Craftex - CT052N 12" Dovetail Jig (Rating: 5)

i decided it was time to try my hand at making dovetail joints, so I purchased the Craftex CT052N 12" Dovetail Jig. I had some 5/8ths boards so I thought a 1/2" dovetail jig would be appropriate. I have a Bosch router, a 1/2" 14 degree dovetail bit and a template that could be made to work with this jig.

There are several measurements and adjustments that need to be made before starting to cut the dovetails. I carefully followed the instructions in the manual that came with the jig, and made my first dovetails. They didn't fit. Not even close. The pin widths were correct - 9/16ths of an inch, but the depth was wrong - too deep. And the tails were way to wide at 5/8ths of an inch.

After re-reading the manual, I discovered a contradiction. In one place the manual requires that the dovetail bit protrudes 23/32nds of an inch below the router plate. In a different part of the same manual it requires only 19/32nds of an inch. I had used 23/32nds, which went some way towards explaining why my joint didn't fit.

So, i reset the router bit depth and tried again. Still no luck. The tails were now only 0.6 inches wide instead of 5/8ths, and the pin depth matched the diagram in the manual (11/32nds of an inch), but the joint still didn't fit.

Next, i recalled some high school math and worked out for myself how far the dovetail bit should protrude from the router plate. Not 23/32nds. Not 19/32nds. The right answer is 16/32nds, or 1/2 inch. This makes the pin depth not 11/32nds, but 8/32nds.

I set up the router for these measurements and got an acceptable joint. A slight tap with a mallet and it fits!

I have no complaint about the dovetail jig itself - it appears to work as expected. But the documentation is very poor. There were at least 3 errors, any of which would make it impossible to create a workable dovetail joint.