What material are hammer chisels made from.
I need to make a long bit to chisel for my jack hammer. I have a Bosch that have been using but it's too short. What would be the best material to make these from to get heat treated?
Jay...Any of the S series of tool steels....I make parts form either S5 or S7 all the time. Heat treats well and holds an edge with severe pounding. Regards, Mark in Buffalo
S-7 works very well and it's easy to find. Almost every one of the mail order places will have up to 1" round. About $70 for 3 foot.
large jackhammer bits used to be AISI 1075. If hardened, you will have a hard surface of 0.1in+ and a tough core. S-Series tend to be through hardening.
Tip;- Make sure the striking end of the tool is heat treated correctly - too hard and they shatter, soft and they mushroom over and jam in the tool socket. - Don't ask me how I know
Quick & dirty get over for long chisels;- scarf weld another chisel on the prepped end of a worn one with Super Missile or eutectic 680 - it's worked for me time over.
The standard here for breaker steels is EN36 case hardened 3mm deep.
Found the following post on the iForgeIron website by a gentleman named Grant Sarver.
Posted 03 October 2010 - 05:35 PM
"Having been a manufacturer of paving breaker steel for many years, over time, I had spectrographs done on every other manufacturers steel. To the best of my knowledge, the only time an "S" series steel has been used is for specific applications and usually that was only .680 chipper steel. These are a commodity product and the finished tool sells for less than the cost of "S" series steel.
For most of the last century 1078 was manufactured specifically for this purpose. Essentially a high silicone 1080. Brunner & Lay (the largest bit manufacturer in the world) uses a modified 1045. Vulcan used 1078 for most of a century and more recently switched to 15B40, a boron steel much like 4340. This steel will spectrograph as 1040/1045 because the boron is minute and often overlooked. I made millions of bits from 8630 and 8640 steel. Many chipper steels are made from 9260, an AISI grade very close to S-5 in chemistry.
Junkyard rules apply.
OBTW: "Jackhammer" bits have a hole down the center. Paving breakers sound exactly like a percussion drill (jackhammer), hence the modern misnaming."
Grant is unfortunately no longer with us.
But when, above, he is quoted as saying he made "millions" of bits- he is not lying.
He owned, for years, a company that manufactured paving breaker bits.
And he did make, and sell, millions of them.
If he says 8630 or 8640, then thats what you should use.