Re: Eagle Surface Grinder

Peter Neill wrote:
On Mon, 26 May 2008 20:13:11 +0000, Christopher Tidy
<cdt22NOSPAM@xxxxxxxxxxxxxx> wrote:


As for wheel grit types, there is as much debate here as the HSS vs
Carbide debate. In general, a harder steel needs a softer wheel, and
vice versa.

Why is this? I'm curious. Is it because lost grit gets embedded in a softer workpiece and then wears away the grinding wheel?

Best wishes,

Chris


The hardness refers to the strength of the bond holding the grit
together, rather than the grit itself.

A hard material will dull or blunt the grit, and if it doesn't break
off then the wheel will glaze and not cut, so a softer wheel allows
the grit to break away easier and then effectively presents a sharp
new cutting edge.

Softer materials don't wear the wheel so much, so can use a harder
bond.

Thanks, Dave and Peter. That makes good sense. Presumably the rate of wheel wear must be kept much lower than the rate at which material is removed from the workpiece, otherwise you'll lose your accuracy, is that right?

Best wishes,

Chris

.

Relevant Pages

  • Re: Eagle Surface Grinder
    ... As for wheel grit types, there is as much debate here as the HSS vs ... In general, a harder steel needs a softer wheel, and ... softer workpiece and then wears away the grinding wheel? ...
    (uk.rec.models.engineering)
  • Re: grinders - sharpening - Sourwood
    ... > Why would I spend the extra $ to get a variable speed grinder? ... but the wheel grit. ... A high speed with a fine grit can excessively heat ... When I tried a 120 grit white wheel, I found it loaded up quickly and I ...
    (rec.crafts.woodturning)
  • Re: sharpening + $10 bench grinder
    ... a water bath for a bench grinder? ... I hope I can "dress" a grinding wheel by using an old AlO ... Sears has cost less than the whole grinder itself. ... 440 is the first practical grit and many people want finer grit than that- ...
    (rec.knives)
  • Re: sharpening + $10 bench grinder
    ... My next grit would be 220, and what you favor after that. ... wheel to create two concavities, easier to grind flat by hand, or just grind ... away with a 185 grit stone to reduce the concavity to a flat bevel. ... I'm guessing the finer wheel is ...
    (rec.knives)
  • Re: sharpening + $10 bench grinder
    ... You can mask up against water droplets. ... grit wheel, then take a smoothing pass on a 120 or 220 grit wheel". ... narrow surface contact and thus urge a harder grade of grinding material. ...
    (rec.knives)