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Bill Schmalhofer

First WIP : Rock Hammer

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Posted (edited)

Doing my first WIP. It’s not a knife, but hopefully you will enjoy it all the same. First, thanks to those who suggested metal combinations for this project. Second, a bit of background. My brother-in-law is a geologist and an avid fossil hunter. I got to thinking that he might think a Damascus rock hammer would be a pretty cool Christmas present; thus was born the idea. Based on the previous mentioned suggestions, as well as the design idea I had, the initial stack of steel.

 

 

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The order is:

15N20 (0.12)

8670 (0.084)

80CrV2 (0.032)

8670 (0.084)

15N20 (0.064)

8670 (0.084)

15N20 (0.064)

8670 (0.084)

80CrV2 (0.032)

Repeat twice more

80CrV2 (0.032)

8670 (0.084)

15N20 (0.12)

for a total of 23 layers.

 

The idea was to have a majority of the steel the ultra-tough 8670 (which would hopefully etch gray), then an almost as tough shiny highlight layer of 15N20, and a final thin dark contrast layer of 80CrV2. The numbers in ( ) are the initial thickness of the given layers. I made the outer layers of 15N20 thicker to protect the billet during weld up and to account for scale loss. The initial width was 1.5 inches.

 

Initial heating of billet.

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Billet welded and drawn to 1.25 inches square. Was using my thermocouple to check the temperature of my new and improved forge (Thanks Geoff for your pinned topic on blown forges!). Got to 2500F and was still going up! Was actually seeing the outer most layer appear to start to bubble. And I know it was the metal because I fluxless weld…

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Billet rounded to 1.125 and ready for twisting.

I unfortunately didn’t get any pictures of the twisting. Twisting a 1.125 inch diameter bar was a real pain. It took 6 heats to get 2 full twists as I stopped well before cooling below bright red. During this I learned a few things that I will incorporate into the next time I do this. The main thing I learned was that, on this bar, I forged down a tip on one end of it to make it a bit smaller to “get a better grip on it for twisting”. What I learned (as people who have done this more than me probably already surmised), is you want to keep the billet as close to even as possible. The smaller tip twisted much faster than the rest of the bar and I eventually twisted it off. A complete waste of material…

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Round twisted bar drawn out to 1 x 7/8 and ready for punching.

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Eye hand punched with plug. I was surprised how fast and easy this was.

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The homemade punch. Just a ¾ round of H13 ground down to the shape I wanted. No heat treat. Worked an absolute dream. Still going to have to make a punch for use on my press though…

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Eye drifted and hammer rough forged to shape.

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Rough ground to 120 grit, ready for heat treat.

10.jpg9.jpg

 

Had to do the obligate “quick and dirty” dunk in the etch tank. The pictures don’t show it very well, but the theory for the stack up worked exactly as I had hoped – Gray body with bright and dark banding.

12.jpg11.jpg

 

The issue and things I have learned.

First obvious issue is the eye. It deformed a bit during punching, and I was never able to get it really worked back out. Second (and this will probably help with the first issue) is I shouldn’t have forged it quite so close to final size before punching. After the forging to shape and grinding, it is a bit smaller in dimension than I was shooting for. Third (as already mentioned), twist full size.

Dimensions are:

Weight: 12 ounces

Head width: 5/8 inches (was shooting for 3/4)

Head height: 3/4 inches (was shooting for 7/8)

Total length: 8.5 inches

Planning on heat treating this weekend and putting a handle on it. Also planning to make a second, larger one for my brother-in-law. My wife (who also loves collecting fossils - has to be genetic...), has already claimed this “perfect for me” sized hammer. Will post final pictures as soon as I get them.

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Edited by Bill Schmalhofer
Addition and subtraction
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Nice!  Thanks for sharing.  Can't wait to see the finished pieces.

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Well, that worked out!  :D  

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I was able to heat treat yesterday: 

Heat to 1600 - cool to black

heat to 1550 - cool to black

heat to 1500 - cool to black

Heat to 1550, soak 3 minutes, quench in high temp vacuum pump mineral oil at 120F. 

Tempered 2 x 2 hours at 425.

 

I am wondering if I actually should temper it higher? Suggestions welcome.

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I have (mostly) finished the hammer. I say mostly because as I was taking these pictures, I noticed I have a bit of clean up to do on the bevels on the face, as well as one more coat of tung oil.

 

Final pictures:

IMG_1905.jpgIMG_1907.jpgIMG_1908.jpgIMG_1909.jpgIMG_1910.jpgIMG_1911.jpg

IMG_1906.jpg

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