# lathe tools, ebay is wearing me out



## unterhausen (Oct 6, 2009)

My limited tool buying funds are tied up in paypal. So I was on ebay for 3 hours last night and ended up with this.

When I regain my strength, I'm going to buy some boring bars and threading/grooving tools. Oh, and some inserts.


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## bluwolf (Oct 6, 2009)

If it makes you feel any better I know how you feel.

Mike


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## wquiles (Oct 6, 2009)

unterhausen said:


> My limited tool buying funds are tied up in paypal. So I was on ebay for 3 hours last night and ended up with this.
> 
> When I regain my strength, I'm going to buy some boring bars and threading/grooving tools. Oh, and some inserts.



That particular cutter is a left handed cutter, which although useful to have in a lathe, is not as useful as the right handed version. The right handed version would be what you use 95%+ of the time when doing turning and facing operations.

Here is a left hand tool:
http://grizzly.com/products/Lathe-Tool-Holder-20mm-Sq-Left-Hand/H8284


Here is the more common/popular right hand tool:
http://grizzly.com/products/Lathe-Tool-Holder-20mm-Sq-Right-Hand/H8283


Will


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## precisionworks (Oct 6, 2009)

Good buy for $20 :thumbsup:

You probably know that it takes a CNMG-43x insert, and there are lots of those on eBay.

At some time, you may want to pick up spare parts - which are carried by lots of sellers.

Shim seat SM-303

Lock pin LP-56

Clamp CK-21

Clamp screw STC-20

You may never need any of those ... unless you break or lose a part in the middle of a job


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## precisionworks (Oct 6, 2009)

> The right handed version would be what you use 95%+ of the time when doing turning and facing operations.


Right hand holders do see a lot of use, as many turning operations are done with the cutter advancing toward the head stock. But a left hand holder is also useful. It allows feeding the tool toward the tail stock, and it also allows facing toward the center of the part. A right hand holder will only face from the center toward the outside, which is not possible on solid stock.


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## Bruceter (Oct 6, 2009)

precisionworks said:


> ....A right hand holder will only face from the center toward the outside, which is not possible on solid stock.



A right handed tool is able to face from the outside to the center of a part. (On a part that is not supported by the tailstock)

A "C" shape insert's main corners are 80 degrees. This give 5 degrees of clearance for both turning and facing without changing tools. To do this, the tool shank should be set perpendicular to the axis of the spindle.

Added: Here is a link that shows how a right handed CNMG holder can both face and turn. 

http://www.iscar.com/Ecat/familyHDR.asp/fnum/752/app/20/mapp/IS/GFSTYP/M/type/1/lang/EN

Bruceter


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## precisionworks (Oct 6, 2009)

You are correct


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## wquiles (Oct 6, 2009)

Bruceter said:


> To do this, the tool shank should be set perpendicular to the axis of the spindle.


Exactly how I set mine up.




precisionworks said:


> A right hand holder will only face from the center toward the outside, which is not possible on solid stock.


I guess there are more than 1 way to skin a cat, since for 3-4 years I have "only" done facing with right hand tools, and always from the outside towards the center - never from from the center towards the outside 

In fact, it was only this week on the 7x yahoo group that I learned for the first time that folks do facing from the center towards the outside. I though everyone did facing like me from the outside towards the center 

Heck, I am still cutting threads in Al and mild steel using the "wrong" method - going straight in, without the 29.5 Deg official/sanctioned/approved/common method :wave:

I guess I just like doing things differently 












I have even had experienced machinists who have handled my 1xD's gave me kudos on how nice and well made my threads were - just don't let them know I use the "illegal" method 

Will


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## unterhausen (Oct 6, 2009)

wquiles said:


> That particular cutter is a left handed cutter, which although useful to have in a lathe, is not as useful as the right handed version.
> Will


Yeah, I'm not done shopping, just wored out. I have found that left hand tooling is useful sometimes, I just can't remember those times right now 

I could probably face with it because the position of my compound relative to the cross slide is really adjustable. I have another tool I'm using for that right now though.

I also want to get more toolholders for my BXA toolpost.


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## Bruceter (Oct 6, 2009)

If you can set it up with the shank paralell to the machine spindle with the insert end near the headstock, you should be able to face and turn with a left hand tool.

Bruceter


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## bluwolf (Oct 10, 2009)

Just when I thought I had a clue....not.

So I'm looking on ebay for the same reasons as Unterhausen.

Because of the advice here I know what kind of inserts I want to use. But the insert toolholders themselves have different designations, whatever you want to call them. 2 insert holders will take the same insert like MCLNR 16-4D or MCLNR 12-4B. What's the difference? Is there a chart somewhere, or better yet a simple explanation?

Mike


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## precisionworks (Oct 10, 2009)

Indexable tool holders, like the inserts themselves, use the ANSI (American National Standards Institute) designation.

http://www.carbidedepot.com/formulas-th-d.htm

http://www1.mscdirect.com/images/solutions/kennametal/toolholderIdSystem.pdf


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## unterhausen (Oct 10, 2009)

bluwolf said:


> Just when I thought I had a clue....not.
> 
> So I'm looking on ebay for the same reasons as Unterhausen.
> 
> ...


The most obvious difference between those two toolholders is that the 16 means it has a 1" shank (16/16), and the 12 means it has a 3/4" shank (12/16). The N means negative rake and the R means right hand. 

I just do a google search on the part number and read the data sheets. Then I look it up on MSC. Time consuming, that's why I'm taking a break from it for a little while.


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## wquiles (Oct 10, 2009)

unterhausen said:


> ...the 16 means it has a 1" shank (16/16), and the 12 means it has a 3/4" shank (12/16)...


This is really important, since the BXA holders only go to 5/8". So the closer to 5/8", the less metal you have to mill/cut to make the holder fit


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## bluwolf (Oct 10, 2009)

Thank you gentleman,

The one thing that's still beating me up is the I.C. part of the designation.

And yes Will I was going to try to stick with 3/4" tooling mostly for that reason.

The more I learn, the more I realize I know absolutely nothing.

Mike


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## gadget_lover (Oct 10, 2009)

http://www.mathwords.com/i/inscribed_circle.htm

In essence, an inscribed circle is the largest circle that can be drawn inside a particular shape.

It's a useful idea, since it's hard to describe a triangle insert that may have different tip radius. The 3/32 radius tip will have shorter sides than a 1/32 radius, even though the distance that matters (from the center of the hole to the side) is the same.

Did that help?

Daniel


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## bluwolf (Oct 10, 2009)

Thank you Daniel,

Yes, it did help. Your explanation was so clear even I could understand it. That's saying a lot.

Is this a good time to mention I was not very good at math when I was in school? Yes, I know. I'm sorry every time I get near my lathe or mill...

Mike


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## gadget_lover (Oct 10, 2009)

You are not alone Mike. I was terrible at math when in school. I passed algebra but never got the higher stuff. Strangely, I ended up a programmer and system administrator. Who knew?

There are many great guides available in books and online. Sometimes you have to learn the jargon to be able to use the tools or formulas, but that's far easier than learning the whole theory behind the math.

My DRO on the mill, for instance, will calculate the proper spots to drill when drilling holes in a circle. It will also figure out how far apart holes need to be when evenly placed along a line, even if that line is not aligned with an edge. It's a great tool to have. 

Daniel


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## wquiles (Oct 10, 2009)

gadget_lover said:


> My DRO on the mill, for instance, will calculate the proper spots to drill when drilling holes in a circle. It will also figure out how far apart holes need to be when evenly placed along a line, even if that line is not aligned with an edge. It's a great tool to have.
> 
> Daniel


Man, I can't wait for my SINO DRO to arrive. Too bad it will be some time in November


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## bluwolf (Oct 10, 2009)

wquiles said:


> Man, I can't wait for my SINO DRO to arrive. Too bad it will be some time in November


 
At least you have your lathe already

Mike


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## wquiles (Oct 13, 2009)

precisionworks said:


> Indexable tool holders, like the inserts themselves, use the ANSI (American National Standards Institute) designation.
> 
> http://www.carbidedepot.com/formulas-th-d.htm
> 
> http://www1.mscdirect.com/images/solutions/kennametal/toolholderIdSystem.pdf




Question: So if I have a boring bar that takes CCGT 32.51 inserts, can the same boring bar also take CCMT 32.51 inserts, and vice-versa?

I ask since some boring bars on Ebay list the bar as using CCGT inserts and some list CCMT, and a few list both, so it is confusing 

Will


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## precisionworks (Oct 13, 2009)

I believe the two inserts will interchange. The only difference is mounting hole tolerance.


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## Bruceter (Oct 13, 2009)

wquiles said:


> Question: So if I have a boring bar that takes CCGT 32.51 inserts, can the same boring bar also take CCMT 32.51 inserts, and vice-versa?
> 
> I ask since some boring bars on Ebay list the bar as using CCGT inserts and some list CCMT, and a few list both, so it is confusing
> 
> Will



The difference between these two inserts is that the CCGT is a ground insert and the CCMT is a molded insert. The second "C" in the call-out is the side clearance angle, so both of these inserts will work in the same holder.

Bruceter


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## darkzero (Oct 13, 2009)

Will, I use CCGT inserts on the two original bars that I got from you. Well I only have the 3/8" now, the 1/2" I sold to PEU along with the rest of the CCMT inserts. I now have the same 1/2" bar just longer. As Barry said the mounting hole tolerance is different. The hole sits lower on my CCGT (21.51) inserts compared to the CCMTs I got from you.
















Correct me if I'm wrong but you can use any CCxx insert on CCMT holders & boring bars.

CCGT 32.51


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## gadget_lover (Oct 13, 2009)

While the hole may be slightly different, the real difference is as Bruceter said. The working surfaces are ground to tolerance on the 'G' versions (.0005inc). This makes the dimensions the same from insert to insert and easily interchangeable.

The M version (from the same manufacturer) should be identical to the G version, but not as consistant (.005 inch) . For great repeatability go with an 'F' model

The first letter of the insert denotes the shape. The last denotes the mount style. The first number tells you how big the insert is. The second number denotes how thick it is. So a CxxT 3 2.5x with any value for X will be interchangable, but some combinations may have more desireable features.

Daniel


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## KowShak (Oct 14, 2009)

gadget_lover said:


> The first letter of the insert denotes the shape. The last denotes the mount style. The first number tells you how big the insert is. The second number denotes how thick it is. So a CxxT 3 2.5x with any value for X will be interchangable, but some combinations may have more desireable features.
> 
> Daniel



The first 'x' denotes rake angle, so if you've got a toolholder that takes CCMT type inserts (e.g. SCLCR), it can only take inserts where the first two letters of the code are 'CC'. Other 'C' prefixed inserts where the second letter is not 'C' have the wrong rake / clearance angle for that type of toolholder, so although they may at first glance appear to physically fit, they are not the right insert for that particular type of holder.


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## precisionworks (Oct 14, 2009)

> the mounting hole tolerance is different. The hole sits lower on my CCGT



There must be a half a dozen triangle toolholders in my drawer ... and at least a dozen boxes of triangle inserts ... hey, they were cheap on eBay 
Some inserts fit some holders pretty well, and get run if needed. The insert may sit a little high or a bit low, but as long as there is firm contact with one side of the triangle (and the triangle sits flat) they all work well. Pretty unscientific, most of the toolholders are unmarked, some of the inserts are not in the box they came in, etc. Amazing that they work at all, but they do as long as the tip is set to spindle centerline.


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## gadget_lover (Oct 14, 2009)

KowShak said:


> The first 'x' denotes rake angle, so if you've got a toolholder that takes CCMT type inserts (e.g. SCLCR), it can only take inserts where the first two letters of the code are 'CC'. Other 'C' prefixed inserts where the second letter is not 'C' have the wrong rake / clearance angle for that type of toolholder, so although they may at first glance appear to physically fit, they are not the right insert for that particular type of holder.



Really? The second letter is supposed to be the clearance (or relief) angle. I can only see two areas where that would impact the tool holder.

1) I would assume that a top quality insert holder (which I do NOT have) might have a pocket that is shaped to fit the slant on the sides of the inserts. Mine are cheap and have vertical sides. I can use 7, 11 or 15 degree (C, P or D) inserts interchangeably.

2) The support under the insert has to be undercut or slanted enough that the insert is supported to the max and yet the holder itself will not touch the work. For small inserts like mine (tcmt221) the difference between a 7 degree and 11 degree insert is very, very small.

So tell me, do the really good holders have pockets with sloped sides that perfectly fit the side relief of the inserts?

Daniel


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## KowShak (Oct 14, 2009)

gadget_lover said:


> Really? The second letter is supposed to be the clearance (or relief) angle. I can only see two areas where that would impact the tool holder.
> 
> 1) I would assume that a top quality insert holder (which I do NOT have) might have a pocket that is shaped to fit the slant on the sides of the inserts. Mine are cheap and have vertical sides. I can use 7, 11 or 15 degree (C, P or D) inserts interchangeably.
> 
> ...


 
Strictly speaking, a 'P' style 11 degree clearance angle insert (e.g. TPUN) is designed to be held at a postive angle to the workpiece, 5 degrees, so while you are using them in a 'C' style toolholder, the rake angle is wrong. The one 'P' style toolholder that have access to is not from a quality brand and is 30 years old and so may not represent current thinking but it does have sloping sides on it's pocket to match the clearance angle on the insert.

The 'C' style tooling I have is all of dubious quality and has no sloping sides to the pockets. On my cheapest (ebay) boring bar the insert can not touch both sides of the pocket when clamped by the screw and it can be rotated a couple of degrees, the insert plainly doesn't fit the boring bar very well, so perhaps thats the reason I'm a bit pedantic about inserts being correct for toolholders....

If the tooling you're using is working, keep doing what you're doing, after all it's a hobby and a hobby is to be enjoyed!


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## gadget_lover (Oct 14, 2009)

Thanks KowShak. That was one interaction that I did not consider.

Daniel


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## unterhausen (Nov 19, 2009)

Do you have a link for where you got those numbers? Trying to figure out the insert screw part number and the shim screw part number.
thanks



precisionworks said:


> Good buy for $20 :thumbsup:
> 
> You probably know that it takes a CNMG-43x insert, and there are lots of those on eBay.
> 
> ...


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## precisionworks (Nov 19, 2009)

The link was easy to find ... a week ago


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## unterhausen (Nov 19, 2009)

I know how that is, I swear I found some documents about the tool before I bought it.


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