FILENAMES:

VNCOL5V.JPG
VNCOL50V.JPG

DESCRIPTION:

These are pictures of Van Norman style collets.
 
Posted by John Kasunich <JEKasunich@worldnet.att.net>. 

The following description was provided:

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Collets for Van Norman Mills

There are two collet sizes that I know of that are
unique to Van Norman mills.  They are known as 5V 
and 50V.

5V collets are used in Van Norman #6 and #12 mills.
The 5V designation is actually a Hardinge number, 
the Van Norman designation appears to be size "C".
The dimensions of a 5V or "C" collet are:

0.850 diameter rear straight section
0.775-18 right hand thread
3-7/8" overall length

According to the Hardinge website, 5V collets are
only available up to 9/16" diameter (round).  The
picture "VNCOL5V.JPG" proves that the website is
wrong, since it is a Hardinge 5V collet, 5/8" dia.
As far as I can tell, 5/8" is the upper limit, there
isn't enough metal in the 0.850" diameter section to
allow for a bigger opening.

50V collets are used in some Van Norman #22L mills, 
and possibly some other models.  (Some #22L mills 
have 40 or 50 taper spindles instead of 50V).  Again,
50V is a Hardinge designation, Van Norman calls them
size 2.  The dimensions of a 50V or "2" collet are:

1.250 diameter rear straight section
1.125-24 right hand thread
4" overall length

Hardinge's website says that 50V collets are available
up to 15/16".  The picture "VNCOL50V.JPG" is a 3/4" 
collet, but I have seen 1" ones made by Van Norman.

Hopefully this info will be usefull to someone who has
(or is buying) a Van Norman mill.

John Kasunich