# cube inside a cube



## mattty (May 12, 2015)

[ame]https://www.youtube.com/watch?v=AuS6HDHc7XE[/ame]

Has anyone here made this before? if so where would i find the meaurements.

Very good video, he makes it look very easy.


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## Swifty (May 12, 2015)

Very neat, I can see a flurry of cubes being made. Wood turners also have a version of this type of thing.

Paul.


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## Jyman (May 12, 2015)

There are called a "turner's cube", and I don't have any measurements but if you google "turner's cube" I'm sure some close to the top will have some measurements 


Sent from my iPhone using Model Engines


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## Tin Falcon (May 12, 2015)

Also an interesting CAD project. 
there is a FreeCAD tutorial on drawing one ans yes give dimensions. 
the more important thing is proportions and ratios.  How long is a piece of string ? 
This is an artistic piece so overall size will depend on taste and available material.
Tin


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## xpylonracer (May 12, 2015)

Article for cubes was in 'Digital Machinist' some years ago, I made the cube at that time but never completed the final cut that would separate the rings, picture attached.
Emgee


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## velocette (May 12, 2015)

Hi 
A copy of an xls file for calculations of a "Turners Cube"
Stored but not tested

Eric 

View attachment TurnersCubes.xls


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## Cogsy (May 13, 2015)

Great - I showed the video to my wife and kids and now I have orders for birthday presents . I hope they're as easy to make as he makes it seem...

P.S. In the comments for this video on Youtube there is a link to the dimensions he used HERE


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## Davewild (May 13, 2015)

mattty said:


> https://www.youtube.com/watch?v=AuS6HDHc7XE
> 
> Has anyone here made this before? if so where would i find the meaurements.
> 
> Very good video, he makes it look very easy.



Sherline do a kit for this, i cant remember but i think it just a brass cube and the cutter.


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## RonGinger (May 13, 2015)

I think the interesting idea in this video is using hot melt glue to hold it together for the final cuts. In the plans Ive seen in the past you had to make turned plugs to fit into each side. The hot melt would be much simpler to do, if it holds well enough. One of the low temp metals would also work well. 

The ring as a collet is also a nice idea- it makes resetting the block for each face simpler- doing that job in a 4 jaw would be nasty.

It is an exercise in accuracy- slight errors will show up in the end.


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## abernat (May 13, 2015)

One of Guy Lautard's Bedside Readers discusses Turner's Cubes in detail including how to calculate the various undercuts, how to build a fixture to hold the cubes in a lathe, etc.

I've turned a number based on his suggestions.

The books are great for any number of reasons.


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## Buchanan (May 13, 2015)

They are great fun to make and you can test your skills and the limits of the materials to the limit. I have turned many on  lathe over the years but now make them on a small CNC mill with two cutters and 3 G codes to produce 4 blocks in a 65mm square wood block. It is simple enough to draw out on paper in cross section add take your dimensions off the drawing especially if you draw it 5 or 10 times oversize.


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## AussieJimG (May 14, 2015)

xpylonracer said:


> Article for cubes was in 'Digital Machinist' some years ago, I made the cube at that time but never completed the final cut that would separate the rings, picture attached.
> Emgee



Your cube looks really great - just the thing for a desk toy. I particularly like the spidery form. Do you have the dimensions?

Jim


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## bazmak (May 14, 2015)

Hi Jim i have just ordered some material to make one i alum.
If you google turners cubes there is one good INstructional site
mainly general eng and setup but has basics and sizes.Plan to make a simple 3 cube to start 50mm size for a card keep at poker.Will post when done


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## AussieJimG (May 16, 2015)

Thanks Baz, after a bit of maths and some "adjusting" on Geomagic I have come up with this for a 24mm cube. I have adjusted the holes to suit my milling cutters and will try to make it on the mill. I intend to leave it intact like xpylonracer's example.

It remains to be seen if I have the patience, concentration span and skills to make it.

Jim


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## bazmak (May 17, 2015)

I read this thread with interest,and as Tin Falcon says there will be lots made
I knew of them but nothing about the manufacture so read a good instructional
post on google so decided to make one.Fairly straightforward but the next one 
should be better.Photos tell the story


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## AussieJimG (May 17, 2015)

Well done Baz. And of course you would chamfer the inner cubes just so the rest of us have something to think about.

Jim


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## Herbiev (May 17, 2015)

Looking superb Baz. Thanks for sharing. Now for a sphere within a sphere :hDe:


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## BrianS (May 19, 2015)

Buchanan said:


> They are great fun to make and you can test your skills and the limits of the materials to the limit. I have turned many on  lathe over the years but now make them on a small CNC mill with two cutters and 3 G codes to produce 4 blocks in a 65mm square wood block. It is simple enough to draw out on paper in cross section add take your dimensions off the drawing especially if you draw it 5 or 10 times oversize.



If you don't mind me asking what 2 cutters do you use for this?  Also, how do you do the undercuts?


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## bazmak (May 19, 2015)

I ground a piece of 6mm sq hss as a std tool and used it pointed
towards the head just as a boring bar cuts.Set the carriage lock as a depth 
stop and wound the cross slide towards the operator to dial Quick and easfor allturning.I used a boring bar to cut the ucut to cut the face flush with the back
edge forming a chamfer.I am currently making another slightly different
and thinking of making a dedicated ucut tool. Will post when finished


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## canadianhorsepower (May 19, 2015)

bazmak said:


> ck
> .I am currently making another slightly different
> and thinking of making a dedicated ucut tool. Will post when finished



Nice work Thm:
but would a woodruff key cutter work for the under cut

cheers
Luc


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## barnesrickw (May 19, 2015)

Thanks for the tutorial.  I'm always looking for a project to do in the shop.


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## bazmak (May 19, 2015)

I have made my second cube,40mm x 4.Slightly different method,quicker and easier.Milled ,chamfered and centre drilled.Held in the 4 jaw as previous and 
machined the largest cbore to size on all 6 sides.
Held in a 3 jaw as previous and machined the 2nd cbore to all 6 sides
Finished the smallest cbore with a 12mm milling cutter to all 6 sides
With the carriage stop set for depth and using the dials its quick and easy
Dims are within 2 thou And concentric to about 3 thou.Havent yet separated
A woodruff cutter or int threading tool would do but i will probably grind down
a small boring bar for the inner ones and a slightly larger one for the bigger 
cbores.This one took about 3 hrs.They get easier and like GREMLINS will
keep multiplying.Any thoughts on variations.O for CNC


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## xpylonracer (May 20, 2015)

In the Digital Machinist article the cubes were intended to be cut by a milling machine and the tool recommended for the final parting cut was a 45 degree dovetail cutter. In the lathe the parting cut can be made by a suitably shaped boring tool.
Emgee


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## Buchanan (May 20, 2015)

Brian S 
You asked what cutters I use, A 10mm diameter and 32mm long cutting edge wood router bit and a 21mm diameter 2mm thick woodruf cutter. 

I have attached photos of the cutters and also the tool paths I use. 

  There are three basic operations. 1 The rough bock is held in a vise and the top and halfway down the four sides are machined in one setting with the 10 mm cutter. The block is then flipped and the same operation is repeated. this gives you a totally square block with the first two stepped holes machined. This is done on the end grain faces. The second tool path is used to machine the other four stepped holes on the 4 side faces. Then finally the woodruf cutter is used to cut the under cuts. A vise with an end stop is used and the jaws are the height of the block for support. I forgot to mention that I drill a 10 mm hole through the center of the block from each side after the first operation. Two stepped plugs are needed for the last four cuts to support the 
center blocks especially on the last cut when they are separated. I glue small pads of elastic band onto the plugs to give a little resilience an clamping and the fact that you are clamping on end grain also helps. This is for a 65 mm timber block. I modified the G code until they worked in pine and then made the proper blocks in Brazilian walnut.  You may notice that the under cut tool path is square ,not round, this gives a better look to the inside of each block.
A hard close grain wood is best. the G codes have been fine tuned over about 16 blocks so far so they are reasonably good and the mill used is a small table top Chinese mill so the cuts are conservative. Total machine time is about an hour. If anybody is really interested I would pass on my G code. Just PM me.


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## Buchanan (May 20, 2015)

Here are photos of the second tool path omitted in the last post as well as photos of the plugs and the machine used. The vacuum cleaner sucks the dust through the bottom of the vice.


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## BrianS (May 20, 2015)

Excellent!  I was figuring that you used a cutter like that but I was unsure.  Now, I know... Thanks for the info.


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## Smithy (May 21, 2015)

I have seen one recently completed using stainless steel (304 grade) - looks  neat


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## Cogsy (May 25, 2015)

I had to have a go at least, so I tried the techniques from the video.

First thing, the ring to hold the cube concentric has to be reasonably thick walled. I used a piece of tube/pipe I had that was the right size but it obviously distorted so my initial 3 through holes were off centre. This meant I had to increase the through bore and my inside cube is spider-web thin. Once I realised I just changed to the 4 jaw and it was very quick to set up each side to within a thou. I don't know why I avoid using the 4 jaw when I don't have it mounted, then once I am forced to use it, it generally stays mounted on the lathe for months.

Secondly, I used the hot glue method and it held just fine. Then I submerged the cube in freshly boiled water to soften the glue - big mistake! The glue turned all the way back to molten. I got the majority out but now I have spots of glue all over the place inside the cube. Next time I'll use some of my new moldable thermoplastic that I know will release all in one lump.

So here's the cube, probably as finished as I will bother on this one, but I think I learned enough that the next will be much better. This one is 35mm outside, 22mm middle and 11mm inner.


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## bazmak (May 25, 2015)

They do get better after the first.Try my method of centre drilling all 6 faces in the mill,then push into the 4 jaw and hold central with the tailstock centre,
nip up the jaws.Should be concentric to 3 thou which is good enough
Turn the larger recess to size on all 6 sides.Then you can grip in the 3 jaw
using the oside of the jaws.I made a bull nose centre to fit the tailstock and again cetralised in the chuck.Then machine the rest of the recesses to all 6 side.
I am currently playing about with mine will post when i find something helpfull
I took my 2nd one to poker night,its quite tactile to play with and as a card keep.Didnt bring me any luck but will persever


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## bazmak (May 26, 2015)

Another cube,my last for this thread.2 simple setups using 3 jaw and 4 jaw chucks.Concentric to a couple of thou no dial gauge needed and speedy
This one i wanted as a poker card protector.Found it quite tactile so improved it
Took off the 8 corners so it now stands on edge,on faces and on corner
mill and centre drill.Centralise in 4 jaw and machine large recess,repeat on all 6 sides. I made a simple bull nose centre,the cube is then held in the 3 jaw and centred.Finish machine all other recesses and chamfer etc.Repeat for all 6 sides


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