Thread: You flatten my back...

I forgot some photos.

I would suggest the following:

1 a piece of 8-10mm plate glass the size of a sheet of W&D paper
2 a number of sheets of wet & dry with GRITS starting at 800# and going to 2000Grit.
3 wet the glass, and lay the sheet of w&D then start gently honing the back of the Irons keep the sheet wet, and clear the grit of residue regularly
4 work through the grits until the back is a uniform finish , at 2000Grit it should be close to a polished finish, at this stage a metal polish can be added to the sheet IE: BRASSO.

I would not recommend machine polishing as this will create highs&lows that will become apparent when you are sharpening the edge.

Do not use an adhesive to hold the W&D to the glass as this could cause ridges / high spots.


just my 2 cents worth ,.

Jeff vk4

Thanks Jeff.

Out of interest, where does one acquire 2000 grit sandpaper ? My local Bunnings certainly don't seem to stock it.

Cheers,

Scott

Scott, Google the Sandpaperman. A mail-order aussie supplier with a wide range of good abrasives.

Michael, I'd be happy to clean up your blade. Have powered seeded gel abrasive discs that should eat HSS. (Worksharp discs mounted on an arbour on the lathe).

Jeff, differential exposure to abrasive is inevitable whether hand-powered or horse-powered. I gave up on W&D by hand for that reason ... lapping plane soles --> some degree of convexity. With a flat carrier and quality abrasive suited to the metal, horse-power works better for me. W&D wears out fast in any case, even with cast iron.

Originally Posted by Ozziespur

Out of interest, where does one acquire 2000 grit sandpaper ? My local Bunnings certainly don't seem to stock it.

Hi Scott

I usually get 1500, & 2000 off EBAY (the brand I use is Matador - Made by the German Company Starcke)

No issues using these

Jas

Originally Posted by rsser

Scott, Google the Sandpaperman. A mail-order aussie supplier with a wide range of good abrasives.

Michael, I'd be happy to clean up your blade. Have powered seeded gel abrasive discs that should eat HSS. (Worksharp discs mounted on an arbour on the lathe).

Jeff, differential exposure to abrasive is inevitable whether hand-powered or horse-powered. I gave up on W&D by hand for that reason ... lapping plane soles --> some degree of convexity. With a flat carrier and quality abrasive suited to the metal, horse-power works better for me. W&D wears out fast in any case, even with cast iron.

Excellent! Thsnks Ern, will pm you to discuss.

Sandpaper Man is good for fine W&D. Also the automotive shops Supercheap Repco etc.

Regards
Paul

Mic-d,
If you still are having troubles bring down to my workshop and it will be fixed, Flattered and Polished easy peasy.

Cheers

Steve

Originally Posted by fineboxes

Mic-d,
If you still are having troubles bring down to my workshop and it will be fixed, Flattered and Polished easy peasy.

Cheers

Steve

Flattery will get you nowhere Steve, they can't hear you.

That's a very generous offer Steve 'cept I just posted it off to Ern this arvo.

Cheers
Michael

Originally Posted by rsser

Scott, Google the Sandpaperman. A mail-order aussie supplier with a wide range of good abrasives.

Michael, I'd be happy to clean up your blade. Have powered seeded gel abrasive discs that should eat HSS. (Worksharp discs mounted on an arbour on the lathe).

Jeff, differential exposure to abrasive is inevitable whether hand-powered or horse-powered. I gave up on W&D by hand for that reason ... lapping plane soles --> some degree of convexity. With a flat carrier and quality abrasive suited to the metal, horse-power works better for me. W&D wears out fast in any case, even with cast iron.

Sounds like a mean set-up Ern!! I'll store that info in the memory banks(until I forget!!)

I know I'm sounding like a broken record, but if flattening backs on very hard steel is something you do a lot, I'd recommend dropping Stu in Japan a line about the problem. A few course ceramic stones will set you back $85 including postage (or at least the ones I have in mind will). That seems a lot, but they will last you a life time, in which caase you'll most certainly end up spending that much on sandpaper. I believe the Sigmas cut HSS without too much trouble.

This recommendation comes off my year-long quest to flatten a LOT of hard old blades. Diamond stones, diamond grit, normal waterstones, sandpaper, oilstones and silicon carbide grit all got abandoned in favour of these ceramic stones (and, um, a drill, but that won't help here).

If you do use sandpaper, I'd just reinforce the point that you really must stick it down with spray adhesive (about $15 from an artist's supply store, but might be cheaper elsewhere). Otherwise the edges will be dubbed and you'll be much worse off than when you started. Even then, I've never been able to avoid dubbing and thus blunt corners with sandpaper, but that's probably poor technique.

Agree that a good stone or 3 from Stu is good to have in the kit. Have to be made for hard steel though. And this blade is plenty hard. Here's what I did:

The prob was deep scratches left from surface grinding on the back. Running into the small back bevel. So a lot of steel had to come off.

I ground the back on a Sorby Pro-Edge, starting with #120 AlOx & finishing with #600 (equiv.) Trizact.

That gave a polished finish to about 5mm from the edge. The blade was slightly dished I think and the abrasives didn't get to the blade middle, leaving some scratches.

The process polished the BB as well (a consequence of the slightly raised belt join at a guess).

mic-d in a discussion indicated that it would be good to get rid of the BB. In retrospect I should then just have jointed the edge, but the BB was small and there were the remaining scratches to remove.

At this stage the belts were worn. A #120 Ceramic would have been ideal to really rip the metal off but that addition is several weeks away.

So phase 2 was to rework the back on the Worksharp abrasives, mounted on 150 mm diameter tempered glass discs on an arbour on the lathe.

Started at #120 with a seeded gel disc. Then up through the grits. Trouble here was expected and got: the corners got slightly rounded over at #120 and took a lot of work with #220 and #400. At that stage I'd gone through four discs with a still unsatisfactory result. One corner with minor scratching; the other with rounding over just under a mm in width. But otherwise the scratches further back were gone and the back was quite polished (abrasive at speed produces a polish at lower grits than abrasive with manual push-pull).

At this stage I was tired of machine work and took the back to a Sigma Power Select II #220 benchstone (from Stu) and a few minutes work at the tip improved it substantially, and then to a Sigma Power #400 for a bit more cleaning up (a Stu special that struggled, which surprised me). After that there's still a small amount of rounding over on one corner. With the bevel redone once that will make for a small diff. in cutting depth. With a few bevel regrinds it will disappear. Some folk like rounded-off corners on their smoothers. Others don't. Will wait to hear from the customer.

PS: just to be clear, and fair to Stu, the #400 struggled with the blade off the #400 sheet abrasive. Not when I came back to it after the coarser grit stone.