Insert Lathe Tooling - an education?

[GlennW]

Speaking of chuck guards..........

I use the Lexan one listed in the MSC, Enco catalog and like it except for the fact that the lexan cracks from opening and closing it and needs to be replaced occasionally. I'll work on the next one and polish the edges before I install it. I hung a rubber sheet on the front edge of it to stop the little stuff and coolant from flinging out onto the floor. Can't see it too well in the pic with it open, but it's up there.



The "bungee cord mod" is my favorite. The "foreword" "off" "reverse" lever has a nice notch to lock it in "off", but they had no spring to hold it there so I just grabbed a bungee cord as a temporary thing and it worked great! (still "temporary") You havn't lived until you drop a tool holder, chuck key, or something on the lever and it starts in reverse when you're not expecting it. Especially if you were in there with a micrometer and knocked something off with your elbow that hit it and started it or even just bump it with your leg!!

A 10" chuck at 2K with the jaws backed out past the body must be a real eye opener

Glenn

[PixMan]

Hey Russ,

You wrote that you use the Sandvik Coromant 151.2 cut-off/grooving tools. I don't know if you knew this, but the Valenite (now Walter Valenite) VSG inserts are the only other ones on the market that interchange with the Coromant 151.2. The Valenite VTG interchange with the Sandvik Coromant double-ended N123 system inserts. In the Valenite line, I use primarily the 5820 grade and especially love the "PG" (precision groove?) chipbreaker. I have holders for both the VSG/151.2 and VTG/123 inserts and find the Valenite inserts are cheaper, available in from more suppliers, and just plain work better.

One thing though, Sandvik uses a letter designation for insert width, Valenite uses a two-digit number that corresponds to width in MM. Also, some holder widths can take multiple insert widths. Here's the crossover scheme:

S to V Holder size takes insert sizes
D = 15 15, 20/D, E
E = 20 15, 20/E, F
F = 25 20, 25, 30/E, F, G
G = 30 20, 25, 30/E, F, G
H = 40 40/H
J = 50 40, 50/H, J
K = 60 40, 50, 60/H, J, K
L = 80 80/L

From this you can see that the first holders would be the VSG "30" or Coromant "G" width blades so I can cutoff or groove a huge range of depth/diameters and widths. With a Valenite VG101 xx 30 or Coromant 151.2-xx-30 blade I can use inserts from about .083" wide up to .163" wide. My tool block holds 32mm/1.26" blades, so I also got a VG101 25 15 blade so I can use the tiniest inserts for thin-kerf cutoff, down to .063".

I also use some of the solid shank VTG / N123 style holders, but not the blades. I like the double ended inserts for grooving up to about an inch deep or cutoffs of smaller diameters. The double-ended inserts are not twice the price of the single-ended.

[jim rozen]

I am really suprised to hear of the PCD portion of an insert falling off/out. I've run the valenite
ones for many many hours, and never had one fail that way, or any other way for that matter.

With my small machines, I've found the TPG221 cermet inserts are just about the best all-around
tooling for this, when machining hard or abrasive items. Or where the SFPM gets very high.
I've stopped buying any kind of coated or uncoated carbide for this use.

Jim

[4FreeAU]

What and how much you actually do is to be considered first. I can attest to you if you learn about insert tooling from a reputable dealer or truly educated
Machinist you will find inserts are not nearly as pricey as you may think. They will save you money if you do much. Longer life, Better finishes, faster cutting. The grinding-to-sharpen time is time you can use to make parts, that means money in. Less money out

[Harold_V]

What and how much you actually do is to be considered first. I can attest to you if you learn about insert tooling from a reputable dealer or truly educated
Machinist you will find inserts are not nearly as pricey as you may think. They will save you money if you do much. Longer life, Better finishes, faster cutting. The grinding-to-sharpen time is time you can use to make parts, that means money in. Less money out

That insert tooling is profitable isn't in dispute. Those who work in production, using industrial machines, profit, and profit well. However, here, we have numerous individuals who have less than industrial rated machine tools. For them, the use of inserts may or may not be of benefit, all depending on the nature of the work they pursue. As far as cutting abrasive materials (glass board, as an example), yeah, carbide is quite useful, but the guy who's turning some mild steel, using a quarter horse motor on a lathe that scarcely weighs 100 pounds, the benefits are non-existent, and the choice to use insert tooling robs him/her of the opportunity to learn something that is essential for their progress in improving their skill level.

High speed cutting tools are very much a part of machining, especially in the home shop, where operators often have shallow pockets and can not afford to invest in thousands of dollars in insert tooling. Skill at the bench grinder, combined with the proper wheel, will serve the home shop machinist far better.

Just sayin"

H

[RSG]

High speed cutting tools are very much a part of machining, especially in the home shop, where operators often have shallow pockets and can not afford to invest in thousands of dollars in insert tooling. Skill at the bench grinder, combined with the proper wheel, will serve the home shop machinist far better.

H

Funny you mention this I was just debating this with my Ohio friend who owns a production shop, he believes the only way to go is Carbide. I think it has it's place and I use it too but some things are hard to do with an insert tool, at least as far I can tell. I mentioned you Harold, siting how you feel every machinist should know how to grind you own tooling and he laughs telling me to get out of the dark ages. I've gotten good at grinding highly specialized tooling with beautiful chip breakers that do not foul on the entire facing cut with .06" doc each pass and works brilliantly. Anyone who has machined aluminum knows how stringy it can be.

On his insistence I recently purchased a profiling tool with a carbide .069" rad insert but have my doubts it will perform as good as my chip breakers for clearing chips.

[SteveM]

I was just debating this with my Ohio friend who owns a production shop, he believes the only way to go is Carbide.
I've gotten good at grinding highly specialized tooling with beautiful chip breakers that do not foul on the entire facing cut with .06" doc each pass and works brilliantly.

He is likely correct - for his use.

For your friend, it is likely much more important that when he changes out a toolbit, the tip is in EXACTLY the same location as the old one.

It's also important that each insert cut EXACTLY the same as the prior one.

If he's making 1,000 parts and has to change the insert every 100 parts, that's 10 tool changes. He can't be bothered with re-setting the tool height, re-calibrating the DRO axes and worrying about if the tool pressure with this one differs from the last one.

He'll could make more parts in an hour than you will in your lifetime.

Anyone that looks at your work and says "you need to with inserts" doesn't know what it is you do. I say you are doing everything right.

Do I have inserts? Yes. One of them is my go-too toolbit for a lot of stuff (a CPxx insert) on a toolholder that can turn and face. But there are a dozen toolholders with HSS on that shelf and I use those as well.

Right now, I am re-swizling my workshop, and one of the things to come out of that is a dedicated grinder bench, which will have at least 4-5 bench grinders on bases that I can swap on-off the bench, depending on what I am doing. It will also hold my Sanford bench grinder and my vintage Delta 12" disk sander among other tools.

Once I have that all set up, I intend to get back to hand grinding more tools.

Just sold my brother a Sherline. He only makes small stuff so that works for him. I'm going to show him how to grind HSS.

Steve

[Harold_V]

High speed cutting tools are very much a part of machining, especially in the home shop, where operators often have shallow pockets and can not afford to invest in thousands of dollars in insert tooling. Skill at the bench grinder, combined with the proper wheel, will serve the home shop machinist far better.

H

Funny you mention this I was just debating this with my Ohio friend who owns a production shop, he believes the only way to go is Carbide.

He's forgotten the basics, and for that I pity him. Much like the guy who can't live without his smart phone.
When you understand the basics (of everything), problem solving comes easy. When you don't, the slightest interference results in stoppage.

One must keep a perspective when insert tooling is the topic of discussion. I use inserts, and always have. I've also used hand ground tools, including carbide. They all have a place, and should be a part of everyone's arsenal of tooling. Even the guy who runs a CNC can occasionally benefit by hand ground tools, especially for short runs. Best of all, when you understand tool geometry, it's easy to see why a tool may not be cutting properly.

Anyone who operates a machine tool will benefit by mastering the art of grinding tools. Those who can't are held hostage by the tool supply circuit.

H

[RSG]

He is likely correct - for his use.
Steve

I know, whether he's being a joker or not he does have more at stake then I. He actually does more grinding than anything. His skill level is top notch!

[Mr Ron]

I have been using a lathe carbide tool holder in a fly cutter on my vertical mill. It works great to clear surfaces on aluminum.