brass bar question

Hi, All:
I have a brass bar, .250 thick, 1.5 wide and 12" long. I need to twist it so
the first and last 2" stay flat but wind up at a 45 º angle to each other. My
first thought was to bolt or weld two long angles to use as a wrench and put
one end in the bench vice and just brute force it. My question is: if I do
that cold will the bar twist or break? If I heat the bar with either a
propane or MAPP gas torch will that work. Is there a better way alltogether?
Thanks for your help and advice.
Roger in Vegas
Worlds Greatest Impulse Buyer
Reply to
Roger Hull
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brass is kinda brittle, it will probably break.. even if your eyes are not close to it, i would use caution and wear eye protection as brass is know to break off and fly apart with force on it.... better than looking for a new eye...
Reply to
jim
Just a guess- it will work as you describe even without the torch but it's going to take a lot of torque. I hope your vise and bench are heavy duty and your angle irons are a few feet long. Naturally, heating it with the torch is going to make it easier to bend.
Roger Hull wrote:
Reply to
tomcas
I would think it would break just because it machines like cast iron. But, that's not why I'm posting. I can't find you phone # again and I saw this tracked machine behind Hanna's that you might want to look at...
Reply to
Sunworshiper
Brass bar can come in "dead soft", " quarter hard" all the way to " full hard" Dead soft will bend like cheese, full hard will snap. Your method sounds reasonable so give it a try. =
Roger Hull wrote:
Reply to
Roy Jenson
The best way to do this is to set up the bar in a 4 jaw chuck with the 2" mark level with the front of the jaws, then clamp 2" of the other end in the toolpost. When the bar is set up true to the center line, you can grip one of the jaws with an adjustable wrench and twist the bar until you get 45 deg.
Reply to
Pablo
I don't keep the proportions of copper and zink in my head but there are several types of brass. Some are mixed for machining some are mixed for bending. It would help to know which you have. If it the latter you should be able to manage with out annealing. If you only have one piece and none to spare go ahead an anneal it just to be safe.
LB
Reply to
Leonard & Peggy Brown
I don't see brass that is only .250" cracking with a 45 degree bend, have bent a lot of brass over the years up to 180 degrees. Wayne
Reply to
Wayne's Locks
For optimum strength, if strength is needed, the bend should take the bar from condition A to condition B. Condition B is the temper appropriate for the application. I don't think there's any heat treatment to achieve condition B. Condition A might be fully annealed, quarter or half hard, or near full hard.
To evaluate what can be done with your particular bar, saw off a piece from the end which is Mill it if needed to get the proportions right, while the absolute size matters little.
Then clamp the ends 0.2 inches and bend with no heat treat to the same 45 after springback as you want with the full 10x scale piece. Check for cracks. If it cracks, or has stress marks, either full anneal and count on less than full strength, or cut another piece and figure out how much to anneal it.
Whatever you do, don't bend it hot. Brass and copper are hot short, that is, they sustain near 0 % elongation before rupture when hot.
So divide everything except the angle by 10, and make a trial. You're only losing 0.025 off the end of a 12 inch piece, after all.
12 x 1.5 x 0.25.... 12/1.5 = 8; 1.5 / 0.25 = 6. Using a larger scale will make the piece smaller, so.... 12 / 8 = 1.5; 12 / 6 = 2. We don't have 2. 1.5 / 8 = 3/16 ; 1.5 / 6 = 0.25 So what will fit in the end of the bar? Clearly scale 1/8. So the bit off the end will be 1.5 x 3/16 x 1/32.
Did I get that right?
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA Unpublished work Copyright 2003 Doug Goncz Fair use and Usenet distribution without restriction or fee Civil and criminal penalties for circumvention of any embedded encryption
Reply to
Doug Goncz

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