Thread: Q's about sharpening

Sometimes, meaning mostly, I wonder where this idea of a burr edge doing the cutting comes from. The burr will be removed immediately you apply it to the cutting task thus it serves no purpose at all.

I saw some tools sharpened by an absolute novice on a Tormek that his family bought him for Christmas. Never sharpened a thing in his life but followed the directions to the letter and boy, I have never seen or felt sharper tools and did they ever give a fabulous finish.

So, with the Tormek system, do you still need to touch up the blade on a stone once you are done?

Personally I think a water-wheel for sharpening turning tools is a waste of time, effort and finances. Way, way too slow and regardless of how sharp you make an edge, you will need to return to the Tormek just as often as you'd go to an AlOx.

Originally Posted by artme

Sometimes, meaning mostly, I wonder where this idea of a burr edge doing the cutting comes from. The burr will be removed immediately you apply it to the cutting task thus it serves no purpose at all.

You'd think so, wouldn't you? Maybe for softwoods, but not for our Aussie hardwoods.

Yet I know damned well that there's a definite difference between a scraper sharpened with a burr and one which has been burnished or honed.

Perhaps if/when Ern finally gets to run his microscopic examination of different scraper edges we'll get a more definitive answer... but until then it's safe to say the "layman's myth" that the burr does the cutting will persist, as it seems to be true.

um as a chippy by trade a "scraper" is made out of a saw thats stuffed , you file it flat then burnish a hook or bur to the scraper , it removes timber fast and is the stage between planing and sanding
that's where the bur comes from , for shear scraping i wouldn't go with out one

But you don't whizz a card scraper over the wood at several thou feet per minute... and on a wood lathe, a 6" dia blank at 1000RPM is moving at some 2000 feet per minute. I doubt you could do 2000 feet with just one edge on a card scraper, let alone every minute for several minutes, as is expected from a turning scraper. (and we are in the wood-turning section, not the hand tools... )

Then there's the small matter of the difference between a hook turned with a burnisher and the wire burr left by simply grinding...

Artme's correct that, logically - and seemingly in fact - the burr is removed almost as fast as it touches the wood. My brain says it must be a fallacy for it to have anything to do with the cut... but from practical experience I know that to all intents and purposes it appears to work.

I suspect it's not the burr, but the ragged edge (on the micro-structural level) that it leaves behind. Honing or burnishing the scraper would give it a smoother, crisper edge. Hence the burred scraper cuts more aggressively, while a burnished one gives the better finish. (And also my interest in Ern's experiment.)


Sorry for going on about it; I like to think I have a basic understanding of how my tools work, but this aspect puzzles and intrigues me... so I welcome any discussion and alternative viewpoints. The question of "how/why does a scraper cut?" could almost be considered my personal Holy Grail.

Originally Posted by Wongdai

So, with the Tormek system, do you still need to touch up the blade on a stone once you are done?

No.

short answer is yes, i have been sharpening tools for some 20 + years by hand a machine, i get great results doing them by hand. the trouble is it takes a lot longer to do it. i have had the tormek for 4 odd years . at first it took me ages to get to grips with it, so i spent a whole weekend trying it out on all sorts. now thats all i use. i find the tormek ( other sharpeners available ) to be a great machine, it keeps the cutting edge for longer. remember its realy two stones in one. meaning if you want to remove steel quickly from a nice smooth stone you have to use the dressing stone which only takes 30 secs. once you have your edge you use the leather wheel to hone the edge. use the wheel towards the cutting edge. i alsi use it for sharpening my stanley knife blades too yes i am a tight a%$