Making clock from Lignam Vitae Crown Green Bowl.

[Dave Huxley]

I have been asked to if I can turn out a hollow for a clock in a crown green bowl which would be presented to a retiring member of my wifes crown green bowling club. I thought I would jam chuck it, but has anyone got other ideas please.
I realise lignum Vitae is one of the hardest woods and would have to be held very firm, any advice would be most appreciated.
If successful I would mount it onto a plinth.
Many thanks Dave

 

[CHJ]

Unless you are experienced in forming Jamb chucks I would suggest a Donut chuck would be more realistic. Certainly a concave receiver to centralise the Bowl on the back plain but the clamping collar of a Donut chuck would hold it in place without the risk of dislodging.

 

[user 5053]

I don't know how much hollowing is needed but I would almost be tempted to carve it out by hand or route it out. A doughnut chuck sounds like a specialist bit of kit and I agree about the cup or jam chuck. It would have to be a very good fit of will come flying out and really only a technique for the experienced.

 

[Doug B]

Dave.

Just a thought, but on the clock i made recently, i drilled out the hole for the clock with a forstner bit in a pillar drill.

 

[big soft moose]

I don't know how much hollowing is needed but I would almost be tempted to carve it out by hand or route it out. A doughnut chuck sounds like a specialist bit of kit and I agree about the cup or jam chuck. It would have to be a very good fit of will come flying out and really only a technique for the experienced.

hardly, any competent woodworker caould make one in about 30 minuites, all it is is a disc / or ring of wood mounted on a face plate (sometimes covered with router matting to increase grip) with four bolts run through it to a second ring - aka the donut , you put the work piece on the disc put the donut over it and do the nuts up - simples

in this case the back plate would have a concave turned in it to accomodathe back of the ball.

if you are worried about the donut marking the wood you can line with foam rubber

cup or jam chuck - the intelligent thing to do would be to bring up the tailstock to stop it coming out. then turn the recess leaving a thing core where the tail centre is - before finally coning it down and snapping it off with the lathe stationary

the trouble with using a router or a pillar drill will be the difficulty in claping a sphere so that it doesnt spin when the cutter bit engages with the wood.

 

[jpt]

I did something similar with an old wooden skittles ball using a glue chuck.

Put a scrap piece of wood on a screw chuck, round it off and then create a concave on the face which is a good fit to the ball.

Put the ball in place and bring the tail stock up to clamp it in place then apply a thick bead of hot glue around the ball and leave for at least 15min.

It should now be held very sceurelly and you can cut the hollow for the clock.

To remove from the glue chuck use a hot air gun or hair drier to heat the glue enough to pull it off.

Then using the hole for the clock you can chuck it to further cleanup and polish the back.

I then use a belt and disc sander to create a flat on the bottom for it to stand on, or you could create a simple stand for it.

john

 

[Tony Spear]

I don't know how much hollowing is needed but I would almost be tempted to carve it out by hand or route it out. A doughnut chuck sounds like a specialist bit of kit and I agree about the cup or jam chuck. It would have to be a very good fit of will come flying out and really only a technique for the experienced.

:roll: :roll:

hardly, any competent woodworker caould make one in about 30 minuites, all it is is a disc / or ring of wood mounted on a face plate (sometimes covered with router matting to increase grip) with four bolts run through it to a second ring - aka the donut , you put the work piece on the disc put the donut over it and do the nuts up - simples

in this case the back plate would have a concave turned in it to accomodathe back of the ball.

if you are worried about the donut marking the wood you can line with foam rubber

Exactly!

Take a look at "A Guide to Work-Holding on the Lathe" by Fred Holder (GMC Publications 2004) and all will become clear! :wink:

 

[Dave Huxley]

Many thanks to everyone for their help and suggetions, I will show my ignorance by saying I have not heard of a Donut chuck, I will certainly have a go at making and using one, not just for this project as I can now see lots of uses for one.
The hot glue is a good idea also but the promlem is that these woods as they call them are very smooth and highly polished and quite heavy, I have never used hot glue so theres something else to have a go at.

I have looked up the book on the internet "A guide to work holding on the lathe" a site called Play.com have them for £11.49 including postage, so I have sent for one.
Thanks again to you all, I have never failed to get help on this Forum and I log on most days and have learnt no end and relly enjoy all your comments, and looking at your work.
Dave

 

[loz]

Dave,

have a look at this - I think a simple cupped jam and masking tape chuck would do the job.

Loz

http://www.cumberlandwoodturners.com/tips/Methods and Jigs for Reverse Turning Bowls.pdf

 

[Tony Spear]

Dave,

have a look at this - I think a simple cupped jam and masking tape chuck would do the job.

Loz

Loz

Were it a bowl we're talking about I'd tend to agree with you. But, we're talking about several pounds weight of LV. here and I'd be very reluctant to trust that to cup chucks, tape or even glue. In this situation, I for one would want a decidedly positive mechanical fixing of some sort before even considering switching on the lathe! :shock: :shock:

 

[loz]

Ah - Thanks Tony,

Only every seeing a "Bowls" ball on TV i had no idea they were very heavy.

Loz

 

[Bodrighy]

They also are weighted somewhere along the line so that they have a bias to one side when rolled to allow them to be bowled around other peoples balls. There have been a few for sale down here for a tenner each but I didn't bother for the reasons being given. I'd be inclined however to go for a glue chuck with the tail up until the last minute or, if it was for a clock drill it out with a Forstner bit on a press. I presume you want the bowl left as intact as possible because of it's purpose so screwchucks etc are out. Isn't there a flat bit on it that may be useful if hot glued onto a faceplate with wedges around it? I've seen a 4' off centre Aussie burr turned that way on a VB so it certainly should hold. Just stand to one side when starting and make sure the lathe is on it's slowest speed at first.

Pete

 

[Paul.J]

Could you not use a router and a jig with the ball held in place on the lathe,if your lathe is suitable of course :?:
Something like what old Norm Abram done when cutting some mortises for a table he once made.
I think this way would be a lot safer than trying to hold it with a doughnut or jam/glue:?

 

[Dave Huxley]

Thanks again for more ideas and suggestions I am really very grateful to you all, as soon as I can get reasonably priced wood (bowl) I will have a go, and will let you know how I get on, my routing skills are barely existent so I think I will go for the donut clamping and might do belt and braces with the hot glue.
Thanks Loz for the web site Cumberland Turners, really imformative and simple to understand the various ways of holding,I have printed it off so it will get well used.
Cheers every one.
Dave

 

[Chrisp]

Dave, ask at a local bowls club as they may have some old ones that they don't use, I've bought some from antique shops for £5-£8 each and there are some on Ebay every now and again.
Regards Chris.