Rolling mill motor

Jonathans

Jonathans

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Jan 9, 2008
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I’m in the process of having a Mcdonald rolling mill made. Rather than chain and sprockets I want to go with a motor and reduction gear box that I have seen others do. What I can’t seem to extract from the WIPs I’ve read is what HP motor and what speed reduction is required.

Any help with that, and a good surplus source for motor and reducer would greatly appreciated.

Another idea is to utilize a hydraulic motor as I have hydraulics plumbed in the shop. Would a system putting out 8gpm be able to power the rolling mill or is it better to stick with electric?
 
Salem and I are in the process of build a set of rolling mills. The minimum is 1/2hp at 20rpm. Make sure your gear box is designed to put out the required torque. The mathe says you need 1,575 in/lb of torque at 20rpm with 2" rollers minimum.
 
Thanks JT. JDM61, I guess depending upon his experience with the build, he might become a source of built mills. With his experience with hammers, I would think it makes him a good candidate.
 
JT, you state that the minimum is 1/2hp. What have you and Salem actually settled on as far as the motor and gearbox?
How far along are you guys with your builds?
 
This is what I found online that I think will do the job, and the price is right.
Any opinions?
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WGA-75M-060-H1
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IronHorse medium-duty worm gearbox, 60:1 ratio, 56C-Face input, hollow, 1.25in diameter output shaft, nominal 1hp at 1.0 SF, 1770lbf-in mechanical output torque, 75mm center distance, cast aluminum housing, top and bottom mount.
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MTRP-001-3BD18
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IronHorse premium efficiency AC induction motor, general purpose, 1hp, 3-phase, 208-230/460 VAC, 1800rpm, TEFC, 56C/HC frame, rolled steel, rigid C-face mount.
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We are going above and beyond the origanial plans. I have re drawn everything up in solidworks (3D cad) and mad a good number of changes for the better. We are running at a good bit more HP then the minimum. He have tossed around the idea of using a hydraulic motor and splitting it off the press power plant. I'm building a 3ph 10HP power plant and so I wil either go that way or use a gear box I have. I found another gear box motor combo that's 7.5HP but it's huge. Considering all funds needed I think cheepest for us is hydraulic motor. With a speed control on the flow line to the motor.
 
If you are going hydraulic, could you power both rollers or is space too tight?
JTknives said:
We are going above and beyond the origanial plans. I have re drawn everything up in solidworks (3D cad) and mad a good number of changes for the better. We are running at a good bit more HP then the minimum. He have tossed around the idea of using a hydraulic motor and splitting it off the press power plant. I'm building a 3ph 10HP power plant and so I wil either go that way or use a gear box I have. I found another gear box motor combo that's 7.5HP but it's huge. Considering all funds needed I think cheepest for us is hydraulic motor. With a speed control on the flow line to the motor.
Click to expand...
 
You would have to adjust a few things and possibly bump up roller diameter but it's possible
 
From what I gather there's not a big advantage to having both rollers powered, for the purposes of these machines. Plus the available torque would be halved to each motor, unless you doubled up the HPU's capacity. Not sure how that would affect performance.... but why overly mess with a proven design. If anything it might improve the machine's grip on the steel, but that's already pretty decent and adequate to the reduction that can be achieved in a single pass without increasing hp and roller size significantly... and then before too long we'd arrive at a new class of machine altogether, more resembling an industrial rolling mill.
It is a good observation though, that the use of hydraulic motors affords the opportunity to power the lower roller should one wish.
 
Salem Straub said:
From what I gather there's not a big advantage to having both rollers powered, for the purposes of these machines. Plus the available torque would be halved to each motor, unless you doubled up the HPU's capacity. Not sure how that would affect performance.... but why overly mess with a proven design. If anything it might improve the machine's grip on the steel, but that's already pretty decent and adequate to the reduction that can be achieved in a single pass without increasing hp and roller size significantly... and then before too long we'd arrive at a new class of machine altogether, more resembling an industrial rolling mill.
It is a good observation though, that the use of hydraulic motors affords the opportunity to power the lower roller should one wish.
Click to expand...
Salem, IIRC, Chuck Bybee had Matt Whitmus build his mill with both rollers powered. That may have to do with those evil titanium mashups requiring more "traction" than plain old steel.
 
Salem, are you retaining the treadle operated roller, or switching to a positive adjustment for the gap more like an industrial roller?
 
jdm61 said:
If you are going hydraulic, could you power both rollers or is space too tight?
Click to expand...


I'm here to tell you, that, contrary to popular belief, there's no real reason to power both rollers for this type of work.

My 5hp mill has only a single roller powered, and I can discern no real difference between it, and all much larger mills I've used with double powered rolls. Many of which, introduce more banana than mine does. Either way, some straightening is necessary no matter what you do, even with two powered, perfectly turned to the same diameter, perfectly aligned rolls. Simply because any variation going into the roller, of the base billet, or differences in heat, will introduce movement.

90% of which is mitigated by flipping the billet each time you feed it, and making sure you feed in square, and straight as you can. Any angle, will cause more warp. Honestly, that'll be the biggest issue of the McDonald style mills. Most commercial units are designed with a large shelf on one or both sides, positioned in plane with the bottom, stationary roll's outside diameter, to keep everything feeding uniformly.


I'm not saying there aren't advantages to double powered rolls, on a really big, really nice unit, but on this style you guys are building, even with significant upgrades, without changing the type of machine completely, I wouldn't think it'll be worth the effort (make any difference).
 
javand said:
I'm here to tell you, that, contrary to popular belief, there's no real reason to power both rollers for this type of work.

My 5hp mill has only a single roller powered, and I can discern no real difference between it, and all much larger mills I've used with double powered rolls. Many of which, introduce more banana than mine does. Either way, some straightening is necessary no matter what you do, even with two powered, perfectly turned to the same diameter, perfectly aligned rolls. Simply because any variation going into the roller, of the base billet, or differences in heat, will introduce movement.

90% of which is mitigated by flipping the billet each time you feed it, and making sure you feed in square, and straight as you can. Any angle, will cause more warp. Honestly, that'll be the biggest issue of the McDonald style mills. Most commercial units are designed with a large shelf on one or both sides, positioned in plane with the bottom, stationary roll's outside diameter, to keep everything feeding uniformly.


I'm not saying there aren't advantages to double powered rolls, on a really big, really nice unit, but on this style you guys are building, even with significant upgrades, without changing the type of machine completely, I wouldn't think it'll be worth the effort (make any difference).
Click to expand...

I figured with the amount "we" bite at a time that one vs two is not a concern. How much do you close the rollers per pass. Have you noticed an advantage with the larger motor. I'm planning on bumping up the rollers rpm and I had figured this will increase the HP demand as well.
 
Hey sorry for the delayed response, been dealing with some big orders, and flu season.

How much you can take per-pass depends on the heat and thickness, as you get thinner, you have to go lighter, especially if you want to keep it moving evenly, and warping less, in my experience. I tend to like to do longer, less wide bars, I used to be limited to about 2.5" width because of the dies on my power hammer, although I'll probably start working at 4-6" width now that I've got bigger hammers and dies, which is more commonly what the bigger producers work with, wider shorter billets, will change some factors.

I can easily get 1/16" reduction per pass (I've taken double, but I can tell it's working the motor), when I'm in the say 0.300-0.750 range (I don't use the rolling mill above this thickness, and my rollers will only separate about 1"), but I go to about half that reduction when I get into the sub 0.300 range. Once it gets lower, there's a chance if the billet cools, or isn't evenly hot, that it'll slip, if I take too heavy a bite. Part of this is my machine though, I've got a large chain/sprocket drive system from the gear reducer to the powered roller, with a little slop that'll slip if I load the motor too heavily.

I keep meaning to adjust it, but it requires some modifications in the form of an idler, since it's less than one link. On the other hand, it's worked great as an indicator of heat and motor load. You can definitely hear the motor straining right before it happens and I can always tell by the sound.


I wouldn't want less than 5hp for my use personally, but I think it would be a waste for a classic "McDonald" style, where you're using that whole foot powered leverage clamping system, which really doesn't give you enough force to take huge bites from what I've seen, offer repeat-ability, or fine adjustment range.

I can usually target a finished billet thickness, on the last heat, ending up significantly longer than my forge, making 3-4 passes on the last heat, and knowing how much scale I typically have to remove to get past any variation in depth, with relative ease with my machine now that I've got a feel for it. Even with the rolling mill FYI, you're going to have depth inconsistency. Just from scale getting mashed in at different depths as the billet temps change, and based on what you beat in previously, unless you grind clean before the final pass.



I'll give a disclaimer though: I only know about the McDonald mills what I've seen in a few videos, and two sort of "thrown together" examples I've seen. I can see it's use, but I don't consider it to really be the same type of machine as a rolling mill with two captured rollers and a hard(locking) distance adjustment, however, I know you guys said you're making some changes, and I admit I may be missing some key feature of the design.


IMO though, I just don't see building a traditional rolling mill, as being any harder that making a McDonald. I'll take a photo of mine so you guys can see how compact it is, yes, it's still 10x larger than a McDonald, but it's only taking up about a 3x3' footprint, and seems to do the same work as my friend's bigger ones.
 
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