followup on scrap tool steel query

Eric Chang wrote:


Oy. 6:1! If someone put a gun to my head and said, "You Will attempt this.", I'd go after it with a six or eight pound hammer and hardly swing it. I'd get it well and thoroughly hot and be 'thumping' it with about a five inch 'swing'. I'd let the heat bleed from the edges into the anvil a little before hammering so that more of the deformation could happen in the middle of the work. I'd be using a one pound hammer when I hit it on the wide faces to straighten it up. Who knows? It might even work.
This learning curve you're trying to climb has a serious overhang.
Another way would be to borrow from the idea of upsetting a tire...
Bend the piece in a swage block, make it look as if you're trying to make a quarter-round gouge.
Measure the width of the piece and clamp something that wide and solid in your biggest vise, somewhat below the tops of the jaws.
Heat the work, place it cupped-side-down in the 'channel' you've made between the vise's jaws and flatten the work.
Repeat until the work gets down to about 2.5:1, then proceed with normal hammer technique.
-- Carl West snipped-for-privacy@comcast.net http://carl.west.home.comcast.net
>>>>>>>> change the 'DOT' to '.' to email me <<<<<<<<<<<<
"Clutter"? This is an object-rich environment.
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...

Hi Pete. Thanks for the rule of thumb. So, this rules out the use of files for making square or circular cross-section tools from?
I did a calculation for an average sized file from my "free" stash:
scale=2 15/16/(5/32) 6.20
This is more than twice as bad as 3:1, and this is with the teeth not ground off. That means that a file is probably unsuitable for edge upsetting, unless one is willing to slop everything over, cover it with flux, and try to get it to stick together, which may have been what the maker of that E-bay pictured file chisel did. Left a lot of "interesting" texture.
Thanks, Eric
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You can work with ratios greater than 3:1, it is just a lot more work. 3:1 you can pretty much stay on the edge. Above that you have to keep flipping to the flat side to remove cupping, which also removes some of the work you did on edge.
I don't know about files at 6:1, though. Sounds frustrating.
Steve
Eric Chang wrote:

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Eric Chang wrote:

No. Try OCS (Old Chevy Spring) which doesn't have to be from a Chevy. Old car springs can be forged, machined and heat treated into good tools.
Make one out of OCS (Old Chevy Spring). Both leaf and coil car/truck springs are made of some very good steel and are usually available free. On coil springs, I cut of one or so rings and heat and straighten (hammer and anvil). Heat to "cherry red" and bury in ashes to anneal. Saw/machine/grind/file to required shape. Heat to cherry red and quench in oil. Clean to bare metal and gently heat to a brown (hard) or purple (not quite so hard but tougher) and quench again.
After he broke his third Snap-on cold chisel, I made one out of truck-size coil spring for my mechanic son-in-law. This was several years ago. He says it may soon need to be sharpened.
Ted
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