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Resurfacing Mill Rolls


#1

Aloha,

I’m new to this list, and all I can say is…Where have you been
all my life?!?! Glad to have found it!

Can anyone help me out with this one? I use my rolling mill
primarily to obtain a smooth reflective surface on niobium. The
last time I had the rolls resurfaced and polished, they came back
with a beautiful mirror finish but they were less than perfectly
flat (don’t touch in the middle), resulting in curved and warped
metal. Can anyone recommend a reputable metal turner/machine
shop to resurface and polish, or chrome, mill rolls properly?
I’ve heard that chromed rolls are preferable because they resists
scratches and rust, but can they take the pressure of rolling
metal to thinner gauges?

Mahalo!

Emily
Captain Cook, HI


#2
   last time I had the rolls resurfaced and polished, they
came back with a beautiful mirror finish but they were less
than perfectly flat (don't touch in the middle), resulting in
curved and warped metal.   Can anyone recommend a reputable
metal turner/machine 

talk to the shop that had them first. anyone can goof. if they
are any good, they will want to correct errors. If not, you gave
them a chance. Also, direct anyone away from them that you can.
Consumers can influence business practices. If everyone with a
problem complains, they will get better or close.

we have one near us selling gold plate insisting it to be solid,
we have been taking her customers away from her. It will
eventually work in any community.


#3

talk to the shop that had them first. anyone can goof. if they
are any good, they will want to correct errors. If not, you gave
them a chance.

I talked to the owner and even sent the rolls back to them (in
Rhode Island) for a second try to get it right, but there was no
improvement. The rolls touch at the ends, but not in the center.
They said that this happens during the polishing phase, and
that’s as good as it gets. Can this be true? Can anyone
recommend a metal turner/machine shop to do the job right? I’ve
heard that diamond polishing or chroming the rolls is the way to
go, but at this point I’d be happy just to have the rolls flat
again. Any suggestions? Thanks!


#4

You can repair some miner damage yourself, simply by taking a
round drill rod @ 10-12 mm in diameter and the length of your
rolls. Then put a piece of emery paper the grit depends of the
amount of damage to your rolls. I would say 240 to start. Put the
emery paper around the drill rod, (The piece of emery paper needs
to be 4-5 inches long), put the drill rod in the middle of the
emery paper, making sure that you do not fold or crease the
paper, the paper needs to be the same width as your drill rod.
Next put paper with the rod in the middle cutting side out,
place the open ends of the paper in your rolls, slowly advance
your rolls so that the drill rod meets both edges of your rolls
evenly. Now comes the hard part, you have watch your drums and
crank your handel at the same time, this is for manuel machines,
you could also so this to your electric also. CRANK & CRANK &
CRANK watching youself refinish your rolls. You should also use a
little machine oil! After you use a coarse paper then you can
use finer & finer grit til you get the finish on the rolls you
want. Try this it does work, IF YOU CAN FOLLOW MY LIMITED AMOUNT
OF INSTRUCTIONS!! I hope this makes since, I have done this
before and it does take time and patience. good luck!


#5

Here is a good tool maker and friend. He can surface the rolls
and do whatever is neccessary.His name is Charles Bissitt from
Sancha Enterprises… tel. 401-231-5740 he’s a good machinist and
has built many machines and tools for people in the jewelry
trade.

hope this helps.
Dan Grandi
http://www.racecarjewelry.com


#6

I have had several sets of rolls done by Pacific Cutter and
Reamer in Oakland, CA 510-654-1844 they do first rate work. They
are done to a 1000 grit finish this is not polished but very fine
matte.

Jim


@jbin
James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601
510-436-3552


#7

Hi,

Maybe that’s as good as it gets in his shop, but with that
quality of work he won’t be in business long!

There shouldn’t be a problem getting a good grinding/polishing
job done on mill rolls. Check your yellow pages for ‘Machine
Shops’; if the shop(s) you call don’t have a cylindrical grinder,
they will probably know of a shop that does this type of work.

Unless you run a production shop that uses the mill several
hours each day, you probably don’t need to go to the expense of
having the rolls chrome plated. A roll made of case hardened or
hardened tool steel is more than adequate for work done with
precious metals.

Good luck!

Dave


#8
They said that this happens during the polishing phase, and
that's as good as it gets

As a machinist/modelmaker with 20 years in a machineshop a can
assure you that this isn’t as “good as it gets”. The person you
were dealing with apparently is only interested in making money
and doesn’t care or take pride in the quality of his work.

I am not sure of the cost, but one option to restore the damage
is to have the rollers centerless ground. Centerless grinding
will assure the roundness of the cylinder as well as the flatness
of the surface. It will also give you a mirror like finish.

A less costly option would be to find a “quality” machineshop
and have the turning and polishing process repeated.

Steve D.