Jarno Tapers

Jarno Taper Dimensions

Jarno

Jarno tapers use a greatly simplified scheme. The rate of taper is 1:20 on diameter, in other words 0.600" on diameter per foot, .050" on diameter per inch.

Tapers range from a Number 2 to a Number 20. The diameter of the big end in inches is always the taper size divided by 8, the small end is always the taper size divided by 10 and the length is the taper size divided by 2.

For example, a Jarno #7 measures 0.875" (7/8) across the big end. The small end measures 0.700" (7/10) and the length is 3.5" (7/2).

The system was invented by Oscar J. Beale of Brown & Sharpe.

Jarno tapers
Taper	Large end	Small end	Length	Taper/ ft	Taper/ in	Angle from center/°
#2	0.2500	0.2000	1.00	.6000	.0500	1.4321
#3	0.3750	0.3000	1.50	.6000	.0500	1.4321
#4	0.5000	0.4000	2.00	.6000	.0500	1.4321
#5	0.6250	0.5000	2.50	.6000	.0500	1.4321
#6	0.7500	0.6000	3.00	.6000	.0500	1.4321
#7	0.8750	0.7000	3.50	.6000	.0500	1.4321
#8	1.0000	0.8000	4.00	.6000	.0500	1.4321
#9	1.1250	0.9000	4.50	.6000	.0500	1.4321
#10	1.2500	1.0000	5.00	.6000	.0500	1.4321
#11	1.3750	1.1000	5.50	.6000	.0500	1.4321
#12	1.5000	1.2000	6.00	.6000	.0500	1.4321
#13	1.6250	1.3000	6.50	.6000	.0500	1.4321
#14	1.7500	1.4000	7.00	.6000	.0500	1.4321
#15	1.8750	1.5000	7.50	.6000	.0500	1.4321
#16	2.0000	1.6000	8.00	.6000	.0500	1.4321
#17	2.1250	1.7000	8.50	.6000	.0500	1.4321
#18	2.2500	1.8000	9.00	.6000	.0500	1.4321
#19	2.3750	1.9000	9.50	.6000	.0500	1.4321
#20	2.5000	2.0000	10.00	.6000	.0500	1.4321

Jarno Tapers

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