finger joint giving me grief

[JPG]

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.

Sure hope the moisture content of the work pieces does not change between cutting and fitting, and, the glue likes tight(0 space) fits.

I totally agree 'in principal', but practically speaking . . .

Maybe my definition of 'equal' is more demanding?

I think a very small amount of pin 'smallness' is desirable(both jig and workpiece), but separation MUST be as close as possible.

BTW if the dado cut is 'wider than the pin', the the workpiece need be pressed against the side of the jig pin away from the blade to maintain spacing.

FWIW: A narrow jig pin can cause the spacing to creep shorter, and a wide dado can cause the spacing to creep longer. Hence the difference in the 'BTW' above.

Inconsistent handling of the pin/dado(router) deviations results in inconsistent spacing and the inevitable headaches that follow.

[charlese]

I'm trying to say the actual width of the pin (as long as the dados will fit over it) has no effect on the accuracy of box joints. The most important distances have to do with; 1) the setting of the pin in relation to the cutter and 2) constant workmanship technique while making the joints.

I can make 3/8" or even 1/2" box joints using the jig shown in my #4 post above. (it has a 1/4"- wide pin). The trick is to have the same distance between the blade and the closest side of the pin and always set all slots against the blade side of the pin. It is also necessary to have the pin at right angle to the jig to accommodate wider boards.

If, for some reason, it is impossible for a woodworker to constantly hold the workpiece against the pin then an exact fit of slot over pin is needed. If there is even a slight bit of slop over the pin, ill fitting joints will ensue. What I am saying is - if the pin is even slightly smaller than the slots, and no sideways pressure is used, the joints will not come out perfectly unless the woodworker is lucky.

How one gets the proper setting of the jig is done by various methods. I use a tapping.
The tapping method of adjustment was first learned by me from watching the "Router Workshop" on TV.
One tap equaling .001" can be just the proper amount of adjustment needed to fit the last fingers of a longer box joint. Trial(s) on scrap wood is needed to make the joint fit.

Some folks prefer an adjustment screw.
My problem with an adjustment screw is twofold 1) the time required to make the jig and 2) the variance (slop) between the threads and the nut of the mechanism. When setting up the jig the rotation of a 32TPI screw 1/8 turn may be too much to adjust the cumulative error of less than .004" Additionally any slop in the connection between bolt and nut can later result in an unforeseen error of width on longer box joints. Trials on scrap wood are needed here as well.

P.S. - After thought - If you have ever struggled to make a pin the exact width of a particular setting of a dado blade you will appreciate using a smaller pin width. The same thing is true when trying size a pin the exact same width as a router bit. All router bits do not retain the exact diameter as the designed size.

[dusty]

You guys that don't like to mess with this sorta stuff can just ignore it. I started the thread and I am going to finish it. You can always make good use of the ignore function. If you haven't messed with that enough to know how to use it, let me know and I'll post a tutorial.

I'm going to start making sawdust on this hopefully tomorrow. I've heard some noise about Christmas returns however so we'll have to wait and see.

[ATTACH]19687[/ATTACH]

[ATTACH]19688[/ATTACH]

[rcplaneguy]

Check this out. Starts the good stuff at 1 min 23 seconds in.
http://m.youtube.com/watch?v=bTd81dlRQiE&desktop_uri=%2Fwatch%3Fv%3DbTd81dlRQiE

And

http://m.youtube.com/watch?v=yLS7QjV3-WU

[rcplaneguy]

Another video of the ibox. I want one!

http://m.youtube.com/watch?v=1oP-FnHfo9o

[charlese]

Check this out. Starts the good stuff at 1 min 23 seconds in.
[url=http://m.youtube.com/watch?v=bTd81dlRQi ... Td81dlRQiE]http://m.youtube.com/watch?v=bTd81dlRQi ... Td81dlRQiE[

EXCELLENT VIDEO!!! See how easy it really is?? No need to do measuring - especially to the nearest thousanths inches - No measuring at all. All you need to do is use existing wood to set the proper distances.

NOTE! The dado blade he used in that video was "a little over 1/4"

Why do some think the only way to do woodworking is to MEASURE to the extreme? Tool manufacturers certainly take advantage of this trend.

[JPG]

EXCELLENT VIDEO!!! See how easy it really is?? No need to do measuring - especially to the nearest thousanths inches - No measuring at all. All you need to do is use existing wood to set the proper distances.

NOTE! The dado blade he used in that video was "a little over 1/4"

Why do some think the only way to do woodworking is to MEASURE to the extreme? Tool manufacturers certainly take advantage of this trend.

A detail left out was the pin/blade offset setup. He skipped over that quite effectively!;)

[charlese]

I think he mentioned it, but all he had to do was use a cutoff of his pin to fit between the pin and the blade.

[JPG]

I think he mentioned it, but all he had to do was use a cutoff of his pin to fit between the pin and the blade.

Yeah, he mentioned 'setting it up' with no 'details'. Since that is very critical, I think it deserved more attention!

Jig pin = = = dado width = = = Jig pin to blade offset determines 'tightness'/spacing! 'offset' = workpiece pin size and affects spacing.

Good suggestion re using jig pin cutoff to set offset! I learned something tonight! Thanks!!!!

[charlese]

Yep! We woodworkers too often fall back to our math teaching or non-woodworking skills/habits to do what can be done more easily by using common reasoning. We just can't help it:( .

It is often times harder on our paradigms to think easier - and that's just too bad;)

If we could just break our old (or more modern) thinking to use the methods used by our forefathers - before modern measuring devices - we would find woodworking easier and not so confounding with numbers.