Sphere cutting jig for wood lathe

Hi @turners

Does anyone know about a good quality sphere jig? I’d love to make a sphere on our wood lathe over the Christmas, wondering if we could get one for the space?

Best,

Petra

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Hi Petra,

Greg Moreton, a renowned professional wood turner, demonstrated his method of making a sphere at a recent meeting of my club. The only “jig” he used was a pair of cups holding the workpiece between centres. Another club summarised the method as:

" This was Greg’s method of turning a sphere . Starting with a square section blank Greg turned a cylinder between centres. Marking the length equal to the diameter, the ends were rounded over. It was then parted off and re-mounted at about 45o between cups on the drive and tail centres. The shadow outline indicating where it wasn’t round was turned away. This was repeated with the sphere at different angles until an acceptable sphere was obtained, finishing by sanding. This is one of the few occasions when sanding is used for shaping."

Greg made this look WAY easier than I’m sure it is. I don’t know if these cups are available commercially, but will find out. I think he had made his. His website is at: http://www.moreton.co.uk/

MJF

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Thanks, Martin!

Do you think we can get something like this next week/before Christmas? I’d really love to enjoy some holiday turning.
I was thinking this https://www.carterproducts.com/media/catalog/category/Perfect_Sphere_on_gradient_backdrop_with_samples_2.jpg

This looks like more affordable option.

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I did not find any products on his website, any luck on your side, @fincheee ?

My club is having a zoom meeting tonight, I will ask if anyone remembers what he said about the cup jigs. I think he made them himself, he makes a lot of his own jigs.

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Hi @fincheee,

Any luck?

I have looked into sphere turning before and I think he could mean this.

You use a light source to throw a shadow on a cardboard circle and then turn your stock to that shape.
The 2 cups are 2 cylindrical pieces of wood with a concave top which hold the sphere once you take it of the stock you have clamped in the vice. That lets you turn the piece in any way and you can finish it to a perfect round and smooth sphere.

I figured…
…is there anyone interested in the jig I proposed?

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Good find @Julia! Yes, the jig I saw demonstrated was self-built by Greg Moreton. The cups he used were similar to Figure 20 onwards in the article you cited above. He did not use any shadow jig, I’m not sure how he did it.

We discussed this at some length in my wood turning club zoom meeting last night. Some members had tried the “shadow” method, and one wrote an article in a newsletter about it several years ago. The overall sentiment was that yes, a sphere can be turned using this method, but it requires considerable turning skill. Instead, at least one member tried a few times then bought the jig sold by Paul Howard (see https://www.paulhowardwoodturner.co.uk/shop/) which seems to be the most popular jig for spheres but pricey at 155 - 165 GBP + shipping. And I’m not sure he makes a version compatible with our lathe, which has different bars to those illustrated.

I may try to make the cup jig at some point, but have no immediate use for it, and it won’t be before Xmas.

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That’s fine, I’ll just practice!

I’m not allowed to use the wood lathe yet but I’m interested in the 69 quid jig. The more expensive one had me thinking about making it!

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Here are instructions, from an old East Surrey Woodturners newsletter.

Sphere turning.pdf (269.4 KB)

Lasercutting a piece of ply with the exact curve and sticking sandpaper in it and shaping the roughly turned close-enough-sphere should work, wondering how make the cup. Maybe the same way somehow!

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Don’t know if you found one but when I made wooden balls I turned them first then I made a sanding jig that held the close to sphere shape between two holes in wooden planks. The planks were held together with thumb screws on long bolts. The balls could turn so I was able to sand perfect spheres against a sanding disc.

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