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Taper Sizes by measurement

Nels

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#1
Taper sizes

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JACOBS TAPERS
JACOBS LARGE SMALL
TAPER# DIAMETER DIAMETER LENGTH
---------------------------------------
0 .25000" .22844 .43750
1 .38400 .33341 .65625
2 .55900 .48764 .87500
2 short .54880 .48764 .75000
3 .81100 .74610 1.21875
4 1.12400 1.03720 1.65625
5 1.41300 1.31611 1.87500
6 .67600 .62409 1.00000
33 .62401 .56051 1.00000
---------------------------------------

MORSE TAPERS
LARGE SMALL
MORSE DIAMETER DIAMETER
TAPER# (A) (B) LENGTH
---------------------------------------
0 .36510" .25200 1-15/16
1 .47500 .36900 2-1/16
2 .70000 .57200 2-1/2
3 .93800 .77800 3-1/16
4 1.23100 1.02000 3-7/8
4-1/2 1.50000 1.26600 4-5/16
5 1.74800 1.47500 4-15/16
6 2.49400 2.11600 7
7 3.27000 2.75000 9-1/2
---------------------------------------

BROWN & SHARP TAPERS
LARGE SMALL
B+S DIAMETER DIAMETER
TAPER# (A) (B) LENGTH
---------------------------------------
1 .23922" .20000 15/16
2 .29968 .25000 1-3/16
3 .37525 .31250 1-1/2
4 .40233 .35000 1-1/4
5 .52315 .45000 1-3/4

6 .59961 .50000 2-3/8
7 .72537 .60000 3
8 .89873 .75000 3-9/16
9 1.06705 .90010 4
10 1.28927 1.04465 5-11/16

11 1.53176 1.24995 6-3/4
12 1.79681 1.50010 7-1/8
13 2.07310 1.75005 7-3/4
14 2.34375 2.00000 8-1/4
15 2.61458 2.25000 8-3/4
---------------------------------------
 
Last edited by a moderator:

abrasivemike

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#2
Another piece of useful, but not as popular, info. is regarding the JARNO taper. All Jarno tapers from #2 to #20 have the same taper which is .600" per foot. The large diameter is as many eights of an inch, (.125")- the small diameter is as many tenths of an inch, (.100"), and the length of taper is as many half inches, (.500") as the taper number. For example, a #8 Jarno taper is 1 inch on the large diameter, .800 inch on the small diameter an the lenght of taper is 4 inches. The Jarno taper is very popular on grinding machine centers and also found on other types of vintage machinery.
 

joe_m

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#3
This is an interesting (that's a euphemism for "frustrating") subject for a newbie like me. I've been seeing charts like that for a while now, and they just confuse me. :banghead:

So why does the chart confuse me? Below is a pic of three MT2. The chart says: .70000 .57200 2-1/2
Well there aren't any two easily identifiable points that are 2-1/2" apart from each other. The only easy-to-find point on all three is the fattest point, and it is .75, not .7. Does the chart mean I am supposed to measure until I find a point where the width is .7, and then measure 2-1/2" down from there and it should be .57200?

For now I've just been stumbling along. Best scenario has the taper engraved on the side. If it's not, then I fall back to option 2: If it fits in my mini-lathe, it's MT1. If it fits in my regular lathe it's MT2, if it fits in the Leblond tailstock then it is MT3. If it doesn't fit in any of those, then it's not for me and I just hide it in a toolbox somewhere dark and pretend it never existed.

Of course you experienced machinists don't need the chart - your calibrated eyeballs can tell an MT0 from a B&S3 at 50 meters. :biggrin:

MT2.jpg
 

Tony Wells

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#4
Those numbers are gaging numbers. If you find an arbitrary point, measure it and move the specified distance and measure again. You're primarily looking for the difference over distance to calculate taper. A quick measure of the big end will give you the other dimension necessary to determine what you have.
 

whitmore

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#6
Another piece of useful, but not as popular, info. is regarding the JARNO taper. ... also found on other types of vintage machinery.
It took a while, but by gaging the tooling on granddad's old Stark lathe, I've convinced myself
that the tailstock and faceplate take Jarno taper #3. Someday soon, the plan is to use the
lathe to make more accessories (the 1920 three-jaw chuck for the tailstock is a very unimpressive item).

It was easiest to measure the taper using a drill gage, which has convenient measured
diameters, and seeing how far the old taper tooling would go into each of the holes...
Then, with all the measurements in a spreadsheet, some calculations and averaging
got me to where the table numbers kinda matched. Wikipedia article on Machine_Taper has
some useful info, as does Machinery's Handbook.
 
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