Roll Mill

kuraki

kuraki

Fimbulvetr Knifeworks
Joined
Jun 17, 2016
Messages
4,679
I've read a couple threads here about McDonald style roll mills. Most seem unfinished, left without updates anyway. Combining what I could glean from the original design, and the various threads I've found on this forum and others, and ease of manufacture, I've come up with this design.

Originally I intended to build a hydraulic press first, but what I intend to use it for, flattening, drawing, and laminating, I think a roll will be cheaper and work better for me initially. I'll still want a press for those things a roll cannot do, but could put it off for a while.

The one thing I haven't seen is a method for driving both rollers. The odd method of capturing the bottom moveable roller in the McDonald design pretty much prevents it from being possible, and on a few Youtube videos I've watched it seems like that is a deficiency as a lot of people seem to have to tug and pull to get their rolling started.

Maybe I haven't had enough coffee today but the resolution seems rather simple to drive both rollers? One roller needing to move makes it a little more challenging, but couldn't a set of idler spurs with a gas spring tension arm resolve that?

Basically, any reason you see that this won't work? (they're just hanging out in space at the moment, assume one is in a fixed position and the other is on a swing arm retained by a gas spring)

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I don't see why why that wouldn't work but why does the bottom roller need to be turning?

If it's free spinning won't it just follow the driven roller and workpiece?

I have never used one so I'm just asking.

Edited to add- I have seen some videos of them in use and I wonder if adding some traction to the driven roller would improve performance. Some sort of non- skid or knurling maybe?
 
Both rollers turning will add more grip to help push/pull the steel through the rollers.
 
MBurks adding "traction" that way would leave marks on the steel, it would be literally a knurled damascus.
 
redbate said:
MBurks adding "traction" that way would leave marks on the steel, it would be literally a knurled damascus.
Click to expand...

Yeah, and it would mess with my one (I think) novel idea. Which is the roller sleeves. The intent behind the sleeves is the ability to swap roller faces quickly, I would have a smooth set for drawing and flattening, a tapered set for rolling bevels, a fullering set, possibly even a ladder set.

That's the biggest reason I'd like to drive both wheels.
 
kuraki said:
I've read a couple threads here about McDonald style roll mills. Most seem unfinished, left without updates anyway. Combining what I could glean from the original design, and the various threads I've found on this forum and others, and ease of manufacture, I've come up with this design.

Originally I intended to build a hydraulic press first, but what I intend to use it for, flattening, drawing, and laminating, I think a roll will be cheaper and work better for me initially. I'll still want a press for those things a roll cannot do, but could put it off for a while.

The one thing I haven't seen is a method for driving both rollers. The odd method of capturing the bottom moveable roller in the McDonald design pretty much prevents it from being possible, and on a few Youtube videos I've watched it seems like that is a deficiency as a lot of people seem to have to tug and pull to get their rolling started.

Maybe I haven't had enough coffee today but the resolution seems rather simple to drive both rollers? One roller needing to move makes it a little more challenging, but couldn't a set of idler spurs with a gas spring tension arm resolve that?

Basically, any reason you see that this won't work? (they're just hanging out in space at the moment, assume one is in a fixed position and the other is on a swing arm retained by a gas spring)

txSudg.png

RxsPVp.png

x9E4IK.png

Iuj69d.png
Click to expand...

How much thick steel you want to flatten , draw or laminating ? Rollers will turning only one way or both ?
 
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I've been on the lookout for one of these for years...Out of curiosity, do you need chains on both sides? Couldn't the motor drive one chain which drives both motors?
Thanks
~billyO
 
You have the rollers rolling twords you. You open the jaws and insert the billet in all the way and close the jaws. The roller then rolls the steel and it comes out twords you. Much safer this way then with the rollers going away from you.
 
weo said:
I've been on the lookout for one of these for years...Out of curiosity, do you need chains on both sides? Couldn't the motor drive one chain which drives both motors?
Thanks
~billyO
Click to expand...

Yes, but it becomes more complicated because I need to reduce the speed coming out of the gearbox to get the 11-12 sfpm most people run these at. So it's easier to drive one roller with the large sprocket and then drive the other roller with that one. You can't just loop around them both or they'll turn the same direction and fight each other.
 
Natlek said:
How much thick steel you want to flatten , draw or laminating ? Rollers will turning only one way or both ?
Click to expand...

I've given it a full inch of travel with the foot pedal, and the height adjusting link will have another 6" of travel. Roller sleeves are 6" wide so in theory it could accept a 6x6 billet. In reality I will likely be working in 2" or smaller squares.

Wheels will turn opposite each other like JT said.
 
An additional reason for driving both wheels is that I will be installing a 4" air cylinder to drive the bottom roller, either initially to see what that added force does, is it faster to use the pedal with less pressure and more, quicker cycles, or the cylinder with fewer high pressure cycles. I'm estimating that under that cylinders force an idle roller will want to seize rather than turn freely.
 
kuraki said:
Yeah, and it would mess with my one (I think) novel idea. Which is the roller sleeves. The intent behind the sleeves is the ability to swap roller faces quickly, I would have a smooth set for drawing and flattening, a tapered set for rolling bevels, a fullering set, possibly even a ladder set.

That's the biggest reason I'd like to drive both wheels.
Click to expand...

I understand, i just assumed these were more for rough forging, like i said I've never used one. Would something say the size of the grip tape on a skateboard effect the final pattern on Damascus?

I'm not quite able to visualize how the sleeve idea will work , what secures the sleeves to the rollers?

I am interested to see what you work out but I realize I am no help so I will shut up and just follow along!
 
An air cylinder might be slicker then you think. you could set the desired finished thickness with an adjustment and then adjust the pressure to the cylinder to give the right amount of bite. Then just run it, the cylinder will continue to close a little on each pass till you reach the limit you set. If it would work it would save a lot of time fiddling with the adjustment ever other pass or so.
 
Have you used one, or seen one in use? If so, what were the actual limitations of the machine that you feel need to be overcome?

It looks to me like you are trying to add lots of bells and whistles to a piece of equipment that exists precisely because it is very simple and just gets the job done.

There does not seem to be any need to drive both rollers: The units that are out there working all seem to work ok driving one roller.

On the one unit I have personally seen in action, the centre-centre distance between the rollers is so small that it would seem to be be a significant engineering exercise to devise a system to drive both rollers with the level of torque needed. Yours seems to use larger rollers. What effect does this have on the forces involved?

Again, it's only the one that I've seen running, but I got the impression that the foot pedal went overcentre during use and that the thickness was set by the adjustment of the turnbuckle (which is shown in black in the CAD drawings, though without any means of adjustment).

The roller sleeves seem like a major engineering exercise as well: they'll need to be inboard of the bearings, so changing them seems unlikely to be a quick, easy job unless you have a particularly cunning plan.

The usual "design" process for successful builds seems to be 1/ find a suitable geared motor. 2/ design the rest of the machine around that geared motor. 3/ build it. 4/ see if it works, see if it breaks, make any modifications necessary. Do you have the geared motor already?
 
JTknives said:
An air cylinder might be slicker then you think. you could set the desired finished thickness with an adjustment and then adjust the pressure to the cylinder to give the right amount of bite. Then just run it, the cylinder will continue to close a little on each pass till you reach the limit you set. If it would work it would save a lot of time fiddling with the adjustment ever other pass or so.
Click to expand...

Exactly :)
 
I spent a few years working in steel mills, and I can tell you that most industrial rolling mills were driven from both top and bottom, but with two separate motors per stand, and usually it was a larger driven backup running a smaller work roll that was not driven. In any case, it was just as much to control head ends and tail ends as it was anything else.

I'm curious to see what advantage if any presents itself on this much smaller and more basic application.
 
Well I can certainly build it without driving both and then add it later if I feel it's necessary.
 
First, if you build a beveled roller, it will turn out curved bars. It would be the same as forging a bevel only .... the blade becomes a banana. The rollers need to be exactly parallel, and there needs to be a fine tuning adjustment to keept the bars straight.

I have several rolling mills for jewelry work. Two are powered. One is single roller powered, and the other is double powered. The main difference is how thick the stock it can roll, and how curled the bar will come out. The single will only do thinner stock and wire. To counter the curve of a single roller, I filp the stock each roll.
 
I understand the banana issue, I was hoping I could counter act it, if I can't I'll straighten on the anvil.

What exactly is it about driving both rolls that allows thicker stock?
 
kuraki said:
I understand the banana issue, I was hoping I could counter act it, if I can't I'll straighten on the anvil.

What exactly is it about driving both rolls that allows thicker stock?
Click to expand...

Twice the "power" pushing the media through the roller.


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