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:
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
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.
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
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:
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.
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.
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.