Insert tooling/HSS

T

Tamper84

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I have been reading and researching, but still have questions. I have talked to some machinist's at work, and they say, use indexable inserts for the lathe. In a shop/ production setting, understandable. But they have also said that they keep HSS around for making custom bits/radius' etc. But mostly they use the inserts.

In a home shop enviorment, it is pretty much economics (IMO). HSS is cheaper, although it does take some work to get it on the lathe versus using an allen wrench. I dont want to start an argument (I have thought about posting as not to start any) rather a useful conversation.

After you get your accesories in line for the lathe, would you invest in the insert tooling? And once you do (did) do you seem to use that more or less then the HSS?

Yes I understand the importance of grinding the HSS for custom radius/ thread tools and understanding the geometry of proper clearance. Also to impress yourself :jester:

The reason I have asked this question, is it seems, the inserts seem to be getting cheaper, and Im wondering if it would be wise to invest in some. But so many choices!!! Any ways, please please dont start a fight on HSS versus inserts.

Thanks,
Chris
 
This can be a "passionate" topic so I hope folks keep a level head. That said, I'll tell you my strategy -which works well for me but others may have valid reasons for different techniques.

It pays to learn HSS as you'll eventually need both.


I tend to use a lot of carbide because it's very repeatable and lasts almost indefinetely if used properly. It tends to stand-up very well to slightly harder materials and gives a finish I really like on non-hardened medium and high carbon steel (and similar alloys). I also use it a lot on aluminum, brass and bronze. It's the only thing that can endure stainless steel -and even at that, carbide wears-out after 5-6 good passes. I've used the same insert for weeks on end with soft steel and AL. The downside is you need to spin faster and to get the finish you want, you need to setup your last DoCs in the optimal range for the kill (which is always a thrilling moment).

I like HSS when I need to cut a real sharp shoulder or to make cuts that must look good under 10 thou DoC. HSS can make crummy metal (like A36) look good. It's also invaluable when you have small diameter work as carbide needs to spin 2-3 faster than HSS. Most lathes can't go that fast. There are ways around that problem but, the finish always looks better on small diameter stuff with HSS.

Inserts are cheap. Pack of 10 runs 25 bucks now -and to me, it's worth the convenience. That said, 1/3 of my toolpost holders are loaded with HSS and I keep several fresh blanks of HSS in 1/2, 3/8, 5/16 and 1/4" around.

Ray
 
I use regular triangular carbide insert tooling for most lathe turning because I abuse and break 'em a lot. Sometimes, I just want to turn the head of a grade 8 bolt or mystery steel that might be hardened, and I'd rather break an insert than waste time regrinding HSS tooling. I make any number of quickie form tools, and use HSS for that, as well as for turning wood, plastic or other stuff that wants a razor sharp acute cutting angle.

Mostly, though I use the carbide insert tools because they do go for a long time, and are repeatable. I mounted two sets of five in their own holders, so I have a set for facing, and a set for turning ready to go. I spent some time getting them set in their holders so the extension is just the same - that way I can switch from right to left hand turning by changing holders in the quick change tool post without any real change in the diameter I'm turning, for example. Quick and easy, I have a variety of angles ready at hand to chamfer the end of a rod or make a nice transition in diameter, etc.
 
Hello Chris

My lathe is a Southbend clone and not very young.
I hate Quick Change Toolposts (Mostly because I cannot afford a swiss TRIPAN).
I made more than four tangential tool holders and as You can se on picture cutting material is not very important.
First band on the thick part made by selfground carbide (broken endmill), next is Crobalt, and then WKE45 HSS and the last is ASP 60 powder HSS.
Regrinding and honing is 2-3 minutes for Crobalt and HSS .
The carbide stick last very much longer and fails much more dramatically needing 5-10 minutes tender,loving care.
Usually I take the one I think has seen least abuse.

Kind regards

Farfar

IMG_1132.JPG
 
some people like making tools :)
I'm using HSS.... Inserts. :)
the same holder takes carbide too.
dont like grinding. dont want to invest in grinders anymore than the HF grinder. which will make some basic HSS bits.
 
Chris,
Your OK discussing that here. There isn't gonna be a bunch of junk, usefull discussion yes, other stuff, Ummm, no. I tend to favor the HSS due to the fact that my small lathe is not rigid enough to really capitalize on the higher surface speeds and deeper DOC capability that you get with Inserts. Inserts are also very expensive over time depending on what you are doing and they are about as fragile as glass. Making an interrupted cut, say making a square piece of stock round to thread it or add a clevis to is extremely hard on the inserts which probably will break at least one edge immediately. Hss can also be custom ground to non standard profiles and you can adjust the rake, side, relief, and tip radius to get a perfect profile and super shiny and smooth cut surface. I have a QCTP and several 1/4, 5/16. 3/8th and 1/2 shank bits that all fit into the tool holders and can be adjusted to get the right tool height. The 1/2 in shanks were an Ebay buy before I knew anything and they use indexable triangle bits. But I rarely use that large of a tool bit in my little itty bitty 7X lathe. Once you have developed a good hand and eye for using the smaller machines and sensing the load, then you might be able to utilize some of the benefits of Carbide, But for me personally I haven't been able to justify the extra cash. I buy a lot of Ebay blanks for 3 -4 dollars a pack and I have a decent wheel on my grinder, so I don't mind taking a moment to grind a bit or sharpen one that is dull. Keep a diamond hone (looks like a file) handy and give em an occasional quick touch up and they work just fine for 90+ percent of all the small machines are capable of doing. Other schools of though, or ideas? Don't be shy, just be polite and civil.

Bob
 
All completely good and valid points made by Bob and I was remiss in not suggesting as Bob stated... HSS works better for smaller lathes. It may be the case that belt drive lathes are better off with HSS too as carbide requires higher pressures and you're more likely to get belt slippage. You'll have to try and see if that's the case as it was with my old TH-42. If your RPMs are going up, down and sideways in the middle of a cut, you won't have a fun time with carbide.

Also, there's a different learning curve with carbide. You could be zipping along and all the sudden, the cut looks terrible. Say what? Hmm, looks OK, it's clean, screw is tight -don't cut work a darn. Look very closely and you might find a tiny chip or possibly a worn spot on the face -and that's the cause of the problem.

With HSS, if your machine is vibration free, you can make nice cuts with DoCs right down to 2-3 thou. Don't even try that with carbide unless you want a finish that feels like a wood rasp.

If you're new to lathe work, tackling HSS and carbide at the same time can have you scratching your head.

Ray


Rbeckett said:
Chris,
Your OK discussing that here. There isn't gonna be a bunch of junk, usefull discussion yes, other stuff, Ummm, no. I tend to favor the HSS due to the fact that my small lathe is not rigid enough to really capitalize on the higher surface speeds and deeper DOC capability that you get with Inserts. Inserts are also very expensive over time depending on what you are doing and they are about as fragile as glass. Making an interrupted cut, say making a square piece of stock round to thread it or add a clevis to is extremely hard on the inserts which probably will break at least one edge immediately. Hss can also be custom ground to non standard profiles and you can adjust the rake, side, relief, and tip radius to get a perfect profile and super shiny and smooth cut surface. I have a QCTP and several 1/4, 5/16. 3/8th and 1/2 shank bits that all fit into the tool holders and can be adjusted to get the right tool height. The 1/2 in shanks were an Ebay buy before I knew anything and they use indexable triangle bits. But I rarely use that large of a tool bit in my little itty bitty 7X lathe. Once you have developed a good hand and eye for using the smaller machines and sensing the load, then you might be able to utilize some of the benefits of Carbide, But for me personally I haven't been able to justify the extra cash. I buy a lot of Ebay blanks for 3 -4 dollars a pack and I have a decent wheel on my grinder, so I don't mind taking a moment to grind a bit or sharpen one that is dull. Keep a diamond hone (looks like a file) handy and give em an occasional quick touch up and they work just fine for 90+ percent of all the small machines are capable of doing. Other schools of though, or ideas? Don't be shy, just be polite and civil.

Bob
Click to expand...
 
You are all right, but wouldnt you like one material in between? You are fogetting Cobalt. I personally believe that for conventional milling, carbide is too expensive, you should use cobalt, same for turning on lathes under 6 inches. Why? Cobalt is more elastic than carbide, will take more abuse, yet endures more than HSS, and costs almost the same....as if it was on me, I would erase HSS and replace with cobalt... All drill bits and tool bits. Then I would have three groups, cobalt, Carbide and ceramics. Then the diamonds a CBNs for special nickel alloys and tough cutting materials.


I would only use HSS on aluminums and bronzes.
 
timbertoes said:
some people like making tools :)
I'm using HSS.... Inserts. :)
the same holder takes carbide too.
dont like grinding. dont want to invest in grinders anymore than the HF grinder. which will make some basic HSS bits.
Click to expand...

Hah hah hah!! You beat me to it Timbertoes!! Ha hah hah!

http://www.arwarnerco.com/c-5-tool-kits.aspx

I usually use carbide only when I need the speed (low SFM metal on large diameter) or hard material. I occasionally actually use it for what it was made for- removing a lot of metal.

Because I need to work a lot more to be truly proficient, I still get a better finish, consistently, with HSS ground bits. I just lightly stone them, in place, before cutting.

I did pick up a small set of the HSS inserts from Warner Co (not the one I posted above), and really do like them, but have not found myself replacing my home ground bits yet.


Bernie
 
Any opinions on the Stellite bits? I must have acquired some in my travels in the past when I had even less of a clue. Now, at least, I think I need to ask about them.
Am I correct that they are harder, stay sharper, and can handle slightly high cut speeds?
Or am I just whistling Dixie? :)

Bernie
 
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