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View Full Version : What machines have Jarno No. 7 Taper?



Dale Lusby
09-14-2010, 06:32 PM
I picked up a 12 inch test bar in a lot of tools I purchased. On the box it says No 7 Jarno Taper. I did some research and found that the Jarno taper stems from Oscar J Beale at B&S that came up with it and has a taper of 0.050" per inch or .600" per foot. My question is to find out what machines have a Jarno taper?

http://i279.photobucket.com/albums/kk138/dlusby22/1d71decc.jpg

.RC.
09-14-2010, 07:09 PM
the 10EE has a Jarno taper, no idea what size though...

lane
09-14-2010, 07:29 PM
I have always read and heard about the Jarno Taper ,but never in all my years ran across a machine that uses it. So that is an interesting question.

Hal
09-14-2010, 07:38 PM
The Monarch 10EE's have a #12 JARNO taper.

Hal

macona
09-14-2010, 07:40 PM
10EEs have a Jarno 12. Tool grinders have Jarno. All jarno tapers have the same pitch, not variable like morse. The number signifies in 1/8ths the major gauge diameter.

mark61
09-14-2010, 08:28 PM
American lathes have it in the head stock. Some grinders use it too. Jarno taper centers are NOT cheap!

mark61

TGTool
09-14-2010, 09:27 PM
I was told at one time that Ford Motor had settled on the Jarno as their standard, which would have meant at that time that machine tools supplied to them would have been built that way I presume.

Later: Okay, I found the reference in the Henry Ford Trade School Shop Theory book, 1934, 1941

In their shop catechism questions it says drills are usually made with Morse tapers, milling machines with Brown & Sharpe tapers, and that Ford uses the Jarno standard taper for lathes.

Question 4, on which taper system is the simplest and why, naturally describest the Jarno because you don't need to go look up tables for the dimensions of any Jarno. Large dia is Taper No/8, small dia is Taper No/10, and length is Taper No/2 since you know they're all .600/ft.

Dale Lusby
09-14-2010, 09:39 PM
Some interesting and good information. Thanks for the responses. I guess I'll just have to go out and find a machine with a Jarno #7 taper so I can use my new test bar:)

Liger Zero
09-14-2010, 09:45 PM
Some interesting and good information. Thanks for the responses. I guess I'll just have to go out and find a machine with a Jarno #7 taper so I can use my new test bar:)


Always good to have an excuse to buy new machines! :D

Don Young
09-14-2010, 11:10 PM
Always good to have an excuse to buy new machines! :D

Especially a Monarch 10EE!!

spope14
09-14-2010, 11:14 PM
A tool like this could be used to set the head stock/tailstock alignment as it has a .050 per inch taper. There are other tools, but it has a use.

Liger Zero
09-15-2010, 12:35 AM
Especially a Monarch 10EE!!

Like you REALLY need an excuse to buy a 10EE. :D

Dale Lusby
09-15-2010, 01:24 AM
Like you REALLY need an excuse to buy a 10EE. :D

Goodie goodie. All the more reason to get one. It's on my short list of tools to acquire in the next few years.