This calculator uses two rods to measure dovetails. The male and mating female dovetails must both be measured with a pair of equal diameter rods. This calculator is based on Mike Kidd's article in the December 2022/January 2023 issue of Machinist's Workshop.
Two rods of identical diameter are placed in the sides of a male dovetail. (Dovetail angles are assumed to be 60°.) The width measured across the rods, the height of the dovetail, and the diameter of the rods is sufficient information to calculate the width at the top of the dovetail. Similarly the width at the bottom of the female dovetail is calculated using the distance between the rods and their diameter. The equations used are shown below.
X is the width of the male dovetail and Y is the width at the bottom of the female dovetail.
The female dovetail is usually cut 0.006" wider than the male for a clearance fit.
Enter the information for either the female or the male calculator and hit the button.