1. ## Turner's cube. Depth of cirlcle please

Having seen other posts about making a Turner's Cube on here, I've got a few spare days and am gonna make one from acrylic (should be nice n polished, I'm diamond machining it).

My question is: which depth should the first circle be please. eg: if the cube is 50mm on each side, is there a formula to tell me what depth I should cut the first circle at? I reckon it would be a function/ fraction of the overall width of the starting cube, say about 75%????. I want to cut each of the faces' circles (picture a dice numbered face 1-6) at the same depth so that it's automated.

2. Don't be a lazy git. (I hope being British in origin I can be nasty to a fellow ex-countryman )

Make cross-sectional sketch and figure it out yourself.

3. Originally Posted by Geof
Don't be a lazy git. (I hope being British in origin I can be nasty to a fellow ex-countryman )

Make cross-sectional sketch and figure it out yourself.

4. I just went back and reread the title. No I cannot help with a cirlcle

But I have to be nice and say I will be interested in seeing how it looks if it is turned optically smooth on all surfaces. It should look fantastic suspended in a window with the sun shining through.

5. Originally Posted by ImanCarrot
My question is: which depth should the first circle be please. eg: if the cube is 50mm on each side, is there a formula to tell me what depth I should cut the first circle at?

I have a crude Excel spread sheet that will size the circle and depth up to 10 steps.

for a 50mm cube it would look like this...

 Cube Size Bore Size Bore Depth Edge Thickness 50.0000 42.5000 7.5000 3.7500 35.0000 29.7500 5.2500 2.6250 24.5000 20.8250 3.6750 1.8375 17.1500 14.5775 2.5725 1.2863 12.0050 10.2043 1.8008 0.9004 8.4035 7.1430 1.2605 0.6303 5.8825 5.0001 0.8824 0.4412 4.1177 3.5001 0.6177 0.3088 2.8824 2.4500 0.4324 0.2162 2.0177 1.7150 0.3027 0.1513

Looks like you could go 5 steps depending on the size of your tooling.

6. Aha! many thanks all, I got the tooling made and have cut out the acrylic blank then, just when I was figuring out how to hold the bugger we got a rush job for some other components that we make (100K's worth) so it'll have to go on the back burner for now. *sigh* I'm deterined to make it though! it should as Geof says, look well nice when done

7. Originally Posted by ImanCarrot
look well nice when done
Look forward to it

John

8. This any help

9. Thanks, all is a bit clearer now- the depth of the circle in jw's seems to be a factor of 6.3 to 6.7 of the circle diameter, whilst steve's is exactly a factor of 5.667 that of the diameter.

I've looked into it and the diameter of the circle seems to about 75% (as i thought) of the long axis of the cube machined (across the diagonals) since the diagonals are governed by the size of the internal cube and this will be exactly the size of the previous larger cube minus this value divided by two all seems pretty straight forward.

Now... will my vacuum chuck hold it and how to centre it hehe. I'll get there!

Iain

10. ## Fals apart at?

If it was 70.7106781 per cent I think it would fall apart?
Does that number look familiar, or was it 85% which is close too 0.866.
One or the other (LOL) you figure it!

11. Originally Posted by neilw20
If it was 70.7106781 per cent I think it would fall apart?
Does that number look familiar, or was it 85% which is close too 0.866.
One or the other (LOL) you figure it!

Neil is exactly correct. The numbers in Excel were that the bore was 85% of the cube and the depth was 15% if the cubes size. The next cube would be the size of the cube minus ( bore depth times two). And then it all starts over again. I played around with the percentages and this is what i found would look good to me and give as many steps as possible. I thought i might try going 7 steps on a 3 inch cube.

I think i might try this one someday. This is more of a millers cube. And i might try making a hybrid cube with circles and squares. It's different than anything i have seen before.

Is it healthy to put this much thought into a 3 inch cube of aluminum?

Steve

12. On a CNC mill you could try packing alternating cubes and octahedrons - which can be caged inside each other rather than being connected by webbing, although you'd probably end up needing to use some very small tools.

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