Grinding wheel hole enlargement ?

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jcfx
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Location: NY

Grinding wheel hole enlargement ?

Post by jcfx » Sat May 19, 2018 7:34 pm

I've got a Emco tool post grinder that I thought I was going to use this weekend but it turns out
the new grinding wheels I bought have a slightly smaller arbor hole and I have to make a washer
for the arbor that was missing too.

The arbor hole in the new wheels are .600 ( 15.25mm ) the old wheel that came with the Emco TPG
has a hole dia of .632 (( 16.06mm) so a difference of .032".

Not a lot of info out there and what there is talks about a diamond core drill or "truing " the arbor hole on a lathe
neither of which I'm too enamored with since it's such a small wheel ( 2.5" diameter )
The new grinding wheels I have were a set so there is a flat, cup, and solid dish shaped wheel.

What method would be best to enlarge the grinding wheel holes, or would it be even be recommended ?

John Hasler
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Re: Grinding wheel hole enlargement ?

Post by John Hasler » Sat May 19, 2018 7:49 pm

Don't do it. Modify the arbor.

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10KPete
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Re: Grinding wheel hole enlargement ?

Post by 10KPete » Sat May 19, 2018 8:42 pm

Don't modify the grinder until you have determined which dimension is the correct one. Search a lot of wheels first.

If your grinder will hold a 1/8" shank tool then get a diamond burr and enlarge the wheel hole just as you would grind a bore...

Never alter the expensive part. Always change the cheap part.

Pete
Just tryin'

John Hasler
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Re: Grinding wheel hole enlargement ?

Post by John Hasler » Sat May 19, 2018 8:59 pm

I'd be very reluctant to alter the ID of a vitrified wheel.

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GlennW
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Re: Grinding wheel hole enlargement ?

Post by GlennW » Sat May 19, 2018 9:36 pm

I'ts not uncommon to alter wheels.

I have an ID spindle for my OD grinder and couldn't find small wheels to fit.

The wheel supplier recommended what "10KPete" did above, and stated that's how it's done, so that's what I do.

I do them on the OD grinder with the wheel held in a chuck and a diamond bur in the ID spindle and bore to size and shape the wheel to suit (recessed center) with the flood coolant running to suppress the dust.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

John Hasler
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Re: Grinding wheel hole enlargement ?

Post by John Hasler » Sat May 19, 2018 9:41 pm

Ok. I didn't think it would be safe, but if the suppliers ok it I'm wrong.

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Gary Armitstead
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Location: Burbank, CA

Re: Grinding wheel hole enlargement ?

Post by Gary Armitstead » Sun May 20, 2018 3:25 pm

I don't care what a supplier says........I wouldn't do it. After forty plus years in the trade, I've seen too many wheels blow up on folks and lost eyes. What's your eyesight worth? Bottom line.
Gary Armitstead
Burbank, CA
Member LALS since 1980
Member Goleta Valley Railroad Club 1980-1993

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GlennW
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Re: Grinding wheel hole enlargement ?

Post by GlennW » Sun May 20, 2018 3:46 pm

They blew up from having the ID enlarged?

So dressing the OD with a diamond will cause the wheel to explode as well?
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Magicniner
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Re: Grinding wheel hole enlargement ?

Post by Magicniner » Sun May 20, 2018 4:16 pm

GlennW wrote:
Sun May 20, 2018 3:46 pm
So dressing the OD with a diamond will cause the wheel to explode as well?
Of course not, but you can't argue with Elves (Elfin Safety), they also insist that tool racks behind lathes are dangerous, without understanding that the danger there is created by someone stupid enough to reach past rotating work or tooling :D

jcfx
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Location: NY

Re: Grinding wheel hole enlargement ?

Post by jcfx » Sun May 20, 2018 6:13 pm

John Hasler wrote:
Sat May 19, 2018 7:49 pm
Don't do it. Modify the arbor.
The thought had crossed my mind, to alter the arbor.
10KPete wrote:
Sat May 19, 2018 8:42 pm
Don't modify the grinder until you have determined which dimension is the correct one. Search a lot of wheels first.

If your grinder will hold a 1/8" shank tool then get a diamond burr and enlarge the wheel hole just as you would grind a bore...

Never alter the expensive part. Always change the cheap part.

Pete
Problem with looking for wheels is that they're far a few in between that fit this TPG.
There's a eBay seller that has the exact brand of wheels that are NOS, but the arbor hole
just a bit too small as I found out. The ID of the new wheels are definitely on the small side ( .587" /15mm )
since the arbor itself is .628" /16mm I would say that the wheel holes should be 16mm give or take.
These TPG's for Maximat Lathes are rare and expensive in the used market, even so I'm still leaning towards modifying the arbor.
GlennW wrote:
Sat May 19, 2018 9:36 pm
I'ts not uncommon to alter wheels.

I have an ID spindle for my OD grinder and couldn't find small wheels to fit.

The wheel supplier recommended what "10KPete" did above, and stated that's how it's done, so that's what I do.

I do them on the OD grinder with the wheel held in a chuck and a diamond bur in the ID spindle and bore to size and shape the wheel to suit (recessed center) with the flood coolant running to suppress the dust.
Unfortunately the ID spindle for my TPG is missing ( another thing to make ), but I'm curious about the diamond burr you mention
is this what you're referring to ?
https://widgetsupply.com/product/sab4-8230dd4.html

Jim

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10KPete
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Location: Nordland, WA, USA

Re: Grinding wheel hole enlargement ?

Post by 10KPete » Sun May 20, 2018 6:21 pm

I love Widget Supply! Yes, those burrs are what I'm talking about but you may want a bit larger and less coarse.

Pete
Just tryin'

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GlennW
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Location: Florida

Re: Grinding wheel hole enlargement ?

Post by GlennW » Sun May 20, 2018 8:29 pm

Mine is a 1/4" diameter pin about 2 1/2" long and has about an inch of it's length coated with diamond grit.

If my memory is working, the wheels I used were purchased as blanks and were 2" diameter and 2" long with a 1/2" bore.

Probably from Diamond Industrial Tool as they have an incredible stock of vitrified wheels.

You might check with them for a wheel that may fit your machine.

http://www.todit.com/
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

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