Getting the rough out

[Lawrence Tarnoff]

I'm working on a maple bowl, about 15x6. I did my rough turning to about 1 inch thickness several months ago using a large recess to chuck it. I now have rechucked it in that recess and discovered some modest warping. Using my bowl gouge, I've pretty much restored the roundness to the exterior, but am unable to get it uniformly smooth. The end grain portions are really rough ... and the same goes for the interior. I've tried the lightest of cuts, to no avail. Before I get out my 60 grit sandpaper, any suggestions?

Larry

[robert baccus]

Could your grip on the chuck be comprised by the warping. I always use a glueblock to eliminate this problem and wood loss.

[Lee Watermann]

Did you true up the recess before you used it?

[Lawrence Tarnoff]

Did you true up the recess before you used it?


The chuck seated firmly in the recess, so I did not attempt to true the recess.

[Faust M. Ruggiero]

Lawrence,
I would have turned a 16" bowl to 1 1/2" thickness. I would have dried for two years because it is humid in the summer here in PA, much like I suspect it is in WI. Your 16" bowl may still be somewhat green, especially if you experienced little enough warping that you can still firmly chuck in the recess without truing it. If possible, I would still do that. Because your bowl shrunk across the grain and not in the length of the grain, when you expand your chuck you are creating pressure that is trying to "split" your bowl through the the long grain. Though I rarely use a recess, the idea is to create equal contact for the jaws all around the circumference of the recess.
Next, let's address the "rough" areas. They are most likely at opposing areas on the sides of the bowl where the straight grain first spins down into the cutting edge. A tool that is not sharp enough, or presented to the wood at too aggressive an angle will lift that grain causing tear out or "bruising". The disturbed grain will feel rough and may not be able to be removed easily with shear scraping nor sanding. The cut in those areas requires a really sharp tool, a light touch and a steep angle of the tool. Drop the handle way down, lay the tool on the bevel and roll it slightly until it just begins to cut with a slicing type cut. The cutting edge will be 45 degrees or so to the direction of rotation. Keep the bevel in contact and move slowly from the smallest diameter toward the rim. If that cut seems frightening to you then turn the tool over till the flute is facing the bowl and shear scrape.
Give it a try. It's only wood. By the way, don't be surprised if you go back to the bowl tomorrow and find your bowl is out of round again.
faust