Leigh 24" Dove Tail Jig

[Jerry Thompson]

The first I used this jig making the test box all went great. I have been out of the wood working picutre due to shoulder surg. Now I cannot get anything right. The finger screws keep falling our and a lot of them are lost. I know I tightened them firmly then real hard. Still they loosen.
Secondly I am trying to dove tail TD on pine. I know pine. This is what I have to do and it is a long story. How does one control tear out. I am using a 13/16 DT bit as the boards are 1" thick.
How would I put a backer board and a front board on the piece? Should I just clamp one front and back and let the good times roll.
The main thing that gets me is the screws. How can I tell if I get them tight enough?
I anyone wishes to help me with this debacal please remember I have almost no mechanical ability but my wife does so maybe she will understand things other than a person coming to the house and showing me.
Thank you.
Jerry

[Joe Cowan]

You could try some Locktight (comes in a squeeze tube at auto supply stores and possibly big box stores)on the screw portion and that will help in the screws falling out. As to the tear out, I use two spacer boards. One of these boards goes on the right side of the jig and acts just like a spacer board, the other one I put directly behind the tail or pin board. When I cut the various pins and tails, I end up cutting into this spacer board (be sure to have this spacer board such that the bit enters into the end grain. This eliminates the tear out.

[Jerry Thompson]

It is also tearing out on the front.

[Joe Cowan]

I have not had that problem. I try to use "climb cutting" when I first start cutting into the wood. With this, you move the bit from the right side of the cut, to the left side. This is a harder way to control the router, but with making light cuts off the start, it helps to cut the wood, as opposed to tearing it out. After I make the cuts on the front of the pin or tail board in this manner, I go back to the correct direction of router movement.

[Jay Rasmussen]

Jerry, I agree with Joe. Try light climb cuts to start, I have had good success even in oak.
Also be sure your bit has a clean cutting edge and is sharp.

[Jerry Thompson]

Could l put a scrifical board in front as well as the back?

[Bruno Frontera dela Cruz]

Climb cutting is the way to go with minimizing tearout.

Probibly not a direct answer but it is the path I took when I counted the setup scap and setup time when using a jig, but put that thing on the shelf and cut them by hand. Unless you are in production I find it faster and more enjoyable to lay out and cut by hand than to fiddle with those jigs.

[Jim Rimmer]

Could l put a sacrificial board in front as well as the back?

I wouldn't. Try the climb cut method; all you need is a very light climb cut across the front to cut slightly in to the wood so when you go through the template the regular way you are not cutting all the way to the front edge when the bit exits the template. You say are not mechanical so think of it this way. The tear out is caused because as the bit exits the wood at the end of the template, the bit is lifting the wood fibers and since you are at the end of the cut and there is no support, the fibers tear out. By doing the climb cut, you are cutting very slightly into the wood so when you come out of the template the fibers are not ending at the edge of the board but are slightly inside the cut so you don't have the 90 degree angle and they don't tear as badly. The backer/spacer you are thinking about would work by providing support to those fibers at that point but it really complicates the use of the jig.

Others chime in here if I'm not making this clear.

[Ray Newman]

Securely clamp the jig to the work table/bench. This will reduce the vibrations resulting in a better cut and keeping the jig fingers, etc., tighter. I screwed my circa 1993 24" D3 Leigh jig to a scrap piece of 3/4" plyw'd. and left 3-4" ears protuding on each side of the jig. These ears provide enough clamping surface to secure the jig.

I also found that pine and oak are difficult woods to dovetail. Not saying they can not be dovetailed, 'ya' just need very sharp and clean bits. See what others said about a climb cut. And sometimes, no matter what you do, the work will still splinter.

[Curt Putnam]

Just used my jig last week. Had my share of problems but not ALL the ones you seem to be having. Haven't a clue about the finger screws - I have no such problems.

Tear Out: It's not the jig's fault. All jigs have the issue. Here's what I do - with varying degrees of success. Backer board. Gotta have it. Even with that, take a very light cut across the back when doing pins or large tails. I've even gone so far as to put tape across the back. Same on the front - if there is room, do the climb cut thing. In ALL​ cases, proceed slowly with sharp cutters.

[Danny Hamsley]

Backer board on the back, tape on the front. Go slow and deliberate.

[Randy Henry]

On the vertical piece (drawer side) climb cut. On the ends, even with brand new bits, I won't try to hog it all off at one time, just kinda nib at it. On the screws, take off all the fingers and make sure the bottom is cleam with no buildup of dust, etc.