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View Full Version : Sharpening angles - scrapers for lidded boxes



jefferson
25th September 2008, 01:10 PM
I've already asked what sharpening angle turners use for scrapers.

Mine are probably 75-80 degrees and work superbly on the base of bowls. But when I try the Richard Raffan method of scraping the last mill or so of the side out of small bowls and lidded boxes, I run into trouble.

With the tool rest set so that the tool is just under centre, the bottom side of the scrapers contacts the wood. I can only bring the cutting edge into contact with the wood if I turn the tool on its side and sheer scrape.

I think I need either relieve the bottom edge substantially, or re-sharped with say a 60 degree bevel so the top edge can cut.

Or am I missing something?

I'd prefer not to touch the tools, as they work so well on end-grain redgum - as Ern would agree I'm sure.

Solutions please.

Jeff

RETIRED
25th September 2008, 01:36 PM
i've already asked what sharpening angle turners use for scrapers.

Mine are probably 75-80 degrees and work superbly on the base of bowls. But when i try the richard raffan method of scraping the last mill or so of the side out of small bowls and lidded boxes, i run into trouble.

With the tool rest set so that the tool is just under centre, the bottom side of the scrapers contacts the wood. I can only bring the cutting edge into contact with the wood if i turn the tool on its side and sheer scrape.

I think i need either relieve the bottom edge substantially, or re-sharped with say a 60 degree bevel so the top edge can cut. that is the answer.

or am i missing something? nope.

i'd prefer not to touch the tools, as they work so well on end-grain redgum - as ern would agree i'm sure.

Solutions please. bring it with you to the turn-on.

jeff :d

jefferson
25th September 2008, 04:28 PM
Thanks for the quick response .

Now all I have to decide is which scraper to put to the sword on the grinder. The big one cost me $260 from memory!

And if I do make the grind angle say 60 degrees, will it still work on bowls? If not, I may just have to replace it.

I will bring them down to the turn on anyway.

Jeff

RETIRED
25th September 2008, 05:45 PM
It really is an arbitrary figure for the angles on a scraper or any tool really. Some work better than others but if it works for you it is ok.

The only part that cuts on a scraper is the top bit where the flat bit meets the bevel.

The only part that cuts on a scraper is the top bit where the flat bit meets the bevel.

The only part that cuts on a scraper is the top bit where the flat bit meets the bevel.

So what I am trying to say is that it doesn't matter what the angle is underneath. In order to gain clearance in a tight radius i.e. a small lidded boxyou may have to increase the bevel significantly for the cutting edge to even make contact.

This is particularly noticeable on thick scrapers and in some instances i have even radiused the underside or bevel in order to get clearance.