# How Many of These Have You Destroyed? ....



## bretthl (Apr 9, 2020)

I need a more robust solution in carbide.  I have destroyed 3 of these asian made pieces of junk.  And I do baby them.  They are ridiculously expensive for what they are.


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## benmychree (Apr 9, 2020)

Perhaps try HSS ------


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## Lo-Fi (Apr 9, 2020)

I've wrecked more by babying them than anything else. My golden rule is that if an idle thought of "is this setup rigid enough?" crosses my mind, I need to stop and have a little word with myself before proceeding. When you say destroyed, do you mean the holder or inserts? 

I'm running MGEH inserts and can finally part effectively after many years of pain and abject failure parting with HSS.


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## JimDawson (Apr 9, 2020)

My 5/8 Accusize has been OK on my manual lathe.  This one I think https://www.amazon.com/Accusize-Ind...1807&sprefix=accusize+parting,aps,207&sr=8-25

But the 3/4'' Accusize parting tool did not live long on CNC lathe.  I went to a Iscar parting tool for the CNC, even killed a couple of those in thousands of parts (@ about $150 each).  But they work well.


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## pdentrem (Apr 9, 2020)

Rigidity, lube, and power feed works for my current lathe, but on my Atlas it was scary at times!
Pierre


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## Alexander McGilton (Apr 9, 2020)

At my technical school and at my current work place there were always ISCAR holders and inserts. Only once did is see one fail and that was from another student on a turret lathe who presumably put the tool on crooked. Sacrifice to say this is one place I won't cheap out. I have a had a number of no name brand solid HSS parting blades explode on me, and have since moved a set of USSR blades with mixed successes,  working on all things except some 3" dia O1. What I learned is that parting blades work best with a cup top to collapse the chip in on its self, also the sides must be relived and/or be absolutely vertical.


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## ThinWoodsman (Apr 9, 2020)

Love those tools - haven't destroyed a single one, despite Mr Cockup dropping in unannounced a few times. I have one for BXA, one for CXA. 
I use an Aloris *XA-7 style parting tool holder for these. The clamping action probably helps keep the insert seated.

If you're breaking these, maybe the tool isn't on center?


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## ericc (Apr 9, 2020)

I just destroyed one this weekend.  They are not forgiving.  A HSS tool is a lot less expensive and struggles but rarely blows up spectacularly.  That's not to say that these aren't useful, they just have their place.


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## Manual Mac (Apr 9, 2020)

Yes I destroyed an expensive one at work many, many years ago.
We ordered a new one & I put it in a drawer & continued to use the HSS blade type which was never a problem.
This was not a production shop, just basically one off parts.
 I suspect it was my fault. I thought I knew what I was doing.


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## bretthl (Apr 9, 2020)

Alexander McGilton said:


> At my technical school and at my current work place there were always ISCAR holders and inserts. Only once did is see one fail and that was from another student on a turret lathe who presumably put the tool on crooked. Sacrifice to say this is one place I won't cheap out. I have a had a number of no name brand solid HSS parting blades explode on me, and have since moved a set of USSR blades with mixed successes,  working on all things except some 3" dia O1. What I learned is that parting blades work best with a cup top to collapse the chip in on its self, also the sides must be relived and/or be absolutely vertical.



Thanks, I will give your recommendation a try.  I just grabbed a new ISCAR GHGR 16-3 off ebay for 30 USD.  That's less than the cost of replacing that POS Shars insert holder.


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## Lo-Fi (Apr 9, 2020)

Thing I've found with carbide of any kind is getting used to how hard you have to drive it to get it to work best. Especially true with parting. It's almost the complete opposite of HSS. Does require quite a bit of grunt from the machine at times, though.


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## bretthl (Apr 9, 2020)

benmychree said:


> Perhaps try HSS ------



Using HSS right now.

You know the GTN holder works until it decides to fail.  I take care to ensure tool is perpendicular and on or ever so slightly below center.


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## bretthl (Apr 9, 2020)

I'm done with GTN.  If anyone wants the Accusize holder (the NCIH19-2 is toast) PM me and I will send it to you snail mail.


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## mikey (Apr 9, 2020)

The Aloris blades are actually quite good. I don't use them often as I much prefer HSS but they work well on lathes powerful and rigid enough to use them.


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## MrWhoopee (Apr 9, 2020)

I became disillusioned with that style parting blade over 20 years ago when I was still in business. Now all of my turning & threading tools are inserted carbide, but my parting blades are HSS.


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## Winegrower (Apr 9, 2020)

Funny, I really like these cheap blades.   Yes, I break one occasionally, but most of the time it’s just the also cheap insert.
I must make sure the blade is exactly perpendicular to the rotation axis, that I use manual feed, because I think that power feed gets too fast as the diameter decreases,  centered height, and lots of lubrication or cooling.   

I am delighted to know that the expensive blades break too...now I know what I’m not missing.


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## Cadillac (Apr 9, 2020)

Gosh I feel lucky. I never had a issue with my 9x20 or my 14x40 and I've always used hss. I think once I stalled the spindle on the 9x20 and it was my fault. I had backed out and when I went to Infeed I went to fast and drove the blade into the work. Blade was fine just made the belt slip. I've over hang my blade about 3" without a problem of course in increments but I thought for sure I was gonna snap it. Didn't have a problem.


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## projectnut (Apr 10, 2020)

I'm happy to say I've never destroyed a single one.  Then again I've never used one.  I always use a P type HSS parting tool


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## ub27Rocks (Apr 10, 2020)

bretthl said:


> I need a more robust solution in carbide.  I have destroyed 3 of these asian made pieces of junk.  And I do baby them.  They are ridiculously expensive for what they are.
> 
> View attachment 320293


When you look at the total lever effect from the side of blade to mounting post of the QCTP, it is a recipe for movement. Add in any movement from compound dovetail and you are toast as soon as the tool digs in. Which it will esp. at slow RPM. I now run at 700+ RPM when cutting off with carbide inserts in steel. Takes a bit of courage at first but it does reduce the number of fails. Any flex at all anywhere in the system will result in trouble. 

When in doubt, I use HSS instead.


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## projectnut (Apr 10, 2020)

When I was taught the "art" of parting it was considered a 1/4 speed operation.  Meaning that at whatever speed you turned the part it was parted from the work piece at 1/4 of that speed.  With carbide and newer profile HSS tools parting today is most often done at the same speed as turning operations.


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## Cadillac (Apr 10, 2020)

I also use a P blade no problems.


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## hman (Apr 10, 2020)

Lo-Fi said:


> When you say destroyed, do you mean the holder or inserts?


Check the right hand end of the holder.  It used to look like the left hand end.  The lower support for the insert is pretty weak in this kind of holder.  I've had a couple fail on me.  Gone back to the T-style HSS blades.


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## Janderso (Apr 10, 2020)

I doesn’t matter what I use as a parting option with the Clausing Colchester 15x50.
Parting is done with the auto feed at a moderate speed,no problem.The old South Bend 13 was not crazy about parting, in fact, it was painfull.
Your lathe makes all the difference in the world.


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## rwm (Apr 10, 2020)

Janderso said:


> I doesn’t matter what I use as a parting option with the Clausing Colchester 15x50.
> Parting is done with the auto feed at a moderate speed,no problem.The old South Bend 13 was not crazy about parting, in fact, it was painfull.
> Your lathe makes all the difference in the world.


I believe this also. I now part with a Portaband. I mean; why not? It's reliable, easy and fast.
Robert


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