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I need a little help...

1K views 7 replies 6 participants last post by  parkerdude 
#1 · (Edited by Moderator)
Hey Guys,

I could use a little help…

I have an original Incra jig, and when I try to make box joints, they come out too tight. I can put them together dry but if I apply glue there is no way that the joints go together wet.

How can I gain a little extra clearance, maybe an extra 1/64 or just a few thousandsths?

I actually broke / crushed a small box trying to clamp the joints closed.

Anyone have a solution?

Thanks,
 
#2 ·
If the joints are the size of the router bit, then try a new bit. Yours may be a little undersize.

If they fit dry, then you can try polyurethane glue. It'll act like a lubricant and the joints should go together easier. Don't use too much, or you'll have a mess to clean up. Epoxy will work too, but is much messier.
 
#3 ·
When I bought my incra I was told to buy router bits made for the incra. Many of the router bits brands sell sets of router bits for the incra. I bought mine from Woodline. Perhaps as Gerry said, changing the bit will solve your problem. pkennedy
 
#4 ·
Hey thanks Ger21, Cheifk, DaveR, I had to remember where my 1" micrometer was and you're right! My spiral 1/4" bit measured .245".

I guess I should have measured it first. I have a new / unused 1/4" straight flute bit that measures .252", I think that will work.
 
#5 ·
Water-based glues will swell the joints. You might try polyurethane glue instead. it will not cause swelling. Don't use too much though (maybe 1/2 as much as water-based) as it expands while drying and you probably don't want more clean-up work than necessary. It's great to have a really tight fit as long as you can get it together.
 
#7 ·
With an incra you can just dial the account for the difference in diameter with the micrometer dial. I used to do it all the time with mine. I had one about 12 years ago when I first saw them at a woodworking show. The guy doing the demo actually measured the dimension of a dovetail bit then preceded to make perfect fitting joints all thaks to the micrometer dial on the jig.
 
#8 ·
Ha ha Julian,

I guess my age is showing. I bought MY Incra jig around 1987, the only thing that you can turn is the locking knob.

The earlier posts regarding bit diameter seems to be the solution. I was trying to cut 1/4" joints with an undersized bit. I changed bits to one of proper size and re-cut the joints and they came out fine.

Thanks again fellas.

later,
 
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