Carbide lathe tool question

[999alfred]

I have recently bought a 7x12 mini lathe at an estate sale. My experience has always been with a Craftsman 101 6" using HSS. But, along with the lathe came a couple of dozen assorted C5 carbide tipped tools, BR5, AR5, E5, etc. Most of them unused. But, I have a problem. When I mount a BR5 in the replacement QCTP it won't cut. I tried a couple more, same thing. I could make cuts with up to .008" in feed, but any more and the tool just stopped. Looking at the leading edge I could see the paint scrubbed off the leading face of the tool. The face of the tool is coming in contact with the work so the cutting edge ain't cutting. The QCTP is this one:

https://www.amazon.com/Quick-Change...61&keywords=mini+lathe+quick+change+tool+post

It came on the lathe.

Like I said I am not experienced with carbide. Also, my first post here

tj

 

[Billh50]

Photos of the setup would help.
Are you sure the tool is on center?

 

[Karl_T]

I ASSUME you are talking about brazed on carbide tooling.

These have to be sharpened before use. a baldor carbide grinder
https://www.mile-x.com/baldor-522/b...-IF0X_SdwfxZp4sJ-tcJ19pKeyYTUtmEaAtCCEALw_wcB
is best but many have found a way to use a green wheel or diamond wheel on something less expensive.

My 2 cents, stay with HSS

 

[Wreck™Wreck]

Tool is above center. Even a broken tool will cut albeit poorly and off size.

Brazed carbide tooling does not need to be ground before use unless it is a form tool that must be ground to your specific form.
Although I have zero experience with very low end tooling of this nature I have found that brazed tools work reasonably well when needed, Micro100 tools work well.

 

[kd4gij]

Unless they come from Harbor Freight type vendors. Then maybe if your lucky.

 

[Dabbler]

A carbide tool is no different than HSS in that you still need to have appropriate clearance angles. The very popular and very inexpensive offshore brazed carbide tolls usually don't have clearance angles ground in. Since you have HSS and I assume experience in sharpening HSS, just use a green wheel on a grinder to get the shape you want, and a diamond hone to get a sharp edge.

When I did that to my set of brazed carbide tools, they cut just fine - before I altered them they wouldn't cut well at all.

 

[999alfred]

That's what I did. I went to HF and bought their cheap set of diamond grinding wheels, $9.99 - 20%, and ground a slight clearance angle. Now they cut just fine. Now a have a couple of dozen extra brazed carbide tools.

AS far as the Balder grinder, I can't see paying 4x for it then the lathe cost.

Thanks to all that replied.