Taper calculator
A taper can be quoted as an angle, a ratio or a taper per foot. They are all the same measurement.
Compound rest angle
2.8624degrees
- Included angle
- 5.7248 degrees
- Taper as 1 in n
- 10.0000
- Taper per foot
- 30.4800
- Diameter change per mm of length
- 0.100 000
- Tailstock offset
- 10.0000
Show the working
- Large diameter = 30
- Small diameter = 20
- Taper length = 100
- Total workpiece length = 200
- difference = 30 - 20 = 10
- Compound rest angle = deg(atan(10 / (2 * 100))) = 2.862 41
- Included angle = 2.862 41 * 2 = 5.724 81
- Taper as 1 in n = 10 != 0 ? 100 / 10 : 0 = 10
- Taper per foot = 10 / 100 * 304.8 = 30.48
- Diameter change per mm of length = 10 / 100 = 0.1
- Tailstock offset = 10 / 2 * 200 / 100 = 10
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- half angle = arctan((D - d) / 2L)
- tailstock offset = (D - d)/2 x total length / taper length
A Morse taper number 2 is about 1 in 20, or 2.86 degrees included.