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TTIT
11th June 2008, 11:52 PM
A bloke showed me how to make one of these thingy's on the weekend and I copied down his formula for calculating the radius and depth of the cuts but it doesn't work out :C:~:no:. He only used 3 sizes of blocks and has the dimensions set in concrete for them so I doubt the formula as he copied it originally was ever used. Tried googling but I don't know what to call the damned thing?!?!? Anyone got a copy of the formula ??????

Manuka Jock
12th June 2008, 12:14 AM
Is that the wigwam for a goose's bridle that my dad was always making when I was a wee kid ? :?

RayG
12th June 2008, 01:59 AM
Is this the same construction technique?

http://www.americanwoodworker.com/aspx/contentdetail.aspx?ContentId=1248&PageNo=1


He doesn't give any formula's, but what was it you were trying to work out?

OGYT
12th June 2008, 06:13 AM
Ern and Ray, thanks for posting this. It's a neat little thingamajig...er.. a.. wigwam for a goose's bridle.
And thanks to Manuka Jock for the name... :D

wheelinround
12th June 2008, 08:27 AM
Vern according to David Springett's book Woodturning Wizardry its a Spiked Star in a Cube

LOML picked it up yesterday for me the book that is :D

the book is available at

Amazon.co.uk: Woodturning Wizardry: David Springett: Books

TTIT
12th June 2008, 09:09 AM
Vern according to David Springett's book Woodturning Wizardry its a Spiked Star in a Cube

LOML picked it up yesterday for me the book that is :D

the book is available at

Amazon.co.uk: Woodturning Wizardry: David Springett: Books (http://www.amazon.co.uk/Woodturning-Wizardry-David-Springett/dp/1861084226)Good that we've now got a name for it :U - Does it have the formula for calculating the depth and radius of the cuts for a given sized cube?????

wheelinround
12th June 2008, 09:15 AM
Yes just finished breakfast so heading into it now Vern post it shortly

mean time a google search will bring you plenty on it

Cliff Rogers
12th June 2008, 09:23 AM
I have that book too but it is in a carton stored at work I think 'cos it is not on the bookshelf here at home. :?

ticklingmedusa
12th June 2008, 09:25 AM
Fred Holder calls a sphere inside a cube a Chinese Ball

wheelinround
12th June 2008, 09:32 AM
send me a PM Vern with your e-mail address I'll scan it and send you the PDF.

Ray

artme
12th June 2008, 09:58 AM
Got a bloke in our club who turns those as demos at T&www Show, and our exhibits at Mt. Coot-tha. He's a bloody masochist becuase he doe other things of that ilk that require a hell of a lot of fiddly set up work and hand finishing.

wheelinround
12th June 2008, 10:16 AM
This is why they are called Orna_Mental Turners artme

wheelinround
12th June 2008, 10:42 AM
Good that we've now got a name for it :U - Does it have the formula for calculating the depth and radius of the cuts for a given sized cube?????

Its sort of a formula Vern but who needs a formular

you have square cube you need 2nd square cube and 4 pointed star with taper to middle square you need to cut away as much to make the star points as needed
then cut away enough to make the square block and seperate it:2tsup:

PDF sent to your web site e-mail addy
Vern
let me know if you get it

joe greiner
12th June 2008, 10:44 PM
It might also be shown in "Wonders in Wood." I don't remember the author, and mine is in a box too, Cliff. It might be easier to buy another copy than try to find it.

The Chinese Ball is a ball within a ball, not in a cube; and maybe another ball inside.

Joe

robyn2839
12th June 2008, 11:19 PM
thats going to be the first thing i make when i finish my turning room ,looks like a great project......bob

TTIT
12th June 2008, 11:23 PM
Sounds like there's dozens of variations on the same theme. Thanks for the help guy's. Gonna play around with the dimensions I've got and see what eventuates (had to avoid the "see how it turns out" pun there!! - might have put the mockas on the project:o)

Cliff Rogers
13th June 2008, 12:05 AM
..and mine is in a box too, Cliff. It might be easier to buy another copy than try to find it.....
:D

lubbing5cherubs
13th June 2008, 04:53 PM
This is why they are called Orna_Mental Turners artme

Ray... Speak for yourself :o:D:D

Gil Jones
17th June 2008, 06:03 AM
Vern,
I just had to try it out. Thanks for the idea.
How did you cut the cones on the faces of the inner cube?
Mine is pine (as from a construction wood 2x4). It is 1.5" x 1.5" x 1.5". The holes are 7/8" dia, and the captive cube is 21/32" square.
It is simple to make, and should keep the Grandkiddies busy for a while.:D

TTIT
17th June 2008, 08:51 AM
Vern,
I just had to try it out. Thanks for the idea.
How did you cut the cones on the faces of the inner cube?
Mine is pine (as from a construction wood 2x4). It is 1.5" x 1.5" x 1.5". The holes are 7/8" dia, and the captive cube is 21/32" square.
It is simple to make, and should keep the Grandkiddies busy for a while.:DTop shot Gil :2tsup: Looks like you've used a forstner bit to drill the holes - yet another variation of the cat skinning technique. To make one with the cones, the bloke that showed me used a 6mm parting toll to cut a groove of the exact diameter and depth for the size of the block. This then left a 'tenon' which was tapered off with a spindle gouge to create the cones. If you get all the dimensions right, you don't cut the full depth on the last groove, pulling up about 1mm short so there's something left to hold the cube in place while you cut to full depth on the inside of the groove against the cone with another tool. The remaining 4 corners are then cut away by hand and any dags cleaned up with a small knife.
Will do a WIP when I get time to tackle one myself.

wheelinround
17th June 2008, 11:35 AM
Ray... Speak for yourself :o:D:D

Nope after seeing Col this weekend at SWWS handed a tom-e-hawke by Stan from Mullumbimby Timbers and use it in his mini lathe sorry micro lathe an old model engineers lathe as a skew even he said got to be a little mental to have a go, then some smart A walked up while he was doing it and said here handing him a penknife and said try this Coll took it said its blunt so I'll use mine and did.

no photos just video of it :2tsup:

Gil Jones
17th June 2008, 12:25 PM
Thanks Vern. Yup, I used a Forstner bit, never got close to the lathe.