3M Microfinishing lapping film

[groeneaj]

Hi,

Could someone please clarify for me the actual grit of the 40, 15, 5 and 0.3 micron 3M lapping paper? and is this the same for the shapton stones eg 1000,4000 and 8000 grit?

Does someone have a good link to a table that I can print out to stop this confusion ?

I basically want to give the scary sharp method a go at restoring some old chisels. I have the waterstones etc, but i'm curious to see how this method compares. I enjoy sharpening and want to get better and try different methods. I'm going to use a grinder for the bevel, but going to use SS to lap the backs of the chisels.

So will 40 micron be a good start for an old chisel that needs to be flattened (I don't have a belt sander, I just want to use this method for now). Or do you guys think I should start off with something that's more course, and if so what sandpaper do you suggest (from the Sandpaper man). Keeping in mind that 40 micron is as course as he has in the 3M range.

Also i'm going to get some 8-10mm float glass tomorrow. I understand that pretty much any glass supplier will be able to cut it to size for me, but does anyone know of a good place in Melbourne (eastern suburbs would be good but willing to drive) to go to that is reasonably cheap?



Many thanks,

Andy

[derekcohen]

Andy

Avoid sandpaper. It will dub the edges.


Try making a cast iron plate and then use diamond paste ...



I used old planes ...

http://www.inthewoodshop.com/Woodwor...mondpaste.html

40u is excellent for flattening. Follow with 15u, 3u and .05u at the bevel edge and back.

Regards from Perth

Derek

[groeneaj]

I have no idea where I could get a cast iron plate from.

I just wanted to experiment with the glass and the 3M to see how it goes.
When you say stick away from sandpaper, are you referring to wet and dry, or 3M microfinishing lapping film, or both?

You have spoilt my fun Derek, I was looking forward to tring it out!


Andy

[derekcohen]

I have no idea where I could get a cast iron plate from.

Read my link.

Regards from Perth

Derek

[pmcgee]

Awww shucks Derek ... that's like taking rabbit meat to a pet-lovers convention



Are you saying the weak must die, so that the strong may survive?

All my braze-repaired planes have gone into hiding in one corner of the garage, shivering under the bench

(Could be good for them - it's time I got some respect around here)

Paul McGee

[groeneaj]

Im probably more confused than before.
You say on your site - LAPPING THE BACKS OF BLADES that you use sandpaper to lap the backs?

[derekcohen]

Hi Andy

Certainly sandpaper will work, as I demonstrated in that article. However look at the effort that went into ensuring that the wear was even and did not dub an edge. That article was written before I had exposure to diamond paste. If you have a choice and are asking which method I prefer and recommend, then it is the diamond paste. Also cheaper.

Regards from Perth

Derek

[rsser]

IME the 3M Imperial Lapping film or Micro-finishing abrasives are far less prone to dubbing the corners than W&D and are effective for lapping. They cut quickly and cleanly and compared with whetstones involve no maintenance. It took a half a sheet of 15 micron to repair most of the damage done to one chisel back by W&D dubbing.

They'll work OK on plate glass but as flatness is critical in lapping a granite reference plate or Woodpecker honing plates are better.

I've tried 90 micron diamond paste on a dead diamond stone was was underwhelmed ... but it was from an ebay seller and so the quality was perhaps questionable.

Grit conversion chart below ...