I kept trying to sharpen carbide, thinking it was HSS.

[woodchucker]

I needed a piece for my boring bar, to cut threads for a left hand 3/8-16 interior.. I have plenty of square for my larger bar. well, I picked out the small piece, had a tough time on my belt sander, my 2 grinders, a cut off wheel... wth..
So I grabbed the larger piece.. same thing.. Must have destroyed the belt.. and the wheels... wait no..
must be some super hard hss. I put it down, was going to make a holder rather than use the bar..
went down tonight, took a magnet, .. it's lightly magnetic.. damn.. it's carbide... where'd I get that round.... it had marks for a cutoff wheel...
So don't make the same mistake... check your steel, it might not be HSS if you can't cut it.

 

[mattthemuppet2]

that's funny, I've had that happen before too. I was trying to sharpen a spade drill insert, which I'm pretty sure is cobalt based on weight, but it took ALOT of work to get through the coating. Really weird, it made a very bright white light before I managed to get through it after a couple of attempts. Impressive coating, that's for sure.

 

[cathead]

You can tell the difference as carbide is significantly more dense(heavier).

 

[woodchucker]

You can tell the difference as carbide is significantly more dense(heavier).

I know, but the pieces were so small it didn't feel heavier. Also, I can't figure out where that came from.
I probably made the cut with a diamond cut off wheel, I just don't remember...
There's a lot of Sh*t I don't remember..
There's a lot of Sh*t I'd like to forget...
There's probably not much room left in the memory banks.. maybe I need to format my head.

 

[RJSakowski]

I always figure that my memory is full so I have to delete something to make room for more stuff. Anyway, that's my story and I sticking with it.

 

[woodchucker]

My smallest boring bar is too big for an internal 3/8 I guess I should have checked b4 trying to shape a piece of steel. And I didn't need to, as the smallest bar already had a threading form. DOH.

Years ago when I was learning (I know I'm still learning), I had a 1/2 piece of tooling, that was mostly cut away and shaped into an inside boring bar... But I broke it..... now wishingI had that. I think I'll just order a 3/8-16 LH tap..

 

[graham-xrf]

I have a carbide rod, 16mm diameter (slightly over 5/8") about 300mm (1ft) long.
I had thought it being so thick and stiff, it might have some use as a boring bar ..
.. but how?
One has to carve a chunk out of it as deep as it needs to go, leaving a bit on the end to be a tool shape.
I settle for a steel bar, with a piece of carbide ex-insert mounted on it's end, sticking out a bit to the side.
To do anything with carbide, I guess you need diamonds!

 

[woodchucker]

I have a carbide rod, 16mm diameter (slightly over 5/8") about 300mm (1ft) long.
I had thought it being so thick and stiff, it might have some use as a boring bar ..
.. but how?
One has to carve a chunk out of it as deep as it needs to go, leaving a bit on the end to be a tool shape.
I settle for a steel bar, with a piece of carbide ex-insert mounted on it's end, sticking out a bit to the side.
To do anything with carbide, I guess you need diamonds!

that or silicon carbide wheels...
I would go with the diamond, less expensive in the long run. The silicon carbide wears, and is bad for you... along with the carbide dust..
both are toxic over time.

 

[ericc]

I have a carbide rod, 16mm diameter (slightly over 5/8") about 300mm (1ft) long.
I had thought it being so thick and stiff, it might have some use as a boring bar ..
.. but how?
One has to carve a chunk out of it as deep as it needs to go, leaving a bit on the end to be a tool shape.
I settle for a steel bar, with a piece of carbide ex-insert mounted on it's end, sticking out a bit to the side.
To do anything with carbide, I guess you need diamonds!

A steel cap silver soldered to the end? The main problem with steel boring bars is their flex. They behave like a cantilever beam. Looking up optimal beam design in an undergrad text shows that the end with the force on it has less stress, so can be weaker.

 

[woodchucker]

My smallest boring bar is too big for an internal 3/8 I guess I should have checked b4 trying to shape a piece of steel. And I didn't need to, as the smallest bar already had a threading form. DOH.

Years ago when I was learning (I know I'm still learning), I had a 1/2 piece of tooling, that was mostly cut away and shaped into an inside boring bar... But I broke it..... now wishingI had that. I think I'll just order a 3/8-16 LH tap..

I went back down and searched. I thought I had another boring bar, I found it in my tap/threading draw. it will barely fit the 3/8 -16.. with the 60 point.. I may give it a try on some scrap.. LH is just a little .. backward, so I need to practice it first. I've done external small LH, but I think this will be the smallest LH internal.