Dovetail Bit Depth Formula

[Thomas Wilson]

If you have a dovetail jig with a fixed comb for equally spaced dovetails, ie Portert Cable Omnijig, then you have to get the depth exactly right. It depends on the angle of the bit and some other things. Mostly, I have done it by trial and error. At some point, I figured out the formula. Here it is for your entertainment. I found it in a box with a bunch of other stuff that I packed up when we sold the house with the old shop.

The new shop is nearly finished so I have been getting stuff out of storage. There may be more entertaining items from the archeological digs soon.

DovetailBitDepth.jpg

[Lee Schierer]

For my jig it "Heighten to tighten and lower to loosen" the fit.

[Thomas Wilson]

For my jig it "Heighten to tighten and lower to loosen" the fit.

Yep. That is the way it works. The formula gets you very close in one try if you have a digital height gauge for setting the router.