Bench grinder setups

[chucketn]

With the help of a friend, I have finally completed Howard Hall’s Delux Grinding rest. I have a 4” aluminum oxide cup wheel and a diamond cup wheel for HSS, and would like to get Silicon Carbide wheels for carbide bits, though I don’t have many carbide tools. I currently have a nice Black and Decker bench grinder with the usual stock coarse and fine wheels on it. I have dressed the wheels, but never changed them.
My question is, is it a real hassle to change from one type of wheel to another? Do I have to true the wheels each time they’re installed? Or is it worth the investment to get another decent grinder or two and permanently set them up as carbide and HHS grinders?
Are 1/2" wheels adaquate, or do iI need 3/4"?
Chuck

 

[Swifty]

I have often seen people say that they use diamond wheels on HSS, diamond wheels are for use on carbide along with green silicon carbide wheels. Aluminium oxide wheels are for use on other steels including HSS.

The use of diamond laps on HSS is ok as there is no speed involved, but the diamond wheels will cause a lot of heat on the HSS unless there is a very slow speed used, but this will not cut much.

Paul.

 

[robcas631]

Chuck,

I don't think you will have much of a problem changing grind stones. It's all straight forward. If your grinder does not bog down, then there is no reason to buy another.

I hope this helps,
Rob

 

[chucketn]

Chuck,

I don't think you will have much of a problem changing grind stones. It's all straight forward. If your grinder does not bog down, then there is no reason to buy another.

I hope this helps,
Rob

Rob, I'm old, slow, and impatient. That's why I want multiple grinders! LOL, it sux getting old!
Chuck

 

[Tin Falcon]

Chuck: Diamond wheels are best suited to carbide not HSS. HSS can ruin a good diamond wheel.
Changing wheels not difficult but does take some time. Wheels need to dressed when the surface gets clogged usually from misuse abuse or grooves or uneven wear. I have had a grinder for over 10 years never trued a wheel for a bench grinder.

I have a jet 6" bench grinder for years most of those years I got along fine with the original factory wheels. Bench grinders are not complicated devises all you need is a decent motor on decent bearing and good wheels. IMHO norton is likely the name to buy.

For HSS the white wheels are recommended. If you want top performance and can afford about $30 each for 6 in grinding wheels then get the new blue wheels. they cut faster and cooler.


At cabin fever I picked up a 60 grit alox gator wheel. Gator is family owned and american made. I have seen some of there products at the home depot.

I would not worry about buying another grinder unless you find yourself changing wheels at least once a week. It comes to economics. time spent vs money spent. Another factor is space. If you have lots of space then you may want to get a second grinder. If it saves time.

Tin

 

[Swifty]

While we are discussing diamond wheels, do members know that if a diamond wheel gets clogged up grinding carbide, the surface can be renewed by touching a soft polishing stone to the face. As the diamond grit is set in a matrix, the bonding media can get "burnished", this is what gets removed with the polishing stone. But gently does it.

Another type of grinding wheel suitable for hardened steels, including HSS, are CBN (cubic boron nitride) wheels. These wheels are plated with the abrasive, a google search will supply more details.

Paul.

 

[robcas631]

Chuck,

I can relate to being older and impatient but machining in a hurry = a world of mistakes and pain.

Rob

 

[Tin Falcon]

I mentioned the Norton blue wheels.

http://www.sharpeningsupplies.com/Norton-3X-Blue-Grinding-Wheel-I-Grade-P37C20.aspx
But I was off on the price. they are now $43 each the price of the white wheels is close to $18 now. so while the blue wheels offer 3x the performance of an alox wheel the price is about 3x as well.
but if time is money and shop time is valued at $ 60 (for a round figure) every minute saved saves $1 This is one of the reasons most pro shops use insert tooting. Time to sharpen cost mony and involves time resetting the tool.

Also a word of caution.
If you invest in good wheels protect them. Either secure the grinder the power source or the wheels or at the very least educate anyone that has shop access. It is frusrating to say the lease to install a good set of wheels after using cheap ones for years only to have a family member grind rusty truck parts on a white wheel made for HSS DAMHIKT. Tin
Tin

 

[Dunc1]

The diamond wheels that I have seen (flaring cup or dished wheel in shape) have a much larger bore - around 1 inch diameter - than the standard grey/white wheels. The grey/white wheels mount on the grinder arbor with a shaft adapter if required. The larger diamond hub appears to be secured by 3 or 4 screws to ? (a flange of some type, perhaps). I have not seen this style of hub taken apart and wonder if it is the only way to mount these wheels. Are there alternates? Do diamond wheels need on-arbor balancing? How?

 

[Swifty]

Diamond wheels, flared cup and straight will generally have an industry standard 1 1/4" bore, you can use adaptor rings to suit other spindles as long as the clamping is larger than the bore.

Diamond wheels are generally not made for freehand grinding, although many do, but use great care as the wheel will soon be destroyed.

Diamond wheels should already come well balanced, I used straight wheels on surface and cylindrical grinders years ago at work, they were mounted on arbors with a tapered internal bore that suited the machines being used, they were never taken off the arbors, but you could remove the complete unit and remount on the machine and it would have zero runout.

Paul.

 

[gus]

I mentioned the Norton blue wheels.

http://www.sharpeningsupplies.com/Norton-3X-Blue-Grinding-Wheel-I-Grade-P37C20.aspx
But I was off on the price. they are now $43 each the price of the white wheels is close to $18 now. so while the blue wheels offer 3x the performance of an alox wheel the price is about 3x as well.
but if time is money and shop time is valued at $ 60 (for a round figure) every minute saved saves $1 This is one of the reasons most pro shops use insert tooting. Time to sharpen cost mony and involves time resetting the tool.

Also a word of caution.
If you invest in good wheels protect them. Either secure the grinder the power source or the wheels or at the very least educate anyone that has shop access. It is frusrating to say the lease to install a good set of wheels after using cheap ones for years only to have a family member grind rusty truck parts on a white wheel made for HSS DAMHIKT. Tin
Tin

Plant Facilities Supervisor came and used ''my" Bench Grinder which we used for HSS and Carbide Tool Bit grinding to grind his axe. I stopped him in his track after my Machineshop Supervisor came into my office very upset.
Reasons,
1. W/o our prior permission , he went ahead to grind his home garden axe.
2. No safety glass.No safety shoes.
3. He knows nothing on grinding though he thinks he does.A fractured wheel
could have killed him.
4. He even tried using the carbide wheel which was ruined.
5. Sent his boss a bill for Grinding Wheel Replacements.

 

[Shikyo]

Hi Chucketn
"is it worth the investment to get another decent grinder or two and permanently set them up as carbide and HHS grinders?"

I cannot advice anything about metal working, however,
I am a wood turner and have some experience in grinding HSS gouges and scrapers. We had to grind our tools sometime every one minute while turning bowls. I have been using a Delta 8" grinder with white alminum oxide wheels for it. I also have a cheap 8" grinder from Canadian Tire(about $40 on sale) with carborundum wheels which came with the grinder. I need the both
since white wheels are expencive ($60) and wear out very quickly and not suited for initial grrinding to change tip shapes of tools or grinding ax or head of cold cheasels etc.For grinding
carbide tools I need probably Silicon Carbide wheels, however, I have only 4 tools while I have 75 HSS turning tools, so I don't have any SC wheel. I use diamond stones for those four tools.
I use expencive white wheels on HSS tools, however, cheap carborundum wheels are quite okay
to use on HSS tools. I used to use them and many wood turners have been using those wheels since HSS is very tolerable to heat, compareing to carbon steel which are most of plane or cheasel blades for wood working. Those realy should be ground with white wheel to prevent heat up.
When any stones are mounted you have to centre them by using a dressor. I was told star shaped one should be used for carborundom wheels, however, I only have diamond types (single, and many). I use the many... type since much cheaper. There is balancing things sold by Oneway, Canadian wood lathe company.
I use them on my Delta grinder. I think they are very good devices, however, I don't recommend on your BD grinder. You should think about it when you'll get a little better grinder.
Some of wood turners are also using boron wheels for their HSS tools. Not, me since they cost
about $500 each and since they are wider, you cannot use guards come with any bench grinder.
I also have to use up 6 new white wheels before thinking of getting some exotic wheels.

I checked about boron wheel prices and found they are now cheaper to $235
(CDN $270) and come in regular size of 8"x1". White wheels are $56 plus 12% tax in Canada.��

 

[chucketn]

I haven''t tried the new setup yet. I'm still building accessories for the grinding table. I have the diamond and white cup wheels installed on the new grinder, but the project is on hold until I return from vacation.

Chuck

 

[Chiptosser]

Chuck, Having multiple grinders are very nice to have. I use one for roughing, and the reversible tool grinder for finish work. Yes!!! I do use hss on my diamond wheel , I have for 38 yrs. just as much damage can be done to a diamond wheel with cabide as Hss ...... It is all in how it is used. You can us a drip tank with kerosene or water to lube and clean the diamond wheel. A white stick as we call it, should be used to clean the bond from around the diamond.
The heat generated by grinding carbide is greater than doing finish work on HSS.
Old wives tails go on for ever! Just like bad habits!

 

[Chiptosser]

Oh! By the way we us Diamond wheels to grind D2 HT steel every day, with coolant.

 

[Shikyo]

"diamond and white cup wheels"
Aren't they smaller diameters than regular bench grinder stones?
I guess you probably need grinders with much faster RPM like 5000 - 7000 rpm.
If it needs cooling or flushing with liquid while in use, it must be quite expensive
equipment.

 

[chucketn]

You are correct,Shikyo. The diamond and white cup wheels are 4" and the origional grey wheels that came on the grinder were 6". The grinder runs at 3600 rpm . But I won't be using any coolant to start. I may add it later if deemed necessary.
The grinder itself was the low end one at Lowes when it was on sale.

Chuck

 

[Swifty]

"diamond and white cup wheels"
Aren't they smaller diameters than regular bench grinder stones?
I guess you probably need grinders with much faster RPM like 5000 - 7000 rpm.
If it needs cooling or flushing with liquid while in use, it must be quite expensive
equipment.

My 4" flared cup wheels state a maximum speed of 4700rpm.

Paul.

 

[Shikyo]

My 4" flared cup wheels state a maximum speed of 4700rpm.

Paul.

So, it must be made for regular grinder. Do you grind tools using inside of cup wheels. Are there things can not be done with regular bench grinder while you do regularly with grinders with cup wheels? I am now wondering if I should consider getting a grinder with cup wheels. Someone said that you shouldn't grind free hand with cup wheel grinder. If that is the case, it could be a very expensive set up.

 

[chucketn]

So, it must be made for regular grinder. Do you grind tools using inside of cup wheels. Are there things can not be done with regular bench grinder while you do regularly with grinders with cup wheels? I am now wondering if I should consider getting a grinder with cup wheels. Someone said that you shouldn't grind free hand with cup wheel grinder. If that is the case, it could be a very expensive set up.

I'm asuming you're asking me, so...
My white cup wheels had a 7/16" bore with a lead insert. My buddy todd who is a retired tool and die guy, bored one to fit the 1/2" shaft on the new grinder. He gave me the diamond wheel, which had a 1 1/4" bor so he made a insert for it to fit the grinder shaft.

Chuck