Cliff

Loose diamonds only work if used in lapping - pressed into a surface 
that will hold the diamonds.

Someone mentioned a cast iron plate - that works.

Someone else mentioned a film you put on the glass into which the 
diamonds are pressed - that works.

Even the leather will work.

Putting diamond paste directly on glass will not work. Rolling grit can 
dent the tool surface, it cannot remove any metal. Picture somewhere on 
my web site.

There is one other matter that is important. It is not the size of the 
grit that matters, it is the density of the points. Fine grits make fine 
scratches only if they are densely packed and hence the number of points 
per unit area is large which means in turn that the force per point is 
small which means that the depth of penetration is small.

Spreading some diamond paste on a lap puts an unknown number of points 
per unit area, so the depth of the resulting scratches is unpredictable.

When I was looking at lapping I discovered that even a few stray bits of 
swarf from a prior step could scratch up the bevel. This is mostly 
because there are so few of them.

In summary, rolling your own stropping device produces unpredictable 
results.

Buying quality abrasives makes sense to me.

Brent

On 2017-05-23 09:26, Cliff wrote:
> Some years ago I built what I thought was going a totally slick 
> sharpening rig.  Three Glass plates and a leather strop the plates were 
> 20" long 4" wide and 3/8" thick
> 
> I got some diamond grits for it.  they were the wrong grits. Too fine. I 
> really didn't know  much about the  sizes of diamond grits.  Still don't.
> 
> I got half,  one, and two micron. They don't seem to make a dent in an 
> edged tool.
> 
> What three grits would you choose ? Assuming you  know more about this 
> than I do.
> 
> Know a good source?
> 
> 
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-- 
Brent Beach
Victoria, BC, Canada