M2 vs S2 steel for lathe bits?

As an old German friend would have said "crazy in the first place, and stupid to end with" Carbon steel went out with the dinosaurs, and the commonly used carbon steel of that era was not just a straight carbon steel, it was the English "Mushet Steel", which turned out to be an early HSS; F.W.Taylor did extensive experiments on the "Art of Cutting Metals" in the 1880s- 1890s and accidently overheated a Mushet tool to near the melting point, they thought that they had likely ruined the tool, but ground it and found that it could be run at about twice the normal speed without failing as would the normal heat treatment provided; this was the birth of what we now call High Speed Steel.
 
n9viw said:
(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!)
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That is a great price for HSS bit blanks, there is a good chance they will work good at least for some things. I suggest you keep them seperate, you may find they get dull within a few seconds when cutting some types of steel. You can resharpen and try again at a lower speed. You may also find the made in the USA bits last much longer.
 
I know that Chinesium is a different animal (whether steel or iron, or even stainless) than American, German, or even English. At $5 a pack, I had no illusions that they would be anything more than a stopgap, but for that price I figured it was worth a shot. The last cutting blank I bought was from McMaster Carr and cost me $15 for just one!! I received several used cutters and one new one in the purchase of my lantern toolpost and holders, and several of the spares were cobalt, so that was a nice surprise. Another nice thing about the HFT set is that it had a 1/8" bit in it that will be a good fit for the Armstrong/SB boring bar I got in the toolholder set, which takes a strange tiny triangular bit.

I'm still planning to grind these driver bits and try them out just for fun, but I might try heat-treating a couple to see if it makes a difference.

I know that grab bags of used bits can be had on the bay for not too much, I'm planning to pick up a few of those next payday.
 
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Those HF bits are not S2. They are M2. I've heard rumors that HF HSS is not really HSS, but rather a high tungsten alloy steel. I've seen both the good and the bad, so there may be some truth to it. If you are insistent on cutting costs, use broken drill bits in either a purpose made tool holder or tool block. I did this and it worked just fine. I also used a broken hex key to make an Acme nut for my SB9 cross slide. It was run really slowly, and it worked well. This steel is too low in carbon to make a decent tool, but it was OK for a single use in brass.
 
ericc said:
Those HF bits are not S2. They are M2. I've heard rumors that HF HSS is not really HSS, but rather a high tungsten alloy steel. I've seen both the good and the bad, so there may be some truth to it. If you are insistent on cutting costs, use broken drill bits in either a purpose made tool holder or tool block. I did this and it worked just fine. I also used a broken hex key to make an Acme nut for my SB9 cross slide. It was run really slowly, and it worked well. This steel is too low in carbon to make a decent tool, but it was OK for a single use in brass.
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I am aware of that, which is why I bought them. HSS covers both tungsten and moly steel, and the T designation actually covers several versions of M class HSS.

The S2 to which I was referring was the broken driver bits I originally mentioned. They may be too brittle to use, and even at that, may not hold an edge well. Regardless, I'm planning to find out. If nothing else, they may make useful bits to have for light work like nylon, brass, or aluminum.
 
n9viw said:
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-)
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i have like 15 packs of the HF HSS, when i go to HF i just get all they have.
 
Another good reference book is "Tool Steel Simplified" by the Carpenter Steel Co. It was one of my reference textbooks from my apprentice classes.
 
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