Cookson's Budget Rolling Mill

[SICraftDesigns]

Good morning all,

I'm needing a rolling mill and while I would love to up my budget I can't really justify the price of a Durston rolling mill for the amount I'll be using it. The only deal breaker with Cookson's budget one is that it doesn't look like you can roll square wire which is exactly what I am needing it for!

Luckily I am able to make my own rollers so, before I go ahead and order, does anyone happen to know the diameter of the rollers as this will determine whether I can grip the thing in my lathe to cut a keyway for the gear using an end mill?

Thanks in advance,

Sam

[Dennis]

It looks from the description and also the video, that the diameter of the rollers is 41mm. If I'm wrong and you get no answers here, a call to Cookson should verify it.

Also bear in mind that while rollers are good at hardening recently poured ingots and reducing wire and offcuts to a manageable size, the result will not be as perfect as using a draw plate, which would be the next stage.

See the recent thread Making Straight Rods, to read about a home made draw bench.

http://www.cooksongold.com/forum/showthread.php?t=9250 Dennis.

[ps_bond]

The other 2 points I'd make are 1) rolls are - or should be - hardened which makes turning fun and 2) square rolls are tipped on one corner, so it's not a keyway but a V groove.

Unless you've been using some very odd keys, that is.

[china]

I' guessing you have one of those Chinese combination mill lathes.

[SICraftDesigns]

It looks from the description and also the video, that the diameter of the rollers is 41mm. If I'm wrong and you get no answers here, a call to Cookson should verify it.

Also bear in mind that while rollers are good at hardening recently poured ingots and reducing wire and offcuts to a manageable size, the result will not be as perfect as using a draw plate, which would be the next stage.

See the recent thread Making Straight Rods, to read about a home made draw bench.

http://www.cooksongold.com/forum/showthread.php?t=9250 Dennis.

Thank you for your input Dennis. I've seen that thread and have been taking notes! Thankfully I don't need perfection for this project due to the amount of subsequent hammering & filing so I was hoping a roller would suit my needs. Also, for this particular project I plan on flattening the square wire to form a rectangular cross section which I don't think I would be able to do with draw plates.


The other 2 points I'd make are 1) rolls are - or should be - hardened which makes turning fun and 2) square rolls are tipped on one corner, so it's not a keyway but a V groove.

Unless you've been using some very odd keys, that is.

I'd be making the rollers from silver steel rod and hardening after machining. In theory a hardness of 65+ HRC should be achievable however even the worst case scenario 60 HRC shouldn't be too hard to obtain. I'd then give them a final polish in the lathe to clean them up.

The keyway I was referring to would be at the end of the shaft where the gears attach to stop them from spinning on the shaft (as can be seen on the end of this replacement roller http://www.cooksongold.com/Jewellery-Tools/Spare-Plain-Roller-Small-prcode-999-AXWD&query=rolling%20mill&channel=uk). It's a lot easier to machine these with a mill but as I don't have access to one I plan on cutting this keyway in the lathe but I am limited as to what diameter of stock I can hold in my toolpost without some modifications.

Cutting the V grooves should be straightforward enough using off the shelf lathe tooling. I had originally hoped I could just buy a spare top roller and run it on the bottom however it appears as though this would not work as I would have no way of driving it.


I' guessing you have one of those Chinese combination mill lathes.

No I have a regular geared toolroom lathe with an 8" chuck. I'd be mounting the rollers in the toolpost and putting an endmill in the chuck to cut the keyway which is why I am restricted in the diameter of the rollers. Thinking about it though if I put a 16mm piece of key steel in my toolpost and cut a V groove along the length then using U bolts I could secure the roller to the keysteel. I wish I'd thought of that a while ago as it means I could clamp just about any diameter of stock in the toolpost.

A milling machine is high on my wish list but for what I'm wanting it to do I would like to have a 4 axis CNC machine which is beyond my ability to program. I'm at that awkward stage where I do't want to fork out on a machine that I can't use but without the machine I'll never learn!

[ps_bond]

I'd be making the rollers from silver steel rod and hardening after machining. In theory a hardness of 65+ HRC should be achievable however even the worst case scenario 60 HRC shouldn't be too hard to obtain. I'd then give them a final polish in the lathe to clean them up.

The keyway I was referring to would be at the end of the shaft where the gears attach to stop them from spinning on the shaft (as can be seen on the end of this replacement roller http://www.cooksongold.com/Jewellery-Tools/Spare-Plain-Roller-Small-prcode-999-AXWD&query=rolling%20mill&channel=uk). It's a lot easier to machine these with a mill but as I don't have access to one I plan on cutting this keyway in the lathe but I am limited as to what diameter of stock I can hold in my toolpost without some modifications.

Can you do finish grinding with your setup?

Understood on the keyway - although you can cut a keyway with a hammer and chisel, you don't need a mill. Still needs good layout though and you'll probably need to fettle it.

[SICraftDesigns]

At the moment no although I have had my eye on a toolpost grinder for a while. I think it's just because i like new tools rather than that I actually have a need for one! For this project I think a buff with some 1500 grit wet and dry would do the job. The forming of the V grooves should give a pretty good finish anyway and I suspect that a grinding wheel to cut them may prove hard to come by.

My concern cutting it manually is the inevitable slip of the chisel scoring the roller but yes, this would be another way of doing it. A good one too if it saves me a couple of hundred quid!

[-Sally-]

Could you not just get a rectangular draw plate?
Sally

[SICraftDesigns]

Could you not just get a rectangular draw plate?
Sally

I didn't know such things existed until you mentioned it! For this particular project I have been asked to melt the gold from a customers ring to make a new one so I'm guessing for this I would need the rollers anyway to shape the gold prior to running it through the draw plates?

[Dennis]

Rectangular wires are among the toughest to draw down, so unless you can sit on the floor and push with your legs, a draw bench might be needed.
You can do a pretty good job cutting it from sheet. Dennis.

[SICraftDesigns]

Well, in a dramatic turn of events I spotted a Durston D2 rolling mill & stand going cheap on Gumtree and so am having it delivered tomorrow! Can't wait to have a play with it but I think I'll need to clear some space in the workshop first!

[ps_bond]

"Cheap" and "Durston" aren't often words that are heard in the same sentence... Congrats - and watch your back lugging the thing.

[SICraftDesigns]

Well I thought that at first and was reluctant having not seen it in person but for the money I figured it was worth a shot! It seems that a shop in Hamilton is clearing out their in house repair facility and either don't know the true value of it or just want rid of it. Either way I was chuffed to bits with the find!

As for my back - it's a long way from the street to the workshop so I'm hoping I can recruit a willing neighbor to help shift it!

And thank you to everyone for your input to my original question - it was very much appreciated!

[Dennis]

Well done, that will give you all you can ever need from a rolling mill and no changing of rollers. Dennis.

[SICraftDesigns]

I finally got around to playing with my new rolling mill last night. I think I need to bolt it to the floor! Or perhaps I was getting a little carried away with the reductions?

One question I have is that I noticed on a few occasions the edges of the wire became a little rough and sharp. I stopped when I noticed this, re annealed and rolled again which seemed to fix the issue but I am not sure whether I was under annealing the wire or whether I was closing the gap in the rollers too much. Any advice would be greatly appreciated.

[enigma]

I haven't used mine for wire yet so can't help there but it does need bolting down, well at least my cheap one does.

[handmadeblanks]

I finally got around to playing with my new rolling mill last night. I think I need to bolt it to the floor! Or perhaps I was getting a little carried away with the reductions?

One question I have is that I noticed on a few occasions the edges of the wire became a little rough and sharp. I stopped when I noticed this, re annealed and rolled again which seemed to fix the issue but I am not sure whether I was under annealing the wire or whether I was closing the gap in the rollers too much. Any advice would be greatly appreciated.

I haven't rolled wire yet either. But I believe the recommended procedure is turning the wire 90° after each pass. Also, I think rolling is only recommended for the initial stage of reduction. The wire should be pulled through draw plates for the final stage. But I am only advising from a book-learned perspective. Never tried in practice.

[Dennis]

I finally got around to playing with my new rolling mill last night. I think I need to bolt it to the floor! Or perhaps I was getting a little carried away with the reductions?

One question I have is that I noticed on a few occasions the edges of the wire became a little rough and sharp. I stopped when I noticed this, re annealed and rolled again which seemed to fix the issue but I am not sure whether I was under annealing the wire or whether I was closing the gap in the rollers too much. Any advice would be greatly appreciated.

Yes if it is on a stand, it is totally unsafe unless well secured to the floor. Even so, they have a habit of working loose if the floor is not suitable. Of course you can ditch the stand.

You should never use all your might, but proceed quite gently for best results.

If you close the rollers too quickly, a sharp ridge will appear with square wire, this of course is why the final profile is more true with a draw plate. So take your time and rotate the wire at every pass. Even re-annealing and putting through again will reduce the wires further, because the rollers are sprung. Dennis

[SICraftDesigns]

Thank you all for your help. I think it may have been me trying to reduce the wire too quickly as you mention Dennis! That also probably explains why I was having to put so much effort in! My logic was that the quicker the wire can be reduced the less work hardening would occur making rolling easier but I'll go slow and steady next time to see if that offers any improved results. For this project the as rolled wire will be fine however I have a few coming up where I'll be drawing the square wire to round so I should get the chance to practice lots!

Thanks again for your help!

p.s. I'll anchor the stand to the ground before my next shot!