Softer metals on diamond stone

[JohnPW]

I read that softer metals like brass, iron, and laminated blades should not be used on diamond stones because the abraded particles will clog the stone and cannot be be removed.

Does anyone have any knowledge or opinion on that ?

 

[Inspector]

I can't say with respect to bench stones but on a machining forum in the US they say for bench and surface grinder wheels soft iron/steel reacts with the diamonds by removing the carbon, dulling them quickly. Only supposed to use them on High Speed Steel or Carbide, preferably with coolant. I would never use any bench stone or grinder to shape or sharpen any non-ferrous metals. No bronze, brass, copper, aluminium, zinc etc. Sandpaper for them.

Pete

 

[--Tom--]

It’s more that the diamonds will stick in the softer material and get pulled out of the plate shortening the lifespan of the plate significantly

 

[Fergie 307]

These materials clog up any abrasive very quickly. I just use a piece of plate glass with a sheet of wet and dry on top, when it gets clogged up just throw it away and get another bit. Lots of water with a drop of detergent helps too for brass aluminium etc, diesel is good for cast iron.

 

[SteveB43]

On a laminated blade, the hard tool steel is the base or underside of the blade, with the softer metal on top. If correct, you could in theory use a diamond stone to form the 30deg bevel on a ground at 25deg blade, because you are only sharpening the first 1 mm or so of the bevel.
You'd get in trouble though once you hit the softer metal in subsequent honing's or for an initial grind.
I know that Matthew at Workshop Heaven recommends avoiding diamond stones with laminate blades

"Honing angles are the same as for carbon steel irons (25 / 30) and being laminated they are a pleasure to hone freehand, keep them clear of diamond stones though as the soft iron supporting layer can damage the diamond surface."

....just my 2p's....

 

[Jacob]

On a laminated blade, the hard tool steel is the base or underside of the blade, with the softer metal on top. If correct, you could in theory use a diamond stone to form the 30deg bevel on a ground at 25deg blade, because you are only sharpening the first 1 mm or so of the bevel.
You'd get in trouble though once you hit the softer metal in subsequent honing's or for an initial grind.
I know that Matthew at Workshop Heaven recommends avoiding diamond stones with laminate blades

"Honing angles are the same as for carbon steel irons (25 / 30) and being laminated they are a pleasure to hone freehand, keep them clear of diamond stones though as the soft iron supporting layer can damage the diamond surface."

....just my 2p's....

I didn't have a prob with laminated blades and Ezelap plates but I always sharpened wet; oil or white spirit. Sold the plates - they don't pay their way, wet n dry paper on a flat surface is much more sensible, used wet.
Thin paper backed that is, lies very flat and stays stuck down when well wetted. Not cloth backed.

 

[JohnPW]

I got this reply from DMT:

We don’t see any issue using softer metals like brass and or iron, although I wouldn’t suggest anything as soft as lead. If you do find that the stone begins to clog with metal swarf. Use some mild detergent and brush to clean.

I have only seen one online advice not to use softer metals (softer than hardened steel) on a diamond stone.

 

[clogs]

Forget the diamond style stone for the soft metals. It will wreck em….
best way to shape is either with a machine and proper cutters or by hand with files n saws…
if ur polishing say a soft casting or a piece of scratched brass….
start with the courser papers ( I prefer wet n dry)then gradually getting finer papers and or polish on a wheel….
u can get a kit to go on a bench grinder but they are pretty worthless….
i made my own double wheeled polisher and it has a 3hp motor…

 

[Jacob]

wet n dry used wet, or oil stone with plenty of oil
If steel you can lift off the swarf with a magnet, which of course you can't do on a steel backed diamond stone. They are a bit pointless really, I sold my 3 expensive Ezelaps.

 

[Fergie 307]

Forget the diamond style stone for the soft metals. It will wreck em….
best way to shape is either with a machine and proper cutters or by hand with files n saws…
if ur polishing say a soft casting or a piece of scratched brass….
start with the courser papers ( I prefer wet n dry)then gradually getting finer papers and or polish on a wheel….
u can get a kit to go on a bench grinder but they are pretty worthless….
i made my own double wheeled polisher and it has a 3hp motor…

In fairness the spiral pointed adapters for a grinder can be useful, if you only need to do small stuff like jewellery. As you say they are pretty useless for larger stuff.

 

[D_W]

I know that Matthew at Workshop Heaven recommends avoiding diamond stones with laminate blades

The coarse diamonds will be pulled off quickly by soft metals, especially by iron or mild steel, and the look of the honing result will be garish, anyway.

But they won't destroy a diamond plate immediately and electroplate hones are destined to be slow once they're broken in.

Brass and other metals that pin could create a problem by just pretty much "writing" themselves onto the electroplate and then getting them off without damaging the nickel plate may not be that easy. There's no great reason soft metals would be ground or finished with diamonds, especially when the diamonds are as poorly graded as what's on electroplate hones (big stray diamonds, even some that remain).