# MT2  /R7



## Mathurin (Jan 8, 2018)

Hi!

Is there a difference between MT2 collet and R7 collet ?

Thanks


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## Billh50 (Jan 8, 2018)

R7 ? or R8?


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## Mathurin (Jan 8, 2018)

R7 collet Is it the same angle and diameter than the MT2 collet ?


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## westsailpat (Jan 8, 2018)

Not even close . Here is a R 8 https://www.ebay.com/itm/R8-Collet-...074522?hash=item48a4b6955a:g:K8QAAOSwU4FaB8h4  Here is a MT 2 https://www.ebay.com/itm/7-Pc-2MT-R...332131?hash=item1a282f3523:g:XyQAAOSw32lY0dfr 
Why do you ask ?


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## Bill Gruby (Jan 8, 2018)

MT2 is a Taper, not a collet. Also I have searched for 2 hours now and have come up empty on an R7 collet. I've never heard of one. MeriTool hasn't got one listed???

 "Billy G"


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## westsailpat (Jan 8, 2018)

"Billy G" whats up Bro ? I just bought a MT 2 collet set for my 6" Craftsman lathe , they are so dam cute . They take a 3/8-16 draw bar .  https://www.ebay.com/itm/7-Pc-2MT-R...332131?hash=item1a282f3523:g:XyQAAOSw32lY0dfr
I looked for a R7 also I found a weird rubberized type collet for a tapping head but it had been discontinued .


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## Mathurin (Jan 8, 2018)

Thanks for your research. I found that R7 or R8 are for milling machine and Mt series are for metal late


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## Bill Gruby (Jan 8, 2018)

With all due respect, my mill has a MT2 taper spindle. I have a Clausing 8520 Mill.


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## Ulma Doctor (Jan 8, 2018)

My industro-lite M500 has MT3 horizontal and vertical tapers


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## dlane (Jan 8, 2018)

Is a R7 a Canadian thing , it’s a new one to me.


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## Billh50 (Jan 9, 2018)

Mathurin,

Where did you come up with an R7 ? None of us have ever heard of that type or seen one.


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## Bill Gruby (Jan 9, 2018)

Whew, I was beginning to think I was the only one that had never heard of an R7 collet.

 "Billy G"


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## RandyM (Jan 9, 2018)

Here is a source that describes things pretty well.

http://www.tools-n-gizmos.com/specs/Tapers.html


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## westsailpat (Jan 9, 2018)

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 .


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## Bob Korves (Jan 9, 2018)

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.


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## 4GSR (Jan 17, 2018)

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.



Well, you know who had influence over the Jarno taper.


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## 4GSR (Jan 17, 2018)

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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## Ray C (Jan 17, 2018)

No such thing as an R7???   So thaaaaat's why my stuff isn't coming out right!


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