Need advice from dovetail artisans on my new Leigh D4R jig - troubleshooting...

[Sean Rainaldi]

Hi,

I have a couple of questions for any of you experienced Leigh dovetail jig artists. I have attached a pic of my test joint, this is my fifth test half blind joint.

I’m excited about starting to build my kitchen drawers but need to iron out a few bugs before I start plugging along…I think I have a couple of issues going on here, I’m trying to sort them out to determine how to proceed with my next batch of test joints.

My first question, with the Leigh split finger design, it seems when I set up the pattern and slide the fingers together, I am concerned about them not meeting each other flush – there always seems to be a small gap between the fingers – tail side, not much - maybe .005 to .010” max, after I tighten them down. I am also never sure if they are lined up perfectly square to the support rods. I was wondering if anyone has off alignment issues (not square to the rods), or not meeting perfectly flush with each other (the fingers). Can this cause the pins and tails to be slightly offset? Can this cause tails to be slightly wider than their sockets (or vice versa), such that the pins and tails would not line up and the edges of the boards are not line up flush – as in the above photo? Or cause too tight or loose of a fit? If so, what do you guys do to mitigate the problem?

I can pinch the figers together but it does not seem to force the gap closed as I tighten them down...

As you can see, one of the joints seems OK and the other two are off, and strangely there are gaps on one side of two of the tails and not the other…

Secondly I have a cupping problem with my boards. When I milled the boards last week they were near perfectly flat as I could get them – no cups or bows, and they have been sitting in my shop for a week now – I just checked them this evening and now some of them have started to cup and bow, most likely due to the temperature changes in a harsh Michigan winter. I spoke with the good folks at Leigh a few days ago and they said that cupping will definitely cause gap problems. I have a small furnace in my garage and overnight it gets down into single digits and during the afternoon I can get it to 50 degrees or higher.

Is there anything I can do to mitigate the cupping and make the boards useable for drawers? Or are they now scrap? I have cut and milled 20 of them for 5 drawers.

Third, can the weight of the router on the support rods – fingers cause the finger array to slightly bow down such that my bit depth changes in the router along the joint? I made sure that all the fingers are flush and fully resting on my boards before I made any cuts.

I think the off joints are most likely a combination of things – what suggestions would any of you dovetail artisans have for my situation?

Thanks for any advice.

PS - I'd like to add that although I have the above described cupping problem with week old boards, the joint in the below pic was made out of two freshly milled boards that were near perfectly flat, no cups or bows, and I milled the doves right after the boards were planed.

[Joe Scharle]

http://www.thewoodshop.20m.com/leigh2.htm

To add to what's on this page, I had a finger pivot slightly, although I didn't know it at the time, as the router ran over it giving me the gap like you show beside one of the pins. While checking the guides 'something' popped out from the suspect finger. Never happened again.

[Joe Chritz]

Sometimes they seem to show up for no reason at all. I have had fingers come loose (my bad) the boards rock (my bad) the boards slide because they weren't tight enough (my bad) but never a problem with the jig itself.

Flat, square stock, don't hog to much material on the cuts, climb passes where needed and try to keep the router in the same orientation and flat at all times. I wax the base and jib top before each project.

Also I now tend to use dado's for the backs of the drawers so I leave the sides long and can "fix" a problem on two of the three boards if needed.

You picture looks like the opposite sides aren't flat on the stock (put a piece of stock under both guide sides and tighten, I leave the stock in the opposite side) or the board was either out of square that much or was crooked in the jig.

Joe

[Tony Joyce]

All these concerns are addressed in the very well written manual that is included, Plus many tips are on the included DVD. I carefully read the manual and watched the DVD that came with my Super Jig and got perfect joints first time out.

Also stick the drawer parts(8'-10" apart & directly over each other) and they may flatten themselves out.

Tony Joyce

[Brian Kincaid]

Sean,
I'll give some advice based on my D4 (not R).
1) When tightening the finger guides make sure the Pin/Tail board is not tightened to the jig. This will allow the finger to center on the rails properly.

2) Since you aren't using the whole capacity of the jig, make sure you have some fingers spaced through the 'unused' part of the jig to keep the rails aligned and square to the jig.

3) When you lock in your pin/tail board make sure the Guide registers completely across the board. If there is a bow you will need to loosen the jig height adjuster (two black knobs) and the depth adjuster (two brass screws), press the guide down on the board, tighten the jig height adjuster, tighten the dept adjuster.

4) You will also want to use a spacer board the same thickness as your workpiece to help keep the finger guides level in the unused portion of the jig.

Really hope this helps. The D4/D4R are really good jigs.

Brian

[John Gornall]

Keep the fingers and bushing clean and waxed. Also wax the router base plate. It makes a big difference having the router move smoothly - less sudden cut throughs and chipping.

[Greg Sznajdruk]

You have a significant temperature swing try bring your parts into your house overnight. Bring your shop up to temp and go get your boards.

Greg

[Sean Rainaldi]

Thanks for all the helpful advice above guys - I'll follow it.

Do you think a very light spray of T-9 would be a good wax for the fingers and router base?

[Charles Lent]

Not sure about T-9 as I have never used it.

I like Johnson's paste wax. I use it on my D4R, my FMT, and the tops of all of my other woodshop machines. I also lubricate the gears and trunions in my Unisaw with it.

Charley

[John Gornall]

+1 for the Johnson's paste wax - a can with a rag in it is always nearby in my shop.

I'm old school - I'm into lubrication as I like my tools to work smoothly. Always amazes me how few people even have an oilcan any more. Try cleaning and oiling the screws on your clamps - you next glue up will be better.

[Kevin Barnett]

MY guess is the bit is not perfectly centered in the base and you are rotating the router as you proceed from the first to the last dovetail. Since the gap seems to be progressively larger, this would account for that. Also, make sure your bushing is not moving as you apply force.

I have this happen to me quite a bit. I haven't totally figured out the reason though.

[David Moody]

The bushings that come with the Omnijig have O-rings you can put on to secure them in the router. I once was lazy and didn't put the O-rings on and noticed that the bushing was loose after a run of cuts. Have always used them since then.

I would highly recommend something like that for any bushings (I use them now anytime I am using a bushing for other cuts, as well). They secure the bushing from loosening and are pretty easy to disengage when you need to take the bushing off.

[martin baker]

Hi, I came across this thread searching to find an answer to my problem which was about the same, after trying all the suggestions, I have finally nailed it! I know this is a bit late , but maybe there are more out there having probs with HB dovetails. I was determined to find the problem, so I went back, to the front of the instruction book & went through assembly all over, so my prob was in the finger guides to the scales , the book reads , always set the scales to the 3/4 mark when ever they are removed & replaced, it was as simple as that! A very precise jig , be sure to follow word for word! Good luck, Martin.

[Wayne Jolly]

I had a similar problem with my jig, a D3 that has been upgraded to D4 specs. I found that by going back to the instructions and following them TO THE LETTER, the jig worked perfectly. When setting up the jig, pay attention to the details. Even a step that seems minor can have an impact on your results.

I will have to say, though, that the fingers not being flush with each other sounds like a separate issue. If you are certain that you have followed the instructions completely, you might try calling Leigh support. I found them to be very good.


Wayne

[Brian Kincaid]

Saw this thread and thought I might be able to help with my experience on the D4 jig.

Turns out, I already had responded... in 2009 :)

Only thing I would add is to use double sided tape on the clamp-bar to add some sandpaper to the work-holding side. Nothing coarse, maybe 220. Helps a lot when holding large pieces like toychest panels.

-Brian

[Derek Arita]

Yes, this is an old thread, however I wanted to add what I just found on my D4R Pro, that was giving me similar results. First, be sure that when routing, you keep the router in the same orientation. I put a center mark on the router base and keep that facing forward at all times. Rotating the router will result in various spacing issues.
On the right side of the joint, there's a gap between the pin and tail base. I had the same issue and it took me a while to find the culprit. The right side of that pin board actually sits on the left side, when mounted in the jig. So, as your router approaches that left side, it is lifting. What's causing the lift is the router base riding up on the scale of the finger assembly. I found I had to file the rim around the scale and tweak the way the finger assembly sits, when lowered onto the pin board.
Now, to make things more complicated, this may be happening on the tail board, pin board or both, so the joint issues are compounded. For me, filing and messing with the scale mount to the finger assembly has helped a lot. Just remember that the scale must sit absolutely flush with the finger surface, otherwise the router will lift and cause the joint problems. First pic shows the gradual gap. Second shows the fix.
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[Charles Lent]

You should call Leigh Customer Service and talk to them about this. It seems to be a quality issue that they should know about. Do future jig owners a favor and help Leigh correct this.
My D4R is about 10 years old and I have never had this problem.

Charley

[Derek Arita]

Charles, I am in contact with tech support at Leigh. Some parts are on the way, so we'll see how this pans out. I'll post if the solution is effective. Thanks, you are right about letting them know incase there is a design issue.