Hey there guys. I have a friend who does mining competition. One of his favorite events is the single jack rock drilling. He doesn't have his own drill steel and I've been thinking of either making him some, or at least getting the materials and helping him make some. I contacted the guy who makes the drill steels for the world's top single jack drillers and he's supposed to send me a spec. sheet on how he builds the steel in the next few days. He starts with 1.25" 1095 and turns it to dimension on a lathe. He's pretty forth coming on the how and the technical spec's the steel has to meet size and shapewise (I was in Grad. school with him), however he won't give up his secret on where he obtains the hex bar. I've been searching the web and have asked for quotes from suppliers that either say on their webpage that they have it or the ones who have such a variety that they "might" have it. I have struck out so far. Several have tried to substitute 4140 for the 1095. So I guess I have two questions. First, does anyone know where I can get about 6' of 1.25" hex 1095? Barring that, my second question is, does anybody have suggestions on what more readily available steel will be as machinable and easily heat-treated as the 1095, while still having the hardness and wear resistance of the 1095? I know there's a few of the old salts on here that might have some ideas for me.

ML

Can't help you on the hex bar but I'd try EM Jorgenson, Crucible and Carpenter. The S series of tool steels are usually employed for rock chisels. I think Jorgenson carries S1 and S7.

I have never heard of 1095 being used for this but it wold be wise to take his advice, I would think if you could find some large round and using top and bottom fullers in a ph you could have hex stock in a short time. My choice would be a shock resistant tool steel such as s-1 I believe I remember that is what they use for jackhammer bits. I wonder what makes 1095 a choice? Must be some reason

I am not certain of the financial limitations but I would look at other steels.

The cost of participating in drilling contests must be relatively high with today's gas prices (thanks to the enviromentalists preventing drilling and refinery expansions) the cost of drill steel material may be incidental in the big picture.

Adding chrome, molly & nickel add to hardnesss of steel but most importantly add to toughness or chip resistance of the steel. A sure way to lose a rockdrilling contest is to have the corners of the cutting edge chip.

The priorities of drill steel are

1) Chip or impact resistance (toughness) as I said earlier the sure way to lose is with a chipped drill steel

2) Abrasion resistance or hardness. This will result in durability of the drill steel.

1095 has only hardness in its favor. It does not have alloys that add toughness. 1095 requires a fairly agressive quench to obtain the required hardness. This creates locked in internal stresses that make 1095 more prone to chipping and cracking.

Tool steel is quenched slowly, maybe even in ambient air, giving time for the internal stresses to equalize, reducing the tendency for chipping of the cutting edge.

If money were no object I would look at tool steels. D-2 may be a good choice as it among the tuffest of all tool steels, but I am not aware of anybody using it for rock drills. S-7 is a no brainer selection possibility.

If this guy is serious about winning, testing of various drill steels with various heat treatments would be in order.

1095 or something very similar (high carbon no alloy steel) was the historical steel that where used for drill steels in mining and quarrying applications.

Alloy steels (chrome, nickel, molly) were not really comercially widespread until after WW II and thus 10 series, plain carbon, steels were typically used for this application in the past.

I am somewhat surprised that 1095 is still being used for championship hand drilling contests. Modern alloys would be better.

Is there a requirement for hex stock or steel? Many older hand drill steels were made from round stock (I have serveral)

Perhaps they were using the shallow hardening of the 10XX steels to get some toughness from not hardening all the way through---need more details on their HT to guess about that!

starting with hex stock to turn on a lathe doesn't make much sense unless only a portion of the tool's length is turned down to a round dimension. How long are the individual tools being used?

Good feedback, thanks guys. The 1095 choice might be due to any number of things. I did ask him if he'd tried S-7 because that's what immediately came to my mind and he said he didn't have very good luck with it. In fact he said he had problems with it breaking which I'd have thought would be a low risk factor for any of the S series. I believe they like to leave the handle / struck part of the drill hex for indexing/gripping. I haven't recieved his spec's yet, but if I remember correctly they turn the first inch or so of the working end down to about 1", then the rest of the shaft down to app. 7/8". for length, they usually have a "starter drill" that is basically just the handle/struck part with the bottom inch turned down to an inch with the chisel point on it. Then they go in about three inch increments up to 16" or so. They use the multiple lengths to keep the surface they're striking at a reasonable range of heights.

Also, actually now that I'm thinking about our conversation I do recall him telling me that his preferred steel was 1095, but he's used 1070 and 1084 because he has a hard time finding 1095. I'm not really that worried about the cost for one set of steel. Are there machining considerations to think about for the other newer alloys? That could be one reason for him getting the 10xx series in an annealed state? Not much of a machinist so I'm grasping at straws here.

I would talk to Grant Sarver at Off-Center Forge 1318 South 83rd Street Tacoma, WA 98408, (800) 993-6744 or (800) 858-8831

He makes the off-center tongs many of you are probably familiar with and designed the KA-75 hammers. These projects were spawned by his love of the craft and good tools.

His real business is making drilling steels that he sells to industry world wide. A great guy who seems always interested in even the smallest projects.

It's not hex but this place claims to have 1095 round stock, you can always forge it to hex.
https://www.speedymetals.com/p-1095-58-rd-303-stainless-steel-cold-finished-annealed.aspx

I did some digging on steels, particularly hardness and toughness.

Charpy V notch testing is a methodology to test the relative fracture resistance of the steel. The test does reflect the exact toughness of the steel in real world applications but reflects the relative toughness of the steel.
The units on Charpy V are foot-lbs and the higher the number the tougher the steel and more resistant to fracture.


Material Hardness (Rc) Charpy V (ft-lbs)

H-13 47 18
H-13 52 10

D-2 55 22
D-2 59 19

S-7 59 85
S-7 55 122

Note: Values are at room temperature. H-13 becomes much more impact resistant at higher temperatures.

I was unable to locate data on 1095 and Charpy V although catalog information described 1095 as brittle when low temperature tempering or drawing temperatures were used and resulting high hardness. When tempered or drawn at higher temperatures and resulting lower hardness, the world brittle was not used.

As to whether 1095 was surface hardened and interior left tough, this would most likely require oil hardening baths. After reading numerous historical and recently written refernece books on mining, I have not seen any reference to quench baths of oil.

I agree with Skunkrvr that Grant or others might be a good source for information. Of course he may be using 1095 or similar as he is competing in the comercial market as opposed to the highly specialized competive drilling contests.

S-7 should be "oven" heat treated with a carefully controlled temperature and be held at quenching temperature for at least one hour (1 hour per inch) and air quenched for maximum results and "double drawn" at the selected tempering temperature. I would recomend using stainless steel foil covering to prevent surface decarbonization of the tool.

It is possible to heat treat S-7 in the forge but the results are less uniform.

Need to Correct previous post

Charpy V notch testing is a methodology to test the relative fracture resistance of the steel. The test does ****NOT*** reflect the exact toughness of the steel in real world applications but reflects the relative toughness of the steel.
The units on Charpy V are foot-lbs and the higher the number the tougher the steel and more resistant to fracture.

Sorry the table of hardness and Charpy V did not come out better. The 3 columns are Material, hardness and charpy and the numbers underneath but cramped to the left is the data

Wheres Frosty? :confused:

"Paging Frosty to the white courtesy phone."

check this link for a source of 1095 and other carbon steels, etc Carbon Steel, Carbon - All Metals & Forge

Hey guys... I'm warming to the idea of using S-7. I have a computer controlled kiln (wife uses it for glass fusing and slumping). It has a "bead door" on the front, so I could stick the working end of the drills in there and do a proper heat treatment. I'm wondering if the heat treatment is why Craig didn't like S-7. He still hasn't emailed me. I'm going to give him another call tonight and try to light a fire under him. I will try to get ahold of Grant and see what he has to say.

Wheres Frosty? :confused:

"Paging Frosty to the white courtesy phone."

Bump...... :D

Bump......

Huh? Whazzat?

Frosty

Huh? Whazzat?

Frosty

I was just bumping this thread back up to the top.

I thought with your drilling background and there being some sort of competition with some hot shot drill builder you might have some input. :confused: ;)

I was just bumping this thread back up to the top.

I thought with your drilling background and there being some sort of competition with some hot shot drill builder you might have some input. :confused:

I seem to have missed that thread.

Then again, when I transfered off the drill crew I swore I'd never touch one again and that'd probably count for building one too.

Still, it might be fun to read. . .

Frosty

I seem to have missed that thread.

Then again, when I transfered off the drill crew I swore I'd never touch one again and that'd probably count for building one too.

Still, it might be fun to read. . .

Frosty

Post #1 from THIS thread that we're posting in now...

Hey there guys. I have a friend who does mining competition. One of his favorite events is the single jack rock drilling. He doesn't have his own drill steel and I've been thinking of either making him some, or at least getting the materials and helping him make some. I contacted the guy who makes the drill steels for the world's top single jack drillers and he's supposed to send me a spec. sheet on how he builds the steel in the next few days. He starts with 1.25" 1095 and turns it to dimension on a lathe. He's pretty forth coming on the how and the technical spec's the steel has to meet size and shapewise (I was in Grad. school with him), however he won't give up his secret on where he obtains the hex bar. I've been searching the web and have asked for quotes from suppliers that either say on their webpage that they have it or the ones who have such a variety that they "might" have it. I have struck out so far. Several have tried to substitute 4140 for the 1095. So I guess I have two questions. First, does anyone know where I can get about 6' of 1.25" hex 1095? Barring that, my second question is, does anybody have suggestions on what more readily available steel will be as machinable and easily heat-treated as the 1095, while still having the hardness and wear resistance of the 1095? I know there's a few of the old salts on here that might have some ideas for me.

ML

Post #1 from THIS thread that we're posting in now...

Uh. . . Hmmmm. Didn't look at it till SOMEBODY paged me.

Maybe I aught to read a thread before replying eh?

Frosty