couple of questions about the PC 4212 jig

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Forum topic by Divotdog posted 01-11-2010 05:44 PM 1485 views 0 times favorited 6 replies Add to Favorites Watch
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68 posts in 3409 days

01-11-2010 05:44 PM

Topic tags/keywords: porter cable 4212 jig dovetail

I did my LJ research on this one with good results so I had no problem with bit depth, etc. from previous forums. But I have a problem centering the workpiece – it looks centered but has to measured out every time. Is there aneasier way to get proper spacing? I am using 3 1/4, 4 1/4, etc. widths and now I think it may be best to use a wider board and then rip it.
This may be more of a router issue but my Rigid router is tearing out on the front side of the piece. I am using yellow pine to learn on and about 20k speed.

Thanks for any comments – Happy Monday!

-- David, Dallas,Tx - golf weather is warming up but it's cool in the shop.

6 replies so far

View CharlieM1958's profile


16274 posts in 4185 days

#1 posted 01-11-2010 07:53 PM

David, I haven’t used my 4212 in several months, so let me first say I am relying on my middle-aged memory (a dicey proposition).

As I recall, centering the workpiece is an eyeball procedure. Are you talking about keeping the pins and tails equidistant from the top and bottom? If you have to measure to know they aren’t perfectly centered, does it really matter? Maybe I am misunderstanding the problem.

As for the tearout, my only suggestion is to be sure your bit is sharp, and don’t force the cuts. Slow works better in my experience.

-- Charlie M. "Woodworking - patience = firewood"

View 8iowa's profile


1580 posts in 3728 days

#2 posted 01-11-2010 07:58 PM

Maybe this will help. It is a Shopnote’s magazine sponsored video on cutting dovetails with the PC dovetail jig.

-- "Heaven is North of the Bridge"

View Divotdog's profile


68 posts in 3409 days

#3 posted 01-11-2010 09:43 PM

Thanks guys. Charlie- the pin on one edge is wider than the pin on the opposite edge of the workpiece. In other words the piece is off center horizontally to start with. It’s only about 1/32 maybe a smidge more but it looks worse!
And so the space at the edge on the tails end also is off by the same amount.

-- David, Dallas,Tx - golf weather is warming up but it's cool in the shop.

View rpalm's profile


57 posts in 3347 days

#4 posted 01-11-2010 11:01 PM

Porter Cable has an advanced manual and other aids at this link for the 4200 series jigs.

-- Robert, I don't understand everything I know about this.

View northwoodsman's profile


242 posts in 3713 days

#5 posted 01-12-2010 04:48 PM

Always test on scrap wood first, then move on to the real thing. If you make sure the scraps are exactly the same width as the finished project components, you can make the neccessary adjustments ahead of time. It even happens occasionally on the Leigh jigs. A good sharp block plane can also quickly remedy the situation, and you have another good reason to justify having a good block plane (Veritas or LN).

-- NorthWoodsMan

View rwyoung's profile


409 posts in 3438 days

#6 posted 01-12-2010 07:37 PM

I found that with my 4212 and the stock bits from PC, if I first used a marking gauge to lightly score the work pieces I got much less tearout.

In fact, there are two benefits to using the gauge to score the work pieces. First you get less tearout and second, you can use the little ledge left by the gauge to help you set the bit depth. The edge of the carbide should just catch in the score line on your test piece.

As far as getting the pieces centered between fingers, just eyeball it. Remember that you need to set up both sides of the jig for width. And cut the matching portions of a joint on the same side of the jig. For example, if you mark the corners 1,2,3,4 then cut the odd corners on the left side of the jig and the even corners on the right (or vice versa, just make sure you keep track of inside vs. outside faces when loading the jig).

-- Don't sweat the petty things and don't pet the sweaty things.

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