View Full Version : Drill rod hardness ... before hardening.

06-15-2010, 01:31 PM
Does anyone happen to know where drill rod (O1 in this case) stands on the hardness scale before being heat treated? This being an AISI #, Brinell or Rockwell hardness, etc. I'm not a metallurgist, but I'm pretty sure it is harder than most mild steels beforehand. I just wanted to know how much harder it might be.


06-15-2010, 02:25 PM
Well, perusing the specs given for the annealed state from McMaster Carr: when you buy it is is somewhere between Rockwell B90-B100, give or take a few points. Strangely, I have the Metal Handbook Desk Edition, and I can't find that information. It refers me to another source.

06-15-2010, 02:33 PM
I use a lot of O-1 steel and have asked the supplier this same question more than once. They always tell me it's about 32 rockwell before hardening. I've never seen this in writing but it would be good to verify that number if someone can find the specifications.

06-15-2010, 02:44 PM
I'm not sure why this info is so hard to find. I couldn't find anything much using Google. I did go back to McMaster and found the info you refered to on the actual catalog page. I usually see info like this on the material selector pages but didn't in this case.

06-15-2010, 04:25 PM


06-15-2010, 04:32 PM
I'd guess the 30 RC range to be close if not right on, but... I'll try to grab a chunk and test it tomorrow at the shop. If i'd have seen this a bit earlier today I could have had it done already.

06-15-2010, 05:30 PM
a rockwell meter seems like an inexpensive thing for a hobbiest to own/chinese to clone, Why don't we all own them allready? It just measures the distance a little diamond puts a dent into an object does it not?
Seems like a valuable tool to test mystery metal with before ruining bandsaw blades and endmills.

06-15-2010, 06:31 PM
Seems like a valuable tool to test mystery metal with before ruining bandsaw blades and endmills.

I don't know about that. A file is a lot cheaper.

J Tiers
06-15-2010, 09:31 PM
The ones I see cost about as much as a used lathe...... but are not as useful.

I still need to make the "rebound" tester more like "downtown". It is still a case of find the bits when I want to use it....

Hard ball bearing, drop down tube, read bounce-back distance. "calibrate" on hard steel, such as a cutter, etc, and soft stuff like hot-rolled.

06-15-2010, 10:31 PM
I don't know about that. A file is a lot cheaper.

Hahaha.. Yeah, thats what I grab when Im looking through my endless supply of scrap high carbon steel on the rack. Before touching it with one of my HSS cutters. Never know with some of the stuff I have got over the years.

But then when I want to put a number to the whole thing I have two wilson testers. One B and C tester and one Superficial tester. The B/C tester is common. The superficial tester is not normally seen in a small job shop but it has its benefits. I have an oven for heat treating so its nice to see what the real numbers are.

So an inexpensive B/C tester is not bad to have. To be honest I prolly have more money wrapped up in all the points and calibration blocks then the tool itself. JR

06-16-2010, 02:07 AM
I had a piece of O1 that I just tested on the B and C scales. It was in the as shipped condition. I was unable to get what I felt where reliable numbers on the C scale since it was so soft, but the B scale appeared to read reliably and came in at Rb 95 which is right in the middle of where Arthur above predicted. That's pretty darn soft.
I hope that helps.

06-16-2010, 02:47 AM
You are looking at serious money for a ball type hardness tester although if it pays its way on or saves an important job it will have paid for itself.

Cost in OZ$ (with out 10% Goods and Services Tax - GST) is OZ$490 x 0.85 ~ US$415 although most of this stuff - new - is cheaper in the USA.

May be some on eBay - but be sure that you get what you need - and that it works to specs.