Box Joint Jig

Rusty,
Using a plain straight bit will work, but you MUST have a back-up piece behind the cut or you WILL blow out some of your cuts. (usually the very last one in the most expensive piece of wood.....) A flush trim bit works a little better, since it has a bit of a slicing cut in stead of a "slapping" the wood as it comes in and out of the cut.

Ha? flush trim bit for box joints?
you can only use bottom bearing bit with a template provided the bearing is 5/8 and the router bit is 1/2. in an esence instead of using a 5/8 guide like a keller router bits which are all bottom bearing. flush trim bits have the same size router bit as the bearing.

Using a standard box joint jig using a Pattern bit (instead of a spiral) works better than using a standard box joint jig just using a straight bit. Sorry if I confused anyone by saying flush trim. My Oldham bits have a little rake, my el cheapo grizzly pattern bits do not.

Hi Doug, me and Bj though maybe we missed out on a box joint technique
I've always used a Super sharp Straight bit for box joints with no problem. but if they're slightly dull, then you may get some tear. it all depends on wood also. I've never used a spiral on box joints due to price. for a price of one spiral bit, I can get 3 new CMT straight bits ( on sale)

18243015 said:

I am planning to build a box joint jig to be used on my router table. I usually see these used with a solid carbide spiral bit. I've never owned one. Is it practicle to use a standard straight bit? What is the advantage of the spiral bit?

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Hi highly recommend the Oak Park spacer jigs that they use on the Router Workshop...

http://us.oak-park.com/catalogue.html?list=boxj--

There is a Discount code to get 10% more off sale prices... super good deal on the set of three...

I just got the set not too long ago... they work great and SIMPLE!!

Thanks for the replies. When I joined this forum I read that the "only dumd question is the one not asked". So here goes...The jig I'm planning to build will be on top of my router table with the bit sticking up thru the table(simular to the oak-park spacer fence). Do I want upcut or downcut bits for this?

I believe that Oak Park sells only "upcut" spiral cutters. I have the box joint jigs with the 1/4, 3/8 & 1/2 cutters, all are upcut. I have no problems with them.

Rusty, the key to understanding up cut and down cut is this: do you want to pull the waste away from the cut? Most of the time the answer is yes. Table mounting means the direction is reversed but still pulling the waste away from your cut. This is why the up cut is the most popular of the two choices. The down cut bit pushes the waste into the cut. This is used to help prevent tear out on the top surface. A good example would be on veneered plywood to keep the veneer from pulling away from the ply. So up cut means away from the closest wood surface to the router and down is towards that surface.

18243015 said:

Thanks for the replies. When I joined this forum I read that the "only dumd question is the one not asked". So here goes...The jig I'm planning to build will be on top of my router table with the bit sticking up thru the table(simular to the oak-park spacer fence). Do I want upcut or downcut bits for this?

Click to expand...

Upcut moves the chips up toward the router... (what you want for the box joint jigs)

Downcut moves the chips away from the router...

IMHO

Just take no notice of the arrows, you can view them either way.