finger joint giving me grief

[fixit]

No, it is very simple. Here is the trick - The box joints for the curved area are made on the bases of small triangles. The triangle's bases are about 2" each. After assembly, the curve is sanded by removing the edges of the sections.

A bit more detail (AND/or even better - pictures ) would help the more dense of us to understand the procedure. I admit to being one of the more dense. I am still puzzled about this one.

[dusty]

Charlese and I disagree on the requirements for consistently cutting good fitting finger joints so I'll not debate the issue. However, here is an article that discusses the requirements and some pointers on the methods.

If that is not what you want, maybe [url=htthttp://www.youtube.com/watch?v=XEeWSepGqYIp://]this[/url] is more appealing.

[charlese]

The building or buying of box joint jigs is the only difference between Dusty's concerns and mine. Here is another article from Woodworkers Journal that discusses methods of making box joints with a table saw, and a router. It also discusses finger joints. http://www.woodworkersjournal.com/Main/Articles/Skill_Builder_Box_and_Finger_Joints_6989.aspx

For those of us requiring (liking) more elaborate jigs, the discussion featuring Nick Engler is for you! Myself being more of a "quickly adequate" jig maker and more of a "feely/fitter" type woodworker - the jig adjustments by tapping with a screwdriver or mallet is ore my style. Never understood the reasoning of taking more time to build a jig than doing the job. When making 1/4" box joints 14" long - believe me - the jig must be accurate. This can be done with a smaller pin and a few taps of a jig.

I'll agree, although never used one. an adjustable jig using a screw is more elaborate. The results of the two types has got to be accurate in order to give results on longer/wider joints.

Remember we are talking about adjustments of a hair's thickness. This small amount makes a wale of difference. Either type of jig must be adjustable to make longer/wider joints. The question is - Do you prefer to play with a screw or use a light tap.

[charlese]

A bit more detail (AND/or even better - pictures ) would help the more dense of us to understand the procedure. I admit to being one of the more dense. I am still puzzled about this one.

Oh! you're not dense! My previous explanation has left you with questions. Remember - it is a god thing to ask questions! Here's some more info:

First - I forgot to say the wood used was poplar and was 1/2" thick. As you can see the 1/4" box joints are actually 1/2" deep.

Another visual solution to the puzzle is to enlarge the above photo (post #4) by pressing "ctrl +" several times. From here you can see some sloped fingers on the side. This is where slats of the lid were joined. (to decrease photo size use "ctrl -" several times or "ctrl 0")

Here's more photos:

Here's the first piece of the lid - with straight joints and triangles.
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Here's that first piece closed.
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Here's the triangles and slats before assembly. Notice the piece on the top of the case. It couldn't fit until the pieces were sanded and fit. Together they had to equal a 90 degree curve.
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[dusty]

will be a combination of two or three other jigs I have seen demonstrated or advertised.

I haven't built one yet (except in Sketchup) but I am going to.

I am going to try to make it real simple so that I don't have to use more time building it than I do using it.

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No dimensions have been determined yet, mostly because hardware is yet to be selected or crafted.

As this project progresses, I'll attempt to add enough detail so that anyone interested can build one.

[eagleta2]

Hi Chuck. Your joints are impressive to say the least. I'm inspired to make mine look as flawless as yours!

Dusty, I'd love to have a copy of your detailed plans when you get them complete. That jig looks better than mine, for sure.

I did get the joints to work out, but frustration and testing let me down the path of screwing my project up. First, I accidentally used the pieces of wood I cut for the bottom of the box and for a floating shelf as practice pieces for setting up the jig and testing the fit of the finger joints. I should have kept the wood with the sides and the front and back pieces.

Also, I got a little carried away when I finally got the joints to work and I cut finger joints where they didn't belong. Oh well, its just wood

The first thing I did was to make a totally new jig. I am more comfortable working on the right side of the blade using the miter slot on the right side of the table...so I made my jig technically backwards from all others that are drawn up. The jig itself is 3/4 ply (4.5" x 15") sitting on top of a 2 3/4" wide piece of 1/4 polyethylene. The jig is held to the miter gauge with carriage bolts. Then I cut a dado through the entire jig. This is the slot where the fingers get cut. Then I removed the plastic shelf and cut a dado for the .375" x.500" oak pin that I used for the index pin. I glued the index pin in and replaced the plastic base and I was on my way.

After a test cut the first finger was way too tight on the index pin so I added a shim to my dado set until the finger dado slid over the pin smoothly. Once I had the correct sized dado established, I cut a series of fingers to test the fit. The joint was so tight it would not fit together. I measured the pins and they were way oversized compared to the width of the dado. So I loosened the quill and adjusted the quill closer to the index pin and tested again. It needed more adjustment and took a bit of fiddling around before the width of the pin was a few thousandths smaller than the width of the dado.

Once the pin was a few thousandths smaller than the dado, the joint meshed together perfectly. It would be nice to have a micro adjustable jig like the one dusty is working on. That way you could use a 32tpi screw in the micro adjust. 2 revolutions would move the fence 1/16 (.0625). 1 revolution would move the fence 1/32 (.03125). 1/2 revolution would adjust the fence by 1/64 (.0156), and a quarter turn would adjust it 1/128 (.0078).

This would be much easier than my method of moving the quill a little bit...then too much...and so on.

So, there ya have it... ina nutshell finger joints are not as easy as some make them look. I happen to like the way they look over the hundreds of other methods used to join two boards that are perpendicular, so I want to continue mastering this joint.

Thanks everyone for your help!

Merry Christmas,
Geo

[dusty]

I made just enough progress to now know that there is some redesign required. I need to resize some components to make this truly a Shopsmith Mark V Finger Joint Jig.

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If you have any ideas that you think should be incorporated, please speak up.

I gotta put a dado blade on the TS and change the insert.

I'll add no more to this thread. There shall be a new thread started, LATER, for the "Mark V Finger Joint Jig". Sorry for the highjack.

[eagleta2]

Please do start a new thread Dusty.

I don't consider this a hijack though. The whole point of this thread was that finger joints were giving me a whole lot of grief, and your jig will work to alleviate that.

If you haven't planned on it, I would like to have the micro adjust use 10-32 hardware so I can know how much each revolution would move the jig. Please provide enough clearance on the micro adjust to use large knobs for those of us that don't have good strong fingers. I think it would be good to use a winged knob instead of a round knob so you could easily see that it was turned 1/8 of a revolution for an adjustment of .004.

Thanks for your work on this
Geo

[jmoore65]

I've gotten a bit fixated on the question of how wide the index pin needs to be.

The two options discussed are 1) same width as box pins and 2) narrower than the box pins.

Is #2 sufficient to create good fitting box joints? Is #1 adding additional checks to ensure that the operator is holding stock tightly against the blade-side face of the index pin?

Are there other reasons why #1 beats #2 - or can it be considered an optional enhancement for those wanting additional support with stock placement?

Jim

[dusty]

It will be my objective to create an index pin that can be made to equal (repeat equal) the width of the desired dado. I believe that really good finger joints almost need to be tapped together while at the same time not need to be forced together.

You can push someone out of your way in a crowd but that does not work with finger joints.

In other words: the router bit or dado bit should equal the pin width, should equal the dado width, should equal the dado depth, should equal the material thickness.