Thread: Leigh Problems

Not sure if I understand your problem.

A pic would help.

Normal causes of gaps like guide bushing not centred on bit, tearout from incorrect cutting, or size adjustment (in or out on the jig combs) don't give the problem you seem to be having.

Incorrect guide bush size, incorrect cutter size, timber not square and in exact same position could explain it, maybe even movement during cut could do it.

All just conjecture, because following the intstruction gave a good dovetailed box first time, the 2nd, 3rd and 4th times made a few mistakes though

Thanks for the suggestions, I will post pics when our 2 year old wakes up. I cut the pins off in a fit of pique yesterday afternoon. So I will need cut new ones.

I thought at first it was incorrect guide bushes as I am using 2 routers. But a quick check with my (admittedly plastic) vernier callipers show them to be exactly the same size. If the bit was not centred then the gap should be consistantly on one side or the other.

Anyway thanks for the input and Merry Christmas

Chris

Have you tried using the same router for both cuts?

Its a bit of a pain I know, but trying to eliminate possibilities.

Haggismuncher,

Looking forward to the photos but I think I know what you mean.
Other info that would help:

Size of jig:
Thickness of timber:
Size of cutters you are using:

(now i remember- I did the same as you with a Gifkins jig. Clamp was not tight enough- kept moving. Probably nor relevant to your situation)

Graham

Does this diagram (with the gapping shown in black) get somewhere near to what you're explaining?



Ray

Thanks Ray, that's what they look like.

As Cruzi said the first thing I would do is try to use one router with one guidebush to see if that eliminates the problem, I think it will. My bet is that the concentricity of the bushes is causing the problem.

Prob not the cause here but important anyway: Check to see if your router sub-base is flat, and press it in various places to see if there's flex.

Many aren't up to jig work and need to be replaced with precision sub-bases.

Fingers crossed the problem is solved.
I had been using two seperate Makita fixed base routers one cutting the tails with the real Leigh Guide Bushing and the one cutting the pins using the Makita bushing it came with. I took Mat and Cruzi's advice and usied one router and it seems like the problem has vanished.
Now I just have to buy a new real Leigh Guide Bushing for the second machine. That of course is when I can see from behind the huge pile of splinters and dust I create (may have to finally invest in a dust extractor and a VRS).

All I now need to do is to stop the damn thing from tearing out (is this possible when using Radiata?) and I will be as happy as a pig in poop.

Thanks to all for advice and suggestions.

Chris

Good result.

Re tear out, have a rummage through here for one technique:

AKEDA DC-16 Dovetail Jig Review

and also google for 'Pat Warner routing' - his website has some useful tips.

Re tearout - always use a backing board. I also use a spiral upcut instaed of the straight bit. (Onsrud 5/16 from Lee Valley) 5/16=8mm

Spiral upcut bits, backing boards the same thickness or thicker than your cut and climb cutting all reduce tearout.

The climb cutting is the best defence against tearout problems along with the spiral upcut, its a technique that Leigh show in their videos, can't recall if it is in the manual.

re. tearout, I have a Gifkins jig rather than Leigh, but it suffers the same problem. Obviously the Gifkins has a backing board built-in as part of the design.

While trying to make dovetailed joints in birch ply for drawers, I found that although the back edge was fine (thanks to the backing board), the front edge was never clean. Small bits of the ply kept flicking off as the cutter entered the material.

The fix? Use a 'fronting board' as well, in my case just include some 6mm MDF on the front of the workpiece before clamping into the jig. Result - no breakout front or rear, and I can make clean dovetails in just about any material.

Originally Posted by Cruzi

Spiral upcut bits, backing boards the same thickness or thicker than your cut and climb cutting all reduce tearout.

The climb cutting is the best defence against tearout problems along with the spiral upcut, its a technique that Leigh show in their videos, can't recall if it is in the manual.

G'day Cruzi,
I read this with great interest, as I found to have the same problem with tearouts. My question is which is better to use, with a table mounted router, the upcut or the downcut? and what's the difference to the edges?
Thanks
Jack