HSS Tooling For The Lathe -Apples and Oranges

[mmcmdl]

I just rounded up a few hundred HSS bits . Form tools indeed woodchucker . Depends on my next lathe as to what I'll keep and what will go .

 

[Earl]

I bought my surface grinder from a machine shop that was shutting down. I ended up with several coffee cans of lathe tool bits. There were all kinds and sizes. That gave me the opportunity to try many types. Most of what I saved are ones that I could read the names on. The ones I can remember are Mo-Max, Rex95, rexalloy, Rexaaa, Ludlum LXX, and Tantung G. I saved some that don't have names but have markings such as M-35, M-42, etc. At the time I did my testing, I had a Heavy 10 lathe. A friend told me to start with the Tantung and I wouldn't bother to test the rest. (I did anyway) The Tantung G from VR Wesson ended up being my favorite. It is a non-ferrous alloy around 53-55 rockwell. It can be ground with a bench grinder (a little slower than HSS) but it can be sharpened to almost a razor edge. I cut a lot of 416 stainless (an easily machinable stainless). I have been using the same Tantung tool bits to chamber and crown rifle barrels for the last 6 or 7 years. They have never been out of the tool holders they started in. I just give them a lick with a stone once in a while and they are happy. The heavy 10 is long gone but the Tangung G is still here. I think that every "home shop" guy has a collection of Chinese tooling, myself included. They work but I am constantly looking for the right combination of speeds and feeds to get a decent finish. I run the Tantung anywhere from 150 to 200 sfm, any reasonable depth of cut, add some high Sulphur cutting oil and I usually end up with a great finish.

 

[Earl]

When I started with my Heavy 10 many years ago, I had a difficult time grinding my tool bits. They worked but looked like crap. I always wonder if they would cut better if they were perfect. I ended up purchasing this grinding fixture off of ebay. The name of the company is Alisam engineering. It consists of an aluminium base and several collets for different size bits - 3/16 thru 1/2. The collets have markings for degrees so you can set any angle you want. The bottom of the base is flat for going straight in to the wheel and also has a 10 degree cut so that relief can be done easily. It makes really nice looking bits that Mr Pete would be proud of. All you need is a grinder with an adjustable rest so you can lower it enough to allow cutting at about the center of the wheel. I no longer care about what my bits look like. I know how I need grind my tools to give me the cuts that I want. This set along with the 3/8 Tantung G blank in it is going to the high school kid down the street when his 10k South Bend lathe gets up and running.

 

[Jimsehr]

Ah, the end of a four day work week =27 days to go.....

I am working on improving my HSS grinding skills to create the perfect threading tool.

This morning I was roughing two pieces of 1/2" HSS at work. First off, I took my 4 1/2" angle grinder and cut off an ugly grind to start over. I was grinding on a piece of, Super M0-Max COBALT, Cleveland OH. Man is this stuff tough!!

I then proceeded to rough the shape as outlined with a sharpie.
The other piece of HSS is from Shars. It's M2, same size.

The difference in grinding time is significant. I thought it would be subtle, it's not.

Maybe this is not a fair comparison? I have some, Rex as well, I assume it is equally tough.

Now I know why batches of old HSS ground blanks are so much money on Ebay. A pile of partially used HSS blanks for $30 now seems dirt cheap.

Apples and Oranges.
McMaster Carr (1) 1/2" X 4" 10 degree bevel- tool blank
PMT15 M2 M42 M48
$37 $28 $32 $62

SHARS M2
$5.70

(Don't point and giggle , I'll clean them up on my DIY Lapping machine later)

From Hudson Tool Steel >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Technical Data » Grade » M42

M42 Super High Speed Steel​

M42 super high speed steel is a premium cobalt high speed steel with a chemical composition designed for high hardness and superior hot hardness. These properties make the steel an excellent choice for machining high-strength and pre-hardened steels, high-hardness alloys, and the difficult-to-machine, nonferrous super alloys used in the aerospace, oil, and power generation industries.

M42 exhibits excellent wear resistance by virtue of high heat-treated hardness (68 to 70 HRC), and the high cobalt content imparts the hot hardness. As such, the cutting edges on tools made from M42 super high speed steel stay sharp and hard in heavy-duty and high-production cutting applications.

APPLICATIONS: Twist drills, taps, milling cutters, reamers, broaches, saws, knives, and thread rolling dies.

 

[Jimsehr]

Jeff
Many times you don’t need a tool to last for a large number of parts. So a easier to grind grade of hss will work fine. I remember 30 or more years ago I got some hss from Sweden called (Flagersta #4 I think )that was easy to hand grind quickly and worked really good. The read from this thread post # 14 has a Lot of good info. The traditional tools group.
I know a lot of home shop guys don’t hand grind form tools but I do it often . That is why I have radius gages .
Jimsehr

 

[Janderso]

Jeff
Many times you don’t need a tool to last for a large number of parts. So a easier to grind grade of hss will work fine. I remember 30 or more years ago I got some hss from Sweden called (Flagersta #4 I think )that was easy to hand grind quickly and worked really good. The read from this thread post # 14 has a Lot of good info. The traditional tools group.
I know a lot of home shop guys don’t hand grind form tools but I do it often . That is why I have radius gages .
Jimsehr

The use of high speed steel to grind your form tools have endless possibilities.
Practice and patience will win the day with this stuff.
I’m learning, every day.