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NeilS
29th March 2009, 02:45 PM
For those who have both the Blu-Max and standard white grinding wheels, has the Blu-Max been worth twice the price?

Neil

funkychicken
29th March 2009, 05:36 PM
I have a pink wheel and a white wheel. When grinding HSS the white wheel wears away fast, while the pink wheel will stay flat

NeilS
30th March 2009, 11:32 AM
I have a pink wheel and a white wheel. When grinding HSS the white wheel wears away fast, while the pink wheel will stay flat

Thanks FC. I'm only just starting to become aware of pink (& ruby) wheels. Looks like the pinks sit half way between the whites and blues. Of course, the bond rating (K, etc) has as much to do with wear as the grit itself. And coolness is another factor for turning tools, where grit size and porosity are factors.

Assuming that your wheels are the same grit size, does your pink run as cool as your white wheel?

Neil

Ed Reiss
30th March 2009, 12:25 PM
...opening a can of worms, but here goes. The only wheels I've ever used are regular gray for HSS and green for carbide.

Years ago I was in a quandary as to the best thing to sharpen HSS with and wrote to Jerry Glaser for some insight to the whole dilemma (this was before e-mail). Jerry answered me with a ten page letter that put me on track with sharpening Turns out that your ordinary, run-of-the-mill gray wheels work great on HSS and even if the steel blues, the temper is NOT lost. So for a great many years it has been the gray wheel that is used for HSS.
The green wheel does a great job hands down of getting a keen edge on carbide bits

NeilS
30th March 2009, 02:19 PM
...opening a can of worms....

Turns out that your ordinary, run-of-the-mill gray wheels work great on HSS and even if the steel blues, the temper is NOT lost. So for a great many years it has been the gray wheel that is used for HSS.

The green wheel does a great job hands down of getting a keen edge on carbide bits

Thanks for your thoughts Ed. Like you, I've been using coarse grey (and finer white) wheels for many years, and yes, the grey works just fine on HSS. The only problem is remembering which of my tools are HSS and which are CS. I still have a lot of old CS turning (and other hand) tools, and its only after I have let one of them blue that I 'remember' which is which. So I tend to, by default, go too slow with all of them and as a result spend more time grinding than I probably need to.

My old grey wheel is getting down a bit and this is what has prompted me to think about alternatives. Wear is not an issue for me, all the ones I have used so far seem to last for ages. What I am after is a cooler running wheel that will allow me to grind a bit faster with all my tools, including the CS ones.

I have found diamond bits work well on TC.

Neil

artme
30th March 2009, 02:35 PM
I have a Blue Max and like it very much.This wheel was developed so that air runs through it and helps to keep the tool cool while sharpening. I still dip into water but that is because I have not become proficient enough and fast enough to take real advantage of the properties of the wheel.

I get good results considering my lack of ability.

Skew ChiDAMN!!
30th March 2009, 04:16 PM
I've used a blue wheel, but don't own one. AFAICT (on the short play I had with the one on our club grinder) it does get a sharper edge than a white wheel, but that's nothing special 'cos it only takes a second on wood to bring it back to the edge the white wheel would give. It also seemed to me to take longer to sharpen, which in my books is a demerit.

I suspect that of I were sharpening anything else besides turning tools, such as plane blades or wood chisels, then it'd be my preferred choice. But for turning? :no:


I have a pink wheel and a white wheel. When grinding HSS the white wheel wears away fast, while the pink wheel will stay flat

As long as you use the whole face of a white wheel, so that it wears evenly and requires minimum dressing, this shouldn't pose a problem. My 6" white wheel is used for all my final sharpening - on a near daily basis - and is still some 5+" after 5 years. (Mind you, I do use a gray for profiling & changing bevels.)

I've been out to show blokes how to sharpen, only to discover that their AlOx wheels are so clogged with steel that they may as well be wrapped in leather. They saw no need for dressing a wheel that is "still flat." On the other end of the scale, I know blokes who've complained that the wheels wear away too fast; only to discover they're putting a lot of effort into trying to shove the tool through the stone during grinding. :doh:

With light pressure, occasional dressing and only using 'em for sharpening, not for shaping, a white wheel should last quite a few years. :)

hughie
30th March 2009, 05:05 PM
The only wheels I've ever used are regular gray for HSS and green for carbide.

I do the same. It started out as the wheel that came with the grinder, so I stuck with it.To date it has performed very well and have entertained the idea of moving to a white wheel. But given the wear rate of the currrent wheel its many years off yet.

Now from an engineering workshop perpective you generally only find the white wheels on surface grinders and these days rarely is grinding done with some sort of cutting fluid.
The bench grinders invariably have grey type wheels and on this all manner of things are ground and sharpened, ie knives, HSS,mild steel,tool steel,home made bull nose milling cutters, cold chisels etc.



I've been out to show blokes how to sharpen, only to discover that their AlOx wheels are so clogged with steel that they may as well be wrapped in leather. They saw no need for dressing a wheel that is "still flat." On the other end of the scale, I know blokes who've complained that the wheels wear away too fast; only to discover they're putting a lot of effort into trying to shove the tool through the stone during grinding. :doh:


I think this is a major part of the problem.


My old grey wheel is getting down a bit and this is what has prompted me to think about alternatives. Wear is not an issue for me, all the ones I have used so far seem to last for ages. What I am after is a cooler running wheel that will allow me to grind a bit faster with all my tools, including the CS ones.

Consider Skews comments as to cool grinding. A light hand will reduce the temp rise dramatically. If also we dont let the tools get too badly blunt, then a light lick on the grinder may well be all thats needed. Also a light pressure will on most occiasions produce a finer cut and finish.

With carbide type tips the only wheel recommended to use is the green one. It will wear rapidly especially if you go at it hammer and tong with a heavy hand. The bonding is soft so as to present sharp grit all the times to a very hard and wear resistant material.

RETIRED
30th March 2009, 06:51 PM
http://books.google.com.au/books?id=lYkneDfgtRUC&pg=PA52&lpg=PA52&dq=grey+wheels+white+wheel+sharpening&source=bl&ots=yfMIWCKGlU&sig=Thka92Dy8Ywy8zCWD4_azn-VSYY&hl=en&ei=nnbQSea6OpTutQP70figAw&sa=X&oi=book_result&resnum=5&ct=result#PPA52,M1

funkychicken
30th March 2009, 09:33 PM
Thanks FC. I'm only just starting to become aware of pink (& ruby) wheels. Looks like the pinks sit half way between the whites and blues. Of course, the bond rating (K, etc) has as much to do with wear as the grit itself. And coolness is another factor for turning tools, where grit size and porosity are factors.

Assuming that your wheels are the same grit size, does your pink run as cool as your white wheel?

Neil

I asked the man at the woodwork shop whether blue was better than pink and he told me that pink's better, but only just.
Since I have to do alot of grinding as fast as possible I has a coolant system (water dripper) so the steel doesn't get hot enough to test.

Keep in mind that I'm using $40 Taiwanese wheels not fancy Norton ones

derekcohen
31st March 2009, 02:56 AM
For HSS steel it does not really matter what you use since it takes high heat and yiu will not damage the temper.

Pink wheels were developed for HSS, I believe (but am open to correction). They are not really as suitable for HCS as white wheels.

While the Norton blue 3X wheel (only available in the USA) is the coolest grinding wheel i have used for HCS and A2 by far, to say it is prefered over a white wheel is to be overly simplistic.

Differences between wheel material will be altered by differing hardnesses and grits. You cannot compare simply by colour.

Always grind plane and chisel blades with the coarsest wheel for the coolest grind. Choose a 36 or 46 grit. This does not apply to HSS lathe chisels.

Regards from Perth

Derek

rsser
31st March 2009, 07:35 AM
Neil, I've used Blu-Max, Ruby, Pink and White (the last three in grits of 60 - 80; Blu-Max only comes in 59 IIRC).

Re your question on whether the Blu-Max is worth it, my answer is no for HSS. With CS turning tools I've not tried them on that wheel but have done plane blades and chisels on it and they've run cooler than on the other wheels on which its very easy to blue the corners.

With HSS, the Ruby wheel ground but also filled quickly. The pink wheel performs a bit better than the white in terms of speed, clogging and temp.

I've not kept track of the bond type with these wheels which as Derek notes is also an important variable. A softer bond means quicker surface breakdown revealing fresh grit edges, giving quicker and cooler grinding.

NeilS
31st March 2009, 03:27 PM
Thanks everyone for your expert advice. All very sound, without getting unnecessarily technical.


So, in summary, for myself anyway...:)

The High Speed Steel used in most modern turning tools is not affected by the heat generated during normal grinding conditions
But, older High Carbon Steel tools are prone to overheating (the dreaded blue) and more care is needed when grinding them
Coarser grit wheels cut cooler.
Use about 40 grit for re-shaping and 80 grit max for touching up the edge on turning tools
A light touch generates less heat
Keeping wheels dressed cleans out clogged pores and exposes fresh grit for a cooler cut
Some wheels are now constructed with a more honeycomb structure to reduce heat buildup
Others (eg Nortons 3X) use a ceramic alumina grit that 'micro-fractures' to provide a constant supply of new sharp abrasive tips that helps prevent overheating
Slower and water lubricated grinders are less prone to heat build up but are also more expensive (leaving aside belt sanders here :) )
Grey silicon carbide wheels will cut both HCS and HSS OK, but cut slower than the various Aluminium Oxide wheels and perhaps are more prone to clogging than some/all of the other wheels.
White AO wheels have been the standard for HSS, and are also good for HCS
Pink AO wheels perform better on HSS than white AO in speed and coolness of cut, and in their tendency to clog. Although not optimal, the pink wheels can be used on HCS, but requires a lighter hand and frequent quenching or heat-sinking
Ruby AO wheels cut more quickly, but also clog more readily
Blue AO wheels were developed to give a cooler cut (honeycomb structure), which is especially beneficial for HCS tools, but at twice the price are not cost effective for HSS
The rate and evenness of wear is a separate issue and relates more to the bond strength used in any of the wheels than its colour type. Soft wheels (eg I) will wear more rapidly than a stronger bond (eg K). Softer bonds will cut more rapidly as they let old grit particles go more frequently to expose new sharper abrasive particles, but at the expense of the life and flatness of the wheel.
I think they are the main points, but any clarification would be appreciated.
Thanks again

Neil

rsser
31st March 2009, 04:30 PM
Nice work of summary Ian. (Do you often get asked to take minutes at meetings?).

Perhaps overly generalised on some points ... eg. you can with care and a light touch do CS with white and pink wheels. It's slow. I use a heavy turning scraper as a heat sink and after a couple of passes rest the tool on it to take some heat out of it. So I wouldn't call white good in this respect and pink bad .. just not optimal.

NeilS
31st March 2009, 06:54 PM
(Do you often get asked to take minutes at meetings?).

Only if I haven't seen it coming and taken measures to avoid it.... :)


Perhaps overly generalised on some points ... eg. you can with care and a light touch do CS with white and pink wheels. It's slow. I use a heavy turning scraper as a heat sink and after a couple of passes rest the tool on it to take some heat out of it. So I wouldn't call white good in this respect and pink bad .. just not optimal.

OK Ern, I picked up the pink is "not really as suitable for HCS as white wheels" from Derek (to whom I defer on all matters to do with sharpening HCS :U ).

So, the collective thinking is that pink wheels are neither "optimal" nor "really as suitable for HCS as white wheels", BUT with a light hand and frequent quenching/heat-sinking they can be used with HCS, just more slowly.

I'll see if I can amend the wording to more accurately reflect that.

Thanks

Neil

issatree
2nd April 2009, 04:37 PM
Hi to all,
This subject has been quite good, so I thought I would add my pennies worth. I use 2 white wheels, 1 is a 60 Grit, the other is a 120 Grit. they have been on my Grinder for approx. 3 - 4 years. I notice in most of the discussion that most of the writers speak of GRINDING ? I Sharpen my tools. I only have to touch them on either of my wheels. I rarely have to use water to cool my turning tools. I keep my wheels clean, & that probably wears my wheels more than the Sharpening does. I use the full 1in. or 25mm. the Sharpen them. To clean the wheels, you can buy a $8-9 Diamond Impregnated Tile cutting wheel from the Markets or Sam's Hardware or similar. They do a marvellous job. Most times I like to use the 120 G. wheel for my Skews, about 9 of them. Love a Skew ?. This for me, puts a very fine edge on these tools. Yes after all this time, I still manage to get a " dig in " now and then. Many years ago I bought one of those pink wheels, never lasted long on the grinder, Threw it to the "Shizenhouzer". I am unable to see what problems are with the White Wheels.
WHITE WHEELS FOR ME ANYTIME.
REGARDS,
ISSATREE.

NeilS
2nd April 2009, 05:32 PM
To clean the wheels, you can buy a $8-9 Diamond Impregnated Tile cutting wheel from the Markets or Sam's Hardware or similar. They do a marvellous job.


Another source of diamond dressers are pranged diamond saw blades, the sort used to cut bricks and concrete. If a few segments get knocked off one of these blades (especially if not equally spaced) it become unbalanced and is history. The remaining segments make an effective wheel dresser. Just three or four segments will see off a few wheels.

I'd be be surprised if diamond saw blade suppliers in your area don't have a few pranged blades for the asking.

Neil

Alastair
3rd April 2009, 12:36 PM
Thanks everyone for your expert advice. All very sound, without getting unnecessarily technical.



So, in summary, for myself anyway...:)

The High Speed Steel used in most modern turning tools is not affected by the heat generated during normal grinding conditions
But, older High Carbon Steel tools are prone to overheating (the dreaded blue) and more care is needed when grinding them
Coarser grit wheels cut cooler.
Use about 40 grit for re-shaping and 80 grit max for touching up the edge on turning tools
A light touch generates less heat
Keeping wheels dressed cleans out clogged pores and exposes fresh grit for a cooler cut
Some wheels are now constructed with a more honeycomb structure to reduce heat buildup
Others (eg Nortons 3X) use a ceramic alumina grit that 'micro-fractures' to provide a constant supply of new sharp abrasive tips that helps prevent overheating
Slower and water lubricated grinders are less prone to heat build up but are also more expensive (leaving aside belt sanders here :) )
Grey silicon carbide wheels will cut both HCS and HSS OK, but cut slower than the various Aluminium Oxide wheels and perhaps are more prone to clogging than some/all of the other wheels.
White AO wheels have been the standard for HSS, and are also good for HCS
Pink AO wheels perform better on HSS than white AO in speed and coolness of cut, and in their tendency to clog. Although not optimal, the pink wheels can be used on HCS, but requires a lighter hand and frequent quenching or heat-sinking
Ruby AO wheels cut more quickly, but also clog more readily
Blue AO wheels were developed to give a cooler cut (honeycomb structure), which is especially beneficial for HCS tools, but at twice the price are not cost effective for HSS
The rate and evenness of wear is a separate issue and relates more to the bond strength used in any of the wheels than its colour type. Soft wheels (eg I) will wear more rapidly than a stronger bond (eg K). Softer bonds will cut more rapidly as they let old grit particles go more frequently to expose new sharper abrasive particles, but at the expense of the life and flatness of the wheel.
I think they are the main points, but any clarification would be appreciated.
Thanks again

Neil


To add 1 more thing:

In general, the softer, cooler wheels need less dressing, as the wheel "self sharpens" more effectively as it wears. With the old grey wheels, (like some above, I will replace with a white wheel when it wears away, but not for a while) regularly dressing the wheel will ensure this, and keep grinding rates up, and temps down.

regards

johncee1945
7th December 2009, 05:16 PM
Hi and thanks all for the summary and clarification, the plus and minuses of grinding wheels. Which is still current in 2009.

Cliff Rogers
7th December 2009, 06:36 PM
I didn't read through what everybody else said. :-

I had a white 60 grit wheel & then got the blue 54 (56?) grit wheel.

The grit was very close to the same but the blue wheel cut cooler.

I replaced my white wheel with a pink 80 grit wheel so now I have 54 grit one end & 80 the other.

The blue wheel does cut colder but it also wears faster.

Here is the thread (http://www.woodworkforums.com/f127/fat-wheels-grinders-37459/) about my set up.

The pink wheel gives a finer finish but it is easier to burn the tip on it.

I shape the tool on the blue wheel & sharpen it on the pink wheel.