# Box Joint Newby...Need Advice



## TinmanCarving (Jul 6, 2015)

Hello, I went out into the shop this morning with the mission to throw together a box joint fixture to see how it all works. I built a crude version to make thin joints using my Ø7-1/4" x 2mm wide skill saw blade on my table saw.

As you can see from the pictures it actually worked...kinda. 

I don't like how my cheap blade does not cut a square bottom slot. I will have to source a purpose built blade I guess.

Also, I learned that if your spacing is off even a few thousands that the stack up on so many fingers will cause problems at assembly.

I think for now I am going to try to design another fixture that has a more stable means of offsetting.

You can also see I have problems getting the stock flush on the bottom. My saw cuts are all over the place. I was holding the stock by hand when I should have used a square and a clamp.

Please share any advice you have.

Rob


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## woodnthings (Jan 24, 2009)

*you need an adjustable jig*

The spacing is so critical, that a jig with a micro adjustment will work best:
http://www.table-saw-guide.com/box-joint-jig.html

A flat top tooth blade will give a better result than a standard construction blade. Maybe something like this:


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## woodchux (Jul 6, 2014)

You have learned with your first attempt at making finger joints precision is key! Well made equipment (jigs, fixtures, blades, bits) as well as lots of practice are IMO the difference between OK and great fit. Consider making less fingers to start, and if you have a router, straight bits can make great fingers too. Be safe.


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## epicfail48 (Mar 27, 2014)

Not bad for a first shot. Like others have mentioned, the fingers are a bit loose, but getting the spacing right is one of the most difficult things to do. I also agree with wood on the blade selection, a ripping blade will generally yield flatter bottoms than a crosscut blade, owing to the flat top. Personally, I use a combination blade with a flat raker tooth. Still get some bat-winging, but its much less that a crosscut blade, and I don't have to change blade for, well, anything


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## Zircon (Aug 1, 2009)

This screw advance box joint jig I made a while ago will do a good job of cutting narrow fingers. It uses a .10" thin kerf Diablo rip blade coupled with a 10 tpi Acme screw thread. I just made this bench. I didn't need a bench. Just wanted a project to use the jig. Lumber ash I think was a cast off counter top from a neighbor who was remodeling. Now I need to find someone who needs a bench to give it to.


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## Masterjer (Nov 6, 2012)

Check out William Ng on YouTube. He has an excellent video instruction on making a fast and very accurate box joint jig. I just made one and it works perfectly. He talks about how to ensure the fingers are .006" narrower than the cuts for a perfect fit.


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