while holding the stock down flat to the sled. I set stops on the sled and cut sides that are perfect matches. If you are carefull you can cut your miters so that three corners have the grain wrapped arround the corner. I plan to build one more sled dedicated to dados. I could do all these things with one sled if I could figure a good way of putting in removable blade slots.

-- Nils, So. Central MI. Wood is honest.Take the effort to understand what it has to tell you before you try to change it.

View Marcos's profile

Marcos

58 posts in 965 days


#7 posted 838 days ago

I would suggest you try to remove one half of that jig, so only the left half of the jig slides along your miter gauge and the piece hangs off the edge and into the saw blade. You can only miter one piece at a time, but it works really well. Use a toggle clamp to hold the piece down and nothing will get moved or pinched. Good luck!

-- Marcos, California

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