Turn bent piece of round brass stock to straighten it ??...

56type

Registered
Registered
Joined
Aug 16, 2016
Messages
178
Was at one of the local flea market type stores and picked up some scrap metal pieces for turning cheap. Among the pieces was a section of what appears to be possibly hardened brass round stock 1.435 in. in diameter about 3.75 in. length. It looks as it has been sheared off at one end and was ragged so I used the bench grinder (hacksaw didn't seem to want to cut it hence why I'm thinking it's been hardened to some degree) to smooth it up enough to get it in the 4-jaw, the other end is mushroomed as if it was pounded/hammered on.

In trying to get it centered up in the 4-jaw I noticed it was bent along the long axis so I'm having trouble figuring out how to go about turning it on the lathe (Atlas 10100) to get it straight/back in round where I can make something useful out of it. I set the DI to roughly the middle of the 3 in. of stock sticking out of the chuck as a starting point since I was having zero luck finding any way to center it in the 4-jaw. Using the middle of the workpiece as a starting point I was able to center it within 0.003 in. at that point on the work.

Setting the DI up at the chuck jaws and rotating the work gives a reading on the DI of 0.092 in. Moving the DI out to just below the mushroomed end of the work & rotating the work again gives a read of 0.075 in., the DI was set up to read off the #1 jaw of the chuck for all three measurements..... chuck end of work 0.092 in., midpoint of work 0.003 in., tailstock (mushroomed) end of work 0.075 in.

My question is...Am I going about this the right way or is there a better way to bring the work piece back into uniform round condition along it's length so that it will be a usable piece of stock to work with ?? Any tips, tricks, voodoo, on set up would be appreciated. Thanks.
 
I would grab it by the best end, face and turn the OD until it's round. Then flip it around in the chuck and turn the other end to more or less match the turned end. If you're lucky you may wind up with a 1.25 dia piece of round stock.
 
I would face both ends. To get the most stock from the piece, I would pinch it between centers and rotate it looking to get the least overall runout. By pinching the piece, you can move the contact points around to optimize runout. I would then drill for centers and turn between centers. If you don't have a lathe dog large enough, a makeshift dog could be made from a muffler clamp.
 
You can also scribe an X across the end with a tri-square, that will get you pretty close to the center
 
Since one end is already mushroomed, it may have been used as a brass hammer for bumping things around to indicate things in. You may just want to keep it for that purpose.

I would not clean it up just for stock, It would go in the stock pile and someday the part you make out of it may dictate the best method of cleaning it up. If you remove material now then it may be to small for something down the road.

With one end mushroomed there may be internal stresses in the material. Once you make something out of it those stresses could be relieved and your part could spring back to somewhere other than what you wanted.
 
Since one end is already mushroomed, it may have been used as a brass hammer for bumping things around to indicate things in. You may just want to keep it for that purpose.

I would not clean it up just for stock, It would go in the stock pile and someday the part you make out of it may dictate the best method of cleaning it up. If you remove material now then it may be to small for something down the road.

With one end mushroomed there may be internal stresses in the material. Once you make something out of it those stresses could be relieved and your part could spring back to somewhere other than what you wanted.

I'm thinking of making some small bolt roller greasing tools for the M14 rifle. Basically these are little more than a glorified brass thimble with a hole of proper diameter in the center for grease to be placed, the tool is then slipped over the roller of the M14 bolt & pressed down to force grease into/around the bolt roller. Similar in all respects to packing a wheel bearing. The tool just wastes less grease and makes the task both easier & cleaner to perform with the added benefit of a uniform amount of grease being forced into the roller while forcing contaminated grease from the roller.

Bolt roller greasing tool
 
I would grab it by the best end, face and turn the OD until it's round. Then flip it around in the chuck and turn the other end to more or less match the turned end. If you're lucky you may wind up with a 1.25 dia piece of round stock.

This is how it's set up right now... I used the mid-point to set it up as I thought that point would give the best overall result with least amount of material waste. I have no idea what purpose the piece previously served but it was ragged at both ends. I'll have to turn the mushroomed section down to get a uniform diameter over the whole of the work piece.

As suggested I'm going to use the live center to try to minimize any wobble since the piece is bent and off center and to also minimize deflection. Once I get a uniform O.D. I will try to face it, then knurl it & start making the greasing tool I have linked to in the last post. Probably make a few extra to have on hand or maybe for gifts later. Thanks to all who replied.
 
Hammered on brass=work hardened. Might be much harder to machine than your run of the mill 1/2 hard brass.
 
...
Hammered on brass=work hardened. Might be much harder to machine than your run of the mill 1/2 hard brass.
The area of concern would be the mushroomed end right? Is it possible to anneal the piece if that is the case without overly softening the end that is not work hardened? Can metal even be overly softened (not speaking about melting here)?
 
Is it possible to anneal the piece

Only thing I have brass annealing experience with is rifle cases.
About opposite of steels. Heat to red and quench in water. Something that would likely make steel hard makes brass soft.
Just kinda sounded like it might be very hard when you said the hacksaw had trouble cutting it.
Might be worth trying to machine first just to see if it machines ok or not. If it gives trouble then anneal.
 
Back
Top