carbide fun

I don't understand why "you don't want cooling when cutting steel with carbide if you can't flood." That seems counterintuitive. Can anyone shed some light or is this an "old machinist's tale"?

Basically, carbide doesn't like shock. Thermal cycling (like using intermittent coolant) shocks carbide inserts and causes premature failure.

I run 4140, O1, A2, D2 with indexable facemills at work and they last a long time (without coolant). I like the uncoated inserts as they tend to give a nicer finish, but YMMV.

Don't worry about the smoke. I think that's generally the oil on the steel burning off...

Regards,

Robin

"rick" wrote in news:Tlebd.37$vJ.26@trnddc05:

Definately.

Also, how fast will your spindle turn? That's what you need to be turning when you cut with diamond in aluminum. Slow way down for plastic though, you can't get enough feed to keep it from melting at high rpm, unless you have a really fast mill.

You will notice that the cut on aluminum will be almost mirror, that, depending on how rigid the set-up and machine, you can take almost the full diamond depth in cut, at *very* agressive feedrates.

If you can't supply a constant suypply of coolant to a carbie cutter you can induce thermal shock, which will cause the carbide insert to start cracking from the hot cool hot cool transitions. Either supply coolant for the entire process or don;t use coolant at all.

You should not need coolant on a diamond, althought industry uses it a do some home shop folks. Just don't do any interupted cuts with a diamond as they do lnot like interuptions. I picked up a bunch of various diamond inserts awhile back, and generally run the lathe as fast as it can go, and the finishes are like a halogram effect on the shiney side of a CD, just beautiful.......Diamond is also great on plastics of all kinds. Visit my website:

Anthony,

I saw another thread in which you had positive comments about the diamond coated tooling. I recall the tool life increase you mentioned was almost the to-good-to-be-true catagory, which would be expected. Have you found that substantial increases in feedrates are possible?

I have a few other questions for which I would like your input. If you would not mind replying offline, my reply addy is valid.

michael

Me max spindle speed is kinda slow (~3600rpm). The b-3v has a 5hp DC spindle motor with selectable 1:1 or 6:1 gear ratio, so it is rather better at going

thanks for the info on the diamond bits. I will be carefull with them even though they were cheap. I assume they only have one edge that is diamond...

I might just save them for when I want a really snazzy finish or have to machine some abrasive material.

Rick

snipped-for-privacy@hotmail.com (Roy) wrote in news:416ecdb9.43464843 @news.east.earthlink.net:

Actually, we do interupted cuts with diamond every day, all day. And this with *very* agressive cuts. You cannot have a loose insert, or bad seat in the cutter, as vibration is a killer. But, this applies to any insert also.

Anthony,

I have an app where I could use pcd in a devlieg microbore type bar setup, if you know of any likely sources, would appreciate if you could forward me info.

Thx,