MT2 /R7

Mathurin,

Where did you come up with an R7 ? None of us have ever heard of that type or seen one.
 
Whew, I was beginning to think I was the only one that had never heard of an R7 collet.

"Billy G"
 
Interesting the Jarno taper is .600 TPF , where the MT is close to .6 but varies with different sizes . Never heard of a Jarno I would think it's specific to a certain machine ? The B&S taper varies like the MT but it is basically .5 . Still can't find a R7 . Back in the day I was only concerned with R8 for the Bridge port , 5C for the lathe . When we bought our CNC mill it took NMTB 30 , that was a very standard holder , but it was a tapered holder not a collet . You could get that holder with a collet nose witch I did and I then promptly crashed it and that was the end of that . The only other collet I had to deal with was on my Warner & Swasey turret lathe , it had a master collet that held 4 segments .
 
https://en.wikipedia.org/wiki/Machine_taper
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.
 
Bob Korves said:
https://en.wikipedia.org/wiki/Machine_taper
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.
Click to expand...

Well, you know who had influence over the Jarno taper.:wink:
 
Correct me if I'm wrong, Didn't Bridgeport have a B-7 collet at one time? And if I recall, it was a variation of a No. 2 MT.

Edit: Never mind. They had a B-2 and B-3 collet at one time.
 
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