Sharpening Hollowing Scrapers

[Edward Weingarden]

What's the best/easiest way to sharpen the 3/16" square hollowing scraper used in the captive or articulating arm hollowing tools? Thanks.

[Steve Schlumpf]

Ed - I use the flat platform jig on my grinder and just touch the HSS bit to the CBN grinding wheel. Works slick and I have the jig set the same for all the cutters.

[Edward Weingarden]

Steve - can you describe your jig...size, shape, etc. Thanks.

[Thom Sturgill]

I use the edge of the platform to support and a radiused CBN wheel. Angle the cutter with the top angled slightly away from the wheel and start at the back and draw it to the tip around the radius. Repeat on the other side of the wheel for the other edge. Done! I usually do not remove them from the bar.

[Faust M. Ruggiero]

Edward, There are a number of commercial jigs available ranging from an 2 piece flat aluminum clamp with grooves to hold the cutter to the one John Jordan sells for 25 bucks. His jig consists of a hollowed bar with a thumb screw and a thinner rod set at a 90 degree angle. Tuck the leg into the Oneway sliding jig you probably already own and rotate the cutting edge of your bit against the grining wheel. The method Thom describes is taught by the famous David Ellsworth who inspired the radius CBN wheel design. David glues his cutter into the shaft of his hollowing tools. His method works well especially if you are holding a long tool while sharpening a tiny tip. You grind the left side of the cutter on the right side radius and the right side on the left radius. Before CBN wheels became popular, that method was accomplished by merely shaping a radius on a soft grinding wheel. All methods work as long as you get an even grind with the right bevel for your task. Pick one and get good with it.
faust

[Tim Rinehart]

The other threads have well described the technique using either the platform, or a jig to hold the cutter. My one caution, from experience, is to make sure if using the platform that it is close to the wheel and well secured. If you have a very large gap (over 1/16 - 1/8"), the tool can get picked up and shoved between the wheel and the toolrest, creating a very dangerous situation that can result in wheel damage, cracking, or creation of a projectile. Be sure you are wearing ample face and body protection. This is how I sharpen my HSS tools, but I've considered the jig which would remove some of the element of danger.

[Reed Gray]

Edward, check out this video at about 2:30. I do like John's approach to things, and this was before he had a CBN wheel, or even before the radius edged wheels were being made.

https://www.youtube.com/watch?v=M9G16ylEZHQ

robo hippy

[Steve Schlumpf]

Ed, I should have clarified that I use the flat platform that came with my Wolverine sharpening system. Most grinders have a flat rest that comes with the tool when you buy it. That's all you need but like Tim already stated - make sure that the rest is very close to the grinding wheel and that you have a secure hold on the bit you are sharpening.

[Edward Weingarden]

Steve - thanks for the clarification.

Reed - thanks for the link.