Mounting question

[Allen Howell]

I have a piece of Cuban Mahagony that someone wants a fruit bowl turned from. I have roughed the outside and now need to mount it for the inside work. I have a Delta 46-455, 3/4 hp, 12 1/2" capacity (I know, I shoulda gotten the 46-460 variable speed) and the last vessle I tried (8" dia x 10" long urn), it kept dismounting from the Baracuda chuck. I don't want this to happen to this bowl, so I need some advice about how to mount this one (see photo for dimensions). I have a 3" faceplate that I was considering using, 'though I have not done much with faceplates. Questions:
(1) Is the 3" large enough for the bowl? (2) What size screws should I use? (I know that some of you recommend sheet metal screws and intend on using them) (3) Is there another mounting method I should consider?

All help is greatly appreciated.

Allen

[Marty Eargle]

Something that size should be fine in your chuck. You just have to make sure you follow the manufactors instructions (ie: tenon size, square vs dovetail) and make sure the lip above the tenon meets flush with the jaws of the chuck. I only have an Apprentice chuck from PSI and turn bowls around or larger than what you're showing.

But, the biggest rule I think in turning...if you don't feel comfortable doing it...don't.

[Josh Bowman]

Allen the chuck may be a little small. You might try using a steady rest, I know it helped me on an oak hollow form that didn't want to stay mounted. Here's a SMC link to one John Beaver made:
http://www.sawmillcreek.org/showthread.php?157912-Home-Made-Steady-Rest

[Michael Mills]

First, this is jmho…
I do not know the type jaws on your chuck as I have a Nova.
On mine I can get 100mm or 100mm powergrips. They are both rated for about the same diameter. However, the standard 100mm is not made for long (as in your 10” long urn). The powergrips are needed when the item gets extended due to the leverage it creates.
I suspect that is why your urn kept coming dismounted, if your jaws were only ½” or less deep.

As to your current project your 3” faceplate should be sufficient. The screw length would depend somewhat on how much waste you will have at the bottom. I would try to have an inch into the wood, I use #12.

You may also be able to use your chuck; maybe you can find some specifications on suggested max length of the work piece. I would think 6" may be a maximum but I don't have that chuck.

That said, is the wood green? Will you dry it prior to finish turning? The base may take a long time to dry as thick as it is.

[Lloyd Butler]

Allen,

The chuck should work fine. Make sure that you do not make the tenon so long that it touches the bottom of the jaws and the sides fit the profile of your jaws. Make the shoulder at the base of the tenon that you will grip a nice 90 degree's so that the chuck jaws can sit snugly up again it. Then put the piece in the chuck and pull up the tail stock for extra support while you start turning.

Start hollowing, but leave a center shaft from the tail stock into the bottom of the bowl as long as you can. Then nibble away at the base of the shaft to reduce it's size and then remove the tail stock and separate the support shaft. Not the bowl should be light enough that you can finish off the inside.

You should also check the chuck for tightness as you are working along just so that it does not surprize you at the worst time.

Lloyd

[Faust M. Ruggiero]

Allen,
Since you are asking this question, I assume you may not have done much deep hollowing. I expect you may have a couple catches as you hollow this project. I think you should opt for the most secure mounting method available. I would be using a 6" face plate with 8 or 10 short screws. I would plan the bottom of the vessel to finish inside the circumference of the screw holes so no wood is wasted. Even a minor catch will shake the vessel askew and take your piece out of round further destabilizing in the event of a catch. Turn it around and flatten the bottom between centers, remove the nub by hand and mount the face plate.
faust

[Michelle Rich]

I would get a tenon turned & use my 4 jaw chuck, but I would keep my tailstock up until the last minute..by then the bowl will be light enough to turn without it.

[Allen Howell]

Thanks, all for your suggestions. It always amazes me how many different ways there are to do the same thing. I am generally more comfortable using my chuck, so I think I will use it and keep the tailstock in place until the end.

The wood is green and I will turn it at the 1:10 ratio, seal end grain and wait.....as long as I can.

Thanks everyone!

Allen

[James Combs]

Allen the chuck may be a little small. You might try using a steady rest, I know it helped me on an oak hollow form that didn't want to stay mounted. Here's a SMC link to one John Beaver made:
http://www.sawmillcreek.org/showthread.php?157912-Home-Made-Steady-Rest

Josh +1 for use of a steady rest. If you think you would prefer a metal one check out this fabrication tutorial (http://www.sawmillcreek.org/showthread.php?151550-Steady-Rest-Fabrication/page2). Go to page 2, post #21.

[Michelle Rich]

Allen: I forgot yesterday to pass on this old wisdom of using a chuck. Your tenon should be 40% (at minimum) of your bowl diameter. This gives it good purchase & enough that the tenon doesn't break off if you get a catch.

[charlie knighton]

Allen, there has been many good suggestions, i will only add one


it kept dismounting from the Baracuda chuck

that is a sign that your chuck needs oiling, just some 3 in 1 oil in the gears, works wonders

[robert baccus]

Please don't waste good cuban mahogany with screws or tenons. use a 3" glue block mounted on a small faceplate. cut the block true on the lathe--use thick CA glue and bring the tailstock up for pressure and centering. usually a small glueblock can be knocked off with a heavy putty knife and mallet. if it does not cooperate cut it 2/3 through with a parting tool and saw the rest. piece of cake. i do 20-30 of these a year up to 100# wet vase blanks. good luck-------------------old forester