Dear Orchidians, One of the schools, at which I teach, has an old
rolling mill which needs to be resurfaced. The rollers are flat and
approximately 80mm. Is there a business in the Boston/Providence
area that refinishes rollers? Could I just take them to my favorite
machine shop?
Munya, Definately. A good machine shop will resurface that mill for
you, no problem. It’s well within the type of work they do. Be sure
to ask for a super-smooth finish on the rollers, and ask if they
feel it needs to be heat-treated for maximun hardness. Often, mills
are only heat treated on the outer-most surface, and not too deep
into the metal, depending on the quality of the mill. So, it might
be a good idea to invest in re-heat treating for hardness if they
recommend it. It shouldn’t add much to the machining cost.
Resurfacing rolling mills is easy to do, the rollers may be as hard
as all get out from usage. I am a machinist, and have made new
rollers for myself. The cost factors can be setup time in the shop,
which varies greatly then the actual work time, my shop is $75 an
hour, heat treating is $50 per run through the oven. If I may
suggest that you ask a machine shop make you some new rollers that
are made out of S7 steel and have them heat treated. They will last
forever.
If I may suggest that you ask a machine shop make you some new
rollers that are made out of S7 steel and have them heat treated.
They will last forever.
I once destroyed a set of rolls for my power mill (don’t ask) so I
had the replacement rolls made from S7. They were heat treated to
RC54. In the 12 years since I had them made they have developed a
few blemishes from the rolling of wire through the flat mill. I have
since found out that S7 is considered a little too soft for this
use. If I do it again I will probably specify A2 rather than S7 for
the rolls as that is what I have made my side rolls from and they
have stood up to lots of use. Another option is 52100 but I
understand it is more likely to distort in heat treating.
Jim Binnion
James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160
@James_Binnion
Member of the Better Business Bureau
I was able to resurface a very abused Oliver rolling mill using my
10" Atlas metal lathe and a toolpost grinder. It took a lot longer
than the operation would have taken on a cylindrical grinder, but the
end result was perfect rollers. The rollers themselves were hard
after the operation but I probably only removed about .002" of
surface.
I held the rollers between centers, as they already had centers (a
60 degree conical hole) in them from the initial manufacturing.
No real point to this except to say that it can be done by most
competent machinists, especially if you seek one out who has a
cylindrical grinder. Of course later that year someone left the
window open in the shop during the rainy season (in Oregon, any time
of year) and the rollers ended up with a rust spot. So I’ll be doing
it again…
Before I resurfaced them (must have been several years ago) I asked
on Orchid about it and the folks from Durston said that they also
will resurface rollers. Might be worth it to check.
My experience with rolls is that they are surfaced hardened and can
not be cut with cutters on a lathe, but have to be ground with
abrasives. I think that MJSA/AJM have a list of jewelry related
machinist in the Boston/Providence area; maybe on their web site.