Mokume draw plate.

S

Sandow

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Jun 13, 2013
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I wanted to try my hand at making copper and nickel silver mokume pins. I saw a method that involved drawing the bundle through a plate with a series of progressively smaller holes that seemed easy enough. Was wondering what the step down needed to be in order to be able to draw the bundle with hand tools. Was thinking .010" per step was reasonable at first but I think that might be a bit aggressive as I work toward my target diameter of around 1/4" before turning it down to 3/16". Anyone here done it?

-Sandow
 
Most folks use a rolling mill with round wire dies. I can't imaging drawing through drawing dies/plates by hand at 1/4" and larger. I find 1/8" about the max you can hand draw in well annealed silver.

I don't know if this will work for your project, but a while back I made mokume round stock for some jewelry. I twisted three strands of annealed 10 gauge silver/copper/brass wire tightly. I annealed and re-twisted for a tighter twist. I then hung it vertically and silver soldered it with 60% silver solder. After a bit of clean up, I rolled it round in the mill. It wasn't quite perfect round, so I sanded it a bit and then rolled again. That gave me a length of solid round stock somewhere around 3/16". It was OK, but a lot of work.

I never did the second idea I had, which was a seven strand twisted bundle. It was to be a 12 gauge brass core with six 10 gauge strands of alternating silver/brass/copper around it. In theory, that would be much rounder when rolled.
 
I concur, pulling rod that size by hand through a draw plate with a pair of drawing tongs would be unlikely.

Man, I wish I could get a hold of a jeweler's rolling mill. I watch eBay from time to time, but haven't scored anything yet. Any of you good people have any recommendations as to what to look for? Stacy? Page? Goldsmithy? Anyone else?
 
Draw Bench is not all that hard to make, sturdy plank of thick wood and some bits and pieces and a set of draw tongs.
 
Saw a video where a guy was doing a bundle that looked that big by hand but some draws did look very hard. Don't think he was pulling it all the way down to round though. My loading press has an eight inch throw. If I can make a clamping fixture I can do the draws on that once they get tough.

Holes with a 2 degree taper and .005" steps seem reasonable?

I assume the mokume will work harden and the pins being hard seems like a good thing. If it is possible to pull in that state, should I or will it embrittle too much?

-Sandow
 
The problem I run into if the metal isn't annealed (and sometimes even when it is) is the end breaking off in the tongs before the pull gets completed.
 
To draw metal it has to be well annealed, or it will have fractures. I anneal every couple of draws, or whenever the draw feels resistant. I would not want the pins hard when done. Hard things break, softer things bend. 8" isn't going to be enough for much of a draw.
When drawing larger gauge wire ( 12 gauge), I sit down and put my feet on both sides of the plate, with the tongs in both hands. I then use my back and legs to draw the wire.
Another important thing is to lube the plate.
 
I have 2 rolling mills. Non-ferrous metals work great. Ferrous metals don't play nice with a rolling mill, when cold. The steel plates with all the tappered holes are call draw plates. Also not good for ferrous metals. Rolling mills are also sold with a "power" feature (it's own motor). Well into 4 figures and when I tried one on a piece of steel years ago, it didn't work well.

A word of caution about buying rolling mills. The new mills coming out of China are crap, crap, crap. The rolling mill I bought 30 years ago is still working just fine.
 
bladsmth said:
To draw metal it has to be well annealed, or it will have fractures. I anneal every couple of draws, or whenever the draw feels resistant. I would not want the pins hard when done. Hard things break, softer things bend. 8" isn't going to be enough for much of a draw.
When drawing larger gauge wire ( 12 gauge), I sit down and put my feet on both sides of the plate, with the tongs in both hands. I then use my back and legs to draw the wire.
Another important thing is to lube the plate.
Click to expand...

Yeah, there is always time for lubricant... I did some experimenting a few years back swaging surplus 50 bmg bullets back into round. Lee sizing wax was the biggest PITA to use on large runs, but the results blew every other lube I tried out of the water.

I really just wanting to make enough at first to pin a knife I'm working on but a simpler idea occurred to me that would give a much longer throw than my press. With the plate in my vise, I could mount a long steel tube to the floor or bottom of the bench and just weld a clamp to the tube at the about the hight of the plate. I would still need to at least get the tip through the plate but that applies to every method.

What you say about the fracturing makes sense. Larger cracks in the copper could probably be filled by heating it all to the melting point of the nickel silver but the tiny stress fractures wouldn't allow that kind of reflow without getting the copper up to the melting point.

Since I don't need much and I was going to turn it to diameter anyway, I think I might try just banging out a rough rod with a hammer. If I like working with the stuff I'll give the big lever and draw plate a try.

-Sandow
 
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