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jaybird
09-20-2010, 10:37 PM
Looking for some information about using dressing stick to freshen up grinding wheels. I am not sure how aggressive I should be when dressing a grinding wheel. One thing I am sure about, a dust mask or respirator must be use. Wheel dust canít be good for you.

I took your advice Forest and got a bigger container of water and was surprised to see the water sizzle when immersing the cutter into the water

Carld
09-20-2010, 10:52 PM
The aggressive or easy dressing depends on how out of shape the wheel is. Sometimes I use a diamond dresser to rough the wheel flat and the smooth out the bumps with a dressing stick. Most the time I don't let the wheel get grooves in so I just lightly dress it.

I have found that to take an out of round condition out you have to lightly push the dresser against the wheel to just take some off the high side of the wheel. Sometimes I have to use the diamond dresser to do that.

Davo J
09-20-2010, 11:05 PM
If it needs a good clean up a dresser like in the link below with the red handles work best, then use the diamond dresser.
http://www.google.com.au/imgres?imgurl=http://www.nolansupply.com/small_images/23111210.jpg&imgrefurl=http://www.nolansupply.com/superabrasives.asp%3Fsupercategory%3DGrinding%2BWh eel%2BDressers&usg=__HqoVL3qCS_v7d7jQ2anZpK5Lva4=&h=202&w=200&sz=26&hl=en&start=4&zoom=1&um=1&itbs=1&tbnid=wbv6AYKrr7wXrM:&tbnh=105&tbnw=104&prev=/images%3Fq%3Dgrinding%2Bwheel%2Bdresser%26um%3D1%2 6hl%3Den%26sa%3DN%26tbs%3Disch:1

Dave

Doc Nickel
09-20-2010, 11:16 PM
I get excellent results with this simple setup:

http://www.docsmachine.com/machineshop/dresser4.jpg

The collar guides the diamond point using the front of the tool rest. Click here in my Project Pages (http://www.docsmachine.com/projects/) and go to the 8" Baldor refurb. It gives a quickie little demo of the dresser.

It's dirt simple- too simple, in that it's tough to adjust the collar in any kind of fine increment. But it works, and the wheels run dead smooth- it's a huge and noticible difference.

The problem with any hand-held stick or dresser is that no matter how firmly you hold it, it will follow the eccentricity of the wheel. With care, patience and time, you can correct it, but with a firmly-set dresser like this, assuming your tool rests are pretty firm, it's easy and quick to get very good results.

Shortly after I posted that, one of my Guild regulars posted his version (http://www.network54.com/Forum/9013/message/1284230366/Inspired+by+Doc...), which does have a clever threaded adjustment. He's got a bit too much angle on the diamond point in my opinion, but it otherwise works quite well, and it's a simple design.

Doc.

jaybird
09-20-2010, 11:30 PM
I am grinding 10% cobalt HSS cutters. The wheel is true and un-grooved. I am dressing the wheel to keep the grit sharp. I do not need to re-shape the wheel.

J Tiers
09-20-2010, 11:37 PM
using the right hardness of wheel is supposed to do the grit sharpening automatically, or so the theory goes.

Reality is that you probably have the wrong wheel for the job, as most of us do.

I hate all wheel dressers..... the star wheel ones don't seem to work, not on the hard wheels most bench grinders have. Diamonds are sensitive to the way you use them..... and it's a rare bench grinder with a guide available on it that is worth anything.

A pox on the lot...........

Evan
09-20-2010, 11:38 PM
We need to clarify the terminology. A dressing stick refers to a hand held stone made of either silicon carbide or silicon oxide. A piece of broken wheel of either type will serve just fine.

A wheel dresser is often known as an Armstrong Dresser after the inventor. It's the tool with the spiked wheels that grinds down the grit when held against the wheel.

The diamond dresser is as Doc has shown above and is effective on nearly all types of wheels.

For best results a diamond dressing point should be used in a jig that sweeps the point across the wheel in a fixed arc. It is the most effective way to true a wheel. Many commercial diamond points are mounted on a very fine threaded shank so they are easily adjustable in use. Trying to use one hand held is a waste of time and money.

For best longevity and value a diamond point should be at least 1/2 carat although smaller ones are available. Smaller sizes don't have the heat conduction capacity to keep the diamond below it's heat breakdown temperature which is about 800 degrees F.

Doc Nickel
09-21-2010, 12:11 AM
Many commercial diamond points are mounted on a very fine threaded shank so they are easily adjustable in use.

-The diamonds for my Sioux valve grinder are mounted in a 3/8" fine-threaded shank with an aluminum knob pressed on the opposite end.

They'd work great for this kind of bench-grinder dresser (just make a square, threaded block) but they run better than $30 each, whereas the smooth-shank ones can be had for less than $10 each (or even $5 for cheap imports.)

Considering all my bench grinders (seven, including the monster 12" one- I have 14 total grinders in the shop) I probably should invest in a big one- as you said, half a carat or more- and see if it'll last longer.

Doc.

metalmagpie
09-21-2010, 02:15 AM
I had a setup one time which had a wide piece of spring steel (thin, maybe 2" wide) which was riveted at the top to a block which fed a diamond via a threaded handwheel, and was riveted at the bottom to a machined piece which rode in the miter gauge slot on the grinder table. The spring steel was oriented so the edge of the wide side was towards the grinding wheel. To use it, you pressed it against the miter slot and held the base, and pulled the diamond back and forth across the wheel face. The diamond could easily move sideways across the wheel face, but could not move in and out because the spring steel didn't bend hardly at all in that dimension. You could do a pass, then turn the handwheel a little and then do another light pass. Good tool. Sold it with a Darex setup.

Black_Moons
09-21-2010, 02:49 AM
What about this kind? http://www.arceurotrade.co.uk/imagecache/99dcf944-63a9-4820-a7c5-c31055e21722_198x125.jpg

A diamond 'grit' applyed to a metal backing.

ulav8r
09-21-2010, 12:55 PM
Doc,

You could add another clamp collar behind that one. Use one that has only one screw to clamp it and put a screw thourgh the face of the collar to rest against the current collar. Use that screw to adjust the location of the current collar. That would give controllable fine adjustment.

Or, you could thread the shank and use a threaded collar.

sidneyt
09-21-2010, 01:34 PM
I am grinding 10% cobalt HSS cutters. The wheel is true and un-grooved. I am dressing the wheel to keep the grit sharp. I do not need to re-shape the wheel.

If you do not need to reshape the wheel then the dressing stick should work fine. Unless you are setup to use a diamond dresser I have found it is more difficult to use and control. The dressing stick is an inexpensive alternative that is easier, IMO, to use.

Deja Vu
09-21-2010, 03:57 PM
I've been following this thread(among others) and I got such a good chuckle from this as I would have imagined J expressing it.

.....and it's a rare bench grinder with a guide available on it that is worth anything.


Hah! I feel fortunate(actually a gloat!) that my five or six assorted grinders are of "rare" value as they all have guides that are indeed worthy. :D