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diamond discs

Posted by oldsailorsknives 
diamond discs
June 28, 2017 09:13AM
does anyone have experience using diamond discs for finishing? this is an example [www.ebay.com] I know when using a fabric disc for polishing we use the same compounds as the lapidary folks.


Edited 1 time(s). Last edit at 06/28/2017 09:17AM by oldsailorsknives.
Re: diamond discs
June 28, 2017 09:39AM
I have never seen them until now, the look promising however.

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--Shawn Houston
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Re: diamond discs
June 30, 2017 06:44AM
Keep us posted if you pick one up Scott, curious how long they last
Re: diamond discs
June 30, 2017 09:53PM
I have used a couple of those made by 3M to sharpen knives. If I remember correctly, they were 9 and 6 microns in particle size. Worked quite well for that. I was told that they were used to sharpen razor blades in factories. As in the replaceable blades in utility knives.
Re: diamond discs
August 07, 2017 04:08PM
I almost exclusively sharpen knives on thick glass plate using lapping microfilms..

However for polishing It would need a machine I do know about.
( That means I should make one grinning smiley )
Seen lapping machines in labs but they are not able to polish bigger surfaces
than small sample and even that took relatively long..
Cant really imagine using them for polishing the blade
unless I spend 48 hours by that..

Re: diamond discs
August 09, 2017 05:44AM
I was looking at 8" lapidary 'flat lap' something like this [www.therockshed.com]. variable speed, water cooled.
Re: diamond discs
August 11, 2017 09:05AM
Scott, it could be awesome for sharpening bevels..

I am a bit sceptical about finishing knifeblades evenly as:

1) Your knife will have to have perfect flat surfaces to mach the lapping base
flat otherwise there will be hollows and high spots and if try to work it
like on a stone to cover whole surface it wont give attractive finish..

2) You wont have sccratch pattern of a same direction as satin.

So you only could use high level of mirror and it would be skill difficult
and not possible with just any blade.. Maybe some soft leather under
polishing disc could work nicer for finish..

I think it isnt ideal for the purpose at the price..

Re: diamond discs
October 10, 2018 08:47AM

In previous posts I stated something but was not correct in all aspects:

I build this (link) and use it:

I originally intended to use it only for checking and correcting straightness of pimary grinds and overall
shape while most removal is done by belt grinder.

I soon started to use it for careful adjusting of the edge thickness
and as first step of sharpening as well before the stones.

Perhaps now I also use it as the last machine surface refinement
after which I go straight to hand satin finishing. I ve said this will not work well..
But well, it does.. Surface after worn P240 is around P600 or higher satin when it
comes to scratches depth.. it doesnt look nice as scratch pattern is circullar not straight
but as there are not really any deeper scratches it is fairly easy to put
P800-1200 satin over it.. I use 300mm diameter disc so my contact area
is fairly big, allowing to use P240 at high speed and so it works really
fast but as the pressure is low finish has very smooth scratches.
Water takes care of any excessive heat and loading.
SiC breaks down fast so it start aggresively but after a 2minutes or less
it can produce semi-mirror fininsh that you can start to hand satin by P1000
just after.. It takes skill tho I am still learning so it isnt as easy as described
but this method works for me the best so far..
It is very suitable for big blades and kitchen knives, flat and convex grinds..

EDIT: As using SiC that gets quickly broken down need to spend many discs
and change them very often except the very last one when the smoothest
surface is desired. As well in total this takes more time than on belt grinder.
But for me result is more consistent and it is easier to control pressure
and contact points and big contact area allows for more even edge thickness..


Edited 1 time(s). Last edit at 10/10/2018 08:54AM by JSCT.
Re: diamond discs
October 10, 2018 07:32PM
I use one of these for manually flattening bench stones. Works great for the money, though it's obviously not the highest quality diamond plate out there. Having a huge 12" diameter to work on is nice when flattening big stones.
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