Is this old Tyrolit CBN cup any goof for HSS and/or tungsten?

[PekkaNF]

Hello,

One guy is selling a CBN disk that is:

a) Imported in year 1986 or something, although unused. How do these things "age".

b) has designation I can't find very readily information:
12A2 150-5-2 609492 10/I
BM120 R50 B76

I'll get "12A2" that is a saucer disc.

I'm guessing following:
B stands for CBN
M?
120 grit in um (fairly fine)
R50? could be concentration, like "C50" concentration. This letter could be hardness as well, that would explain "R" i.e. pretty hard.
B-is bond type (Resin)
76 bond designation

I was told this is fine with HSS and HM-cutters. How is it?

Pekka

[Pete]

For grinding single- and multi-edge solid carbide and carbide-tipped tools, for example reamers, engraving tools,
turning tools

http://www.tehnotools.com/upload/iblock/23a/23af832a425e5402b6caa9256c05cfa6.pdf

Page 6 of the link - middle of the page

[PekkaNF]

Thanks,

But I don't see how it helps me with these questions.

I think CBN should be fine with HSS, but I don't know what grit/concentration/hardness is required to sharpen HSS lathe tools.

Pekka

[Pete]

It wont wok well - the gring wheel you listed is exclusivly for carbide. It will grind HSS but the abrasive loads up with the HSS, over heats and wear very quickly.
Pete

[Fergus OMore]

I think that the comments are both right and wrong.
If one wants to remove substantial quantities of (say) hss tooling, I would simply move to a conventional wheel fit for purpose.

If, however, I wanted to finish hone the tool- after the grinding as above- I would go for the 120 grit wheel.

In fact, you will recall my efforts to help Mad Nick with his build up of a Kennet grinder, well mine has a 120 grit wheel on an arbour for this. I get a mirror finish which reflects my dirty thumb nail

The concept is- and always was that a lathe tool cannot produce a better finish on its work than it has itself.

Cheers

Norman

[PekkaNF]

Yep, I got another opinion that it is designed for carbide and probably works for wood working router bits and such, very well and with pretty good feeds. I'll probably pass this, because even "old" it costs more than four cheapos. Alhough if it replaces four chapos and would be proper in every respect I would consider it good.

I have one fine russian diamond cup wheel for carbides, I need wheel for HSS and CBN probably would be my best bet for detailing.

As F. OMore guessed my need would be finishing and last touches, not grinding from solid. This changes approach pretty much. Not only loading of the wheel, but I hope to get away without wet grinding.

For blank shaping and roughing I would be using conventional wheels. Just hope to come up with a system that neuralizes ans contains all sparks without too much noice, but that would be another thread when I have something to show.

PekkaNF

[Fergus OMore]

Actually, I have about FOUR

I also  have a Quorn and Clarkson and - well, you know how things are

All that the wheel is removing really is the microscopic ridges left. As yet I have felt no need to renew the wheels!

You CAN do the same with a lot of other alternatives such as prgressive grades of diamond paste( which is messy) or a  variety of Arkansas stones( and if you are old and shakey like me, think again)

Frankly, I'd get one or a diamond one and forget all this reminders of how steel does this to diamonds and all sorts of old wives tales. In the home workshop the wear is pretty minimal

Others may disagree

Cheers

Norman

[PekkaNF]

I also  have a Quorn and Clarkson and - well, you know how things are
Norman

I KNOW  (I have four lathes of different age and pedigee and not singe good one - _{I also have one basket case under somewhere}). Least you have a Clarkson! Do you do also cylindrical grinding?

Pekka

[Fergus OMore]

Laughingly, I have a very old Myford which had been used to turn mahogany on an empty gear box and had an assortment of missing teeth. 

It's now beautiful-- apart from its paintwork. I jet washed it with detergent to get rid of the muck and had the bed and saddle reground locally for £250.
OK there are cheaper ways and -----dearer ways but I'm happy enough.

As for cylindrical grinding on the Clarkson, the answer is 'No' but I fancy putting my little Unimat clone on it.
Insanity runs in the family with the noses