Author Topic: Rolling brass into a circle?  (Read 871 times)

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Chris333

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Rolling brass into a circle?
« on: May 31, 2017, 04:56:36 PM »
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On the left are etched parts from a brass loco kit. On the right are etched parts that I had made. Obviously theirs are a thicker metal, but how did they roll them into a perfect circle like that?



I tried rolling mine with an exacto handle on a piece of cork, but they never end up right.

Help!   :|

Lemosteam

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Re: Rolling brass into a circle?
« Reply #1 on: May 31, 2017, 10:32:17 PM »
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Try finding a metal cylindrical part that is a little larger than the finished diameter so the ends do not overlap.  Use several stainless hose clamps with something to protect the etch between them. I think you may need to warm up the brass to get the kinks out, as you tighten the clamps a little at a time. And after they are tight,mark it up again (oven)  and drop it into cold water to set the form.  You should be able to finish the curve at the bottom by closing the curled part.

Those other parts were lilely roll formed between two cylindrical rollers, and maybe a third to curl it up.

Chris333

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Re: Rolling brass into a circle?
« Reply #2 on: May 31, 2017, 10:54:38 PM »
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Quote from: Lemosteam

Those other parts were lilely roll formed between two cylindrical rollers, and maybe a third to curl it up.
Where do I  get one of these?

peteski

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Re: Rolling brass into a circle?
« Reply #3 on: June 01, 2017, 12:50:12 AM »
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Where do I  get one of these?

This might work unless the minimum bend diameter is a bit too large for your cylinders:
http://www.micromark.com/3-in-1-Metal-Worker
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Chris333

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Re: Rolling brass into a circle?
« Reply #4 on: June 01, 2017, 03:21:50 AM »
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This might work unless the minimum bend diameter is a bit too large for your cylinders:
http://www.micromark.com/3-in-1-Metal-Worker

Dang a mini version of that for around $50 would be nice  :D

Found this:
http://www.ausee.com.au/shop/item.aspx?itemid=2331

Still costly $$$
« Last Edit: June 01, 2017, 03:23:40 AM by Chris333 »

Lemosteam

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Re: Rolling brass into a circle?
« Reply #5 on: June 01, 2017, 07:31:26 AM »
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Dang a mini version of that for around $50 would be nice  :D

Found this:
http://www.ausee.com.au/shop/item.aspx?itemid=2331

Still costly $$$

Min bend radii is 15mm for a 30mm diameter.

You do your own etching, why not try to etch a tube by wrapping the mask around it.

narrowminded

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Re: Rolling brass into a circle?
« Reply #6 on: June 04, 2017, 12:28:32 PM »
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That three roll concept exhibited in each of those designs is how that's done.  It controls the force uniformly on the spans between the rollers so, if the material passed through is uniform thickness the resulting bend between the spans is also uniform.  You drive the first and third rolls through gears with an idler gear between to correct the rotation.  If you had a set of gears small enough you could make your own but as with so many of these things, by the time you fool around with it or if you have to purchase a set of gears, three at a time, you're probably way ahead to just buy one.  A quick search suggests the street price of that unit is about $85.

If you're really wanting to not spend the money and IF the material is thin enough you might get away with two rollers, one sleeved with rubber hose to act as the forming force on the sheet.  If it worked at all you could probably get away with no gears, just driving the rubber sleeved roller, and form as small an ID as the adjustable hard roller allows.  The rubber sleeved roller could be almost any size which is helpful if you were to have the  rigidity needed over the span, plus the hose thickness.  In any rig, the key is the uniform force pinching a span of the material.  The rubber roll would flex at some distance straddling the hard roller C/L, serving that purpose.  I would guess .005" brass might work and maybe as much as .010".  Definitely a trial and error job... if it would work at all. :|
Mark G.

daniel_leavitt2000

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Re: Rolling brass into a circle?
« Reply #7 on: June 12, 2017, 12:36:19 AM »
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