Learning to sharpen HSS lathe bits......A lesson in futility.....

[Runs With Scissors]

Why abandon triangular inserts? These are cheap - MSC is not

Pardon Our Interruption...

No sir, I am not abandoning that.

I totally believe you about using "cost effective" bits.

I basically 'shot my mouth off" before I finished watching that video

I was just trying to "decode" which tool holder to get for my machine.

Stay tuned.......I'm still watching that video.

 

[DustyRusty]

Slow watcher, slow learner???

 

[Runs With Scissors]

So I have some questions about the choices for the characters.

I need help in filling in the 3 blanks

M-------- pin and clamp
T-------- Triangular inserts
_---------Need help this one (tool holder style.....lots of choices and I haven't a clue)
_---------need help here too. ( Rake angle positive, negative, neutral......again no clue)
R--------Right hand tool
08------1/2 inch square. (this is the biggest my QCTP will accept)
_--------Need help here too (
A--------4 inches long


MT ? ? R08_-?A

in the background of @TheOldHokie post, I see a 1/2" version of what he sent me


https://www.ebay.com/itm/3003527608...brand=Shars+Tool&_trksid=p2332490.c101224.m-1


but that is a

Model# MTAN R-08-2A

• Shank Size Square: 1/2"
• Overall Length: 4"
• Insert I.C: 1/4", T: 1/8"

So that is a negative rake, and the IC is 1/4 not 3/8......Big deal or not?

 

[TheOldHokie]

So I have some questions about the choices for the characters.

I need help in filling in the 3 blanks

M-------- pin and clamp
T-------- Triangular inserts
_---------Need help this one (tool holder style.....lots of choices and I haven't a clue)
_---------need help here too. ( Rake angle positive, negative, neutral......again no clue)
R--------Right hand tool
08------1/2 inch square. (this is the biggest my QCTP will accept)
_--------Need help here too (
A--------4 inches long


MT ? ? R08_-?A

in the background of @TheOldHokie post, I see a 1/2" version of what he sent me


https://www.ebay.com/itm/300352760812?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=271845,271023&meid=27de54f8fa7a4390b54a032771ed274f&pid=101224&rk=4&rkt=5&sd=300517030246&itm=300352760812&pmt=0&noa=1&pg=2332490&algv=DefaultOrganicWebV9BertRefreshRankerWithCassiniEmbRecall&brand=Shars+Tool&_trksid=p2332490.c101224.m-1


but that is a

Model# MTAN R-08-2A

• Shank Size Square: 1/2"
• Overall Length: 4"
• Insert I.C: 1/4", T: 1/8"

So that is a negative rake, and the IC is 1/4 not 3/8......Big deal or not?

That will work but I consider it pretty light. You should be able to find a tool block with 5/8" slot to fit your tool post. Or you can always grind a 5/8" down to fit a 1/2" block.

You are in the learning/experimenting phase so I would suggest you dont spend a lot up front.

Dan

 

[Yooper]

It was so easy when I first got into this game. It was generally triangular and square inserts. Negative rake tooling was just starting to come into its own. I can’t keep up with all the different shapes and geometry and where they each shine. I’ll take a few pictures of what I use on my lathe and pass this on to you.

 

[Runs With Scissors]

It was so easy when I first got into this game. It was generally triangular and square inserts. Negative rake tooling was just starting to come into its own. I can’t keep up with all the different shapes and geometry and where they each shine. I’ll take a few pictures of what I use on my lathe and pass this on to you.

Thank you. I appreciate it.

What rake angle do you suggest?

 

[woodman55]

Gotcha!

Well i found a video that seems to explain how to "decode' the "alpha-numeric soup" of tool holders.

The guy seems to know what he is talking about and so I took his logic and came up with a tool holder number of

MCLNR083A

I made some assumptions on how to massage the numbers..........like going with a 08 instead of his example of 12 and went with A instead of B, in order to find a tool that will fit my machine.

Low and behold the inter-web kicked back a holder that might be what I am looking for?
https://www.mscdirect.com/product/details/05696711
https://www.mscdirect.com/product/details/05696711

Any thoughts?

great video, I have watched some of his videos before. He seems quite knowledgeable. I don't own a lathe, I just like watching stuff being made.

 

[Yooper]

Oh man! That is a very good question to which I have forgotten through the years. I will post a link to a conversation on Practical Machinist that may or may not enlighten us to help answer this.

Choosing Rake Angles for Carbide Inserts Material and Machining Considerations? - Carbide Inserts | Carbide Turning Inserts | Carbide Inserts Manufacturer/Supplier - Apple Carbide Tools

The choice between a positive and a negative rake angle […]

applecarbidetools.com

I’ll post pictures in a couple of days of what I use. Couldn’t get it done today or tomorrow because I am retired and my days seem to be taken up by other peoples plans

 

[Yooper]

As promised, this is an image of what I use. These go in a 3/8" tool holder of which I bought a set that includes RH, LH, straight etc. I'm sure you know what I'm talking about by now. Dan is absolutely correct about the clamp style being the best but too late, this is what landed on my doorstep a number of years ago. BTW, I buy my inserts from McMaster Carr because they are usually of decent quality. Buying the cheap ones off of eBay has been an exercise in futility. Buy once cry once when it comes to inserts.

 

[Runs With Scissors]

As promised, this is an image of what I use. These go in a 3/8" tool holder of which I bought a set that includes RH, LH, straight etc. I'm sure you know what I'm talking about by now. Dan is absolutely correct about the clamp style being the best but too late, this is what landed on my doorstep a number of years ago. BTW, I buy my inserts from McMaster Carr because they are usually of decent quality. Buying the cheap ones off of eBay has been an exercise in futility. Buy once cry once when it comes to inserts.

View attachment 135311

Thank you for the pic.

If you get a chance, could you take a pic of the "numbers" printed on the actual "bit holder tool"?

That is hardest part for me to find. For the life of me I cannot find one that is not a "negative rake" and has all the other attributes listed above. (i.e. 3/8 IC, Triangular bits, screw and clamp.....etc)

Since they were returnable, I decided to try the ones I linked to in post #7, and as usual, @TheOldHokie was correct. I was disappointed.

I could get a decent looking finish on my "mild steel test bar", but I had to take such a deep cut that my machine would stall or "uncomfortably" slow down to a near stall.

 

[lynnmor]

As promised, this is an image of what I use. These go in a 3/8" tool holder of which I bought a set that includes RH, LH, straight etc. I'm sure you know what I'm talking about by now. Dan is absolutely correct about the clamp style being the best but too late, this is what landed on my doorstep a number of years ago. BTW, I buy my inserts from McMaster Carr because they are usually of decent quality. Buying the cheap ones off of eBay has been an exercise in futility. Buy once cry once when it comes to inserts.

View attachment 135311

I made the mistake of buying a less than package quantity from McMaster, they tossed the loose inserts in a bag and all were chipped. Yes, they replaced them.

 

[TheOldHokie]

I made the mistake of buying a less than package quantity from McMaster, they tossed the loose inserts in a bag and all were chipped. Yes, they replaced them.

Thank you for the pic.

If you get a chance, could you take a pic of the "numbers" printed on the actual "bit holder tool"?

That is hardest part for me to find. For the life of me I cannot find one that is not a "negative rake" and has all the other attributes listed above. (i.e. 3/8 IC, Triangular bits, screw and clamp.....etc)

Since they were returnable, I decided to try the ones I linked to in post #7, and as usual, @TheOldHokie was correct. I was disappointed.

I could get a decent looking finish on my "mild steel test bar", but I had to take such a deep cut that my machine would stall or "uncomfortably" slow down to a near stall.

How much spindle horsepower do you have. You may be forced to go with lighter tooling.

1/2" RH CTAP Tri-Lock Tool Holder

www.shars.com

This is negative rake and works fine on my 1 HP 11" Rockwell.

 

[Lil Foot]

What I most commonly use:

 

[Lil Foot]

Insert threading tools:

 

[Lil Foot]

Never used this long boring bar yet:

 

[Lil Foot]

More:

 

[Lil Foot]

The inner 7 from the last pic are the only ones I've purposely bought.
I was running a Hardinge AHC at the time, and everyone else was using HSS.
I smoked everyone's production rates.

All the others I have acquired with machines I've bought, or tooling packages I've purchased for other tools, and they were just bonuses.

 

[Lil Foot]

Incidentally, the boring bar on the left side of my first pic is the best boring bar I have ever used.
(out of thousands, over 51+ years)

3/4" x 6 1/2", solid carbide. (rigid as hell)
Great selection of insert styles, grades, radii, and coatings available.

 

[Lil Foot]

Once you have settled on an insert tool, keep an eye out on eboy for inserts.
I regularly find partial packs of name brand inserts for a fraction of their normal prices.

 

[Runs With Scissors]

Thanks to everyone for helping me out.

After some "intensive research" I have decided to "try" HSS inserts.

A few things that I have noticed/realized/learned.

My machine is pretty small as compared to many of yours which puts me in a "weird category" that is somewhere between "mini hobby lathe" and "Big 'Ole Industrial lathe"

One thing that struck me as odd, just this weekend, was that all of the tooling that came with the machine, some 10+ years ago, was HSS.....I literally have "hundreds" of HSS blanks, but the Old Man did not have even one "carbide" bit.

Hmmmmmm.........So maybe/probably the Old Man that used it before me "knew something"??????.....He did have a massive work shop.

Long story short.....I found a company that makes HSS inserts, and so I ordered a LH and RH tool, and a few inserts.

At 10+ bucks per insert, they are not cheap, but I am hoping that they are a good choice for my machines size, capability and my experience level.

They get great reviews on the "machinist sites" that I have been perusing, and apparently they are "easily" and quickly sharpened on flat stone, so they last a long time.

I have also decided to "not give up" on my "lathe bit grinding", but just "take my time" and practice, but am keeping my "options open" for carbide tooling as well.

I will post my results when I get a chance to try them out.