How do I know if it's sharp enough?

[Frederick Skelly]

Good evening folks,
I don't know how to tell if my lathe tools are sharp enough. With a plane iron or a chisel, I'm polishing to 6000 grit and then stropping. My test is splitting a piece of paper.

With my lathe tools, they go on the grinder at 120 grit and go straight to work. The tool seems to be cutting well. But what if I'm just too new at this to know any better.

How do I know I'm at least doing ok?

Thanks for teaching me!
Fred

[Roger Chandler]

If the tools are cutting well, they are sharp enough. The biggest mistake for newbies is not sharpening often enough. Many because they fear grinding the tools away, but when the cut is not producing a good surface, or becomes laborious, then a trip back to the grinder is in order.

[Frederick Skelly]

Ok. That makes sense. Thank you Roger!

[Brian Kent]

There is a big difference between the sharpness needed for using a slow hand plane or tapping a chisel, and what it takes to slice wood off an object spinning at 50 to 3000 rpm. So 120 grit works. But it is also wearing down the tool quickly so it needs a whole lot of quick passes.

[Reed Gray]

Some times for finish cuts on softer woods, or on some woods that just don't cut clean no matter what you do, a finer edge and a high shear or skewed cutting angle will help. I don't think there are many who hone past about 1000 grit.

robo hippy

[Frederick Skelly]

Thanks guys. I just didn't know, especially since it does seem to cut just fine.
I made a Wolverine jig knockoff last night and plan to make Cap'n Eddie's Ellsworth jig today. Neither one is as good as what Oneway makes, but they"'re good enough to start with. Better than last weekend's experiment in free-handing. Still gotta heat treat that HF sindle gouge, too.....

I'm learning...

[Lloyd Butler]

Frederick,
when sharping on a regular grinder, you will know your tools are as sharp as they can get off the grinder when you see fine sparks tripping over the leading edge and down the flute. The outside edge is then meeting the inside edge. With the jig, it should not take more than a few seconds to get back to this point when sharpening as your are really not wearing the cutting edge back too much.
As mentioned, turning does not need as sharp as hand planes since the lathe is pushing the wood at you rather than you pushing the tool at the wood like a hand plane.
Depending on the grinding angle you use, you may end up with a fine burr at the leading edge of your tool. Some people will hone this off from the flute side for a final cut so that it does not impede the tool getting into the wood. For roughing cuts, it is not a very tough burr, and brakes off quickly with the wood clunking on the cutting edge.

[Frederick Skelly]

Thank you Lloyd. I was seeing the sparks you mentioned. So it looks like I'm getting there!
Fred

[Bob Bergstrom]

A tool is dull when you feel you have to push the handle to keep the cut. Also if the the gouge doesn't start to cut easily and keeps skipping out out of the cut. This happens quite often on push cuts on the exterior of a bowl. On the interior of a bowl, one should be able to take very light cuts for a consistent length without skipping or excessive pressure. If proper presentation is given, you should be able to keep cutting with even taking away the hand on the tool's flute and controlling the cut with the hand on the handle only.