Self-Sharpening Pick

Looking much closer to home, rodent incisors are also self-sharpening:

I think self-sharpening as you describe costs service life relative to a tool with hard steel throughout the point, which is easily sharpened by grinding. If you have a grinder.

When old yard tools wear down I build up the edge with welding rod.

7018 has held a good edge on an axe that my uncle used on rock, for instance.

jsw

Did you have a look at US 982832 (1909) yet?

Best regards, Spehro Pefhany

This may not be of any use to you but I do belong to a Mineral Society and in all the outings I've ever been on the hammer of choice and the one I also use is this unit (Estwing E3-22P 22-Ounce Rock Pick). This thing stays fairly sharp considering that you are breaking rocks with it but It does seem to hold it point very well. Double pointed

12 pound hammer swung all day would be a serious workout...

Sphero Pefhany

SP:

Thank you for the interesting reference which was consulted. My apprehension about the durability of the design may have been shared with a public that may come to a more determined opinion by trial.

The pick I saw had, like my poor standard version, a one piece head which disposes the belief that its superiority was a feat of integrated metallurgy. A mining history list has the question on the table, so far with slim result apart from the remark of a self-sharpening, serrated knife that has seen long domestic service.

In addendum to my initial offering, I add that my friend purchased the tool new about two thirds of the way into the last century at some bygone hardware store now replaced by boarded windows in what may, in all likelihood, be a scarecrow town. So, pursuit of origin along that avenue doesn't promise.

Without others reporting a hit or light bulb going off, perchance a search for a manufacturer's association will be my next turn.

I appreciate your response.

Regards,

Edward Hennessey

J:

The sledges we use for remote heavy work toll 16 and 20 pounds. A day with them is a hump but there are fewer days on a project when rock feels that kind of weight. Handle vibration and the resultant trigger finger pathology by transmitted vibration remains a menace we temper by sleeving the handles with shock-absorbing foam and tethering the shafts to the wrist. Releasing the grip right before impact diminishes physical problems radically. After practice, you get good at it...and thankful.

We agree on Estwings being good tools. For smaller stuff, they are superb. Not recalling model designations, their crack hammers and the mason's style heads earn a place in the trucks.

Thanks for the comment.

Regards,

Edward Hennessey

...

Well, one speculative approach (which may not be anything like the tool in question) would be to take the advice from hardfacing heavy equipment bucket edges and apply it to a pick. That being, to hardface the side that normally takes the most wear, but NOT to hardface the other side, so that the edge will wear sharp (where an edge hardfaced on both sides will wear blunt.) A high-shock hardfacing is called for - they exist. I still regret not having my shovel handy when powder torch hardfacing was being demonstrated, but for a pick regular arc-welding hardfacing rods would probably work; You might want to build up the point with 7018 (or

8018, 12018) before hardfacing, so the point has some meat for the hardfacing process, then grind it to sharp (fron the softer side) after hardfacing. A powder torch would probably not require that step. I would suspect that the outer face would be the better one to hardface on a pick.

Differential tempering would be the way it's done, probably would take a LOT of experimenting to leave the center hard while softening the surrounding metal. The tempering would have to be done so the heat is just getting to the center when quenching occurs. Custom knife makers do this a lot, in two dimensions but not three, leaves a hard edge and a softer back for flexibility. As far as current manufacturers, there are probably none out there that do it that way, would be very hard to do on a production basis. Easier(and cheaper) to dump the lot into a furnace at so many degrees for such and such a time, then out. Probably the original was some small manufacturer's output that was basically handmade. You might be able to find a blacksmith or bladesmith with the knowledge to duplicate it these days.

Stan

I'll bet that the hard outer layer that stays sharp has a high percentage of manganese. It's work hardening and likes to be hit. Yes? But how would that be done, some kind of hot bath? Perhaps laid in a shallow pan of mysterious salts at red heat?

"Ecnerwal" wrote in message news: snipped-for-privacy@mx02.eternal-september.org...

L:

I have some Army pick-mattocks that we might be able to try this on. When the master of these things can be lured, maybe we can experiment.

Thank you.

Regards,

Edward Hennessey

Differential tempering would be the way it's done, probably would take a LOT of experimenting to leave the center hard while softening the surrounding metal. The tempering would have to be done so the heat is just getting to the center when quenching occurs. Custom knife makers do this a lot, in two dimensions but not three, leaves a hard edge and a softer back for flexibility. As far as current manufacturers, there are probably none out there that do it that way, would be very hard to do on a production basis. Easier(and cheaper) to dump the lot into a furnace at so many degrees for such and such a time, then out. Probably the original was some small manufacturer's output that was basically handmade. You might be able to find a blacksmith or bladesmith with the knowledge to duplicate it these days.

Stan:

You have the brass ring.

If the name of the manufacturer can be found, maybe the pick can. That is step next.

My friend did confide that the tool had cost him what was then a small fortune, which price would be required to fund the painstaking process you clearly describe.

If my quest comes to capture, I'll report on the performance. Thank you very much.

Regards,

Edward Hennessey

"Phil Kangas" wrote in message news:ig5lkk$g1h$ snipped-for-privacy@news.eternal-september.org...

These hammers are most likely a manganese alloy. phil

Here's a link to manganese steels:

And here's a quote from that page:

No better casting alloy has ever been developed for high impact service. Cast manganese steel has unique properties that cannot be achieved with rolled manganese steel or by low alloys in cast or wrought form. In fact, it has been said that modern scrap shredders could not exist today were it not for cast manganese steel.

As an AMSCO manganese steel casting goes into service, it is extremely tough throughout, with very high impact and elongation properties. However, a new manganese steel casting is not hard ? the surface of a new heat treated casting is about 200 Brinell hardness.

Once a manganese steel casting goes into service and typically undergoes repeated impact, it cold works or work hardens. The work hardened areas of manganese steel castings can reach hardnesses as high as 600 Brinell, depending on the amount of impact. This work hardening process is self-renewing as long as high impact service continues.

Another unique advantage of AMSCO manganese steel castings is that while high impact regions undergo work hardening, the interior of the casting retains its low hardness and high ductility. Thus, the high hardness work hardened surface of the casting is fully supported by the ductile interior of the casting. This provides the necessary toughness to absorb impact without failure.

PK:

Thank you for your worthwhile contribution to my education. Now I have to ponder all this and push further.

Regards,

Edward Hennessey