Thread: Diamond paste sharpening

Lynndy will be pleased to have her wash trough back

Derek,

I have always used DMT diamond stones, and avoided waterstones, for the reasons you mentioned. For the final honing I use Veritas honing compound rubbed onto a lightly oiled offcut of MDF. Hopefully Carbatec or Lee Valley will start selling the diamond pastes that you mention soon.

Rocker

I suppose you could use that on plate glass as well? Or do you think it needs to be used on something that will capture the grit rather than allowing it to 'roll' around?

I've tried it on plate glass and found the glass scrached which may affect the action on the paste and lead to contamination if you use the same glass for the next grit.

ron

Glass with a plastic sheet on top should work. Like the Veritas lapping kit. I wonder if Overhead Transparency sheets would be ok?

The best surface is a cast iron machinist's lapping plate. These are seriously expensive! Not going there unless someone wants to make a donation.

A closeup:

On the 40 micron Jarrah block I scored a similar cross hatching. This created ridges so I smoothed the block with a plane leaving fine lines. The paste becomes inbedded in the grooves. So far the Jarrah has not dished. If/when it appears to do so I will just use another piece.

Keep in mind the danger of cross contamination. This will show up as scratches in the steel surface. Wipe everything down carefully, especially if using a honing guide (so far I have mostly done this freehand).

I am waiting on a set of Shapton ceramic waterstones (1000, 5000 and 8000 in the Professional series) and will report on these later.

Back to the diamond paste - I have a 400 grit diamond stone, which is the same micron rating as a 40 grit paste. On the paste I was able to flatten the back of a 3/4" chisel blade very rapidly. It left a scratch pattern much smoother than the 400 stone. This leaves me to consider that the stones may not have as uniform a grit as the paste (but I do remind myself that the 400 stone is not a DMT, just a cheap Chinese copy - although it has been flat and great value-for-money from Carba-tec - I originally got it to flatten waterstones).

Regards from Perth

Derek

What do you call "seriously expensive"? I've been thinking about getting a lapping or surface plate for other metal working activities.

I suppose the other question is what damage the diamond paste would do to the plate? If it wears the blade of a chisel or plane, wouldn't the diamond cutting action wreck the cast iron plate too?

SC

They are upwards of $500.

The idea is that the diamonds become enbedded in the cast iron.

Regards from Perth

Derek

FWIW I'm playing with wet and dry for sharpening purposes and a piece of float glass 10mm X 100mm X 800mm was $45. And yes it does scratch when grit goes astray.

This is all novel to me as a bumbling amateur but it was a fun to hone down to 2500 paper and shave the hairs off my forearm. Might be why I'm getting funny looks on the train these days.

Question how suitable would a plate of stress relived and milled flat steel be as a base for the diamond paste?

As it is stress relived it would resist warping, the milling would make it flat enough for the purpose of sharpening, and if I could get the cross hatch cut into it it Or fine drilled depressions into the surface just like the DMT plates it should be little different to a cast iron machinist's lapping plate for far less money.

Cheers for the advice.

I'm a retired Marine Engineer. We always did lapping of compressor valves and similar on a thick glass plate, usually round in shape. Yes the glass does "scratch" and takes on a cloudy appearance. A quick wipe over with a cloth and spirits gets rid of all contaminants.

As i am just setting up my shed, and being reminded by this post that I would need to sharpen things I nipped down to my local glazier before xmas. For $20 a bought 2 sheets of 10mm float glass roughly 300mm x 400mm. These had all their edges and corners bevelled for safety. I have siliconed the sheets together (one atop the other) to form a solid plate. I will mount this surface plate into a light frame with a ply lid to protect it from damage.

If you find that your grinding paste dries out in use it is a simple matter of adding a few drops of light oil as you lap to return it to a paste.

Lapping can be very therapeutic.

prozac

I took one of my spare 50 x 100 x 8 mm blade from D2 batch 01 which does not have a bevel ground on it and rubbed some Veritas rouge on one side to use it as a makeshift machinist's lapping plate. I am glad to say that it works much better then any wood or leather stropping surface I have used, you can put a fair amount of down pressure without risking a dig in. The Veritas rouge did drift around allot and I thing the grid lines would be very helpful to catch the Veritas rouge or diamond paste.

I may just have to have a few of these made up for me in a larger size.

Derek, if you're having good success with these on Jarrah, is there any reason you couldn't use MDF? I've been using the Veritas green honing compound on MDF with great success and it occurs to me that an oil based paste might work equally well. It's certainly a cheap alternative to a series of 12 diamond plates!