Dovetail Slide Measurement Over Rods

Two gauge rods of diameter D seated in the acute corners give an offset k = D(1 + cot(alpha/2)) from the reference flat to the over-rods measurement, alpha the included dovetail angle (commonly 60 deg, so k = 2.732 D). For a MALE (external) dovetail the over-rods measurement = flat width + k; for a FEMALE (internal) dovetail it is opening - k. A 60-deg male dovetail with a 2.000 in base and 0.500 in rods measures 3.366 in over the rods. Solve either way: enter the drawing flat to get the target mic reading, or the measured over-rods value to back out the flat. Use a rod that contacts the flank below the corner. First-principles trigonometry (Machinery's Handbook); the print tolerance and a verified gauge govern.

offset k = D(1 + cot(alpha/2)); male over-rods = flat + k, female over-rods = flat - k (inverse: male flat = over-rods - k, female flat = over-rods + k). alpha the included dovetail angle, D the rod diameter.

Dovetail slide measurement over rods - first-principles trigonometry as in Machinery's Handbook (Industrial Press), 'Checking a Dovetail Slide', by name; public domain.

Pure trigonometry, public; the dovetail-over-rods rule is a standard Machinery's Handbook shop-inspection method.

Estimate. AHJ and licensed professional govern.

Field names used by the API: dovetail_type, known, dimension_in, pin_dia_in, angle_deg, offset_in, over_pins_in

• Offset k = D(1 + cot(alpha/2)), alpha the included dovetail angleMachinery's Handbook, Checking a Dovetail
• Male / female male over-rods = flat + k; female over-rods = flat - kdovetail geometry