# First attempt at finger joints



## Dvoigt (Dec 6, 2007)

So I today I gave it my first "real" attempt at finger joints with my Freud dado blade. I made up a little jig (to avoid buying one of the $100 ones) and gave it a go. I suppose it was ok for my first try but the joints were not very tight, and I was off alittle on one piece so the edges didn't line up. And I got alot of chip out, probably because I was using oak that was slightly less then 3/4"... maybe around 5/8" and I had initally tested on 3/4" stock. 

Any pointers on how to improve?

Thanks
D


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## Rob (Oct 31, 2006)

Does your jig have the ability to slide the indexing pin back and forth to the blade? This will allow for fine tuning of fit.
As far as tearout, you can either use a backerboard behind the stock or scribe a line at the top of the cut...this will cut the fibers before the saw blade hits them.


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## Dvoigt (Dec 6, 2007)

No adjustment, it is similar to this style: http://www.cabinetmaking.com/pages/fingerjig.htm and this one http://woodworking.about.com/od/woodworkingplansdesigns/ss/BoxJointJig.htm


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## breakfastchef (Jan 14, 2008)

I have to get onboard this thread as tearout using baltic birch plywood is totally annoying. I have tried three times to make a jig for box joints; twice for my router table and once for my table saw. This is really a difficult project.

I abandoned the router table concept as both a spiral upcut and a regular 1/2 bit cause tearout on the plywood face entering the bit. I tried to build a jig for the table saw using the kerf of my blade (around 1/16") and found the pins were not square. Dumb me, thinking that a normal sawblade would work. This was a much betterattempt at building a jig.

I am seriously considering a box joint jig from Rockler for my router table, but I am afraid that any bit I use will cause breakout on the face of any plywood stock I might choose to use.


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## johnv51 (Oct 27, 2008)

The only completely effective solution for plywood tearout on finger joints or dovetail joints is to sandwich the plywood between two pieces of wood or plywood.


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## Tony B (Jul 30, 2008)

*Finger Joint Jig*

This is an adjustable Box Joint Jig I made. It is important to have adjustability because the need arises for a different "tightness" in soft woods and hard woods. The main panel with the 'finger' on it is also removable and replacable to allow for different size finger joints. 
For 'newbe's', a finger joint and a box joint are one and the same.

Also keep in mind that when you make a jig, any jig, it must be precise and not something you just throw together. Accuracy is paramount. When I was new at woodworking, I just slapped a jig together and was always disappointed. Then someone showed me the light. It must be made with the care of a fine piece of furniture because that is what you will be building from it.

Also, ignore the table saw blade, I put the jig on the table saw just to demonstrate how it fits and just noticed the standard kerf saw blade. The jig is used with dado blades.


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## woodnthings (Jan 24, 2009)

*I need a little help here.*

:huh: I've never made finger joints, but am very interested, so here's my question: I've seen the box joints cut one piece at a time and one dado at a time...Why not stack all the pieces to be cut together, back them to prevent tear out and have at it, one dado at a time? I think the connecting , or adjoining sides would have to be staggered over 1/2 a joint or dado for this to work? BTW, Tony, what is the purpose of the front piece, on your jig? Is it for clamping? Does it just prevent the workpiece from getting away and into the saw? Can you explain to us beginners? Also, please explain the "adjusting" feature,and do you have to adjust for each dado? It would seem to me that the adjusting should be made by shimming the dado, rather than moving the workpiece. Can you explain for us beginners, please?:icon_smile: Bill


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## Tony B (Jul 30, 2008)

*Bill*

I will attempt to answer you questions in order. 
Here goes:
Q: I've seen the box joints cut one piece at a time and one dado at a time...Why not stack all the pieces to be cut together, back them to prevent tear out and have at it, one dado at a time? 
A: If you are working on small pieces they can be stacked a few at a time but it can be dangerous to yourself and to your work. The danger to yourself would be that you can lose control and the whole thing performs a kickback of sorts. Keep in mind that stacked dado cuts take out a big chunk of wood at a time. The danger to your workpiece is that while removing a big chunk of wood at a time, the slightest shift if your workpieces (a few thousandths of an inch) and they wont mate. I suppose you could use a clamp but vibration could work your clamp lose and spell disaster. To make one dado cut only takes a few seconds. If a board is 10 inches wide, I can make all the cuts for it in about 30 seconds. Flip it over to the other end and in another 30 seconds, the piece is finished. I have stacked 2 at a time when using thin pieces of 1/2" or less. Most often, I am using 3/4" stock and my pieces can be as long as 3 feet. 
Q: "what is the purpose of the front piece, on your jig?" 
A: The front piece just makes the whole assembly more stable. Without it, the cut down the middle might want to close, warp or shift.
Q: "please explain the "adjusting" feature,and do you have to adjust for each dado?"
A: Working with wood is not like working with machined steel. The same kind of precision is just not there. The dimensions of the wood and the jig are constantly changing with humidity and not necessarily in the same proportion. When making a box joint, you should always make a test piece. More often than not, the pieces will be either too loose or too tight. This becomes more noticable as the errors become compounded in a wider piece with more fingers. The problem comes from the spacing between the dado cuts and not from the width of the stacked blades. By slightly shifting to the right or left, you can usually get it perfect after just one or two tries. 

I hope this helps.
BTW, I don't know what you mean by "one dado" at a time. Can you explain and I will answer.


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## Tony B (Jul 30, 2008)

*Bill - More info*

Your statement..." Do you still use the spacer block to set the offset initially. " The answer is YES.

Using the spacer trick for the first cut will get you close to where you need to be. Rarely will you ever be ‘right on’ the first time. You only have to be off by less than 1/100th of an inch and the fingers won’t fit right. Close, but no cigar, unless you are very lucky. A half inch dado is a half in dado but again, you will not be adjusting the thickness of the blade or cut, you are adjusting the spaces between the cuts. Anyway, after the spacer trick, make two test pieces, then throw the spacer away. The pieces should fit together with just a little bit of pressure. If the pieces are too tight, slide the moving part of the jig in the direction away from the blade. If too loose, move the sliding part of the jig in the direction closer to the blade. The amount of adjustment will be very very slight. Then make another set of 2 test pieces. Fit them together again. Make another adjustment if necessary. If all fits OK, make sure the height of the blade is set so that at the joint, each piece barely protrudes. It will be easier to sand away the protruding fingers than it would be if you had to sand away the whole side to get everything flush. Once you get everything right, there will be no further adjustments.
Usually the thickness of the stock should help in determining the dado size to use and you are correct in your assumption. It is a matter of ‘what looks good’. 
It was mentioned previously about using a thin backer like ¼ in Luan or MDF or whatever you have laying around to prevent blowout. This is correct but I will omit references to it for simplicity in explaining the procedure. 
This is going to be much easier to do than to explain, so actually make a test piece as I describe what to do and it will become obvious. 
Step 1. Take your test piece lay it up against the jig backboard and slide it over until it touches the index pin on the jig. The index pin is the little ½” piece that sticks out of the jig. Turn on your saw and run it through the dado blade. Do not drag the jig backwards back over the spinning blade. Shut the saw off, remove your piece and it will look like Fig 1A.
Step 2. Take this piece and rotate it 180* from right to left and place it over the pin so that the edge of this piece is even with the saw blade slot and the bulk of it is over to the right of the jig. As in Fig. 2. Now take the other test piece and butt it against the original test piece so that the new test piece has it’s edge over the saw slot as in fig 2A. While holding both pieces, turn on the saw and run the jig through the blade again and the lower corner of the new test piece will be cut out by the blade as in fig 2B. Now put the original test piece off to the side for now. 
Step 3. Take the new test piece and slide it over until the dado cut is up against and over the index pin as in Fig. 3. Turn on saw and run it through the dado again and you will end up with something like fig. 3A
Step 4. Lift up the test piece and move it over to your right again and put the new slot over the index pin. Run it through the blade again and you will end up with something like Fig. 4. Keep doing this until you get to the end. More than likely the end will not be an even full cut but this don’t matter now. 
Step 5. This step is not necessary for your test piece but will be for the real one. Flip the board upside down and repeat all of the steps so that one end of the board looks exactly like the other end. See Fig 5. You will need two pieces like this for your box. Put these off to the side. 
Step 6. Get your original piece and place the slot you cut over the index pin with the short side to your right. Run this through the blade like in Step 4. And Step 5. After you make two pieces like this you will have all 4 pieces. 
This is basically the whole procedure. You only need 2 test pieces for fitting. You will soon figure out short cuts as you go. I am too lazy to detail them at this point in time. If I was in my shop and had my camera handy the photos would explain it faster and easier without all this typing. When I re-do this, I will put it in my photo album. I hope this helped you.
Offhand, I don’t know of any videos but I am sure there are plenty of them. Sorry I cant help you there.


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## woodnthings (Jan 24, 2009)

*Hey Tony..Great Post!*

If I can't understand this, I'm lookin for new hobby! Thanks, Bill:laughing:


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## Dvoigt (Dec 6, 2007)

well... i got a store bought box joint jig off ebay for $40. The guy said it was a Eagle America Miter Gauge Box Joint Jig, but it looks just like the one that Woodsmith sells... http://www.woodsmithstore.com/wsboxjointjig.html

He didn't have any instructions for it, and I would like to avoid spending $10 on the DVD from woodsmith. Any pointers?


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