Part Material Selection

J

jephw

Aluminum

Joined

Jul 23, 2020

• Sep 10, 2021

• #1

Good day everyone.
I am making a set of punches for an air hammer, starting with 3/8" diameter up to 1.50" in 1/8 increments. Could anyone recommend me the best material to use for this job? It needs to hard so it does not mushroom when used, but at the same time not brittle so it doesn't break easily.
I appreciate any insight given.
Thanks.

 

Mtndew

Diamond

Joined

Jun 7, 2012

Location

Michigan

• Sep 10, 2021

• #2

What material will you be hammering?
Maybe try a hardened tool steel of some sort.

 

mhajicek

Diamond

Joined

May 11, 2017

Location

Maple Grove, MN, USA

• Sep 10, 2021

• #3

Hardened S7 would likely serve you well.

 

J

jephw

Aluminum

Joined

Jul 23, 2020

• Sep 10, 2021

• #4

Just pins, mostly 4340 and equivalent.

 

J

jephw

Aluminum

Joined

Jul 23, 2020

• Sep 10, 2021

• #5

mhajicek said:

Hardened S7 would likely serve you well.

Click to expand...

Would this require hardening after machining or ready for work after i have turned it?
Also, how is the machinability of this material?

 

G

Gobo

Titanium

Joined

Jun 4, 2013

Location

Oregon, USA

• Sep 13, 2021

• #6

Just make sure it is made from billet.

 

V

Vancbiker

Diamond

Joined

Jan 5, 2014

Location

Vancouver, WA. USA

• Sep 13, 2021

• #7

mhajicek said:

Hardened S7 would likely serve you well.

Click to expand...

This ^ X10

 

mhajicek

Diamond

Joined

May 11, 2017

Location

Maple Grove, MN, USA

• Sep 13, 2021

• #8

jephw said:

Would this require hardening after machining or ready for work after i have turned it?
Also, how is the machinability of this material?

Click to expand...

You can hardmill and hardturn it in the hard, but it'll be easier to machine soft and then harden. Do any polishing after hardening.

 

M

MaxPrairie

Hot Rolled

Joined

Jul 9, 2015

• Sep 13, 2021

• #9

jephw said:

Would this require hardening after machining or ready for work after i have turned it?
Also, how is the machinability of this material?

Click to expand...

Agreed, S7 is the best option. We have a part we make from S7. The first time we made it we used annealed S7 then hardened. Pretty stringy and was hard to break a chip. Since the part only gets hardened to 40-45 HRc we started hardening the part before machining. Almost machines like a 4140 prehard but not quite as crisp. You will likely want to go harder, quick googling says about 55.