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Retrofitted a motor to a rolling mill?


#1

Ok: Has anyone retrofitted a motor to a rolling mill?

Charles Friedman DDS
@Charles_Friedman1
Atlanta


#2

Hi Charles,

Has anyone retrofitted a motor to a rolling mill?

I motorized a KARAT rolling mill with 4 to 1 reduction .

I removed the crank & replaced it with a roller chain sprocket. For
power I used a 110VAC reversible surplus gearmotor that I fitted with
another chain sprocket. A length of roller chain transmits power from
the motor to the mill. The wiring consisted of a double pole/double
throw switch for reversing the motor & an on/off switch.

Total cost was under $75.

I’m sure other mills could be retrofitted similarly. The exact sizes
of the sprockets & motor are dependent on the applications the mill
will be subjected to. If surplus gearmotors aren’t available, new
ones are available from companies like Grainger (800-225-5994).
Grainger also has the sprockets & roller chain. The Surplus Center
(www.surpluscenter.com) in Lincoln NB may have surplus gearmotors.
The electrical components are available at any good hardware store.

Not connected with any of the companies mention, just a satisfied
customer.

Dave


#3

Yes; I had this done several years ago. The man who did it for me
used a cleveland reducer to lower the rotation rate of a 1/2 hp
motor and couplings found in basic equipment supply catalogs. I
still have this system although I have not used it in years. If you
are interested I would be willing to sell it. It is very heavy and
you will nedd a 2 hp motor to really get the power for rolling. If
interested contact me at 713-861-0706 and we can talk. I am located
in Houston Tx. Frank Goss


#4

Your best bet would to be to find a good motor shop who carries most
of the major brands. You may be able to call with all the info you
have and see if they give you any hope. Then you will probably need
to take the motor in for matching. Pay very close attention to all
the details because sometimes it is a “minor” detail that makes it
unworkable. I’ve never done this on a rolling mill but I frequently
run into equipment where the motor has been designed just odd enough
that you have to go to the OEM and pay their price. A good motor shop
with experienced help is the best bet, sometimes small shops are the
best.

Good Hunting.
Dan Wellman


#5

yes but it’s kinda complicated. you need to have a reducer gear to
increase torque from your motor to mill. then you have to build a
pulley set up to attach in place of your hand crank. it requires a
lot of machinist type work. then you rig up various mounting jigs to
apply pressure to your belt system. one way is to hinge you motor
plate and weight the motor. you then put a belt that is short
enough to suspend the motor - the weight tensions the pulley on the
motor. the down side is you wear the bearing out faster too. I did
this at a time when my own time was not accounted for. Truthfully in
my mind you will spend way more time and money than it’s worth to
mechanize your mill. A far simpler approach would be to price your
work a little higher and let the factory people make your sheet and
wire. Keep the mill around to make small runs out of stock. I
usually keep about every 4th size in silver wire and plate and just
run out any between sizes if I need them before I can get it
delivered.

Talk to you later Dave Otto


#6

yes but it’s kinda complicated. you need to have a reducer gear to
increase torque from your motor to mill. then you have to build a
pulley set up to attach in place of your hand crank.

 Actually, it's not that hard. A high horsepower, probably 1 or 1

1/2 hp motor with a chain drive gear, and a gear on your rolling mill
where the handle goes will work.

A belt and pulley would not work very well, if at all. A chain drive
will. A motor that will not strain when you begin rolling is what is
needed. Small reductions each pass would make it easy.

Richard in Denver


#7

Hello Charles

Ok:  Has anyone retrofitted a motor to a rolling mill?< 

My Husband is an Electrician and is presently retrofitting a motor
to my small rolling mill.

Hi There. I read some other replies to your question and thought I
would add my 2 cents worth. I purchased a new, surplus gear motor
from Princess Auto in Calgary, Alberta, where we live. This was my
criteria and intent:

  1. Every rolling mill will require a different input torque
    requirement for the various uses you personally require of it . Try
    to assess how much torque that might be, and add about 20% to that
    requirement so you will never stall the motor from overloading it. (
    A lot of gear motors have integral thermal protection from
    overloading and stall situations as well.) A torque wrench can be
    used to come up with that measurement or an educated guess should
    be sufficient.

  2. The name plate on any gear motor will tell you the input power
    required. 120 volts ac 60 cycle power is quite common. It will also
    give you the internal gear ratio ( this is the step down gear
    reduction which trades RPM for Torque. ) If your gear motor is a
    4:1, this means that the motor turns 4 revolutions to 1 revolution of
    the output shaft you wish to connect to the rolling mill.

3)Hand drive your mill and assess how fast (RPM)you want your mill
to run with the electric drive and be a comfortable, safe speed.
This is another of your specific requirements you will need to
determine what gear motor and other parts you will need.

  1. I am old school and think of torque in inch/ounces or
    foot/pounds. Europe usually produces gear motors in metric terms like
    Newton/meters or other terms. It will usually have a maximum power
    output capacity on the nameplate as well and is likely expressed in
    watts output.

  2. Have fun with the shopping for the gear motor and arriving at
    exactly what you need so you do not have the (after assembly blues)
    when performance is not quite what you want and need. People do all
    sorts of puzzles for enjoyment only, and this is no different.

This is the basic you will need when purchasing what you
need for your project.

Some to help you in putting things in understandable
terms is as follows:

  1. Once you know your output rpm required to run your mill at the
    right speed for you, go to the surplus store and select from all
    gear motors available. If you are lucky enough to get a gear motor
    with a high reduction ratio which is the RPM you want right off the
    bat, you will be able to connect the output shaft of the gear motor
    directly to the input shaft of the mill.( where your handle now is
    driving the mill). This is done with a drive coupling which can also
    adapt different shaft sizes to make them compatible. This is the
    best scenario since you won’t require sprockets, a chain, a chain
    guard, and a method of slide adjustment on the motor mounting to
    allow tensioning the chain properly to drive the sprockets. Without
    that preferred ratio, you will have to further reduce the RPM to the
    speed you require with all the chain and hardware referred to.

  2. To put requirements in more understandable terms, the following
    is helpful: One horsepower is equal to 550 foot pounds per second. (
    It will lift 550 lbs., one foot, each second) It is a measurement of
    total work within a given time period. One horsepower will also
    equal the work done when lifting one pound, 550 feet in one second.
    Obviously, this is quite a bit of force for bench equipment.

  3. European measurement on the nameplate for power will be expressed
    in metric units of watts. This is easy when you know that one
    horsepower is equal to 746 watts. This means that approximately
    seven and one half, 100 watt light bulbs are consuming electricity
    at a level of one horsepower. The gear motor I bought for Karen’s
    rolling mill ( and hope to install soon) which is rated on the
    nameplate as 520 watts is approximately 3/4 horsepower and should be
    sufficient for her requirements.

I hope this is helpful, Dan Karen Bahr “the Rocklady”
(@Rocklady) K.I.S. Creations May your gems always sparkle.


#8

Hi Charles, I fitted a washing machine/tumble drier motor to my
Durston.The handle was unscrewed, and replaced by a large diameter
pulley, with a small pulley on the motor.

You need access to a fitter/turner to modify the pulley to fit the
mill.

I'll email pics offlist.

Regards
Larry


#9

Karen Thanks for the excellent

Can you give us the specifics of your conversion: what mill, what do
you run: wire or sheet and what metal, how fast do you crank down on
thickness, how often do you anneal? What was the hp and the speed of
your motor? Do you find a difference in the quality of the rolled
material that depends on the speed of rolling? I know that the last
roll should be a smaller change than the previous rolls and that for
that last roll, even rolling is required, but I do not know the
effect of speed. You have given the most logical approach, but the
specifics will help nail down what is important. Some people have
stated that a belt drive does not work too well and that a cog chain
drive is the only way to go: any comments?

Thanks
Charles Friedman DDS
Atlanta


#10

If you going to refit your rolling mills there are a few safety
issues you should take into consideration. Safety issue always sound
very logical but it is amazing how complacent we all get when it
comes down to ourselves. I have seen a couple nasty accidents over
the years due to poor conversions. The main issues from my experience
are, who else is going to use it , the speed the mills run at (I have
seen some that snatch the metal), covers to protect you from moving
parts so hair, clothes, fingers etc don’t get caught. The last one
that comes to mind (I am sure there are more) is a safety switch that
can be hit with the knee or foot just in case you can’t reach the
switch. I have always found it handy to have hand mills even when
power mills are available. I have seen people trying to mill small
bits of metal using tweezers to hold it; it is amazing how long
tweezers can get :slight_smile: Chris