Hollowing tool cutter grind

[Jim Slovik]

I made a hollowing tool that looks similar to the Ellsworth style with a 3/16" HSS cutter. My question is about the grind I should use. What I did so far was I rounded the tip to the same angle as my scrapers (not sure of exact angle) and also took the grind slightly to the left side. This seems to work pretty well but I didn't know if there was a better way to do it. Before I made this I had never used a hollowing tool before therefore, I have nothing to compare it to. Any input would be appreciated.

[Jeff Nicol]

Jim, When you are hollowing the tool is mostly just scraping. I have tried lots of different grinds and sizes of cutters and have gotten what works for me. I make them out of circle saw blades and tool steel also. THe smaller the cutter the easier it is to control and some cut better being pulled out from the bottom to the opening. It is just a practice thing that you will find the best for you. You can see in most of the catalogs what the commercial cutters look like so that is a good place to start.

Hope this helps a little,

Jeff

[Bernie Weishapl]

I sharpen mine to the same angle as my scrapers. They work rather well.

[Jim Slovik]

Thanks for the replies. It sounds like I'm on the right track.

[Steve Schlumpf]

Jim - sorry I am so late to the party! I use a lot of different grinds on my hollowing bits because I use them for different cuts. The square cutters are for hogging out wood and as such I have a very sharp angle on them so they will be very aggressive when cutting. I use disk cutters for smoothing the inside of the hollow forms and use a fairly blunt nose on them so they are less likely to dig in.

It is experimentation on your part in figuring out what works best for you. My tools are have fairly radical edges but work perfectly for me. Remember that it's just metal - grind it a little and see if it works better or worse. Lots of variables when dealing with grinds! Good luck with it!