End Grain Hollowing problems

Re: End Grain Hollowing problems

TDaniel

>I have made a few goblets recently but am no expert on them. I mount the blank as you do, then drill the inside with a large Forster bit to within 1/4" of the final depth. Then I hollow the remainder with a 1/2" sorby gouge (actually 5/8"), and make a final pass with a very heavy scraper. Then I turn the outside of the bowl and work my way back to the chuck, sanding as I go. I do not use a tailstock except for the drilling with the Forster bit. When all is done I part off with a thin parting tool at an angle so the bottom is concave.

TD

Re: End Grain Hollowing problems

Keith Tompkins

>HI Bob, Check out Stewart Mortimer's technique....I use something similar. A detail spindle gouge works well for this.

The gouge can actually be used as a drill by forming a divot in the center of the piece, then pushing straight in. Sounds worse than it is. Then, working from the inside out, remove wood with the tool at a 45 degree angle (approx.) with the handle lowered.

You can turn translucent pieces with this method.

Re: My results with hollowing using an end mill.

Al Crandall

>Thursday I had a chance to try hollowing end grain using a 3/8 ball nose end mill for the cutter. It was used in a standard end drilled boring bar and held in place with the usual set screw. Before the test I really didn't think it would cut any better than a scraper with a good burr. After the test I had changed my mind. It could be made to cut very aggressively going across the grain in the bottom, as I had no trouble cutting a swath about as deep as the radius of the cutter. The finish it left was clean with no chatter or tearout. The sides could be wiped clean using the endmill and the transition to the side cut was cleanly cut also. The test piece was green box elder. The shavings tried to stream off the cutter edge like you would expect from a hook or ring tool, but the geometry of the mill at its centerline in the ball area acted like a chip breaker, and the shavings were forced straight back along the centerline of the mill and wound up hitting me in the face. Had the mill been mine in my shop, I would have thinned the steel at the ball area so the shavings could pass over the centerline of the mill and stream out of the work past my right elbow.

A positive to using a two flute ball nose end mill is that when the cutter gets dull, you have another sharp edge waiting to be rotated into place. A second plus is that it effortlessly drills its own hole in the spinning work. A negative is that sharpening a ball nose end mill by hand takes a finesse like sharpening the Ellsworth grind by hand. Its flute is a multi-axis spiral, but it can be done with a little patience. I think I need to drag out some of those old endmills just rusting away in my tool boxes and give them a second lease on life.

Re: End Grain Hollowing problems

Peter Teubel

>Personally, I use a 1/2" spindle gouge with a fingernail grind and the "back hollowing" technique (made famous by Richard Raffan). It is extremely fast and efficient. I then clean up the rough hollowing with a 1/2"-thick radius scraper. No chatter whatsoever with THAT tool.

Its worth the effort to learn and master the back-hollowing technique. I use it for the beginning of ANY endgrain hollowing project.

Re: End Grain Hollowing problems

John Lucas

>Tug

I believe the problem is the length. I just made one that was 11 inches and tried several tools and cutting techniques. All chattered with anything but the lightest cut. This was using a Vicmarc chuck. I built the 3 wheeled steady rest similar to the one Dominic built. It solved the problem.

Try hollowing the inside then form the outside.

John Crissman

>I got better results this way regardless of what tools I used. My pieces are all roughly the same length/diameter. I think this is also what TD recommends.

Good luck,

John