Harry Marinakis

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Posts posted by Harry Marinakis

  1. Up until today I have been hammering on leaf springs, coils springs, etc. Today I started playing with known metals (wrought iron and O-1 steel). They both cracked on me during hammering.


    1. I took a wrought iron rod, flattened it into a flat strip about 3/16" thick, and tried to bend it around a 2-inch diameter pipe with some gentle taps. It cracked. What did I do wrong? Did the iron cool too quickly while in contact with the pipe?

    2. I bought some O-1 steel (3/8" x 1" rectangular bar). It cracked just hammering to thin it (see photo). The piece in the photo is still 1/4" thick. Was I working it too hot or too cold?


  2. I understand that junkyard steel is a big unknown.

    For the past month I've been hammering on A36, leaf springs, coil springs and this jack hammer bit.

    That jack hammer bit was the toughest stuff I'll tried, by far. I had to get it really hot and pound it with a 4-pound hammer to get it to move. Is that consistent with 1050?

    The leaf spring was also pretty hard, but nowhere near as hard as the jack hammer bit. The coil spring was softer still.

    I did buy some A36 and W1 to make things out of known steel, but right now I'm playing with junk. I guess I really should stick with known steels.

    Aspery's Vol I purchased.

    Thanks all.


  3. 13 hours ago, ThomasPowers said:

    please look up grain growth.   Were the other pieces you tried the same size?

    The references that I have suggest that jack hammer bits are S7 steel, and soak times for normalizing and hardening at 30 minutes per inch. Since the tool is 1 inch thick, I used 30 minutes.

    The only other piece I made was a 1/4" leaf spring knife blade, and I know that's just a knife-shaped object.

  4. Normalizing - After forging was complete, I heated it for 30 minutes at non-magnetic and then let it air cool.

    1050? I have been playing a lot with leaf springs and coil springs, and the jack hammer bit was a helluva lot harder than either of those steels. It barely budged under a 4-pound sledge, unlike the spring steel. 

  5.  Critiques, please

    Newbie here, in the process of making some basic tools to make knives, flint strikers, and other little things. I am using junkyard steel for now, like leaf and coil springs.

    I found myself in need of a hot cut. So I made this chisel from a jack hammer bit (that was about 1-1/8 inches thick). It was hard as hell, had to work it really hot and coax it with a 4-lb sledge until I got it thinned out a bit.

    Obviously didn't turn out as planned, taller and thinner than I intended, but here it is. For my use it should be adequate, though. I ground an appleseed edge.

    Normalized it for 30 minutes when it became non-magnetic, but then I had trouble running the forge at a low enough heat to soak it at that color. It kept getting hotter. What can do to fix this? If I turn down the gas any lower it sputters out.

    Quenched in oil until ambient and immediately tempered at 450 deg F for 2 hours. Plan for second temper at 500 deg for 2 hours.

    I made a knife, but that was a little forging and a lot of grinding. This is the second thing I've ever forged, but the only grinding was to form the edge. The amount of scale loss was astonishing, I will have to plan better for that next time.



  6. 14 hours ago, Frosty said:

    Mine is better insulated and adjustable isn't a useful description for making comparisons.

    Frosty The Lucky.

    What would be, then? is this better?

    Both propane forges are about the same size -  approx. 15" x 6" x 6"

    His is home-made and mine is a modified farrier's forge.

    He has only one 5"x5" opening and I have two 4"x4" openings.

    He has about 1" of kaowool and I have 2"

    He has a charcoal grill regulator and I have an adjustable reg 0-15 PSI

    His forge burns 10# of propane per hour and mine burns about 3# per hour, for the same subjective heating results (I worked on the same leaf spring in his forge and mine).


  7. Dumb newbie question, looking for confirmation

    I made a 1/8" thick knife blade out of a leaf spring. After quenching in oil, I wanted a differential temper. So I heated a piece of leaf spring and put the back of the knife blade onto the hot steel.

    I was looking for the change in colors across the blade, but the entire knife blade turned dark charcoal grey immediately. I didn't see any color changes develop across the blade.

    Does this mean that the hot leaf spring was too hot to effect a controlled differential temper?

    Does this I mean I overheated the knife blade to ~700 degrees almost immediately?

    I don't want to do anything else with the knife blade until I figure out what the hell happened.

    I assume that, next time, I shouldn't get the leaf spring so hot.


  8. A 20# propane tank cost me $13 to fill

    Advice from a beginner:

    My friend's 2-burner forge burns almost an entire 20# tank in 2 hours, which is about as long as I can swing a 4# hammer. So - $13 per day.

    My 2-burner forge burns 1/3 of that, and my forge seems to heat about as well as his. So - about $4.50 per day


  9. 8 hours ago, matto said:

    Why get rid of all scale, the one you are coping has forge and scale marks?  But you'd does look good! 

    Next time I am going to use ebony wood for the grip, and try to avoid any grinding or polishing