Porter Cable dovetail jig help

[Brian Runau]

OK. I have the bit depth correct and making good joints, nice fit even sides, but my registration of the work piece left to right in the jig must be off. Setting up the4 tail board and milling it, I get pretty even ends. When I switch to the pin side of the jig it is cutting offset cause @ 1/6" offset when putting the two pieces together.

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Appreciate any help. Brian

[Ron Citerone]

I have only done half blind on my PC jig. Both pieces are cut at the same time. On those I never had that problem. (Had other issues🥵)
On the dovetails you are cutting are they done together or individually? I am thinking maybe the adjustable stop may not be square? Again, I have only done half blind so hopefully others can chime in.

[Brian Runau]

I have only done half blind on my PC jig. Both pieces are cut at the same time. On those I never had that problem. (Had other issues🥵)
On the dovetails you are cutting are they done together or individually? I am thinking maybe the adjustable stop may not be square? Again, I have only done half blind so hopefully others can chime in.

Stop was set with work piece flush and tight across bottom of the jig for through dovetails. One side does tails with 3/4" od bushing then lift and turn 180 degrees then put in pieces for cutting pins using 5/8" od bushing, Same stop etc..... . Brian

[glenn bradley]

I have had mixed success with the Leigh dovetail jig; mostly really good. I have just started making drawer parts a bit wider than finished width. I then rip them to actual width as required to make a perfect fit. Is this a cheat? Maybe . . . don't care :D

[Bill Dufour]

I never quite got mine perfect so I just make the boards a bit wider and joint off the extra after the dovetails get done. If they differ from side to side that just makes it look handmade.
BilL D.

[Brian Runau]

I have had mixed success with the Leigh dovetail jig; mostly really good. I have just started making drawer parts a bit wider than finished width. I then rip them to actual width as required to make a perfect fit. Is this a cheat? Maybe . . . don't care :D

I've done that going for perfection. I usually hand plane to clean up. Turning the jig around to do pins, the top has lateral movement since it only goes down on top of the backer board on top. This took a lot of it out. Brian

[jack duren]

I’m confused. You can’t get equal amounts on each side? I have an Omnijig, so I’m not sure if they adjust the. Same..

[Richard Coers]

It just takes time and patience to get the fixture set up. No magic, just plain ole test and adjust. Remember that some adjustments have to be half of what you think because you are taking a little stock off both parts. Once I got my Omnijig where I wanted it, it never got changed and the router became dedicated to that process. If you don't like tweaking, buy a Keller.

[Tim Greif]

I found out the hard way that one of the most common problems of alignment offset is caused by not having the dovetail bit perfectly centered in the router's guide bushing. I tried all sorts of fixes to no avail until I read about the issue in a tool review. See the link below for a review of the Porter Cable dovetail jig. Read all three pages of the review, especially the items discussing bit centerning in the guide bushings. That fixed all my alignment issues. Maybe your problem is different, but it's worth thinking about. Good luck.
http://www.thewoodshop.20m.com/pc4112.htm

[Richard Coers]

If you don't spin the router around and present the same side of the bushing to the finger assembly, centering the bit doesn't matter. But if you rotate the router every other cut, then it has to be centered, Absolute perfection is required on the drawer stock you put into those fixtures. That is the main reason they are fussy and the main reason I bought a Jet drum sander. The Keller I mentioned in an earlier post doesn't make you sit on a piece of drawer stock, so it doesn't need as well prepared stock.

[Ron Citerone]

If you don't spin the router around and present the same side of the bushing to the finger assembly, centering the bit doesn't matter. But if you rotate the router every other cut, then it has to be centered, Absolute perfection is required on the drawer stock you put into those fixtures. That is the main reason they are fussy and the main reason I bought a Jet drum sander. The Keller I mentioned in an earlier post doesn't make you sit on a piece of drawer stock, so it doesn't need as well prepared stock.

Rich, everything you said makes sense to me. I’ve only made 3 sets of drawers with my PC. (Half blind) with ok, but not great results. I decided next time I am going to make sure the drawer stock is perfect. I suspect my problems lie with the wood prep.

[Myles Moran]

It's been a while since I've cut dovetails on mine, but I want to saw the big issue with alignment for through dovetails is making sure the same side of the joint is against the stop for each cut. That is to say when you assemble to joint, the edge of each piece that was against the stop block should be on the same side, not opposite. If you assemble the joint "backwards" is the alignment between the two pieces improved?

[jack duren]

#1… router plates are made with tolerances. I was having issues as each time I made a joint and checked, it was either loose or too tight. My Bosch center was off so much I couldn’t center the template. At first I didn’t pat attention to it. After I found out it was centered, I purchased a new route4 plate from Routerman and problem was solved..

#2… if you parts are offset, it needs to be fixed. It should be even on each end..If not you’ll get a twisted drawer..

[Lee Schierer]

I have the Rockler version of the Porter Cable dovetail jig. I had similar problems when making half blind dovetails. On my jig the offset stops are made of plastic and fairly flexible. Loosening and tightening the screws was difficult without removing the template and the clamp for the vertical piece. It took quite a bit of effort to get the left hand and right hand offset stops exactly the same while adjusting the cuts to center the pins and tails across the width of the board. If your stops (see circled portion of the photo) are plastic you may have the same issue.
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[Lee Schierer]

Brian, I was looking for something else when I ran across a little device that might solve your Porter Cable Dovetail jig problem. There is a Centering Jig for Porter Cable Dovetail Jig (4216) (https://www.etsy.com/listing/1578628075/centering-jig-for-porter-cable-dovetail)

[Ron Citerone]

Lee, I am confused here. You state your jig is a Rockler version but the pic says Porter Cable?

My porter cable jig has a metal piece there. It is formed not machined and precisely mad. I suspect the quality of that part adds to some of the issues I have on half blind dovetails.



I have the Rockler version of the Porter Cable dovetail jig. I had similar problems when making half blind dovetails. On my jig the offset stops are made of plastic and fairly flexible. Loosening and tightening the screws was difficult without removing the template and the clamp for the vertical piece. It took quite a bit of effort to get the left hand and right hand offset stops exactly the same while adjusting the cuts to center the pins and tails across the width of the board. If your stops (see circled portion of the photo) are plastic you may have the same issue.
515524

[Lee Schierer]

Lee, I am confused here. You state your jig is a Rockler version but the pic says Porter Cable?

My porter cable jig has a metal piece there. It is formed not machined and precisely mad. I suspect the quality of that part adds to some of the issues I have on half blind dovetails.

Yes my jig is a Rockler and it is the same design as the Porter Cable. I used Brian's photo instead of going to my shop and photographing mine. The side adjustment piece on the Rockler jig is plastic.

I also noted that the drawer pieces would slip if they were less than 3/4 the width of the jig due to uneven clamping pressure. I made two pieces of 1/2" poplar that I place under the clamping cam on the side opposite the piece being machined. I put a rare earth magnet in the block that goes under the vertical clamping bar so it doesn't fall off. Since doing that I've had no more slipping issues.