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Lathe Mandrel?


#1

What do you guys use for holding a ring accurately while turning it
in a lathe?I modified a Rathburn ring stretcher a few years ago and
it kind of works but its not accurate enough for my liking.I can get
it to run true with a bit of mucking around but if I remove it from
the lathe and try and re centre it it takes forever.I figure there
must be a better tool that is more precise.I use a small lathe with
only 150mm between centres so I can’t use my ring mandrels.Any
suggestions? Thanks, Colin.


#2

I use a set of soft jaws which I have machined to hold rings by the
inside diameter or the outside diameter. Normal runout is about 1-3
thousandths of an inch. If I need high precision then I touch up the
jaws at the appropriate diameter for the ring I am going to work on.
The advantage of this set-up is that you can hold any ring size with
the same tool.

here is a pictuRe:

Daniel J. Statman, Statman Designs
www.statmandesigns.com
@Dan_statman


#3

I would make an expanding arbor:

http://www.homemetalshopclub.org/news/apr97/apr97.html has an
article on making one

http://yarchive.net/metal/expanding_collet_make.html a post about
making one.

The idea of turning soft lathe chuck jaws will work quite well too.

What kind of lathe do you have?

@Felice_Luftschein_an is Felice Luftschein and Nicholas Carter. See our
web pages http://www.cartertools.com/nfhome.html


#4

Colin We use both Expanding Mandrels and Straight Shank Expanding
Mandrels. Straight Shank Expanding mandrels need to be machined
quite close to the needed diameter. There are photos, descriptions
and prices at
http://www.use-enco.com/CGI/INPDFF?PMPAGE=332&PARTPG=INLMK3 Or check
your local metal working and/or machine shop.

Rod Grantham
www.granthams.com