Spindle Grind for Raffan's Back Hollowing Technique

[Don Stephan]

Would like to know how to grind a 1/2" spindle detail gouge for efficient back hollowing. I've had success deepening an end grain box or cup with my 3/8" spindle gouge with a slightly rounded tip, but after the first couple passes widening the hollowed interior I can't get more shavings - something in the grind must be blocking the cutting edge. Earlier discussion here told me my early problems were due to not keeping the gouge firmly against the side of the opening (along with the tool rest) but I'm still not getting quite the results I'd like. I have no problem with having to use scrapers to remove ridges and refine the curve - that tradeoff is easy given the speed and ease with which a shallow to mid-deepish hollow can be formed.

I'm not familiar with the nomenclature for grinds, but I've been grinding at 30 degrees, pushing the gouge forward as I roll onto the flutes (as shown in Mike Darlow videos) with only a very slight convex curve on the sides of the cutting edge. Thanks in advance for your help.

[Mike Peace]

In his book on boxes, Raffan calls for a fingernail grind on the spindle gouge used for hollowing. That is, don't make it too pointy. He calls for a 45 degree or longer angle.

[Paul Heely]

This is what the gouge I use for back hollowing looks like. No there is not really a flat spot on the cutting edge, but it sure does look like there is in the picture.

207386

Good luck. I had a heck of a time with back hollowing until Raffan showed me how to do it. If you can find someone who knows how to make the cut, it may help to spend some time with them.

Paul

[Bernie Weishapl]

Ditto what Mike said. My fingernail grind on the left side is about twice as long and the right side. Around 5/8" to 3/4" long. Raffan at a demo told me that would be good.

[Paul Heely]

If you go to the CSUSA website and look under turning tools, you will find a closeup of what the grind on the Raffan end grain gouge looks like.

Paul

[Don Stephan]

Thanks for the lead, I'm pretty stupid not to look for a signature version. Since I need a half inch detail gouge I'll just buy that one and try to describe/draw the grind before I have to touch up.