Grinding Wheels

[JimM]

I've got a standard 6" bench grinder but the wheels seem to be very soft and also throw out a tonne of dust. Are all grinding wheels the same or do you get what you pay for and I should be avoiding the car boot cheapys and buying a known brand ?

Also bearing in mind I use the grinder for sharpening HSS lathe bits and other general steel shaping would I be better off getting some green silicon carbide wheels or are these just for carbide tools ?

Thanks

Jim

 

[mocaquita]

Hi,
There are many different grinding wheels available. For technical data on wheels I would Google one of the big manufactures like Norton. Should be enough there to give you a headache. For your application, all you need is an aluminum oxide wheel with a grit of 60. That should be good for all purpose handgrinding of HSS sticks. If you desire, and have a two wheel setup, get something a little courser for roughing and a little finer for a finisher.

Dave

 

[Deanofid]

This is a good question, and I hope some of the other tool grinder types chime in here.

I've been grinding my own tools for years, and use a Norton 60 grit aluminum oxide wheel. It doesn't do what I expect from it.

When I worked in a job shop, we ground our own tools for the lathe. I could grind a 1/2" sq. HSS tool from start to finish in just a couple of minutes without getting the tool bit hot. I wish I knew what kind of wheel we used then. With my current setup, it takes me 10 minutes to grind a tool. The wheel won't cut fast enough to keep the tool from over heating, so it's touch 'n wait, touch 'n wait. I still get good tools, but it takes blinkin' ferever.

Dean

 

[gunboatbay]

The Home Machinist Forum has a couple of excellent discussions on this subject as 'stickies' on this page:
http://www.chaski.org/homemachinist/viewforum.php?f=4&sid=5f04b2a6d775ed0688cc672e00073773
Some of the posts are by very experienced people.

Though not cheap, I've had great success with these wheels:
http://www.leevalley.com/wood/page.aspx?c=2&p=32981&cat=1,43072,43080&ap=1
http://www.leevalley.com/wood/page.aspx?c=2&p=62012&cat=1,43072,43080&ap=1

 

[JimM]

Thanks Gunboat, that's a very useful link - looks like I'll be trying to source some Norton wheels

Cheers

Jim

 

[Seanol]

Guys,
I just bought an 80 grit wheel to try out. Looks similar to Gunboatguy's at almost half the price:
http://www.sharpeningsupplies.com/Norton-White-Grinding-Wheel-P38C20.aspx

No affiliation other than as a customer.

Sean

 

[TroyO]

Sorry for adding a bit of a "Necro Post" but the info is relevant to this particular thread, and since it's the one that I found the most useful info in when searching for "Grinding wheels" I figure I'd update it.

I ordered the wheel from the site linked above ( http://www.sharpeningsupplies.com/Norton-White-Grinding-Wheel-P38C20.aspx ) in a 6"x3/4", 60 grit wheel. It arrived today. Some folks on the other forum listed ( http://www.chaski.org/homemachinist/viewforum.php?f=4&sid=5f04b2a6d775ed0688cc672e00073773 ) had some misgivings about the wheels on that site as they didn't have industry standard grinding stone letter/number codes.

Well... they still don't, LOL. I have a Norton Part number, ( 07660788246 ) but the Norton website doesn't specify what the wheel hardness is, or the code (IE 38A80-KVBE )

HOWEVER.... I think there's good reason for that. They aren't surface grinder wheels. They are designed as bench grinder wheels. I think maybe the industry standard nomenclature for surface grinding wheels isn’t used so they aren’t mistaken as being for that application?

That being said, on the box in big old letters:

"FOR HIGH SPEED STEEL TOOLS
*Premium Aluminum Oxide
*For professional sharpening and reshaping"

On the back:
"Grinding wheel for High Speed Steel Tools.
Made from sharp, friable white premium aluminum oxide abrasive
grain in a soft bond. These quality wheels grind cool and run true producing a burn free finish. They are available in extra fine (150), fine (100) and medium (60) grits.

APPLICATION:
Norton Grinding Wheels fit all popular bench and pedestal grinders. They are idea for grinding, shaping and sharpening high speed or hardened tool steels. These wheels can be used dry, with water or with oil.”

I think, in my book if Norton (Who makes about the best abrasives I know of) thinks it’s ideal for High Speed Steel... I probably will too. ;-) All told, $25 shipped for that AND a grinding wheel dressing stick...pretty sweet deal.

I can post what I think of it in actual use once I get it mounted up.

 

[TroyO]

So, I mounted it up, trued it and ground a quick lathe bit. It worked GREAT... removed material faster and smoother than the regular "grey" wheels by far!

Even with fresh trued wheels I was never able to get HSS to grind smooth... it would catch and bounce on the grey wheels. On this one, a nice smooth even drag. Very controlable, and a lot less heat.

If you have been grinding on the grey wheels that came with the grinder, do youself a favor and drop the $15 for the upgrade!

 

[doc1955]

I use Norton 32a which is an aggressive cutting wheel. If its just touching up a cutting edge with minamal material removal I use a Cubic Boron Nitride Cup wheel. The Norton 32A is a good wheel and will cut with minimal heat build up. I mainly use the cup wheel for my cemented carbide tool bits.

 

[d-m]

This topic has caught my interest. so question, what are the green wheels that come on the H F grinder that most guys have to sharpen with? I don't get bad results with it but I know it could be better. And wile i'm here can someone tell me how to clean my oil stone it seems to have a build up on it of steel, sorta the stone version of file pinning .
Thanks
Dave

 

[Kermit]

And wile i'm here can someone tell me how to clean my oil stone it seems to have a build up on it of steel, sorta the stone version of file pinning .
Thanks
Dave

MY first choice would be repeated applications of WD40 followed with soft cotton tshirt material. Soak it, wipe it, repeat. Don't scrub

Kermit

I;m assuming we are talking soft rectangular whetstones like the one you sharpen knives etc. on....

 

[shred]

And wile i'm here can someone tell me how to clean my oil stone it seems to have a build up on it of steel, sorta the stone version of file pinning .
Thanks
Dave

I hose my stones down with brake cleaner every so often to clean them. It doesn't seem to hurt them any more than using them does.

 

[lordedmond]

try soaking them in a bio soap powder water mix over night gets the old oil out a treat , makes them look and work like new


Stuart

 

[doc1955]

To clean my oil stones I grab a scarp piece of steel and take some coarse lapping compond put a dab of compound on the steel and take your stone and pretend your stoning the steel with the lapping compound under the stone. This will clean your stone and put a new surface on it and it will cut like a new stone. After I do this I use alcohol to clean it.

 

[jonesie]

to get faster cutting and less heat build up try using a courser wheel like a 46 grit and get one with an open bond. keep the wheel dressed with a diamond or a carborundum dressing stick. the finer wheel loads up and then they do not cut but will build up alot of heat ,keep the water handy to keep them cool jonesie

 

[d-m]

Thanks guy's did not mean to steel the topic
Thanks Kermit yes thats what I was referring to the soft oil stone
And every one else thanks I will give these suggestions a try.

And back to the topic I was wondering if it is worth the expense to replace the green wheels that come on the H F grinder with a aluminum oxide wheel?
Dave
And for an afterthought I have been thinking of buying a cup wheel and running a light cut on my mill table. it' a well used tool master and the table shows it I know I could never get out the divets but can I take off the hight spots and clean it up a bit?
any thoughts?
Dave

 

[rake60]

WHOA!

I have often been accused of being over safety conscious here.
Get ready for one more Safety Lecture....

A grinding wheel is basically a batch of abrasive material bonded into a disk, then finised
to become a grinding wheel.

Any soap or solvent applied to that wheel could weaken the bonding agent that holds it
together. If a grinding wheel comes apart it will cause personal injury.
There are no "ifs" about it.

I can see the arguments already.
"In my industrial shop we flood our grinding wheels with TrimSol, a lithium soap based coolant."

We did the same thing in the industrial shop I worked for.
Ask the purchasing agent of your shop how much those wheels cost.
The difference will quickly become apparent.

NO NOT use soaps or solvents to clean store bought grinding wheels.

Use that cheesy sharpener and you can true up a 6" grinding wheel up until it's only 5".
Just be sure to adjust the rest plate in after every sharpening.

I totally expect to catch flak for this post.
I don't have a problem with that.

I'd rather be called down for a post than learn of someone having a grinding wheel
grenade in their face.

Rick

 

[TroyO]

I think they were talking about using solvent/soap/cleaners on a sharpening stone, not a grinding wheel.

Good point about grinding wheels though, I never would have thought about it. The one I got from Norton specifies it can be used with dry, with water or oil, but I bet they mean some kind of specific oil and definitely not brake cleaner, alcohol, or other harsh solvents.

I will try to keep it in mind.... I could totally see myself shooting brake cleaner at a wheel if I didn't know better. (And now I do.)

 

[d-m]

Rake
I love a good Safety Lecture And comming from someone with the experance to back it up makes it even better, I read it twice and will never forget the lesson at work we have regular tail gate sessons even when we have been doing the same job for years and every once in a wile I think dam I didn't know that.
Dave

 

[doc1955]

I was referring to a "slip" as they are called a hand honing stone.
I agree you don't want to use any thing on a grinding wheel if it is not rated for wet conditions. I have seen what happens when a grinding wheel explodes fortunately no one was hurt but could of been very easily.