Dressing/trueing grinding wheels

Subject may well be boring but there are few issues related to that.

1. I have found procedure of trueing grinding wheel to be a messy one. To begin with, every aluminum oxide/silicon carbide grinding wheel, even a new one, needs trueing after installation and occassionally during use, when got dull or groved. Procedure, regardless how done, produces considerable quantities of fine dust which fly around shop and likes to settle on slides of other machines. These need covering to prevent later damage and floor of shop needs good hoovering later. Looks tedious and probably some dust will still find its way to machines and contribute to wear.

What remedies could be offered other than an obvious one to move all grinding equipment to another room?

2. How to proceed with "trueing" correctly? I have found that even new wheels are showing 1mm of "throw" and sometimes even worse than that. Despite all efforts I am finding it difficult to reduce said "throw" to less than 0.25mm or so, even with use of some simple guides etc. It seems that grinder vibrations and resonances with table are responsible.

I have tried both diamond and abrasive block meant for the business.

Is it accptable to settle with such small throw (0.25mm on 200mm wheel), or I should struggle to get better than that? How to improve situation?

Martin

Absolutely negligable unless grinding most of the day every day.
The brunt of the dust is from dressing maybe 20 fold, again negligable and relatively confined.

Diamond tips are used for all grinders, in the case of a surface grinder they are mounted on the bed, spinning wheel lowered and bed wound across a couple of times. For finishing cut the wheels dressed again coolant running and controls any dust.

A shop vac with the hose end arranged to be very near the source of 'dust', will collect most of the dust. If the grinder has a way to attach the hose to the end bell of the grinder that's the best.

It's amazing how much dust control is possible with just a minor amount of effort.

Pete

Hi Martin I have a diamond with a screwed ring that I made and use the front of the tool rest to guide the diamond and keep face square adjusting as necessary and then just lightly dressing the face with a dressing stone see pictures.

David George

Martin - You do not mention which type of grinding machine you are referring to. With universal type centre grinders and surface grinders you would typically “ring” the wheel for soundness then rough the wheel to shape under coolant using the the jog button. Once it is roughed it can be run at normal speed and dressed under coolant. At this point the wheel should be dismounted and fitted with a suitable arbour and balanced on leveled edges. Once balanced, the wheel is returned to the machine and dressed again. This process can be repeated until the wheel runs with zero or little vibration.>>

Either way, contamination of other workshop equipment is always best controlled by flood coolant.>>

If on the other hand you are only talking about using an off hand grinder then bung it on a workmate up the yard and bobs your uncle!>>

Rik>>

Good idea to take the bench grinder outside to dress wheels. I have mine right at the main garage roller door so when dressing I have a large pedestal fan blowing the abrasive muck out of the shed into the yard. Plan is to build a bit of a lean-to and move the grinders outside eventually.

The old style star wheel dressers with a large heavy cast iron handle might be better for truing up badly wobbly wheels. Or you couild try buying a good brand name wheel, Norton etc, as some of the cheap Chinese ones are dreadfully made in this regard.

I have the wheel type dresser and the silicon carbide sticks as well as single point diamonds. Recently I purchased a cheap Chinese dresser that has become my favorite.

https://www.banggood.com/Sintered-Diamond-Grinding-Disc-Wheel-Stone-Dresser-Tool-Dressing-Bench-Grinder-p-1038408.html?rmmds=search

I am fortunate I have enough shop space that I can keep the grinding operations quite far from my lathes and mills.

Many thanks for your ideas and advice.

@jon - At least it is good to know that small throw is acceptable. In practice I have also noticed that dressed wheel cuts better and not much deleterious effects related to any remaining eccentricity are noticed.

Yes, it is dressing, not actual grinding, what produces most of dust.

@Peter Krogh - My grinding rest would obstruct area where hosepipe to hoover need to be fitted. On the other hand modification of wheel shield might allow for this idea to be tried - will have to have a look.

@David George - I am actually using something comparable but your approach seems more straightforward. Will try. Easy enough.

@Rik Shaw - I am not an owner of surface grinder or cylindrical grinder. Regarding cooling, I wonder if some sort of arrangement can be made for bottom of grinding wheel of my bench grinder to be immersed in bath with water. Is it in your opinion a legitimate idea or something daft?

Yes, I know, cooling *is* important. and now my machine (means ML 7 lathe which also serves as a makeshift miller with aid of vertical slide) is devoid of this luxury very much like offhand grinder. However mid next year I will get a proper miller (total mass of this machine is approx. 1 ton) and she will have cooling system installed.

@Hopper - That is very much what I did. My grinder is also at the garage door, about 15 feet from lathe. Still this dust is annoying. Taking it outside for dressing would be tedious. It is bolted, it would need bolting outside etc.

@John Reese - Didn't try this one. May try in the future. Sad truth is that Chinese stuff is competitive in price but also increasingly in quality. Sometime ago I have kissed goodbye to European carbide inserts. Chinese are coming at 10% of European price and recent batch ex Mitsubishi (still sent from China) is doing miracles at price of 1 USD each. European versions are simply a ripoff.

Martin.

Martin - Immersed wheel? I have a Wickes dual stone grinder where one stone revolves at high speed for conventional off hand grinding with the second, larger stone running at a much slower speed in a bath of water, useful for knife blades and the like. I think that if you ran a high speed wheel in a bath of water you might end up feeling a little damp - but maybe not - I've never tried it!

Rik

I was told when using a surface grinder with coolant to start the wheel, turn on the coolant then turn off the coolant before stopping the wheel. I think the wheel can absorb quite a lot of coolant and become very unbalanced to the point of dangerous, possible wheel breakage. So I would be very wary of a water bath apart from almost certainly getting soaked very quickly.

Mike

Perhaps it is good idea to ask wheel distributors about possible troubles with cooling, to begin with.

Edited By Martin Dowing on 26/10/2017 11:18:51

I just went to the trouble of making a new hub for my grinder as I suspected the wobble was partly caused by lack of positive location for the flanges, now the flanges run very true but a new wheel still had a wobble, will have to dress it true. I have a Dormer drill grinder which has a built in diamond dresser. The wheel guard can be closed to contain the dust from dressing but who dressed it and forgot to close the guard? What a mess! Luckily it is not in the same room as the machines.

Mike

Remember some years ago,a friend of mine had a crankshaft grinder,big wheels running under coolant. When the grinding was finished,he left the machine running to spin out the coolant,otherwise,he said that the next startup might burst the wheel due to being off balance.

You can use a pieces of metal tube attached to a magnet to connect to a vacume cleaner to collect wheel dust but not for grinding sparks because of fire risk.

David

I have read some of this with interest, the only thing to consider is that the wheel cuts. A glazed wheel will get hot and not remove metal and the only answer is to clear the glazing with a 'Star wheel' dresser. This removes the glaze and gives the matrix open grains to cut.

With new wheels then a diamond dresser is used to true up the periphery, you can then use the star wheels to open up the wheel grains. A star wheel used on a new wheel does not remove the out of roundness.

There are pertinent regulations governing abrasive wheels and I would hope some of the amatuers have duly read them. Having seen wheels blow up, both big and small I would treat every wheel with respect.

Abrasive wheel course are available, as industry will not allow none cert. holders to work on abrasive wheels. It is too dangerous.Only do what you are competent to do!

Clive

I use a cheap diamond dresser (from Machine Mart) - for a few years now - and it's always done outside the shop on the Workmate (my 6" grinder is attached to a small table that can be quickly clamped securely). Up till now, I have just used the edge of my forefinger (against the front of the tool platform) to guide it across the wheel, which works but is far from ideal. I like David G's idea of a screwed fitment to guide it, fine-adjust the depth and keep it straight.

Mmmn - My TUIT list isn't getting any shorter I'm afraid...

IanT