Leigh Dovetail Jig Tips and Tricks?


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Established Member
23 Apr 2008
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A Wood Haven
I have recently acquired a very nice D4 24" Dovetail jig from a fellow forum member. I've had my first play today after getting the right guidebush and a new dovetail bit for my router.

After numerous trials with the Half Blind dovetails I got reasonable results but not as great as I'd have liked. I'm working with pine, and I'm not getting any tear out or anything but I'm not getting a perfect fit. I've realized some of this is down to my placement of the fingers not been perfectly symmetrical and a few other bits, one begin than the base of my router doesn't offer the best support, so I think I will make it a larger plywood base tomorrow. I'm just after any general tips and tricks really that I may have missed out on. I'm thinking maybe I should have started with Through Dovetails but I want Half Blind for this application. I find myself a bit stumped by the Imperial measurements, I know 3/4 of an inch is 20mm (more like 19) and I know that 23/32 is 18mm close enough, but what is that on the scale?

Heres a few pictures of a few attempts:

I broke my first Dovetail cutter. It was blunt anyway. Caught the fingers as I was pulling the router out.

My best attempt.

Any help offered is much appreciated.

Two things that are very important is to make sure your guide bush is perfectly centred. Also depth of cut for each type of router bit is important. The instructions will give you all the information for each bit.
The placement of the fingers do not have to be perfectly symmetrical, thats the beauty of the Leigh. You should be getting close to perfect results with the D4, I'm sure a bit more practice and you'll be fine.
Hope this helps,
Thanks Neil, I think my guide bush has something to do with it I'll check it tomorrow.

The thing is the symmetry of the joint does matter, if you make a box with the same finger arrangement all around it then can not match up just right. I found out on my not test piece as the middle tail was a little off and on each side it showed up differently. I can barely understand it myself, its difficult to explain but I did read it in a review tonight whilst I was reading bits an bobs to pick up tips. I'll keep trying in the morning.
They can be a pain to set-up but you do get great results when everything is..

I set the cutter depth by lowering the cutter through the fingers until it meets the top of the wood then lock the plunge, this way your cutter is set at a depth of zero to the jig.... then lower the cutter to the correct depth, but may still need a slight adjustment once you have done the first cut. If the cutter is struggling and making a nasty whining noise STOP as the depth is too low and will damage and blunt the bit.

It may be a good idea to check the whole jig, just go through the setup guide in the manual and loosen all the parts that needed fitting when new and reset them...

Don't worry, it's a great jig and I'm sure you will have it tamed in no time!!
I do not own one of these jigs but have used them before. I would add that any adjustments to the depth of the cutter should be very minute ones each time as it makes a big difference to the fit of the joint. Keep practicing James, you will get there. :wink:
You do not need symetrical joints to get a good fit, If however you want to use a different spacing say to allow for cutting the top off a box then there is a chapter an asymetric joints in the book.

If that a leigh bush? you need the correct diameter for the jig to work, similarly you need leigh bits with the correct angle preferably 8mm shank as the 1/4" ones can chatter and cut oversize.

A thin 3mm sub-base will help a lot but don't go any thicker as you end up with too much bit sticking out of the collet.

Also watch the videos on Leighs site

When you get the hang of it the resulys should be like this, thats a 25mm maple front

Northampton's a little far, but at the last Yandles there was a really nice guy demonstrating the Leigh stuff.
No question was too hard or too much trouble for him.
There must be a similar thing near you sometime in the future?

Thanks for all the response.

The guide bush is a trend 11.1mm guide bush for use with the Leigh Jig. I've got the right bit for through dovetails I've checked the back. Its nice and sharp and brand new too.

I've ran through the whole set up and made sure everything tight. I think one of the major things is that my routers base is to thick and not giving enough support meaning I'm getting a lot of wobble. I'm off to try some more now so will report back tonight.

There is a Brimarc shop near me that will be having a demo day in may so I will be going to that. Hopefully I'll have it sorted by then. I need to see if he can get me a VRS for the D4 as thats quite a needed bit of kit really.
I didn't find teh VRS offered that much more support but it does stop you getting a crotch full of shavings

Out of interest, what type of router do you have? I have that small 1/4 router 1020W that you see in a lot of brands, similar to the Makita RP1110C, but the cheap McKeller version (which is actually a good machine for £30.)
Chems":2chxxy1j said:
The thing is the symmetry of the joint does matter
As long as mating parts are routed from the same side of the jig it doesn't matter.

On a recent batch of DTs using my leigh, I was getting a variable fit and discovered the base of my (cheapy bosch) router was not dead flat. Might be worth checking yours.

Good Luck

hi..to cut neat dovetails with a leigh i find dimensioning the material correctly helps also follow leighs guide to marking up ... i make sure i clamp both sides of jig with same thickness material and last but not least make sure my pencil is sharp....if in doubt consult your manual and watch the vid as good tips are shown ...follow all that and you'll find you've made a great purchase hope it improves for you and let me know if the vrs makes things improve.......
Disaster has struck. I'm not having much luck. Was just homing in on a good solution, had sorted out the base of the router and a few other bits, working on a test cut and all of a sudden the depth lever lets go bringing the bit up into the guide bush which shatters the bush open like a crushed can and breaks the routers motor. :( I'm not having much luck. Fortunately the bit is ok.
I use my Elu MOF177E which is what the DW626, Trend T10/11 and CMT are based on.

James, before you use it again get a fine height adjuster for your router. This is a must as it will not let the router lift in use. (As you have found to your detriment. :cry: Personally I would buy a good quality router like a DW, Elu, Makita. Something along those lines as it will be much more accurate than the one you have for this sort of work. I use an Elu MOF96 on mine and also a DW 621, both are avaliable in 1/4" and 8mm and are a good router for the price. You could go for one of the 1/2" machines that has been mentioned but it is a lot bigger machine to balance on the jig. HTH. :wink:
Thanks Maliee, I have the big Triton which is great. This little router is ok actually its just that you need to set the plunge lock every now and again as it slips and I hadn't fully engaged it. I took the router back to Focus this afternoon and told them that it has stalled in a cut and won't restart and they refunded it no quibbles which was great. Just need to pick up a new guide bush on monday for £6. I spent the day working on my router table and making up some guards for my table saw crosscut sled. I also squared up a load of timber to practise with the jig on. To be honest its a blessing in disguise, it can get a bit to much like hard work when your pluggin away on one project endlessly. Whilst in focus I bought some 4mm plexi-glass type stuff so I will get to work tomorow making a bigger base for the router so when I'm set to go everything will be spot on.
i've used my leigh jig (18" version) four or five times now and have always got spot on results.

it was a few months ago so my memory is a bit hazy on how I managed it but think the trick was to sneak up on the fit by when using the straight cutter and deliberately under-doing it (having the fingers out too far), then shaving it and test fitting, gradually moving the fingers in a notch each time until the fit was perfect. did this with scrap piece, once perfect then put through the real pieces in one batch