Converting a Hand Rolling Mill to Power Rolling Mill
Hi All,
Is there anyone who has converted a hand rolling mill to a power
rolling mill. I couldn’t find anything in the archives and I knew one
jeweller that had but has passed away.
As I remember he had used a love-joy coupler to connect a gear
reduction motor to his Cavalin Rolling mill. I don’t have the exact
spec. though.
Any Ideas.
Thank
Jim
Jim Zimmerman
Alpine Custom Jewellers & Repair
Is there anyone who has converted a hand rolling mill to a power rolling mill. I couldn't find anything in the archives and I knew one jeweller that had but has passed away. As I remember he had used a love-joy coupler to connect a gear reduction motor to his Cavalin Rolling mill. I don't have the exact spec. though.
Jim, I have just what you are looking for. Although I didn’t do it
myself, I just inherited a Cavalin rolling mill (5" flat) from an
old friend who passed away last summer. He did the job himself; he
was a petroleum engineer but terrific with tools and mechanical
things. The mill has a transmission ? (not sure what this piece is
called) with a connector to the mill gear, then an apparatus with a
belt which connects to the motor. I have digital pictures of the mill
I can send you off list and if the motor/transmission has any info on
them, I’ll write that down for you when I’m in the studio
next…later today. I also have a friend whose mechanical engineer
husband devised the same setup for her small rolling mill and I think
he consulted the other friend when he motorized the smaller mill.
Donna in VA
Jim and Donna,
A few years ago, in our UCSD jewelry studio, we made plans to
motorize one of our 2 rolling mills. We were planning to use a motor,
forward and reverse switch and transmission from Granger, and have a
campus machinist make the coupler. As the Craft Center Director and I
were double-checking the parts we had planned to order, one of my
students came up to see what we were doing.
“Oh, you’re planning to make a motorized rolling mill!”, she said.
“My husband has one of those in his machine shop. I was using it one
day and my finger got caught in the roller. The end of my finger
popped like a grape, but it healed OK.”
When we heard that, we cancelled our plans to motorize the mill on
the spot. We didn’t want to take the chance that a student might get
hurt in that machine.
Several years later, I answered an ad for a “home-made motorized
rolling mill”, in fact, I bought it. (I don’t know why, now.) A
jeweler had set it up with an electric motor, chain driven, that had
no on/off switch. You just plugged it in and it rolled. The guy
selling it asked if I wanted to try it out with a piece of silver
sheet he had, but I declined. I had no interest in getting my
fingers anywhere near those spinning rollers! That mill will probably
get converted back to a handle driven mill, eventually. Anyway, if
you’re planning to motorize, be sure you’ve got safety in mind. I’d
install a foot actuated “dead-man switch” to provide a fail safe way
to stop that thing if it grabs you.
Oh, and good luck!
Jay Whaley
Hi Jay.
Thanks for the concern. I been working around them for thirty years.
After seeing or hearing about accidents that evolved auto rollers I
have a great respect for them.
These accidents have a range from having the metal tweeze also
getting flattened (Mild).
To fingers getting pitched badly (Moderate).
To neckties going through with the wearer still attached. Luckily
the Forman wheeled up with a pair of scissors in the nick of time.
This could have been really bad.
Our solution is to make wood tweezers out of tongue depressors. At
least if they go though the mill, they don’t mess up the rolls. I do
have other rollers that are hand driven for small work.
Hi Donna,
Your pictures are a great help. Thanks very much. I’ve already
started pulling the parts together. I found a nice geared reducer on
ebay along with a reversing drum switch for an excellent price. I
going to buy the motor new off of Grizzly tools. I can either buy the
Lovejoy coupler direct from the company or Amazon.com. Amazon???,
well they sell everything else, I suppose. My mill is a combo so I
can
do rod stock also.
The Jeweller I knew used a half horse motor, but I think I’ll use a
one and half horse. Just so it wont stall out. I found a table on
someone’s lawn they were tossing out for the base. I like free items.
Thanks for the picture to reference.
Jim
Jim Zimmerman
Alpine Custom Jewellers & Repair
Hi all
Not to pile on here, but I definitely second what Jay said.
When I was at Cranbrook, we had a pair of ancient old powered
rolling mills. (One for sheet, and one for square wire.) The word was
that they dated to the 1920’s. Looking at the way they’re made, I
don’t doubt it. These things were real monsters. 220V motors about a
foot in diameter. Just for fun once, we took the sheet roll, took a
sheet of silver about 4" wide, and set the rolls to take an.010"
reduction on it. Once it had a good grip, we killed the power. The
thing had so much momentum, and was reduced so far, it kept rolling
for about 30 seconds. That was at least 3" inches, even with a big
bite on a big piece of silver. I can’t tell you how far it went for
sure, because it ran off the end of the silver billet. Even with the
power cut. Ponder this before you get too enthusiastic about power
rolls. Absolutely you should rig some way to stop the rolls NOW.
Waiting for the machine to spin down may be more of your hand than
you really want to sacrifice.
Regards,
Brian Meek.
PS I ended up with most of the guts of one of them after we blew up
the main reduction gear on the sheet roll, and scavenged the gear off
of the wire roll. I converted it to hand use, and machined up new
sheet rolls for it. It’s got most of the big bits needed to put power
back on it. And I’m not even thinking about it. This should tell you
something.
We didn't want to take the chance that a student might get hurt in that machine. I had no interest in getting my fingers anywhere near those spinn ing rollers!
Jay, thanks for the safety concerns. Before I inherited this machine
I’d used it a lot and the friend who had it motorized was extremely
careful. Part of the setup is a switch for turning it on and off
right beside the rollers. As to spinning, the rollers seem to move
very slowly. I’m careful to observe safety standards - no long
sleeves, loose clothing, aprons, jewelry or hair near machinery.
Although I also have scissors and a cutter on the wall next to the
mill in case any cloth gets into the milI, prevention is my first
line of defense. I have 2 other rolling mills and use the motorized
one mostly for rolling down metal sheet.
Donna in VA
I was using it one day and my finger got caught in the roller.
I don’t know anything about this, but it seems pretty simple, if one
was determined. But, related to Jay’s post - the commercial
motorized mills you buy run very, very slowly. The Durstons max out
at 40 rpms, and most go down to 5rpm. Not much faster than you roll
by hand if you are vigorous about it. I wonder if some of Jay’s
references are about home built machines running at more like 150
rpm or more - that would be a foolish thing to do. I know some mill
rollers go pretty fast - the difference is that there’s no people
around them in operation…
I have a motorized 3 hp wire and sheet mill that I am quite happy
with. I have used it quite a bit and see no likelihood of injuring
myself as I am aware of what I am doing when I am operating it. Same
as any tool or machine I use. I can do roller textured that cannot
be achieved by any hand mill. I know, I tried and stopped before I
caused physical damage from the strain of trying. At 61 years of
age, a power mill has made a difference in what I can do and how fast
I can do it. With any profession one must assess the advantage
against the risk of using power tools (or torches).
Richard Hart G.G.
Jewelers Gallery
Denver, Co
Our solution is to make wood tweezers out of tongue depressors. At least if they go though the mill, they don't mess up the rolls. I do have other rollers that are hand driven for small work.
Excellent solution, and if you are trying to hold small pieces of
stock you can get bamboo tweezers with rubber tips from photo supply
houses that sell chemicals for developing. Eventually they will all
be gone; to bad.
Dan
Our solution is to make wood tweezers out of tongue depressors. At least if they go though the mill, they don't mess up the rolls. I do have other rollers that are hand driven for small work.
I use a piece of corrugated cardboard cut into a strip and just push
the stock into the roller. Then I recycle the cardboard…
Richard Hart G.G.
thing had so much momentum, and was reduced so far, it kept rolling for about 30 seconds.
Fascinating topic. I wonder: is there an automated rolling mill with
a safety feature that causes the rolls to separate, rather than
trying to stop their momentum?
Lorraine
It was asked if " I wonder: is there an automated rolling mill with a safety feature that causes the rolls to *separate*, rather than trying to stop their momentum?"
Such mechanisms exist as do ones with an auto-reverse and others
with positive braking systems. Most use a system of photoelectric
beans and safety bars to trip the safety mechanisms.
But they are not “converted hand rollers” they are purpose built
industrial machines and are nor cheap nor small.
To steal and mangle a punch line from an off color joke… “And the
salesman (in this case) said you can have it safe, cheap and good…
pick 2 of the 3”…