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

[Lo-Fi]

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.

 

[bretthl]

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.

 

[bretthl]

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.

 

[mikey]

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.

 

[MrWhoopee]

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.

 

[Winegrower]

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.

 

[Cadillac]

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.

 

[projectnut]

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

 

[gerritv]

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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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.

 

[projectnut]

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.