Rolling Sheet silver for bangles

**stu_clouds** · 03-03-2010, 02:11 PM

hi,

just a quick question, does anyone here roll silver from ingots into sheets? does it take long?

Also what thickness do people use for cuff bangles both self rolled or bought in sheets?

regards

Stuart

**ps_bond** · 03-03-2010, 02:47 PM

Originally Posted by stu_clouds

just a quick question, does anyone here roll silver from ingots into sheets? does it take long?

Also what thickness do people use for cuff bangles both self rolled or bought in sheets?

Yes, yes, 0.9mm generally for simple constructions.

Oh, and I use a geared rolling mill - I don't think I'd enjoy going back to rolling out ingots without it!
Forging the ingots out initially saves a lot of effort though.

**stu_clouds** · 03-03-2010, 07:54 PM

how i wish i had a geared rolling mill, sadly im still at my parents and i dont think they would take kindly too me attaching the stand too the tiled floor, so i have to use the smaller mill attached to my workbenches.

thank you for the advice iv nearly rolled a sheet down to .9mm finally.

**Lindyloo** · 04-03-2010, 01:25 PM

I have a question about the mills. The Durstons seem to have two descriptions of gears. They all seem to say they have spherical helical drive gears. But some (the more expensive ones) say they also have a gearbox with a reduction of a particular ratio. What do these mean?

Also, if you melt down metal, and then pass it through the mill. In my limited experience, it seems to crack and split. So what have I done wrong? A tutor once told me that each time you melt the metal, it becomes more brittle, and needs to be melted with some casting grain included to improve the purity. Does this help?

**ps_bond** · 04-03-2010, 01:46 PM

Originally Posted by Lindyloo

I have a question about the mills. The Durstons seem to have two descriptions of gears. They all seem to say they have spherical helical drive gears. But some (the more expensive ones) say they also have a gearbox with a reduction of a particular ratio. What do these mean?

We could do with a Durston rep to answer these...

Helical gears are sort of an angled version of "normal" (spur) gears - they offer better power transmission than spur gears (and run quieter at speed, but that's not relevant for hand-driven rolling mills!). They're spherical if the gear teeth are cut onto a spherical body, or slice of a sphere. These gears drive the rollers from the input shaft (the handle for non-reduction rolling mills).

Adding a reduction gearbox onto the input shaft reduces the output - so every time you turn the handle, the input shaft turns 1/4 of what it would without the gearbox - BUT it has 4 times the torque, so while you have to turn it 4 times as many turns, you use 1/4 the effort.

Also, if you melt down metal, and then pass it through the mill. In my limited experience, it seems to crack and split. So what have I done wrong? A tutor once told me that each time you melt the metal, it becomes more brittle, and needs to be melted with some casting grain included to improve the purity. Does this help?

There's a bunch of possible problems, not least of which is the potential for contamination (solder, oxides, hydrogen embrittlement etc. etc.). Many of the casting grains have additives to improve flow at pouring temperature and modify grain formation characteristics as they cool - I think the Cooksons literature goes into some of this - so adding a small amount in to scrap does help.

There's other issues at work regarding alloy segregation & the likes, but I'd need to refer to Brepohl to be sure of my facts.

**Lindyloo** · 04-03-2010, 01:58 PM

Thank you Peter. That answers my questions. The mill we used at college must have been a non-reducing one, because one turn got the metal through, and sometimes it was a bugger to move if you turned the rollers down too far. I am just considering buying one. Really can't justify the dearer ones, but I'm a bit worried that I may wish I had, if I struggle with the non-reducing ones.

**stu_clouds** · 04-03-2010, 03:26 PM

i wish i had bought the larger ones, trying to roll out a good size sheet of silver is a nightmare, but it saves me going too the gym i suppose

. the smaller one is fine for reducing wire though. i shall certainly be purchasing the larger one as soon as trade picks up for us.

regards

Stuart

**Lindyloo** · 05-03-2010, 12:58 PM

Would you consider the cheaper brands, or is it only Durston for you Stu?

**stu_clouds** · 05-03-2010, 02:51 PM

Durston all the way, you get what you pay for really. i just wish i had held out for the geared one grrrrrr. ah well we live and learn.

**CDW Designs** · 01-04-2010, 04:21 PM

Hi Everyone
Talking about Durston rolling mills I have recently bought one and want to know how strong are the rollers for 'thinning' silver sheet and for making bangles or heavyish pendants what is the best thickness to use? Also should they be kept covered when not in use? Mine is a new one and luckily geared but I am anxious not to ruin it by using it wrongly. I am not an expert jewellery more experimental and 'learning amateur'. I still havent got round to uploading any photos yet as I dont know how to>>>>>>>