Rolling Mill nearly completed!

S.Grosvenor

S.Grosvenor

Fulltime KnifeMaker
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Jan 24, 2010
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This has been one of those, "filler" builds but it's nearly complete:D



The builder, (not me), is making it very heavy duty, with a vfd. EXCITED!:thumbup:
 
VERY COOL!


Is there a hydraulic component to this press or are you using leveraged body weight?
 
This is powered by leverage, 3 different force locations.

Started with the plans then proceeded to change things.
 
That is very cool. Rolling mills are sounding more tempting to me since I could theoretically put one in my garage.

Question, looks like your using a gear box possibly. If so can you give some details on that guy.
 
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Details and more pictures coming soon.
Yes it is a gearbox the electric motor will bolt directly to the gearbox.
 
Are both rollers going to be powered?
Your going to need some support to keep it from tipping over.
I used a 1750 rpm 2 HP motor into a 60:1 gear reduction then further reduced it about 2.5:1 with 4" rollers gives me about 12 FPM feed rate. With both rollers being powered.
 
Most power driven rollers have a hydraulic jack or a screw jack adjusting the clearance space. I have used a lot of rolling mills over the years in the jewelry industry, and never seen one with foot pressure controlling the space between the rollers. It does not seem that it could provide even spacing and sufficient pressure. You need rock solid resistance to the rollers being forced apart. The pressure between the rollers is many tons. Even if the foot lever could provide enough force, the mill shown has no spacing adjustment. It would need a set of large screw shafts that would adjust a stop for the lower roller. That way when the lower roller comes up it would stop and make a parallel and consistent thickness between the rollers. On many rolling mills these shafts are adjusted by two large hand wheels on the left and right side of the top.

Is this your design alone, or are you making a copy of someone else's rolling mill who has tried out the foot lever thing?
 
Thanks, I have seen that video with Dee, and seen the Macdonald mill at Anvilfire. Theirs use a jack screw with a multiple leverage system in a tip-and-lock setup, IIRC. In your photo, the turn-buckle and foot lever looked different. I was concerned because the MacDonald type has a more complex leverage and adjustment system. If it is based on the same lever principle, it should be fine. The turn buckle may be a bit harder to adjust than a jack screw wheel.

The powered rolling mills I have used have a different setup, but apparently the MacDonald type will work with hot steel pretty well. I do like the one man multi-pass ability. I might look into modifying one of mine with that ability ( but probably will use hydraulics or pneumatics instead of foot power).
 
Jim McGuinn said:
Are both rollers going to be powered?
Your going to need some support to keep it from tipping over.
I used a 1750 rpm 2 HP motor into a 60:1 gear reduction then further reduced it about 2.5:1 with 4" rollers gives me about 12 FPM feed rate. With both rollers being powered.
Click to expand...

I'd like to see the details of how you powered both, you had to reverse direction from one to the other.
 
There is a WIP on here look for rolling mill build. It has a 2 HP motor into a60:1 gear drive box with 2 output shafts. The motor and gear box are located at the bottom and to the rear opposite the peddle for better balance than the one shown. One side of the gear box has a sprocket with chain going directly to the top roller on right side. The other side of the gear box has a 6" gear that contacts a matching gear mounted on a jack shaft to reverse the rotation. This shaft also has a sprocket and chain running to another shaft that is the pivot for the lower roller plate. With another chain going to the lower roller. This set up reverses the rotation and keeps the chains the same length no matter what the distance between the rollers .
It has a large jack screw with 3 spoke adjustment nut that is easily adjusted. The peddle assembly is similar to the McDonald mill, but without the adjusting lever. The idea is to adjust the jack screw to the point where the peddle will bottom out and the linkage locks up.

When I first designed it I did not think I would get enough pressure with the foot lever. But with a 36 to 1 leverage my 240 lbs gives over 8,000 lbs of pressure at the rollers .
I haven't figured out what the lbs per sq inch would be. But I'm guessing it would be comparable to a 20 ton press with a 2"x4" die in it.
With the foot peddle you can instantly release pressure if needed.

In addition to this the rollers push the material out to you instead of pulling it in. This is for two reasons first , safety making it impossible for the operator to get caught up and hands drug into the rollers .
Second when you get the steel down to a thin bar it would curl up and look like a piece of ribbon Christmas candy if it were being pushed through the rollers. But since its coming out towards you a steady pull will keep it straight

Jim
 
JIM,
First, the numbers aren't right.
You weigh 240 pounds, your foot does not. If your legs are strong enough your foot will apply pressure up to 240 pounds, at which point your other foot, and thus your body weight, lifts from the floor. You could not be touching anything , much less pulling on a billet, to get 240 pounds of force applied to the pedal. The actual foot force applied to the pedal is probably less than 50 pounds. Just for the sake of discussion, lets just assume you could stand on the pedal with both feet and pull a billet through the rollers. That would theoretically yield about 8000 pounds of force by the 36:1 mechanical advantage.

( ignoring mechanical loss, which gets pretty high in these situations) If you apply that 8000 pounds of force into a 2"X4" die, you get 1000PSI ( 1/2 tons per sq.in.), not 40,000PSI ( 8 TSI). It would take a very small die .... 0.4"X0.5" .... to get 40,000PSI. These are the theoretical values, and are greater than the actual force delivered. In many cases, the actual force delivered is half the theoretical value.

For a roller, it is a different calculation than a die. Assuming the contact surface of a roller and a hot billet is .25" wide ( I am sure it is actually wider, which would lower the value) and the billet is 2" wide, the theoretical force would be 16,000PSI ( 8 tons). This isn't the actual rolling force due to several factors, but would be the rating of the mill.

I would guess the delivered force in a single powered roller setup with a 36:1 foot operated leverage system applying the force from 240 pound person would be a couple tons pre square inch max. Not huge, but a heck of a lot better than beating on it with a hammer :)

BTW, double powered rollers prevent the curl in the billet.
 
That sounds about right what ever it is it does the job.
I've been too busy to get back to it and finish it up. Here in a few weeks Steve Scharwzer is going to make some mosaic damascus on it. I'll post some photos.

BTW the two powered rollers keep it straight until you get it down to around 1/8" thickness. I was watching on the back side of the rollers and the stuff would nearly tie its self in a knot as it was being pulled into the rollers.
 
I'm really interested in this. We've been talking about building one this summer. My questions about this revolve around the lever. First, the 1" square (guessing it's size) that supports the lever seems to be directly on 6" channel. Is there a 1/2" thick plate underneath that would keep the base channel from bending. The mechanical advantage of the foot lever appears to be about 12:1, and it's made of aluminum? Could be stainless, but it looks like aluminum. I could be way off here, but the pins in the lever don't look like they could support 8000 lbs. Lastly, where's the big spring to return the foot lever?
 
I will try and answer all questions, and maybe even get a video, when I get it in place and running.
 
Great looking forward to seeing it in action maybe we can compare notes. I've been painting and reassembling mine. There is not a lot out there on rolling mills.
 
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