# Insert Holder Recommendation



## bigmojo (Dec 13, 2015)

Hello all.

Proud new owner of a 1941 LeBlond Regal 17 with a 1.5 hp motor and a top speed of ~480 RPM. - I know, slow, but i'm turning metal on a piece of history. She built submarine parts at the Manitowoc shipyard in WWII so I'm quite happy taking my time working on it. The lathe came with a Phase II 250-300 quick change tool post and 250-30x series tool holders. (Max shaft size of 3/4")  I currently have a 5 piece set of Turning bars with 1/2 inch shanks and both TPMB & TPMW inserts.  The TPMB and TPMW bits i have cut a very nice groove and thread like beasts, but they are less than ideal for facing or turning down SS. 

I will mostly be turning mild and stainless steel. All of that said I am looking for some recommendations on a set of 3/4 shank bit holders and bits. - then again, maybe I'm not using the bits i already have correctly??

TIA


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## Paul in OKC (Dec 14, 2015)

The holders you have should be fine. I would look to inserts more suitable to stainless, if that is what you do the most.


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## bigmojo (Dec 14, 2015)

Thanks Paul. I have to admit there are way too many options, acronyms, and numbers for me to get my head wrapped around. 

I have TPMB 321/322 and 433 inserts as well as the TPMW 222. 

From what i have read:
A. I should stick with HSS bits as the lathe i have does not turn fast enough to take advantage of carbide
B. The 431 / 432 are better suited for facing and general turning

Would that be accurate?


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## mikey (Dec 14, 2015)

I should think those TPMX inserts would work okay for roughing but they might be a bit of a challenge getting a good finish, especially at such low speeds. For stainless, HSS would definitely finish better for you and I personally would go with that.


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## Wreck™Wreck (Dec 14, 2015)

Getting a nice finish on 303,304 and 316 stainless even at low SFM is the easiest thing that you will ever do with a lathe using insert tooling, chip control and tool life are a different matter entirely (the nest of unbroken chips may well drive you mad). For general turning and facing using one tool an 80° diamond or trigon insert will work well, triangles are not well suited to both operations with the same tool, flood coolant is essential.


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## Dan_S (Dec 14, 2015)

bigmojo said:


> .
> From what i have read:
> A. I should stick with HSS bits as the lathe i have does not turn fast enough to take advantage of carbide
> B. The 431 / 432 are better suited for facing and general turning
> ...



A) sfpm is what matters, A 8" diameter bar spinning at 480rm is roughly 1000 sfpm, and that's pretty fast for anything other than aluminum 
B) that depends on the feed rate and the chip breaker. 

This page will help you understand insert nomenclature.
http://www.carbidedepot.com/formulas-insert-d.htm


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## Wreck™Wreck (Dec 14, 2015)

bigmojo said:


> B. The 431 / 432 are better suited for facing and general turning
> 
> Would that be accurate?



The difference between Triangle 431 and 432 tools is the nose radius in 1/64 ths. The first number (4) is the inscribed circle in 1/8's, the second number (3) is the thickness in 1/6'ths. A 1/2" inscribed circle triangular insert used in a small hobbyist sized lathe is a large tool indeed.

As mentioned above, a triangular insert is not well suited to Facing and OD turning *with the same tool in the same orientation *due to the tool geometry. 
The best option, short of changing tools, is to choose a shape that has the lowest acute included angles.


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## mikey (Dec 14, 2015)

I own a 5-piece set that uses TPMX inserts and agree - you have to change tools to face and turn. They work but carbide doesn't finish nearly as well as a sharp HSS insert or a HSS tool in stainless, at least not for me and not at low speeds. TPM inserts have no chipbreaker so stainless will give you looong chips, another reason to change to a more modern tool geometry.


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## bigmojo (Dec 14, 2015)

So if i am reading this right i would be looking at a CNMx32x?
That would give me an 80 deg diamond with 0 relief, reasonable tolerance, a .375 IC @ 1/8 thick thus fitting into a 1/2" holder.
Alternatively, since I would still need a new bit holder as the ones i have are all for T bits, i could get a 3/4" holder and would be looking at a CNMx43x bits?  All in HSS correct?

Thanks all.  In case nobody has mentioned it lately...this forum is awesome!


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## Dan_S (Dec 14, 2015)

bigmojo said:


> So if i am reading this right i would be looking at a CNMx32x?
> That would give me an 80 deg diamond with 0 relief, reasonable tolerance, a .375 IC @ 1/8 thick thus fitting into a 1/2" holder.
> Alternatively, since I would still need a new bit holder as the ones i have are all for T bits, i could get a 3/4" holder and would be looking at a CNMx43x bits?  All in HSS correct?



Big tool holders & inserts are only really needed if you're going to take large depths of cut. Not to mention they cost more.

for example I run this set on my little 8" lathe, and it uses ccmt/ccgt 21.51/21.52 inserts.
http://www.grizzly.com/products/Glanze-Turning-Tool-Set-1-2/H5681

1/4" insets are usually rated for a depth of cut up to about 3/32" 
3/8" inserts up to about 1/8"
1/2" a little over 1/8"

My recommendations would be to go with 1/2" or 5/8" shank tools that run ccmt/ccgt inserts. Take a look at this starter kit from AR Warner, it uses CCMW 32.52  t-15(a type of hss) inserts.
http://www.arwarnerco.com/p-15-kit-11-12-inch-turning-c-right-hand-left-hand.aspx

the benefits of these holders, is that you can also run CCMT, & CCGT carbide inserts that are cheap and plentiful.


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## mikey (Dec 15, 2015)

If you wish to use a 3/4" holder, take a look at this one as well: http://www.ebay.com/itm/NEW-TOOLMEX...070259?hash=item4d1ffbb0b3:g:KhcAAOSwFAZTsaiX

This is the 3/4" version of the tools Dan recommended. This tool will both face and turn without reorienting the tool and uses CCMT and CCGT 431/432 inserts. These tools will probably work better than the older TPMX type tools as the inserts have a positive geometry. Download the insert catalog from Seco or Iscar or Korloy and determine which grade, nose radius and chipbreaker you want to try and look for them on ebay to save costs. 

I'm not aware of anyone who sells HSS inserts for this size of tool. If you go with 1/2" tools then AR Warner will have them. You might call them to see if they have HSS inserts for 3/4" tools - never know.

You can always grind HSS tools for much less than inserted tools will cost you. 3/4" HSS blanks are not cheap but one tool will last you many years with care and they will work well on your lathe - something to consider.


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## bigmojo (Dec 15, 2015)

Thanks guys.  I think i am on my way.  Ill keep the 1/2" holders and just ordered some CCMW bits from ARWarenco.


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## mksj (Dec 15, 2015)

You may need to use a shim or spacer with 1/2" tooling in CXA holders to get the correct cutting height, standard for these holders is usually 3/4".  The 1/2" should work just fine for the Hp you are driving it with. One advantage of the 3/4" size when using carbide inserts is that they are much more common in this size and usually less expensive. I would agree with mikey, I have a slightly smaller lathe with BXA holders and my primary go to insert is the CCMT/CCGT in a 331 or 332 sizing. They seem to hold up quite well.  I use a series of different inserts depending on the material/cutting, so is you are switching back and forth with materials or rough to finish, it may pay to have  other holders with different inserts.  All is good, and great that you are up and running.


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## Wreck™Wreck (Dec 15, 2015)

mksj said:


> You may need to use a shim or spacer with 1/2" tooling in CXA holders to get the correct cutting height


Leave the spacers/shims with the tools if possible, if this is not easily done, when using a QCTP , use whatever method you like to center a tool, measure with a 64 ths scale rule from the ways to this height and set all tools there, this will be more than sufficiently accurate, write this dimension on the front of the lathe for the next tool setup.

The main advantage of a QCTP  (aside from the ability of using an infinite number of tools) rather a then a 4 way is easy height adjustment.

I realize that many hobbyists are rather obsessed with such subjects as "proper tool height", in practice you will find that being off a small amount (.010" is not unreasonable with a scale) means very little. I make hundreds of parts per week with 3 different lathes using this method without problems. 

I do not imply that sloppy set up is a good practice just that pinching a scale between the tool and part and eyeballing it is equally as inaccurate.

If it is beneficial that the tool be closer then that, say parting to 0 X then by all means do whatever it takes to accomplish this.


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## Bill C. (Dec 16, 2015)

Don't overlook cemented carbide tool bits.  Need a green wheel to touch up the cutting edges.  If you try inserted bits I found it helps to hand feed to see and feel how much pressure it needs to cut.  Then use light power cuts until you are satisfied your lathe can handle it pressure.


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## Bonearzt (Jan 28, 2016)

Dan_S said:


> A) sfpm is what matters, A 8" diameter bar spinning at 480rm is roughly 1000 sfpm, and that's pretty fast for anything other than aluminum
> B) that depends on the feed rate and the chip breaker.
> 
> This page will help you understand insert nomenclature.



Hi All,  new guy Eric here with a question.
Does the chart & nomenclature  on the carbidedepot website translate to HSS inserts too?

I have an SB 9A and do most work with brass & nickel silver tubing.

Thanks in advance for all your knowledge!!


Eric


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## mikey (Jan 28, 2016)

Bonearzt said:


> Hi All,  new guy Eric here with a question.
> Does the chart & nomenclature  on the carbidedepot website translate to HSS inserts too?
> 
> I have an SB 9A and do most work with brass & nickel silver tubing.
> ...




No, not as far as I know. 

Why not just grind some HSS tool bits? Cheaper and will work better than carbide on your lathe.


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## Str8jacket (Jan 29, 2016)

Get a diamond tool holder and some crobalt hss blanks and never look back. They are a bit expensive for original purchase but the amount of metal you can move and the finish on stainless is worth it for me as a newb it helped a lot.


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