|451 forum posts|
I have a small diamond wheel (I bought it from Arc Euro Trade) serving an Harold Hall's "Tool & cutter grinder" and would like to know what's the best way and instrument (dresser ?) to use to dress it.
Can anyone help me, please?
Edited By Dias Costa on 09/06/2011 15:34:29
|Stephen Benson||09/06/2011 15:45:04|
199 forum posts
On Ebay you can buy a diamond wheel dresser, how ever I have been unable to work out whether it is device for dressing diamond wheels or it is a diamond tipped device for dressing normal wheels.
So I would be interested in this thread as well.
|John McNamara||09/06/2011 16:00:17|
1309 forum posts
You dress diamond wheels with a stone dresser
You dress stone wheels with a diamond dresser
I found some good videos here:
Edited By John McNamara on 09/06/2011 16:01:15
|263 forum posts|
For dressing diamond wheels you really require what is known as a brake dresser.
It really is the only correct way to get them perfectly true.
Not cheap though, a new one will cost towards a grand. I was lucky and picked a Norton one up on eblag a while back for £27, at that included one brand new and another hardly used carborundum wheels.
2314 forum posts
I have little knowledge of this but seem to remember that with the conventional stone wheel the (diamond) dresser's use is to remove spent abrasive particles and thus expose fresh sharp ones. With a diamond wheel there is only one lot of diamonds and the
function of the ( stone ) dresser is to remove the material accumulated from grinding that is clogging up the wheel. The stone wheel can (should?) be dressed when fitting to enure balance whereas, of course, this is not possible with the diamond wheel.
Well guys is my recollection correct?
|466 forum posts|
I understand that a piece of York stone presented to the diamond wheel will work quite well and remove the accumulated rubbish. I hasten to add that I have not tried this but a tiler who was working for me at the time used this method. I can see no reason why it should not work. Observations gentlemen?
|Clive Hartland||10/06/2011 19:42:20|
2474 forum posts
To expose new grit on a stone wheel you should a Star dresser which has a multi head full of spiked metal wheels. These dig into the matrix and remove the bond and exposes new grit.
Using a diamond dresser on the wheel only smooths the surface and trues its shape and in fact lessens its ability to cut.
With a diamond wheel it depends which sort, a rubber bonded type will only burn if done with a stone and the harder type of bond will have diamond grit pulled out of the matrix.
I have not yet happily dressed a diamond wheel! Preferring to let it do its work gently and slowly and not forcing a tool being sharpened.
|263 forum posts|
The reason for the brake dresser is that as the diamond wheel starts to become true again, the brake dresser automatically reduces the friction of the stone to the wheel.
Using a lump of stone to do your dressing, I personally don't think you will get a perfectly dressed diamond wheel, as it will be relying on 'finger feel' or sight to detect when it is truly flat and square.
For those who have never seen a brake dresser, here is mine. The carb wheel is gently fed onto the diamond wheel face, and starts to spin, being driven by the diamond wheel. As it is running up, a centrifugal brake (on the other end of the spindle) starts to put a holding pressure onto the dressing wheel, so starting to gradually wear the face off the diamond wheel, and as stated above, as the diamond wheel is trued, the brake pressure reduces.
BTW, the 3 diamond wheels in the background, the two dirty ones are diamond cut off wheels, about 3/32" wide, the clean one is just a standard narrow grinding wheel. All for use on the surface grinder.
The use of diamond bonded wheels in the model engineering fraternity has only recently, in the last few years, started to be used. So really, although the wheels can be obtained reasonably cheaply, the methods of dressing haven't yet caught up with us from industry. So that means, until the dressing facilities really come down in price, or you are lucky and find a cheap one, you just might be stabbing in the dark with theories about how to dress them correctly.
Here is a second hand one at a very reasonable price
|Nicholas Farr||10/06/2011 21:31:57|
1989 forum posts
for those who don't know or haven't seen a star dresser for stone wheels that Clive has discribed, here is a photo of one with a new set of replacement star wheels seperation discs, pin and bushes.
Edited By Nicholas Farr on 10/06/2011 21:53:52
Edited By Nicholas Farr on 10/06/2011 22:00:23
|94 forum posts|
Well Bogstandard has said it all dressing diamond wheels is not going to be cheap. The single diamond, multiple crushed diamond and the star wheel are all for the grit wheel dressing.
The embedded diamond wheel comes in several forms. Some use metal plating to hold the diamond grains in place. Others use resin or rubber like compounds or even diamond grit embedded in a thick brazed coating.
For the final grind I use a soft copper wheel. The wheel is coated in olive oil and a sprinkle of diamond dust added. Enough to cover a match head is about right for a 50mm wheel. The wheel is then rolled under pressure - ball race mounted on a wooden handle serves well. The aim is to impregnate the copper with a number of the grains of diamond. Being mean I wash off the surplus with white spirit and allow the white spirit to evaporate saving the diamond grains and olive oil for refreshing the surface as it needs to be done frequently. Vodka would also work and smell better!
The bumps in a diamond cut off saw are readily removed by use of a reasonably soft stone such an old brick. The trick is to press the brick into the wheel very gently but firmly and use a very high speed with plenty of water. Messy but then the coolant keeps the dust under control. Unfortunately any truing removes diamond and the wheels have only a very thin layer. If the wheel is significantly out of true I would reject it as faulty. Using light but firm pressure from a large heavy chunk of metal that has a good flat face should do all that is necessary on small wheels. It is essential that the finer grades of diamond wheel are not used to rough out or you risk making profile wheels. The edge being ground needs to be kept in motion to use the whole of the surface.
Regards - Pat
|451 forum posts|
Pat (and others) has already said the most important. However I would like to share my experience in the dressing diamond wheel.
To regularize the surface of my diamond wheel I started to try with a regular dresser, one of those that presenting a rectangular metalic surface with abrasive particles scatered over it. Almost ruined it and practically no effect on the grinding wheel, diamond ...
Thanks to all who helped.
Edited By Dias Costa on 14/06/2011 13:57:15
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.