Lets talk about dressing bench grinder wheels

[chips&more]

It’s not easy, maybe impossible to true a bench grinding wheel using any kind of dressing devise with your hands and no tracking support. The typical vibrations of a bench grinder and the uncontrollable movements of your hand will all telegraph into the wheel being dressed. Also, some dressing devises will follow the contour rather than cut is own path leaving a clean wheel but still not round and true. A diamond is the best and then it needs a good support that tracks uniformly across the stone/wheel. Even a simple guide block holding the diamond with a step that hangs on the outer edge of the tool rest and moved manually is better than just your hand(s)…Good Luck.

 

[British Steel]

BS, I think I know the diamond loaded discs you are talking about, BUT, then you say they only cost "a quid each" ( 1 quid=1pound=approx.$1.75 US ). If my conversion is correct, then I'm confused, I've never seen a 4 1/2" diamond angle grinder disk costing much less than 18-20 dollars, Please elaborate. Thanks JR49

Ouch, something (other than healthcare ;-)) that's cheaper in England for once! Aldi are an Europe-wide supermarket / discount store, buying low in huge quantities, no fancy stores or whatever, sell pretty low too - and.yes, 4-1/2" discs in packs of five for a fiver, six quid BUT only in stock two or three times a year :-/
Their other lines once or twice a year are air.tools, power tools, etc with a 3-year.guarantee (And no.quibbles) at around half the price you pay.in tool/car accessory shops. I like 'em, the food and.booze.they sell are pretty good.too

 

[Round in circles]

That's handy to know BS ,
Do I take that you are using the disc rotating under power of the whizzer on a switched on grind stone or are you merely sliding it back and forth across the tool rest & wearing one small flat on it at a time ?

The builders left three 9 " part worn ones a few weeks ago after they had cut a hundred or so engineering bricks for my 900 mm ( 36 inch ) high raised bed gardens .
I only have a 4 " Bosch hand grinder so will try the later when the stones need cleaning up a bit .

_______

Not rotating, just held flat on the toolrest edge first and moving side to side- it wears a flat on the edge of the disc exposing the diamond chips, if you look closely (through your goggles and face shield, of course!) you can see the individual chips glow as they dress the wheel...
The dust is probably pretty toxic so I'm chicken and wear a mask when dressing wheels, it makes a he'll of a lot of it when you've let the wheel get rounded off at the corners![/QUOTE]


Thanks BS,
I thought you meant that. i checked today and still have two used embedded discs also from Aldi for my 4.5 " whizzer .
having a decent tool rest/steady will help no end .

Yes your right about the crud coming off a wheel that's being dressed, get a few lungs full of that a day and your soon well on your way to the bone yard or a bonfire site with silicosis , cancer or emphysema or all of them.

Having a decent air extraction off the stone is handy . When I had the farm , my old set up used to draw contaminated air off the stone in a 22 pond water pipe & take it through a 1/4 filled barrel of water. So all the muck was taken out by the water before being exhausted to the outside of the workshop at ground level into a box filled with very open cell sponge material .
In the workshop I had a big 24 inch dust extractor fan system in a home made wooden box as I also played at fine furniture making & renovations .

 

[John Hasler]

Ouch, something (other than healthcare ;-)) that's cheaper in England for once! Aldi are an Europe-wide supermarket / discount store, buying low in huge quantities, no fancy stores or whatever, sell pretty low too - and.yes, 4-1/2" discs in packs of five for a fiver, six quid BUT only in stock two or three times a year :-/
Their other lines once or twice a year are air.tools, power tools, etc with a 3-year.guarantee (And no.quibbles) at around half the price you pay.in tool/car accessory shops. I like 'em, the food and.booze.they sell are pretty good.too

We have Aldi out here in rural Wisconsin. They located their (rather small) store across the street from Walmart. No tools, though.

 

[george wilson]

I FULLY recommend using the newer white wheels rather than the old gray ones. They cut a LOT faster, Been using the white ones since the early 70's. As far as I am concerned,the old gray ones are just not suitable any more,now that we have better wheels.

I'd avoid the Camel brand wheels,and get Norton. The Camel brand wheels just aren't as good.

I use a straight shank(about 5" long) diamond dresser with a single bort(black diamond) in it. Just clamp a small C clamp to the shank,and run it against the outside edge of the tool rest while holding the diamond straight in. The edge of the tool rest needs to be smooth and parallel. If it is not,grind it thus.

I also do the same thing when putting a beautifully even bevel on wood chisels,or even on gouges. I clamp a C clamp on the chisel ,and adjust it outwards till the chisel will rest on the wheel at the correct angle. Every time I quench,I can put the chisel's bevel back exactly as it was before. Makes bevels with no facets on either straight chisels or on gouges.

My old Craftsman flat face grinder has "double jointed" 2 piece tool rests that can be adjusted many ways. They have a 2" straight piece of steel,with a slot down the middle. A wing nut holds another steel piece,bent at 90 degrees,to rest the tool on.These new Chinese grinders have only 1 piece tool rests,which are not very versatile,and may not be possible to get far away from the wheel to grind chisels like I described. The tool rests on my old grinders are just 1/8" thick steel,bent to shape. Nothing fancy,but they work great. If you can modify your grinder's tool rests,it would be a good thing to do.

I have had these old flat faced grinders since the early 60's. The flat faces are excellent,because the motor of the grinder doesn't get in the way of draw knives when grinding. Big,fat, round motors hit the handles. And they are ridiculous anyway,because if you open a Chinese grinder up,the motor's diameter is WAYYYYY smaller than the outside of the motor housing. It is just large to fool you.

 

[george wilson]

A correction: I clamp a small C clamp on the CHISEL,not the TOOL REST!!. Sorry. That must have been confusing.

 

[JR49]

A correction: I clamp a small C clamp on the CHISEL,not the TOOL REST!!. Sorry. That must have been confusing.

Thanks George, as usual,every time I (and I'm sure a lot of others) read your posts, I learn something. This tip on using the C-clamp is one of those valuable tid-bits that I will remember and use many times. 20 years from now, when I teach my grandson this trick, I'll be sure and say " I learned this from George, a machinist friend". Thanks again, to you, and all the others who responded on this topic, JR49

 

[Splat]

I had saved this writeup from "Hardold_V" on another forum:

"Diamond dressed wheels cut hot and require considerably more pressure from the user in order to make them cut well. It's not that they're not sharp, it's because there's so much surface area in contact with the part being ground. The wheel tends to act like a bearing of sorts.

Absolutely nothing wrong with using a diamond to true a wheel for offhand grinding as long as you do something to rough the surface after truing the wheel. The difference in how fast and how much cooler it cuts is astounding.

The best results are achieved by using a star type dresser. This type dresses by impact, so it fractures the grains as well as dislodging them from the wheel, leaving a quite sharp wheel that cuts freely and quite cool. Problem with star types is they're somewhat difficult to use without wasting a lot of the wheel, and your shop will get much dustier than with other methods (because you often have to dress longer to get the wheel running true. Star dressers don't do well getting a wheel running true). Personally, I don't like them, so my shop doesn't have one. If I ran a large grinder, such as in a weld shop, I'd have one sure. They're perfectly suited to such dressing.

There are sintered silicon carbide dressing sticks available from supply houses. They're typically 1" square and maybe 6" long. For your use, assuming you'd be doing typical home shop type grinding, one made of 24 grit abrasive would serve your purpose well. I haven't checked what's available so I can't provide much more in the way of guidance. Could be you'll have to settle for a different grit, but don't get one that's very fine (under 46 grit is best). You need but one of these things to last you a lifetime. They're a wonderful investment, especially when you consider they cost under $5.00.

Use such a stick to touch the wheel to rough it up a little after getting it running true with your diamond. Apply it carefully, so you don't alter the wheel profile, or get it out of round. Always pick a sharp corner or edge on the stick, so you don't dull the wheel.

As a side note-----there's also a boron carbide dressing stick----small--maybe ¼" thick, ½" wide and maybe 3" long. They're expensive and don't do as good a job as the silicon carbide one does---so choose wisely if you go this route. The boron carbide stick isn't sintered, it's one piece and hard---its' the hardest substance next to diamond--so it slowly rounds off, which then dulls a wheel instead of cutting it like the sintered silicon carbide stick does. Harold"