# Brazed Carbide Fail



## foleda (Jan 7, 2016)

After a case of sticker shock while shopping for an inserted carbide parting tool I cheaped out and bought a brazed carbide parting blade instead.  Turned out to be a case of
"getting what you pay for."  It worked fine cutting off a few aluminum and brass parts but when I used it to cut off a part turned from a grade 8 bolt it started out fine, with a nice chip curling out of the cut, then about 1/4 inch in stopped cutting. I backed it out of the cut and found:




Inspecting the other, unused end reveals that it comes pre-cracked for your parting pleasure:


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## roadie33 (Jan 7, 2016)

Where did you get it?


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## joshua43214 (Jan 7, 2016)

lol, I have a Shars tool that looks almost exactly like that one, only mine is broken at both ends...

Get a cobalt HSS parting blade and never worry about the costs again. They are easy to sharpen, will cut anything, and last a lifetime.


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## middle.road (Jan 7, 2016)

Parting a Grade 8 fastener is going to be tricky. They're tough and hard. Not the best material to try and machine
and then if it's also an import bolt. Quite a bit of load on a parting tool.
IMO a Cut-off wheel and then clean up with a tool bit or heavy carbide insert tool would be best.


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## foleda (Jan 7, 2016)

roadie33 said:


> Where did you get it?


The tool is from Shars.  I have emailed them photos.  I'll follow up with their response.


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## brino (Jan 7, 2016)

Hey Dave,

Great photos!
Horrible tool!

-brino


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## foleda (Jan 7, 2016)

middle.road said:


> Parting a Grade 8 fastener is going to be tricky. They're tough and hard. Not the best material to try and machine
> and then if it's also an import bolt. Quite a bit of load on a parting tool.
> IMO a Cut-off wheel and then clean up with a tool bit or heavy carbide insert tool would be best.



The steel used in grade 8 fasteners is indeed tough stuff which makes if very nice for making parts that require high strength.  I find that it machines nicely with carbide insert tools and leaves a beautiful finish.  If I need to turn off the head of a bolt I use HSS because of the interrupted cut.  The HSS tool dulls very quickly.

The part I was making (an alignment pin) could have easily be cut off external to the lathe but I had a (nearly) brand new
cut off blade that I wanted to try out to see how well it handled a tough job.  With the pre-existing cracks it did not stand a chance.


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## foleda (Jan 7, 2016)

brino said:


> Hey Dave,
> 
> Great photos!
> Horrible tool!
> ...



Thanks,  I used a $15 USB microscope for the microphotography.  It was advertised as a 5 megapixel camera but I have only been able to get 640x480 images from it.


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## mattthemuppet2 (Jan 7, 2016)

that does look crappy. Couple of things with brazed carbide. One, it needs sharpening out of the box. Look at the unbroken end - it's got a chip on the cutting edge. I use HF diamond cutting wheels in my dremel to sharpen mine and it makes a world of difference. Two, it's really unforgiving, especially in steel. The slightest bit of flex, chatter or a jam and BAM it's chipped or broken. I went through 3 brazed bits in quick succession on a recent project. Gave up, slowed down and used HSS. Now I tend to only use them for high speed finishing cuts in crappy steel.


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## middle.road (Jan 7, 2016)

foleda said:


> Thanks,  I used a $15 USB microscope for the microphotography.  It was advertised as a 5 megapixel camera but I have only been able to get 640x480 images from it.


You might still be able to get 5mp out of it. Has to do with the capture software.
Check the setting on the program that you're using. Needs to be in 'Still' Capture mode.
I was able to get 1600x1200 (2mp) out of mine.
I just went to fire up the laptop that I use it on to refresh my memory which program I used,
and of course the dang thing doesn't want to boot this afternoon.


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## dlane (Jan 7, 2016)

640x480 looked good to me, the full size pics loaded quick , any larger pics in thumbnail image take forever to load full size.
Thanks for the full size pics.


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## joshua43214 (Jan 7, 2016)

Strange...
All my grade 8 bolts part like butter with HSS parting tools
/shrug

Grade 8 is not especially hard, something like Rockwell 35 or there abouts. Less than pre-hard and about the same as 1144 which machines nicely with HSS. Nothing compared to a cobalt (>60 Rockwell) tool. Just slow the lathe down, the tool will hold up fine.


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## kingmt01 (Jan 10, 2016)

All depends on the machine. Some handle parting better then others. My mini lathe the only thing I use to part on it is a hacksaw.


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## astjp2 (Jan 10, 2016)

I have been ebaying good tooling, takes time but it can pay off by allowing me to get some else's surplus.  Tim


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## foleda (Jan 16, 2016)

Shars sent a replacement but it is no better, possibly worse the the first one...carbide is cracked on both ends.


The other end


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## mattthemuppet2 (Jan 16, 2016)

time for your money back and a P1 or P1N HSS blade
http://www.shars.com/p1n-p-type-hss-cut-off-blade
that's the one I have, works a treat


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## kingmt01 (Jan 16, 2016)

I'd insist on a refund. That is pretty crappy they can't even check for your complaint before sending new ones.


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## brino (Jan 16, 2016)

foleda said:


> Shars sent a replacement but it is no better, possibly worse the the first one...carbide is cracked on both ends.



.........and boy did they send that to the wrong guy (one with a good with a microscope!)
-brino


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## foleda (Jan 16, 2016)

mattthemuppet said:


> time for your money back and a P1 or P1N HSS blade
> http://www.shars.com/p1n-p-type-hss-cut-off-blade
> that's the one I have, works a treat



I have asked Shars to replace it with a cobalt (M-42) HSS blade or a refund.

I have a P1 blade I use on my 7x10.  It works fine for smaller parts (up to 0.5 in or so) but I broke one when it grabbed
trying to part a 1 in dia part there.  I am looking for something a little heavier for parts up to 2-2.5 in on my 12x36.



brino said:


> .........and boy did they send that to the wrong guy (one with a good with a microscope!)
> -brino



No microscope required, both cracks are visible to the naked eye with good lighting.  The USB microscope does make it
easy to get photographs for documentation.

I have no illusions about the quality of cheap imported tools but I do expect them to be at least minimally functional.
Shars did not hesitate to send a replacement.  Perhaps if they get enough complaints/returns they'll push back on their
supplier and demand better QC.


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## Finster (Mar 29, 2017)

UGGGGHHHHH..... That's a shame. I wish you could buy good quality tooling that's USA made without selling your youngest daughter. I'm in the same boat. I buy a lot of China stuff and rarely am I happy with it. It always" needs" something.  Good luck, I'm going to try and not get started because I can ramble about this subject for hours.


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## tq60 (Mar 29, 2017)

There is strong then there is hard.. 

Hard material breaks under incorrect application where strong material does not give way.

High grade bolts are indeed harder material but they are designed to be strong under tension thus are not hard like tool steel.

They machine well and if one has good dies they can easily be threaded if one needs to add some but that ruins the grade.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## cjtoombs (Mar 29, 2017)

I had all kinds of problems parting, I purchased the inserted carbide parting tool from Shars.  It worked out quite well, but it is pretty pricey.  I suspect that those cracks are due to stresses set up between the carbide and steel body after the brazing compound hardens and the tool cools.  They will probably all be cracked the same way.


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