M2 vs S2 steel for lathe bits?

[n9viw]

I'm in the middle of a house-building project, and I have all kinds of burned-out T20, T25, and P2 driver bits that the cheapskate in me can't bear to throw away. Now that I have a lathe, I wondered if a person could use them to make cutters for the old lantern toolpost and holders.

According to https://www.makeitfrom.com/compare/...teel/SAE-AISI-S2-T41902-Shock-Resisting-Steel , there's not a whole lot of difference between M2 steel (HSS) and S2 (hardened steel, which most driver bits seem to be made of). I haven't tried it, but I'm planning to carve some cutting faces into a few of them to try it out. As they're hex, I'll need to grind two of the corners off a bit to get them to fit the Armstrong holders, but I'm taking them to the grinder anyway, so...

Has anyone else tried this?

Nick

 

[mmcmdl]

S10 was known as Stenar back in the day . I made up a lay up plate way back when and eventually sold it on the bay for $10 or so . Nice tool steel .

 

[Ulma Doctor]

High speed steel keeps an edge longer than S2 and will retain hardness even into the stages of turning red

the S2 will work for softer materials and maybe even 12L15 steel, possibly 303 stainless with good geometry
you'll be grinding the bits , so you'll need to harden them if they get hot for the grinding and loose their temper

let us know how it goes!

 

[mmcmdl]

https://www.hobby-machinist.com/threads/i-am-old-overweight-and-a-bit-rusty-but.43102/

 

[n9viw]

S10 was known as Stenar back in the day . I made up a lay up plate way back when and eventually sold it on the bay for $10 or so . Nice tool steel .

I saw Stenar referenced in the 1958 How to Run A Lathe book, but didn't know what it was. Thanks!

High speed steel keeps an edge longer than S2 and will retain hardness even into the stages of turning red

the S2 will work for softer materials and maybe even 12L15 steel, possibly 303 stainless with good geometry
you'll be grinding the bits , so you'll need to harden them if they get hot for the grinding and loose their temper

let us know how it goes!

Thanks for the specifics. I'll make a few cutting edges and try them out this weekend. I keep a small can of water next to the grinder to keep them from getting too hot while grinding (mostly to save my poor fingers!).

Now that I have the Armstrong holders, I understand why SB had those funky angles on their cutting bits- because of the funky angles on the holders! Most edges I've seen from the grinding tutorials I watched wouldn't work well, because they're designed to be held perpendicular to the work, whereas the Armstrong holders keep them at an angle. I suppose a guy could use the 'left hand' holder to cut right-handed and use a squared-off cutting face, but then the holder itself gets a little too close to the chuck. Two schools of thought, I guess.

 

[mmcmdl]

S is used for shock resisting dies , not for cutting tools . M would be more suitable .

 

[n9viw]

S is used for shock resisting dies , not for cutting tools . M would be more suitable .

I figured as much, and have been collecting old bits on the bay and wherever (Harbor Freight actually sells a variety pack of S2 HSS bit blanks for $5, heck of a deal: https://www.harborfreight.com/5-pie...lathes-40641.html?_br_psugg_q=lathe+tool+bits - I bought three of em!), but thought I could make these work in a pinch because, as I already said, I'm a cheapskate. It's going on a $225 lathe, what could go wrong? Safety glasses ON! B-)

 

[Nutfarmer]

Try it and see how it works. They used to use forged high carbon steel. It should work as well as that.

 

[n9viw]

I saw Stenar referenced in the 1958 How to Run A Lathe book, but didn't know what it was.

Turns out I was mistaken, the reference was to Stellite, not Stenar, which is completely unlike S2. Can't find an online reference to Stenar as a metal.

 

[RJSakowski]

I figured as much, and have been collecting old bits on the bay and wherever (Harbor Freight actually sells a variety pack of S2 HSS bit blanks for $5, heck of a deal: https://www.harborfreight.com/5-pie...lathes-40641.html?_br_psugg_q=lathe+tool+bits - I bought three of em!), but thought I could make these work in a pinch because, as I already said, I'm a cheapskate. It's going on a $225 lathe, what could go wrong? Safety glasses ON! B-)

M2 is used for lathe tools because of its high hardness and high tempering/annealing temperature. M2 has an as quenched hardness more than 65RC and begins to soften above 1050ºF. S2 is a medium carbon steel and has an as quenched hardness of 60RC and will be reduced enough to make the tool unusable for steel at around 400ºF, a temperature easily reached at the cutting edge when machining steel.