Bushes and routing dovetails

[jow104]

I received the weekly woodworking tip from Woodsmith via email this week and I am a little puzzled. The tip implies to me that it is possible and usual to make dovetails using a router freehand mode, or am I creating a faux pas.

Router Bushing Thread Lock
When routing dovetails, I use a guide bushing on the base plate of my router. But the vibration of the router can sometimes cause the threads of the bushing to work loose. So I came up with a simple fix for the problem.

Now I install the bushing on the base plate, I wrap the threads with Teflon tape as shown in the drawing. This is the kind of tape plumbers use to seal pipe threads. Since I've been using this trick, I haven't had any problems with the bushing coming loose.

[bsrlee]

I think you have run into one of the ways 'Yanks' use dovetail jigs - they seem to be inordinately fond of using a fixed guide collar with all jigs, rather than a ball bearing guide fixed to the router bit. For many applications this does not present a problem, the manufacturer simply says 'use a x/yy diameter guide and a a/bb diameter dovetail bit' - whixh are the correct size for his particular jig. Trend UK & Woodrat also do this with most of their gear, but use really odd sizes so you HAVE to buy their bits )which are HSS instead of carbide).

Where this comes unstuck is when you need to make your own jigs & templates as you have to calculate the difference in diameter of the bit & guide vs. the cutout in the jig. Much more room for errors.

The rest of the world just use the correct size ball-bearing bit & don't have as much to shake loose.