# Parts offset when using dovetail jig



## fishcad (Apr 15, 2012)

I'm new to dovetails and am using a Porter-Cable 4210 jig. I've done a few half-blind dovetails and am now working on a project with through dovetails. I've got a pretty nice fit by moving the pins template forward about an 1/8". The fit is good but the two parts do not line up. The two parts are about 1/8" off (see photo). The two end pins are equal but the tails are not centered. I'm thinking about moving the offset guide 1/8" left and placing an 1/8" shim between the offset guide and the board when cutting the tails. This will keep the tails board in the same place. I would then leave the shim out when cutting the pins which would "pull" the pins board in line. This may be a kluge and I'm certainly open to better ideas.


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## neville9999 (Jul 22, 2010)

Your jig needs to be adjusted, its just set up wrong. N


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## 4042 (Sep 30, 2004)

I agree, should not have to use any shims. Re-check setup


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## Gerry Kiernan (Jul 19, 2007)

If this problem continues to plague you you can also cut the boards a bit wider than needed, and trim after assembly.


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## DonkeyHody (Jan 22, 2015)

Are you using two different routers for the two bits? If so, the problem could be a difference in the centering or outside diameter of the bushings. I had the same problem and solved it by moving one bushing off-center (if it's as bad as yours, you might have to move both bushings in opposite directions.


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## Nickp (Dec 4, 2012)

From your description you are cutting the ends one board at a time...

That being the case I would freehand center the board first in the center of one of the template fingers and the second board centered on the gap between the template fingers. This will ensure both pieces are centered but offset accordingly.

Are you aligning the board to the left edge...? try the above instead...no shimming necessary...

Are you using a bushing or bearing guided bit...?


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## greenacres2 (Dec 23, 2011)

I've been using the Incra to cut dovetails for a few years, but still can't part with my PC jig, and would return to it except for the board centering. For all the good things about the PC 42xx dovetail jig, the need to center the workpiece in the curved end of the fingers is difficult. I've wondered why they don't manufacture that into the templates, but as i read this thread i'm wondering why i never made a few indexing marks in my templates. Is this a crazy idea, or might it work? 

earl


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## Nickp (Dec 4, 2012)

greenacres2 said:


> I've been using the Incra to cut dovetails for a few years, but still can't part with my PC jig, and would return to it except for the board centering. For all the good things about the PC 42xx dovetail jig, the need to center the workpiece in the curved end of the fingers is difficult. I've wondered why they don't manufacture that into the templates, but as i read this thread i'm wondering why i never made a few indexing marks in my templates. Is this a crazy idea, or might it work?
> 
> earl


Great idea...you could also use a small square for additional visibility...


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## fishcad (Apr 15, 2012)

Thanks for the responses, but a couple say I have not set it up correctly. Can you elaborate? When I cut the tails (mislabeled in my photo) I centered the board on the template fingers and the tails are centered on the board. (Actually surprised I got it on the first try.) I then set the offset guide against the tails board according to the instructions and aligned the pins board against the offset guide. Seems that if the tails are centered the pins should be centered. I'm using the router bits and collars that came with the dovetail jig.


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## 4DThinker (Feb 16, 2014)

It is possible your bit isn't centered in the bushing when mounted on the router? That was my problem when using my PC dovetail jig the first time. Had to get me a bit centering cone to be sure I had the bit centered in the bushing before the problem went away.


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## fishcad (Apr 15, 2012)

Turns out the problem is that there is some play where the template mounts to the studs on the front of the jig. For the tails I pushed the template all the way to the left. For the pins I tried pushing it all the way to the right and was pretty close. I moved the template slightly left and got everything lined up. I had to move the template forward quite a bit (pins line in front of where the boards meet) to get a nice, tight fit.


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## fishcad (Apr 15, 2012)

I suppose a real woodworker would have cut the pins by hand but I'm just a guy who makes things. I can't make consistent, uniform cuts by hand. Hence the kluge with one of my rolling bins.


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## greenacres2 (Dec 23, 2011)

Cool solution Donn!! i'm guessing the cuts in that picture are about 60" above the floor??

earl


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## fishcad (Apr 15, 2012)

Yep. The boards are 5' long.


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