followup on scrap tool steel query

Eric Chang · 2004-09-15T16:51:53+00:00

Hi. A short while ago, I asked a question on this forum about whetherit was worthwhile to rework Harbor Freight punches and chisels intoblacksmithing hot work tools. The general tone of the repliessuggested that I try to use some other source (cheaper, more suitable,less deformation when hot). The reason I originally asked is that Ihad to make an emergency punch out of mild steel. There was nosuperquench available (period accurate shop) and the punch died afterthe second hole through 1/2" stock.I did not find any star drills at garage sales. These are gettinghard to find. I did go to a sale where this old woodworker wasdisposing of some junk. He had a box full of junk and broken toolsthat he was selling for a quarter each. So, I bought severalscrewdriver bits and things that looked like good steel. There wasalso a huge chisel in the box marked "cast steel" with an arrow emblemon back. This was too nice to chop up, so I sharpened it and it worksjust great. The woodworker asked me what I was looking for, and Itold him junk tool steel. He pulled out a huge box of old files andtold me that I could have any ones that I wanted for free. Then, hesaid that he suspected that I am a blacksmith. He suggested that wecould make a deal. I could make some woodcarving blades and he wouldmake handles and we would swap. I had a worried look on my face, sohe fetched one of his creations for me. It had an ugly stock removedblade, and a beautiful exotic hardwood handle. I started to get hispoint. If I could work the steel, he could do the wood. He thenshowed me another tool with a deformed edge. He said, this is whathappens when you use mild steel or you don't temper correctly. Talkabout preaching to the choir!!! Amazing what folks you could meet atgarage sales. Now I might have to learn something about knifemaking.Anyway, I tried making a punch out of one of those bits. It lookedlike a wide flat bladed screwdriver with a 3/8" shank. It wouldbecome a 3/8"...

Sep 15, 2004 23 Replies

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Eric Chang 21 years ago

Hi Carl. Thanks for the tip. How heavy a hammer would you recommend for the typical cross section (about 6:1 ratio, 15/16" x 5/32" thick)?

Thanks, Eric

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Steve Smith 21 years ago

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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Carl West 21 years ago

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

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