>Good day all; I am working on my first short, squat hollow form and am still working on removing the inside through the small 1.250" hole at the top. I was lying in bed (where most of my design work is done!!) wondering how I would reverse chuck this to clean up the bottom. I would like to add a small piece of contrasting wood to the top to reduce the hole size, so that means using this hole and a smaller chuck is out of the question.
I do not have a vacuum chuck and was not sure if some type of jam chuck and foam pad would work. The piece should be 5" tall and 4" wide.
I am no expert, infact just started working wit kollow forms. I have found though a jamb chuck using the tail stock to hold the piece works well for me to clean up the bottom.
I am sure, at least hope, some of the experts will step in here with other methods and ideas.
I use two methods. If the neck is fairly tough I take a scrap piece of wood mounted to a faceplate and turn it to fit the neck opening. I make it snug enough to drive the piece. If I'm too concerned about making it this tight then I make it fit without any slop and use blue painters masking tape to "lock" it to the mandrel. Then I put the tailstock in place and turn it with the tailstock there until there is just a little cone left that I can carve off. You may have to adjust the tailcenter to get it centered perfectly before tightening it.
If the bottom is thin I use a cone center without the center pin and just leave a bigger area to carve away.
If the neck is too fragile I make a really long mandrel out of scrap that will fit all the way to the bottom of the vessel. I put 220 grit paper on this and use it to drive the vessel with the tail stock in place.
I had one very small opening vessel that neither of these methods would work so I turned a concave are that would let the shoulders of the vessel sit inside. I turned a small pin in the center to fit my small hole in the vessel and then taped all this together. It took quite a bit more time to do accurately but worked perfectly.
>Try turning a long tapered jam chuck with a spigot on it to grip in the chuck. Something about five inches long and start the diameter at the chuck about 2 1/2 inches and taper to 1/2". this will fit 90% of neck openings.If you need to, you can make a shoulder at any location on the taper. I keep a couple different diameter ones laying around all the time. Real easy to dig em out of the shavings when I need them and alter them to fit.Mark with a pencil the location of #1 jaw on the wood.Always put it in the chuck with that reference mark at #1 and you will only have to true it up slightly for use.
The San Diego Woodturners had a jig made up to hold hollow forms while turning the foot. It was covered on Page 15 of the May 2002 issue of More Woodturning. I purchased one of the jigs and find it works very well. You can't actually purchase them, because they ordered a lot of 50. When those were gone there weren't anymore. You can however make yourself one out of wood that will work quite well. I made one for my sister-in-law out of wood and it worked as good as the one that I purchased.
If you have a high speed internet connection, I'll be happy to e-mail you Page 15 from the May 2002 issue of More Woodturning. You should be able to make one from the description.
>That would be greatly appreciated Fred. Email is wbm golfer@hotmail.com.
Thanks also everyone else. Now I have to see which is best for me as I noticed last night I gave a couple tiny cracks near the top, so I do not think it will be very strong to accept a jamb type chuck.
>If you go to the San Diego Woodturner's home page, and click on the tips section, you will find an article we wrote to explain the use of the jig. Its called the Kirsten Kone (named for Oskar Kirsten - our club member who invented it)
