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High speed parting blades--why?

Bluechipx

Hot Rolled
Joined
Dec 29, 2008
Location
W. Mich
New tooling comes and goes but I don't remember anything as revolutionary as the carbide insert style parting tools. I was a former user of the HSS blade for parting, when I used it I developed what I call the HSS parting tool grimace, a squinting, puckered up facial expression in anticipation of what inevitably is bound to happen. Then my brother, who worked 2nd shift in a shop doing cut-off on 2 1/2" steel bars with an Iscar carbide insert style parting system, said as an experiment, he increased the feed on the lathe one step at a time to see where it would fail. He was amazed how fast he was feeding with still perfect results. Finally it broke either the insert or the blade, I forget which. He insisted I buy this type, which I did and never looked back. If anyone is still using the HSS blade for parting do yourself a big favor and give the insert blade a try, possibly the best tooling advance I have ever seen. If you are confidently using a HSS blade with good results, you are to be admired as an elite machinist! Thoughts?
 
New tooling comes and goes but I don't remember anything as revolutionary as the carbide insert style parting tools. I was a former user of the HSS blade for parting, when I used it I developed what I call the HSS parting tool grimace, a squinting, puckered up facial expression in anticipation of what inevitably is bound to happen. Then my brother, who worked 2nd shift in a shop doing cut-off on 2 1/2" steel bars with an Iscar carbide insert style parting system, said as an experiment, he increased the feed on the lathe one step at a time to see where it would fail. He was amazed how fast he was feeding with still perfect results. Finally it broke either the insert or the blade, I forget which. He insisted I buy this type, which I did and never looked back. If anyone is still using the HSS blade for parting do yourself a big favor and give the insert blade a try, possibly the best tooling advance I have ever seen. If you are confidently using a HSS blade with good results, you are to be admired as an elite machinist! Thoughts?

I am happy for your success, but my experience is exactly opposite. Yes, they initially cut wonderfully, but the edges fail very easily (chip) forcing a new insert to be installed and they are very expensive. I have a HSS blade on a Phase II holder that is more than 10 years old and doing fine. I have resharpened it maybe 6 times. I am very experienced with cut off tools and I have used the carbide insert tool holder on 2 large very stiff lathes in like new condition.
 
+1 for the carbide insert blades, especially Iscar. Their Tang-grip with the L shaped insert is pretty hard to beat.
 
I am happy for your success, but my experience is exactly opposite. Yes, they initially cut wonderfully, but the edges fail very easily (chip) forcing a new insert to be installed and they are very expensive. I have a HSS blade on a Phase II holder that is more than 10 years old and doing fine. I have resharpened it maybe 6 times. I am very experienced with cut off tools and I have used the carbide insert tool holder on 2 large very stiff lathes in like new condition.

The carbide insert system for cut off has a unique top geometry the forms a chip narrower than the groove, if you are successful with a HSS blade you must have a certain way of sharpening the tip that makes it work for you. My congratulations on that, one question though, do you use power feed when parting? It's still hard for me to imagine a person using HSS with a calm, relaxed look on their face when doing it!
 
I remember reading Tom Lipton's book Metalworking Sink or Swim where he was talking about parting on a manual lathe.

Quote,"If you're scared of parting, watch a CNC lathe do it. It's too dumb to be scared." Very true! :D

Also, I have had bad experiences with cheapo cutoff systems. I had a Hertel one time that was worse than HSS. :eek:
 
I use an HSS parting blade and get good results. When I first started out I used hand feeding thinking I would have more "control" over the cut. I found this to be the exact opposite. If the tool is ground and sharpened properly it works much better for me with power feed.
 
The carbide insert system for cut off has a unique top geometry the forms a chip narrower than the groove, if you are successful with a HSS blade you must have a certain way of sharpening the tip that makes it work for you. My congratulations on that, one question though, do you use power feed when parting? It's still hard for me to imagine a person using HSS with a calm, relaxed look on their face when doing it!

Your really coming off as a carbide salesman with this line.

Your new here, read the archives, the HSS/Carbide/Ceramic debate has several
threads over the years.

Brand new HSS cut off blades are still being made & sold every day, there is a market
for it.
 
I use a small chainsaw sharpening stone parrallel to the long axis to put a slight dip on the top of the hss blade. I think this rolls the chip to be narrower then the cut. I seldom part and, for me, the last tiny bit is the hardest. I think that I probably need to go to crazy high rpm to get the sfm needed.
Bill D
 
I suppose they can be ground for a special thickness for grooving or a special tip shape. You do not have to part with the tool.
Bil lD
 
The carbide insert system for cut off has a unique top geometry the forms a chip narrower than the groove, if you are successful with a HSS blade you must have a certain way of sharpening the tip that makes it work for you. My congratulations on that, one question though, do you use power feed when parting? It's still hard for me to imagine a person using HSS with a calm, relaxed look on their face when doing it!

I never use power feed when parting. I like to feel the cut as it progresses. That way if a chip bind starts to occur, I can back off and clear the cut immediately. One hand on the infeed and the other on the oil brush.
 
I suppose they can be ground for a special thickness for grooving or a special tip shape. You do not have to part with the tool.
Bil lD


Right on, Bill! I have both, and often grind HSS for O-ring grooves, snap-rings etc. Yes, I could grind carbide too but parting inserts are pricey.
 
I'm sure everyone has their own system, but I like blade holders that use a slight positive angle. On my L&S I use a straight blade holder, both work well for me. I use 7 degrees rake when sharpening and I NEVER grind the top of the blade. It is unnecessary. Cut off operations are very much a feel thing for me. It is necessary to get exactly the correct tool load. Too light is bad and too heavy is as well, but there is a window when the tool load is perfect and it is a feel thing to find it. The tricky part is that every material is different. That is why I never use power feed.
 
Your really coming off as a carbide salesman with this line.

Your new here, read the archives, the HSS/Carbide/Ceramic debate has several
threads over the years.

Brand new HSS cut off blades are still being made & sold every day, there is a market
for it.

No, Doug. He's not a spammer. a bit adventurous maybe (giant bottle rockets :D), but not a spammer.

That Chinese spammer must be making you trigger happy. :D
 
No, Doug. He's not a spammer. a bit adventurous maybe (giant bottle rockets :D), but not a spammer.

That Chinese spammer must be making you trigger happy. :D

I know that, I said that the "first line" in his post looked suspect.
I even colored it RED for illustration.
 
Here's a good question, has anyone ever needed the insane fastest feed on bigger lathes? I think that it should be standard on lathes to have a 'creeper' speed. So many times I do an operation that the slowest feed is still to much. I put a gear in the initial drive that reduces the feed by exactly half, and I need it often. Of course when threading you have to remember to double the pitch. My Axelson will do .300" per revolution, fastest and .004" slowest, still too fast for many operations.
 
New tooling comes and goes but I don't remember anything as revolutionary as the carbide insert style parting tools. I was a former user of the HSS blade for parting, when I used it I developed what I call the HSS parting tool grimace, a squinting, puckered up facial expression in anticipation of what inevitably is bound to happen. Then my brother, who worked 2nd shift in a shop doing cut-off on 2 1/2" steel bars with an Iscar carbide insert style parting system, said as an experiment, he increased the feed on the lathe one step at a time to see where it would fail. He was amazed how fast he was feeding with still perfect results. Finally it broke either the insert or the blade, I forget which. He insisted I buy this type, which I did and never looked back. If anyone is still using the HSS blade for parting do yourself a big favor and give the insert blade a try, possibly the best tooling advance I have ever seen. If you are confidently using a HSS blade with good results, you are to be admired as an elite machinist! Thoughts?

HSS holds up to shock very well and it properly sharpened with good coolant flow does well. They last a long time and repeatedly they can be sharpened. They are great on a manual lathe. CNC usually will use carbide.

Like drills and end Mills it is the case with drills people prefer HSS because carbide can shatter and it often destroys the part. I have seen one shop which valued carbide highly. They were largely very successful with it. It was funny when the manual guy would cut material always preferring carbide he could break a few because he cut it way too hard. No biggie yet on manual I hate when carbide shatters. Just me.
 
Thoughts?

Yeah, I gots thoughts. Mine are that yer doing it wrong if it scares you, or isn't working.

Power feed cutoff ROCKS! And it's kinda cool when you got a chip pan covered in little coins of coiled up chip, too.

HSS, carbide, whatever. Just different flavors of the same thing. Each has it's place.

If you can't get HSS parting tools to work for you, eventually, you will really hate buying inserts and parting tool blades, as the seat for the tool inevitably gets mangled by a blown up insert at near zero surface speed.
 
I never use power feed when parting. I like to feel the cut as it progresses. That way if a chip bind starts to occur, I can back off and clear the cut immediately. One hand on the infeed and the other on the oil brush.
I'm the opposite. I think the power feed's smooth, steady pressure provides a better cutting environment than my shaky hands.
 
I switched over, happily, to using Aloris carbide wedge-lock parting blades in an Aloris holder, except for the rare cases when, not so happily, a really narrow blade must be used or when a small mushy workpiece needs the scary sharp edge of HSS.

And I agree about using manual infeed to find the sweet spot for the revs/material used. Machine feed I can see for a production run when parameters have been determined.

-Marty-
 
Here's a good question, has anyone ever needed the insane fastest feed on bigger lathes? I think that it should be standard on lathes to have a 'creeper' speed. So many times I do an operation that the slowest feed is still to much. I put a gear in the initial drive that reduces the feed by exactly half, and I need it often. Of course when threading you have to remember to double the pitch. My Axelson will do .300" per revolution, fastest and .004" slowest, still too fast for many operations.

i always wished for slower feed, even on the drill press.
 








 
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