Sharpening hollowing tools.

[Mark Burge]

Hey guys, sorry for dropping out of the conversation for so long. Just haven't had much shop time lately and what I did have wasn't lathe work. And on that point, when I did get some time on the lathe, I found that I really needed to spend a good bit of time sharpening my tools. I've always had questions about my Sorby hollowing tools, though. The instructions say to sharpen by flattening the top of the tip. This doesn't make much sense to me because that would take away any burr and isn't that what a scraper uses to cut? Any insight would be appreciated.

[Tim Rinehart]

I just bought a Sorby hollowing tool with a small oval tip on it, and it had no rake to it at all. I suspect the intention is that by having it neutral raked (and no burr), it's easier to control when under the shoulder doing final clean up, with little chance of ugly catch. The one I'm referring to isn't one of the tools with a flat bottom on it (hollowmaster or Multi tool), it's one that is completely round, but with a swan neck.
That's just a SWAG...see what other responses you get.

[Michael James]

I have the benjamin's best with the disk and they have the same suggestion. It massaged the wood fairly well, did not cut... My woodcraft guy suggested sitting with a diamond hone and getting it up to speed. I just took it to the ginder and away we went. Not my primary hollowing tool, but I like the flat bar. Good luck with this issue.
mj

[Ryan Baker]

A scraper can be used either with a burr or without one. Generally for hogging off material you are working without the burr. A burr is sometimes used to make fine finishing cuts in some woods. The burr does not last long in that case. (It's basically the same thing as a card scraper.) A negative rake scraper depends on the burr.

I don't sharpen my Sorby-style tips on the top, even though Sorby does say that. You can do whatever works best for you. I don't normally use scrapers with a burr except for shear scraping (with the tool elevated at roughly a 45 degree angle).

[Matt Owen]

I have the Sorby tear drop scraper tip. I took it to the grinder to give a relief angle of about 10 degrees. After that, I usually sharpen with a diamond hone, stroking the bevel from the bottom to the top. This raises the burr for me, which is what I use to cut. Hope this helps.

[Scott Hackler]

On my cutting tip (Sorby Hollowmaster), I ground the angle back a bit more than stock. Then I will take a diamond hone flat across the top, to start with no burr and THEN drag the hone from bottom to top all around the edge. This gives me a fresh sharp burr. Works pretty good for me. I haven't really liked not having a bur on this tool (or any scraper for that matter).

[Mark Burge]

Thanks, all. I'm going to get out my honing equipment then and get to work.