Lathe tooling

[trevj]

Trev, you aren't trying to inject a dose of common sense into this train wreck are you?

I've been a on and off hobby machinist since I was in my teens 45 years ago. In all that time I've tried out the various carbide tooling here and there along the way. I found that for some things it is needed but for 99% of the machining I do I far and away prefer HSS tooling for the lower cost and ease of shaping the tools to suit my needs of the moment. And, odd though it seems to some around here, the HSS cuts most cast iron, most steels, aluminium, brass and plastic just fine.

On the other hand when I am forced to use carbide tooling for some materials I find that whatever tips or brazed cutters I do have are always the wrong ones for the needs of that moment. And that's something the carbide using shop owners are not mentioning is that we need to read up on the various grades of carbide as well as the shapes when picking out inserts or brazed tooling to do our work.

So I'll just continue to muddle by with my HSS for the most part.

I might as well try.

Some folks will never 'get' lathe work or machining, but it sure was nice to see the lights come on on the ones that did, when we were running the apprentice ACS Techs through their famil in the Machine Shop.

Most of them started out with the same set of fears. Tool grinding, threading, four-jaw chucks. Everyone told them it was hard, so they thought it must be. They mostly found out it wasn't, so much. Some sooner than others!

All skills can be learned, but not if you avoid trying them, or practicing them.

Cheers
Trev

 

[Aries-]

I might as well try.

Some folks will never 'get' lathe work or machining, but it sure was nice to see the lights come on on the ones that did, when we were running the apprentice ACS Techs through their famil in the Machine Shop.

Most of them started out with the same set of fears. Tool grinding, threading, four-jaw chucks. Everyone told them it was hard, so they thought it must be. They mostly found out it wasn't, so much. Some sooner than others!

All skills can be learned, but not if you avoid trying them, or practicing them.

Cheers
Trev

There are some people that just will never get machining, be it lather or mill or CNC. Whrn i took my tool and die apprenticeship and cnc programming courses. There were many people that by the end still couldnt turn somthing smooth on the lathe. One guy i remember on his fibal project (a morse taper shaft) the surface was a wave because he was cross feeding to fast and it was pulling the cutter ibto the part enough it was bogging the motor on the 10hp 3 phase lathes. Or the plastic milk carton full of fisted off hss endmills that people broke.

Some people shouldnt touch machines and stick to other things.

 

[desporterizer]

I was amazed at how well HSS bits turned an old brake rotor into a threaded backing plate for a new chuck I bought. Now that I think about it, the only thing that made HSS bits cry uncle was a piece of "mystery metal" that turned out to be an old torsion bar.

 

[BCRider]

I worked with a guy like that. Great at paper work and planning. Totally lost when it came to having any sort of "feel" for tools or materials. I worked on and off with the guy for almost 20 years and he simply never got it. Any time he was in a shop it was just a disaster.

All skills can be learned, but not if you avoid trying them, or practicing them.

Amen to that......

 

[lejarretnoir]

This applies to any trade. You are either good at it or not.
Same as gunsmithing.

 

[17asleep]

I run Kenametal , and tungaloy brand incerts, the heat yes is supposed to leave with the chip but coolant keeps the part cool as well , a constant cool part lets me ruff then finish right away

If your Inserts are performing right, your part stays cool without coolant. On the other hand, if your insert gets hot during the cut and being flash cooled after the cut by the coolant, it could be getting micro fractures. Also, most modern coatings need the be warm, if not downright hot to perform to their full potential.

Sorry for dragging this farther off topic, but this seems like a conversation where people can learn stuff.

 

[wood800]

When taking .08-.120 thou cuts per side on a part during ruffing the chips come off hot and like bullets, heat does leave with the chip but not all of it, heat does go into the part, cast iron I don't use coolant , I cut a lot of A2 and stainless, those types of metals will work harden without coolant to the point that you can't turn it it's so hard. If not running coolant works for you then all the power to you

 

[wood800]

I run flood coolant on my lathe so incert is constantly being cooled, so the thermal cracking doesn't happen

 

[SND]

Nothing applies to everything. Taking 10lbs of chips off a 100lbs block is not the same as taking 10lbs of chips off an 11lb block, one of them will get hotter by the end.

$200-250 can set up a guy with a turning holder to take either TCMT or CCMT and a box of decent inserts, and you can add boring bars any time to take the same inserts.
But it is more $ than a handful of $3 hss toolbits, that will likely do the job just fine for most.

Most are better off starting by putting some $ in a quick change tool post if it doesn't have one and learn to use it right.

 

[lejarretnoir]

I started off in the early 70's with lantern rocker toolposts and HSS bits. There wasn't much else unless you happened to be in a machine shop where they were trying different things. I had to grind every HSS bit and calculate everything with manual dials. No DRO or CNC then. Everytime you changed a holder you had to setup again. You spent a lot of time setting up, but learned to be quick about it.

If I had to start from scratch today, I'd get one of those Chinese quick change wedge toolposts. I have a nice Dorian with an assortment of Dorian, Aloris and Chinese holders. These will do everything I need for gunsmithing and anything else. I have holders setup with brazed carbide, HSS and carbide inserts. Whatever gets it done easily. My old Rocker toolpost set has sat in a drawer for a long time now.
Yep, much easier, but I haven't forgotten the old ways. Still use the 4 Jaw chuck the most.

 

[Mike Webb]

I have been conventional and CNC machining for over 30 years and the requirements of a home gunsmith are a little different than those of a production shop or even a general job shop. To me HSS tooling will do just about everything I want it to on the lathe for gun work plus you have the advantage of easily grinding form tools and threading tools(55 deg. or 60 deg.). Plus HSS steels give better results when using the lighter, less rigid lathes common for home use. I remember starting in trade school and learning how to grind lathe tools. The instructor gave each student a handful of 3/8 key steel blanks and told us to grind a roughing tool, finish tool and threading tool on the bench grinder. It was days before anyone could grind a halfway decent tool and then we were given HSS blanks to grind. On poster commented on junk tooling pedaled by KBC, I find they usually sell two or more types of the same tooling in KBC, one marked "import" and the other "American made". It is usually best to pay a little more and get the better quality item. On most home lathes flood coolant is not usually an option so HSS and slower speeds and feeds are required for good work. I will say that even for home use a carbide parting tool has a big advantage over a HSS one as long as your machine is rigid enough to stand it.

 

[lejarretnoir]

...On most home lathes flood coolant is not usually an option so HSS and slower speeds and feeds are required for good work. I will say that even for home use a carbide parting tool has a big advantage over a HSS one as long as your machine is rigid enough to stand it.

Exactly! You'll find out very quickly when the lathe starts chattering if it's up to carbide parting. Snapping a parting blade is an experience.
I have a 1979 13x40 South Bend that I always use in high range for carbide. Backgear for threading/chambering unless I'm using carbide. You need to figure out what the capabilities of the machine you have. I can part with carbide and at high speed if it's mild steel and softer metals. 4140 and 416, no chance. It's backgear and lots of cutting fluid.
I think it's been well stated that the carbide learning curve can be an expensive lesson in insert styles and breakage. To the novice machinist, I recommend HSS cutting to learn just exactly how to grind a finish and roughing edge and then learn about rakes and chip breakers. Once you understand that, those carbide inserts will make sense to you. I also resharpen and or grind my brazed carbide tips and some inserts. I've seen some of those cheaper brazed tips ground at the wrong angles. I have my carbide grinder set at the angles I need to work with.