CBN grinder wheel?

T

tmenyc

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I'm resurrecting a conversation I had with, largely, myself last winter; it ended inconclusively when COVID heated up, so now I'm back, seeking advice. There is very little discussion here of using CBN grinder wheels instead of AO for grinding HSS lathe cutting tools. I had a bunch of correspondence last winter with Ken Rizza of Woodturnerswonders; he was very helpful.
My thought process is that I have a very small shop that functions as a part-time office and the core of my vintage fountain pen restoration business; my Logan 820, bench vise and 6" DeWalt bench grinder are in here too. When my adult daughters were children it was their bedroom; it's around 11x10.
While it works really well as a shop most of the time, dressing a 80 grit AO wheel just destroys every semblance of anti-grime I'm able to achieve. Pretty crazy, and stupid, to see that needing to periodically dress the grinding wheel is keeping me from the grinder.
I've been able to deal pretty effectively with the hot metal dust thrown off in normal grinding -- a friend and I made a box from steel that bolts to the rear of the coarse wheel's cover, catching all the dust except what goes straight down. That stuff I catch in a wet paper towel on the base. I've tried vacuuming the dressing dust but it just flies everywhere and leaves a dust layer throughout the room.
So, I'm considering CBN, admittedly first to never have to dress a wheel again, but also for its other major advantages -- smooth grinding, maintenance of size and shape, and the quality and sharpness of its results. Yes, it's dear for a grinding wheel, but it also lasts forever and at $170 for the 8" wheel isn't out of reach. Is it my only alternative? I could in theory get a belt sander, but really don't have the space for it. The bench grinder is bolted to a bookshelf...perfect fit, perfect height, enough headroom. Believe me when I say that I just do not have the space for a separate floor base. I don't know of another alternative. I guess I'm thinking out loud here...and looking for general thoughts, having learned from the wide range of views expressed here.

Also, specifically, whether there are any issues with installing an 8" wheel on a 6" grinder; the correct bushing comes with it.
And, are there any issues with mounting a 1.5" wide wheel? The standard Norton is .75".
Finally, for cutting HSS, generally M2 but also some harder stuff, would you recommend the 80 or the 180 grit?

Many thanks,
Tim
 
Ken set me up with 2 CBN wheels for HSS, he would know which wheels to get given what your grinding. Your explanation is exactly why I changed. I use the belt grinder mostly, just touch a couple of angles with the CBN
 
I got a 600grt CBN wheel on the HF tool grinder I picked up used and it’s perfect for honing a fine edge on HSS and carbide. It is not for doing anything but honing as it won’t remove enough to do a big regrind. I use the AO for that. I’m wondering why you don’t have a HEPA vac, they are really great for getting rid of toxic dust and fumes.
 
My experience with the white wheel when I dressed it, it blew dust every where, even with my hepa vacuum right at the opening, no port on the guards.
 
With thanks for your thoughts, there's progress:
I've decided to pull the trigger on the 8" 80 grit wheel, which is the one Ken Rizza suggested for me for getting tools to the precise shape from a blank but not for honing or adding nose radii at the grinder.

Question: the tool rest on my Dewalt won't fit the 8" wheel; its bracket won't extend the extra inch in OD, and the slot on the rest isn't anywhere nearly wide enough. Ken sells a separate, bench mounting one, here, that looks very steady, but it's expensive. Does anyone here know of another that would work? I don't have a mill or way to shape and cut metal except for the lathe, want to get it right. Thoughts?

And, more questions: WoodturnersWonders sells Rikon equipment with 1750 rpm and advertising low speed. Is this better for grinding tools than my DeWalt, which runs 3450 rpm?

Tim
 
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My two wheels from Ken are 80, and 220, I then have 3 levels of 3x8(?) diamond plates with lapping fluid to bring them in. My primary grinding is still on the ceramic belt. The table looks solid if you have a good place to mount it, I like the size of it.
 
tmenyc said:
With thanks for your thoughts, there's progress:
I've decided to pull the trigger on the 8" 80 grit wheel, which is the one Ken Rizza suggested for me for getting tools to the precise shape from a blank but not for honing or adding nose radii at the grinder.

Question: the tool rest on my Dewalt won't fit the 8" wheel; its bracket won't extend the extra inch in OD, and the slot on the rest isn't anywhere nearly wide enough. Ken sells a separate, bench mounting one, here, that looks very steady, but it's expensive. Does anyone here know of another that would work? I don't have a mill or way to shape and cut metal except for the lathe, want to get it right. Thoughts?

And, more questions: WoodturnersWonders sells Rikon equipment with 1750 rpm and advertising low speed. Is this better for grinding tools than my DeWalt, which runs 3450 rpm?

Tim
Click to expand...

I have the 1HP Rikon 8" grinder. I haven't made the jump to CBN yet, but the grinder works great with the AO wheels for shaping lathe tooling, and it runs very smooth.

As far as the mess is there any possibility of taking the grinder outside? I built an outdoor workbench and set it up with a quick release (two bolts and wing nuts) for the grinder that has worked well for me and keeps all the grinding dust out of the shop. I figure the time used to set up the grinder is less than the time I would be using sweeping and dusting if it was in the shop.
 
In almost any other living situation, that would be great. But, I'm in a New York City apartment...which has made my entire machining operation complex, but it's not changing in this lifetime. So that means no, outside is not an option.

Do you use the Rikon tool rest stand?

Tim
 
tmenyc said:
In almost any other living situation, that would be great. But, I'm in a New York City apartment...which has made my entire machining operation complex, but it's not changing in this lifetime. So that means no, outside is not an option.

Do you use the Rikon tool rest stand?

Tim
Click to expand...

Apartment living must take small shop problems to another level.

I have been using the standard tool rests, they are better than some, and probably similar to those on the Dewalt grinders but still leave something to be desired. Making an improved tool rest is on my project list.
If you are talking about a stand for the grinder, then no. I mount mine directly to a heavy workbench. I ran a couple of bolts up from the underside of the redwood piece it sits on and secure it with washers and wingnuts.

grinder.jpg
 
Aaron,
thanks. The issue I'm dealing with is that I won't be able to use the tool rest on the 6" Dewalt with an 8" CBN wheel. The existing tool rest won't fit. The pictures of the free standing tool rest look like it's too big for the grinder itself, that the rest is much bigger than its base. I can certainly remount the grinder. OR do I need to move to an 8" grinder?
Does anyone here have an 8" CBN wheel on a 6" grinder? With which tool rest?

Tim
 
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