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View Full Version : Sharpening the scraper tip on the Sorby Hollowmaster



Ashes
2nd August 2008, 12:39 AM
I have one of these and don't know the best way to sharpen the cutting tip


any advice?

orraloon
2nd August 2008, 04:08 PM
Find or make a round shaft to fit a cordless drill and tap a hole in the center to take the holding screw. Mount the cutter head and touch her up on an old oil stone.I take it is HSS.
The other option is to contact Sorby and ask if they have a sharpening system to suit.

Regards
JA

rsser
2nd August 2008, 06:13 PM
Yep.

Don't know the tool, but apart from JA's advice above, it seems to have a pointed scraper tip as well ... yes?

If so, you could try knocking up a square of timber or plastic chopping board, drilling a hole close to a corner to take the tip, and then placing the square down on a grinder platform at the right angle and sweeping the square round as you would a scraper. You may need a grub or thumb screw tapped in to keep the bit steady.

(For an image of this idea, google for Soren Berger in New Zealand; he sells a similar setup for one of his cutting tips.)

STOP PRESS:

OK, withdraw all that :- - don't grind the bevel, lap the http://www.robert-sorby.co.uk/hollowmaster.htm

TTIT
3rd August 2008, 01:16 AM
Sorby does recommend lapping the face of the scrapers but I could never see that working 'cos you have to remove so much surface area for so little gain on the edge. For the teardrop scraper, I found it much easier to set the rest on the grinder at 90 degrees and give the scraper the slightest rub right round. This method leaves a slight burr which I find perfect for shear-scraping. To get the angle right, colour the edge with a felt-pen and adjust the angle of the rest until you're removing metal from edge to edge no matter which face you put on the rest (if that makes sense!) then mark where the rest sits for next time.
The hollowing cutter I ended up putting about a 5 degree rake on much the same way. Tilt the rest a couple of degrees off 90 and hold the flat face of the cutter on the rest. It only takes the slightest rub to give you back a good cutting edge.
Works for me and I use them on almost every item I make :U

orraloon
5th August 2008, 10:42 PM
I dug out some pics of a sharpening thingo for a hollowing tool by Bruce Leady. Explains what I was getting at.

Ashes
6th August 2008, 07:50 AM
Thanks guys. In a fit of desperation I decided to look at the documentation that came with the tool, it had sharpening instructions. Who would ever have thought to read the manual eh:D....It recommends lapping the flat surfaces of the scraper. That seems to work OK. will try giving the actual faces a quick touch up though