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

[Runs With Scissors]

Well today I dedicated myself to learning how to take a HSS blank and turn it into a cutting tool.....I have done an OK'ish job so far, but I was dead set on "mastering it" today........

After about 6 hours I have decided to say....

I have hundreds of these blanks (well a lot of them) and I feel a little wasteful by not using them; However, the learning curve is pretty steep.

I basically feel like I "should" learn this for some reason, but the reality is, I am now leaning towards, 'Who gives a damn?".

I would rather be spending my time making shit, rather than burning my fingers and swearing......

It's not like I am going to be stranded on an island with a lathe and only HSS blanks....LOL

I am seriously considering getting Pre-made bits.


Any suggestions?

I am not making "NASA quality" parts, and money is always a factor, but do y'all have any suggestions?

I am considering something like these "replaceable tip" ones

https://www.amazon.com/Joogto-Index...=1723745112&sprefix=lathe+bits,aps,111&sr=8-3

or is this "fixed" style "better"?

https://www.amazon.com/AccusizeTool...745195&sprefix=lathe+bits,aps,111&sr=8-4&th=1



Or do you have a "favorite brand" that won't break the bank?

These will be used on my Craftsman 10" lathe and I do have QC posts now.

Also is "bigger better" (i.e. 1/2 inch is better than 1/4 inch?)

Lastly, is there "different ones" for different metals? i.e. steel, aluminum, brass, etc..etc

 

[Oleracer]

Feel your pain.. I get it done but not well. Never been taught just sorta half azzed it.
2-3 more draws full.

 

[TheOldHokie]

Well today I dedicated myself to learning how to take a HSS blank and turn it into a cutting tool.....I have done an OK'ish job so far, but I was dead set on "mastering it" today........

After about 6 hours I have decided to say....
View attachment 135002


I have hundreds of these blanks (well a lot of them) and I feel a little wasteful by not using them; However, the learning curve is pretty steep.

I basically feel like I "should" learn this for some reason, but the reality is, I am now leaning towards, 'Who gives a damn?".

I would rather be spending my time making shit, rather than burning my fingers and swearing......

It's not like I am going to be stranded on an island with a lathe and only HSS blanks....LOL

I am seriously considering getting Pre-made bits.


Any suggestions?

I am not making "NASA quality" parts, and money is always a factor, but do y'all have any suggestions?

I am considering something like these "replaceable tip" ones

https://www.amazon.com/Joogto-Indexable-Turning-Grooving-Threading/dp/B0BYZJG3BW/ref=sr_1_3?crid=1R9BAVWGH35CR&dib=eyJ2IjoiMSJ9.heImWqNbAL0bRGg7KcgJV7_Lh3VekoIpwOvhxGVC_8ewcavNI37hr4_y025Oe2mNm8Ij-La6ubLhS-XWKn2mYHfiBDvkQbXTJZcq1uJz_8qHQ0e1GFcbwigcBFvf_59spAwMNhLfjGQSFIDn0AZE_QvqRv3A4x6T0uw9gxw_i6C1bhxjuGVHd9E0lcEQPCdACyt_6hz6wtay2JLBxcvoltPyh7LdMpqcDpOFCEMcTbs.lS5LVce8DlH3rw4mphR61yEt_h2bQrnpXQuXUmjNfeI&dib_tag=se&keywords=lathe+bits&qid=1723745112&sprefix=lathe+bits,aps,111&sr=8-3

or is this "fixed" style "better"?

https://www.amazon.com/AccusizeTools-Pre-Ground-Turning-Aluminum-Steel-2662-2003/dp/B0779LLTC5/ref=sr_1_4?crid=1R9BAVWGH35CR&dib=eyJ2IjoiMSJ9.heImWqNbAL0bRGg7KcgJV7_Lh3VekoIpwOvhxGVC_8ewcavNI37hr4_y025Oe2mNotwcGgOkYNc4Lv7VlcIEq1jmRD_Kpn_DXbnDUgXIwCuHQ0e1GFcbwigcBFvf_59spAwMNhLfjGQSFIDn0AZE_QvqRv3A4x6T0uw9gxw_i6C1bhxjuGVHd9E0lcEQPCdACyt_6hz6wtay2JLBxcvoltPyh7LdMpqcDpOFCEMcTbs.7De7XcIefvaXPkUe2BZnjO0fzSQJFztX4anFcRD0TvM&dib_tag=se&keywords=lathe+bits&qid=1723745195&sprefix=lathe+bits,aps,111&sr=8-4&th=1



Or do you have a "favorite brand" that won't break the bank?

These will be used on my Craftsman 10" lathe and I do have QC posts now.

Also is "bigger better" (i.e. 1/2 inch is better than 1/4 inch?)

Lastly, is there "different ones" for different metals? i.e. steel, aluminum, brass, etc..etc

Go indexable and never look back. For your situation I would reccomend toolholders/inserts with a 3/8" inscribed circle.

Dan

 

[Pawnee]

Well you aren't going to throw away those blanks you have and you are one day going to find yourself in a situation where you need an odd shaped cutter to get what you want.

Instead of mastering it in one day, take your time. Watch a couple videos and try grinding a cutter every now and then.

In high school shop we often used round nosed tools for facing, nobody seems to talk about them anymore but they are my favourites for facing.

it's a good skill to have, kinda like grinding drill bits by hand.
Or coming up with wild ass stuff that works great - which seems to be your specialty.

 

[Lil Foot]

Sharpening HSS tool bits is a very basic skill, usually one of the first things taught to apprentice machinists. Having said that, it can also be very frustrating.
Many a novice has spent hours grinding a tool that they are very proud of, only to have it fail miserably in it's first use.
There are lots of utoob videos on the subject, but let me give a few pointers that will ease things a bit.

Be patient, go slowly.

Use compressed air or water often to keep the tool cool- do not let it get hot enough to discolor, or the cutting edge will be too soft to last long. (heat removes temper)

Have a plan, and a goal in mind.

Use soft, friable, open bonded wheels, usually white or pink. They are far more forgiving than hard, closed bonded wheels- they cut faster and produce far less heat.

As a general rule, if you can picture in your mind: The cutting point where it touches the part must be the only point that touches the part; all other surfaces must taper away from the cutting point. This is called clearance; how much and a what angle varies by the use and materials being cut.

Pictured below are some tools I have ground over the years (I have hundreds).
Some 1/2" tools, some 3/8" tools, some machine ground HSS tools, and the two wheels I do virtually all my HSS grinding with.

 

[Lil Foot]

Here is a basic HSS tool clearance grind diagram:

 

[Runs With Scissors]

Thanks all.

After doing some "Duck Duck Go'ing" I found out that the answer to my questions was not as straight forward as I had hoped.

I was able to locate a primer that 'kind of' broke down the "Alph-Numeric soup" of carbide insert tooling.


Lots of stuff to dig thru, but as per @TheOldHokie I found a kit that had at least one "3/8 inscribed circle" bit. (although after looking it up I now know what it means "technically", but I still have no idea what that means "practically" speaking )

It also contains (3) 80 degree bits that are recommended in that primer, as well as some other 'specialized' stuff.

All in all, I think it will be a decent "starter kit".

Its certainly not Sandvik or Kennametal quality, but I think they should work fine.


https://www.amazon.com/gp/product/B07PLYG1Y4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1


As pointed out, I will certainly keep my HSS blanks and "give it another go" if/when the need arises for a "specialty cutter".

 

[Sidekick]

I also have hundreds of the blanks. Good thing is they came from an old tool room and there are many pre shaped that can easily be modified. I mostly use them for plastics and aluminum in my 1950s south bend. Insert bits make turning fun again without wasting time sharpening, resharpening and then resharpeing again till it cuts right.

 

[TheOldHokie]

Thanks all.

After doing some "Duck Duck Go'ing" I found out that the answer to my questions was not as straight forward as I had hoped.

I was able to locate a primer that 'kind of' broke down the "Alph-Numeric soup" of carbide insert tooling.


Lots of stuff to dig thru, but as per @TheOldHokie I found a kit that had at least one "3/8 inscribed circle" bit. (although after looking it up I now know what it means "technically", but I still have no idea what that means "practically" speaking )

It also contains (3) 80 degree bits that are recommended in that primer, as well as some other 'specialized' stuff.

All in all, I think it will be a decent "starter kit".

Its certainly not Sandvik or Kennametal quality, but I think they should work fine.


https://www.amazon.com/gp/product/B07PLYG1Y4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1


As pointed out, I will certainly keep my HSS blanks and "give it another go" if/when the need arises for a "specialty cutter".

I think you are going to be dissapointed in that set.

First thing is you want laft and right handed tool holders. I much prefer the ones with clamps as well as center screws.

The majority of my use is TNMG 33x turning and boring inserts. They are heavy enough to hog metal, have multiple cutting edges, and cheap. When you start breaking them you will realize why thats important.

I also use a lot of ER16 And IR16 full profile laydown threading inserts. They are many times more expensuve than a TNMG insert and very easy to break. Theres a lot of money invested in that drawer of my tool chest.

The other shapes and angles have their uses but I would not start my collection there. I suggedt you buy a full box of TNMG 332 inserts and one left and right hand MTGN 16 tool holder that will accept those inserts. Then let the learning begin....

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[Runs With Scissors]

I think you are going to be dissapointed in that set.

First thing is you want laft and right handed tool holders. I much prefer the ones with clamps as well as center screws.

The majority of my use is TNMG 33x turning and boring inserts. They are heavy enough to hog metal, have multiple cutting edges, and cheap. When you start breaking them you will realize why thats important.

I also use a lot of ER16 And IR16 full profile laydown threading inserts. They are many times more expensuve than a TNMG insert and very easy to break. Theres a lot of money invested in that drawer of my tool chest.

The other shapes and angles have their uses but I would not start my collection there. I suggedt you buy a full box of TNMG 332 inserts and one left and right hand MTGN 16 tool holder that will accept those inserts. Then let the learning begin....

Dan

Thanks for the 'starting point" Dan.

If I am reading it correctly, the '16' is too big for my machine though.

I would have to go to a 08 I think.

Although I see the 08 does not have the "optional seat and seat screw" ?





Production Tool Supply has them and I live only a few miles from them.

Is this the style you would suggest?

But in the 08 size for my machine?

 

[Yooper]

Dan is right on the mark with indexable tooling. I’ll add this from my experience owning the same lathe you have. The last number in the indexable chip represents the radius of the insert tip that does the cutting. Keep this number at 1. Example: 321 versus 322 or 323. Our lathes don’t have the hp and the rigidity to push the larger radius tips through steel. You can get away with it in 360 brass and some aluminum but that’s about it. Carbide likes speed and feed neither of which our lathes have.

I guarantee you the day will come when you will need to sharpen a hss tool bit to cut a groove, radius etc. ( see Bill’s collection above) I’ll add this tip to invest in a honing stone to put the final finish on the tool. It makes a huge difference on surface finish and the tool will cut longer also. Good luck!

PS. Don’t go with negative rake tooling. This is signified by the letter N in the insert description. Example: TNG 321 versus TPG 321. Negative rake tooling is awesome but it takes power and rigidity etc. You will be much happier and a lot less frustrated if you take this advice.

 

[TheOldHokie]

Thanks for the 'starting point" Dan.

If I am reading it correctly, the '16' is too big for my machine though.

I would have to go to a 08 I think.

Although I see the 08 does not have the "optional seat and seat screw" ?





Production Tool Supply has them and I live only a few miles from them.

Is this the style you would suggest?

But in the 08 size for my machine?

View attachment 135063

Sorry - gave you a bad number and I edited my post.

I have multiple toolholders from HHIP and they hold up decently well.

Carbide Pro is an excellent source for low cost inserts.

Yooper makes an excellent point about 321 versus 332 and horsepower and he knows your machine.

Dan

 

[Runs With Scissors]

Dan is right on the mark with indexable tooling. I’ll add this from my experience owning the same lathe you have. The last number in the indexable chip represents the radius of the insert tip that does the cutting. Keep this number at 1. Example: 321 versus 322 or 323. Our lathes don’t have the hp and the rigidity to push the larger radius tips through steel. You can get away with it in 360 brass and some aluminum but that’s about it. Carbide likes speed and feed neither of which our lathes have.

I guarantee you the day will come when you will need to sharpen a hss tool bit to cut a groove, radius etc. ( see Bill’s collection above) I’ll add this tip to invest in a honing stone to put the final finish on the tool. It makes a huge difference on surface finish and the tool will cut longer also. Good luck!

PS. Don’t go with negative rake tooling. This is signified by the letter N in the insert description. Example: TNG 321 versus TPG 321. Negative rake tooling is awesome but it takes power and rigidity etc. You will be much happier and a lot less frustrated if you take this advice.

Thanks for the tips. I really do appreciate them and will heed them.

So, I am going to return that set from Amazon when it gets here, and I have decided to get a LH and RH tool holder with the "set screw and clamp" style.

Do I need a MTGN style tool holder with TPG 321 inserts?

 

[TheOldHokie]

Thanks for the tips. I really do appreciate them and will heed them.

So, I am going to return that set from Amazon when it gets here, and I have decided to get a LH and RH tool holder with the "set screw and clamp" style.

Do I need a MTGN style tool holder with TPG 321 inserts?

That is a good general purpose turning tool holder.

But TPG 321 is a positive rake insert and that MTGN toolholder uses negative not positive rake inserts - e.g. TNxx 321.

Dan

 

[Runs With Scissors]

That is a good general purpose turning tool holder.

But TPG 321 is a positive rake insert and that MTGN toolholder uses negative not positive rake inserts - e.g. TNxx 321.

Dan

So I need a MTGP toolholder so I can use TPG 321 inserts?

 

[TheOldHokie]

So I need a MTGP toolholder so I can use TPG 321 inserts?

Why TPG? Use the MTGN holder with TNMG inserts.

 

[Runs With Scissors]

Why TPG? Use the MTGN holder with TNMG inserts.

I thought that because @Yooper said that my machine was too light duty for negative rake tooling, I would then presumably have to go with "positive rake" tooling?

Dan is right on the mark with indexable tooling. I’ll add this from my experience owning the same lathe you have. The last number in the indexable chip represents the radius of the insert tip that does the cutting. Keep this number at 1. Example: 321 versus 322 or 323. Our lathes don’t have the hp and the rigidity to push the larger radius tips through steel. You can get away with it in 360 brass and some aluminum but that’s about it. Carbide likes speed and feed neither of which our lathes have.

I guarantee you the day will come when you will need to sharpen a hss tool bit to cut a groove, radius etc. ( see Bill’s collection above) I’ll add this tip to invest in a honing stone to put the final finish on the tool. It makes a huge difference on surface finish and the tool will cut longer also. Good luck!

PS. Don’t go with negative rake tooling. This is signified by the letter N in the insert description. Example: TNG 321 versus TPG 321. Negative rake tooling is awesome but it takes power and rigidity etc. You will be much happier and a lot less frustrated if you take this advice.

 

[TheOldHokie]

I thought that because @Yooper said that my machine was too light duty for negative rake tooling, I would then presumably have to go with "positive rake" tooling?

I missed his edit. I dont know your machine and he does but my 11" swing 1 HP Rockwell has no problem with negative rake tooling. That said its not asked to do anything approaching a "heavy" cut.

Dan

 

[Runs With Scissors]

I missed his edit. I dont know your machine and he does but my 11" swing 1 HP Rockwell has no problem with negative rake tooling. That said its not asked to do anything approaching a "heavy" cut.

Dan

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?

 

[TheOldHokie]

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?

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

SHARS 5/8" X 4-1/2 RH MTAN INDEXABLE TURNING TOOL HOLDER TNMG NEW !] | eBay

Model# MTAN R-10-3B. TNMG 331 DM YBC252 w/ Finishing chip breaker (PART #424-1731) /. TNMG 331 EM YBC202 w/ Finishing chip breaker ( 424-1769) /. TNMG 432 DM YBC252 w/ Finishing chip breaker ( 424-1735) /.

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