Re: jarno taper in SB headstock ?


sblatheman
 

In depth experience at the factory. Hands on the original blue prints.

Ted

On Dec 18, 2015, at 9:09 PM, Arn Jones ltousig@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:

 

What evidence do you offer?

Have you looked at my evidence?



On Fri, Dec 18, 2015 at 5:54 PM, Latheman latheman2@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:
 

There were NO Jarno tapers in South Bend lathes

Ted

On Dec 18, 2015, at 5:55 PM, Arn Jones ltousig@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:

 

I think many of the later South Bend lathes used Jarno tapers in the spindle socket, usually shorter than standard but with 0.600 inches per foot taper.

Same for Clausing lathes, all my 5900 tooling comes up as extremely close to Jarno taper. 

It is difficult to measure taper to the third place, small errors in measuring diameter cause large errors in the calculated taper per foot.

Also, many lathe manufacturers were cagey about telling customers the spindle socket taper, they wanted to sell the adapters and not have people making their own.

Some of my analysis of the taper per foot on 5 spindle nose adapters for SB 10" and 13" lathes

Taper per foot
South Bend heavy 10 and 13" lathes Very close to the stated taper of 0.6023" per foot, documented in HTRAL.  Could also be short Jarno 13.
1 1.6065 1.5565 1 0.6000 Beale had publications as early
2 1.6175 1.5675 1 0.6000 as 1901, so could have been the  2
3 1.582 1.532 1 0.6000 standard SB used.   3
4 1.6165 1.5665 1 0.6000 Oscar J. Beale = Jarno   3
5 1.6185 1.568 1 0.6060  
   
Note that an error in measurement of 0.001" on the diameter gives 0.012" taper per foot increment!
Note that an error in measurement of 0.0005" on the diameter gives 0.006" taper per foot increment!
Ave 0.601
St dev 0.002683
Coef of var 0.45%
1.6065 1.5565 1 0.600 4.00%
Uncertainty, +/- inches per foot Cumulative diametral error, 0.001"
One-third magntd cardinal points 0.10 0.22 0.46 1.00 2.15 4.64 10.00
Distance between diametral measurements, inches 0.5 0.0024 0.0052 0.0111 0.0240 0.0517 0.1114 0.2400
0 0.10 1 0.0012 0.0026 0.0056 0.0120 0.0259 0.0557 0.1200
1 0.22 1.5 0.0008 0.0017 0.0037 0.0080 0.0172 0.0371 0.0800
2 0.46 2 0.0006 0.0013 0.0028 0.0060 0.0129 0.0278 0.0600
3 1.00 2.5 0.0005 0.0010 0.0022 0.0048 0.0103 0.0223 0.0480
4 2.15 3 0.0004 0.0009 0.0019 0.0040 0.0086 0.0186 0.0400
5 4.64 3.5 0.0003 0.0007 0.0016 0.0034 0.0074 0.0159 0.0343
6 10.00 4 0.0003 0.0006 0.0014 0.0030 0.0065 0.0139 0.0300

The second section above shows the error in determining the taper per foot when the measurement of the diameter has a certain degree of uncertainty.

Lucas, AKA Arn Jones

On Fri, Dec 18, 2015 at 4:11 PM, 'Jim Ortman' jofab@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:
 



Hi All,
    I made mine.  I just dialed the compound in with the taper of the spindle, installed a chuck, put a piece of round stock in the chuck, turned the taper till it looked close and test fit still in the chuck.  When I was sadisfied with the fit I removed the chuck and turned a 60* center right there in the spindle.  I made the center long to go far enough through a face plate and to touch up the center when needed.  Works for me!  My 2 cents though.
 
JimO
 
Subject: Re: [SOUTHBENDLATHE] Re: jarno taper in SB headstock ?

 

Hi Dimita,
The 14 is the same size as the 13. I picked one up on ebay. You have to wait for one to come up.
Good luck,
Charlie


On Thursday, December 17, 2015 2:30 PM, "Rangelov rangelov@... [SOUTHBENDLATHE]" <SOUTHBENDLATHE@...> wrote:


 
I tried fitting a center into my SB 14-1/2 lathe spindle. A MT4 was way too small, wouldn't seat at all. A MT5 was way too large wouldn't even start to go in.

I looked at the files section. It shows that a MT3 adapter is used and that the spindle opening should measure 1.325 (I measured about 1.300).

Is there a center that would fit my spindle? A MT4 -1/2 or a Jarno taper?

Where would I find the MT3 adapter? Who might supply it?

My problem is the 14-1/2 is too unique and unpopular.

Thanks, Dimitar
__________________________________________________________
>2a. jarno taper in SB headstock ?
>    Posted by: "Ken Campbell" deltainc@... deltaperson1
>    Date: Thu Dec 4, 2014 11:25 am ((PST))
>
>i see some jarno taper tooling  at  0.600 per inch ... my sb 13 inch spindle  is 0.602 per inch.  anybody tried jarno tapers in their SB ??
>
>ken, 13 x 40 .
>__________________________________________________________
>2b. Re: jarno taper in SB headstock ?
>    Posted by: "Ken Campbell" deltainc@... deltaperson1
>    Date: Thu Dec 4, 2014 11:31 am ((PST))
>
>heh, i am another one who somebody told me my SB 13 spindle was #5 morse ... i ran out and got one, #5 to #3 morse ... ... heh, cheap education ... trust but verify ...
>
>ken
>__________________________________________________________


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