Pinging Frank Ford

[Your Old Dog]

Frank, going through you very interesting workshop website.

When doing dovetails and measuring the slot with your method, do I only have to subtract the diameter of the add the diameter of the two rods to the measurement of the parallels or is there more math to it? While math is one of my strongest interest, it is by far my weakest skill as well. I'm seeking a way to come up with nice sliding fit dovetails in aluminum. I already bought the dovetails but am half afraid to mess with them.

http://www.frets.com/HomeShopTech/Tooling/GiantToolHolder/giantholder02.jpg

[JCHannum]

If all you are doing is measuring an existing dovetail to cut a duplicate, there is no math needed. Just use a couple of rolls smaller than the depth of the dovetail and measure the width with the adjustable parallels.

Cut the new dovetail smaller at first, measure with the same pins, and the difference will tell you how much wider it needs to be made. The pins do not even need to be the same size, I use a couple of drill bits with ungoobered shanks to accomplish this.