# Dovetail jig setting



## neilyweely (28 Oct 2008)

I bought a dovetail jig some time ago, the box standard 300mm one, as made by axminster, perform, screwfix etc..
At the weekend I was showing a pal how easy it is to cut dovetails with a router and the top (horizontal) piece of wood kept slipping whilst being cut, which obviously caused problems. On closer inspection it was discovered that every time the clamp was used, after screwing down the bolts, the top (handle part) of one of the bolts was slipping upwards and releasing pressure. This was resolved by knocking the plastic grip back down, placing all the bolt in the pillar drill vice and drilling a small hole to slip a retaining pin in, thru the plastic handle then thru the bolt itself and out the other side. Problem sorted, or so I believe. It should hold the plastic knob down firmly allowing pressure from clamp to be exerted.
This should be ok, right?

The main problem is this - whilst re-assembling the jig I noticed that one of the plastic guides that the wood sits against to offset one part of the dovetail from the other (the vertical piece of wood from the horizontal) has slipped and was at an angle. I released the screws, straightened it out and realised that it has to be set exactly correct in order to offset the cuts and make it all fit together. 

So, short of digging out old joints cut on the jig, with the same bit, is there a way to set the plastic guides to the correct position? I am using a bearing guided DT bit, which I believe is 15.1mm long blade, 14.3mm wide, a 7'angle and with a half inch (12.7mm) bearing. This is, I think, the standard bit for these jigs, and the bits I have bought are the same dimensions as the one that was supplied with the jig. I am not a lot of good at maths and stuff, so if anyone does know a way to do this without equations and stuff it would be appreciated!! :? :?  (dig these faces!!!)

Thanks in advance

Neil


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## Racers (28 Oct 2008)

Hi,

The tails and pins are of equal size so I think it will be half the spacing of the pins.


Pete


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## maltrout512 (28 Oct 2008)

That sounds about the distance Pete. As I only use the Woodrat I don't have that problem.


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## neilyweely (28 Oct 2008)

OK, I kinda guessed that, but wasn't sure. Thanks a lot Pete.
Maltrout - where is the best place (cheapest) to get a 'rat in the UK. As far as I knew there was only the one supplier, one of the catalogues I get, and it seems expensive. I know it's gonna cost me, but I want one!!! All those I have spoken to that own one say they wouldn't be without it, and I am realising I am not that talented with a chisel, so........

Thanks folks. I will get a ruler and measure the offset and see how we go from there.

Neil


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## WellsWood (3 Nov 2008)

Actually from memory (I have the same jig but haven't used it since getting into doing DTs by hand) the offset between the 2 stops is 1/2" - it being half the length of one pin and one tail.


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## maltrout512 (4 Nov 2008)

Neil PM sent


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