CBN Grit Sizes for Lathe Tool Bits ?

[Downwindtracker2]

My 7" Wissota brand grinder only has general purpose wheels, a 46 and a 80. They are slow and hot for grinding bits. I gather to achieve both the surface finish and tight tolerance these parts are going to require, I should use HSS bits on my Taiwanese DF1224g . CBN wheels unlike soft A/O wheels are very easy for me to get. The recommended grit sizes I was able to find out about, are all over the place. THX

 

[PeterT]

That's a great question, watching to see answers. All I know is I have seen some spectacular finishes on (albeit conventional wheels) of #60 which my woodworking brain says way too coarse. Obviously more to it than that. Metal grinding is just different.

Just curious if you don't mind, what makes CBN 'easy' for you to get?

 

[David]

I use a 180 gr CBN wheel to sharpen my HSS woodturning tools. I also have a 600 gr wheel but I rarely use it as the keener edge makes no difference and seems to break down quicker.
When I'm turning I will often touch up a tool every 8-10 minutes. I don't even turn the grinder off.

For lathe tooling a 180 gr wheel may strike the balance between speed and finish. My wheel has round edges so I don't use it to for lathe tooling.

 

[Downwindtracker2]

My wife has ordered from Baltic Abrasives for diamond lapidary wheels for her rock and gem club. Though the prices are in Euros, they are still a good deal less than the American Diamond Pacific. The club grinder/polishers get a lot of abuse. I know because I get " Honey, could you look at xxxxx"

 

[Downwindtracker2]

Good Morning guys, a follow up.

The availability of soft aluminum oxide grinding wheels is pretty limited. I simply gave up on them. Instead I ordered CBN wheels. The wood turners love them for their HSS chisels. I have a General 26020 wood lathe that I picked up cheap at an auction and HSS chisels. I can use the same grinder for both lathes. When I sharpen my wood working chisels and plane irons, I do so in stages with up to 8,000 grit water stone then power strop with polishing compound. You can never be too sharp. Metal working and wood turning don't need that kind of sharp . For the tool bits I can initial shape on my 1" belt sander, finish up shaping with an 80 grit CBN wheel then use a 320grit. I'll hone with a 600 grit diamond plate. After a great deal of reading that is the plan.