Making Large "Turner's Cubes" on an Engine Lathe

[widgitmaster]

Well, I got bored doing production in my little shop, so I decided its time for a little fun

For starters, I have acquired two chunks of 303 Stainless! They are 5" dia and 3 1/4" long! So I setup my little horizontal band saw, and cut the bar stock into cubes around 3 1/8 x 3 1/8 x 3 1/8. Then I used my face mill to rough them down to around 3.010" cubed. Lastly, I put new carbide inserts into my face mill, and took one final pass on all six sides leaving a nice smooth, flat, parallel, perpendicular, and square cube! Then I drilled a 1/2" hole to the center o the cubes from all six sides.

Widgit

[widgitmaster]

Now I need to make a fixture plate that mounts on my lathe's spindle, to do that I will use the back plate with D1-4 cam lock studs from my 3-jaw chuck!

I found a nice block of aluminum in my scrap pile, and machined one surface flat and counter-bored it to fit snuggly on the backplate. Then I transferred the three holes from the backplate to the aluminum block, and drilled & tapped them for 1/4-20 UNC around 3/4" deep.

After fastening the block to the faceplate and to the lathe's spindle, I turned the OD and face true. Then I removed the block from the faceplate, and put it in my Mill's vise, I had to remove one of the jaws to get it to fit!

Then with a 1/2" 2-flute end mill, I machined a square pocket in the center of the block around 1/8" deep. In order for the cubes to fit in this nest, I had to go and extra 1/4" past each corner with the end mill.

Now the cubes fit snuggly in the center of the block!

Widgit

[widgitmaster]

Then with a drill chuck, I drilled 4 holes in the block and tapped them for 1/4-20 UNC around 3/4" deep. Now I need to make some custom straps to hold the cube on the corners where it will be strongest as I remove material with the lathe.

The clamps are 1"x1"x3" aluminum, with a .290 dia hole down the center of the long side. Next I milled a step in the end and in the side of each clamp, so it will hook on to the cubes!

Widgit

[widgitmaster]

It's been a good day, I have made the fixture and its clamps, and spent a few hours running the lathe! So far I have finished 3 of 6 sides in one of the cubes!

I can't wait to finish these, as I have always wanted to make one for myself! They look so cool!

Tomorrow I will finish up the lathe work, and spend a day deburring and polishing!

Widgit

[Geof]

FUN????? Your idea of fun is one h*** of a lot of work. But I guess you are correct, it is fun when you don't have to do it and are just doing it for the satisfaction of making something neat.

Some day I plan on making one but I think I will cheat in my lazy old age and program a CNC to do it.

[BobWarfield]

Something strangely hypnotic about those cubes. Even one that's spoiled. I have one I started but spoiled a while back. I should get going on another.

Do you plan on making 2, or is the extra cube for insurance?

They're even fun to draw in a CAD program:



Geof, if you're going to cheat with CNC, you need to make a whole series with different things inside. Perhaps one for each suit of cards or some such:



I've seen some odd things come out of lathes:



Cheers,

BW

[widgitmaster]

The day I can't put in a good day's work, is the day I'll start worrying!

I like to work, and I wanted to show a good solid procedure for holding a delicate stainless part in the lathe! I'm sure there ares dozens of ways to make these including CNC, but I wanted a truly perfect one or two if possible!

Nice cubes Bob! I'll have to experiment with my CAD program to see if I can make some of them!

Widgit

[widgitmaster]

One is finished & deburred!
It was a lot of work, but well worth the effort!

Widgit

[BobWarfield]

That's a beauty!

You've a good eye for proportion on that one.

Widgit, what are your preferences for boring bars? I'm curious about this project, but also for your mill's boring head.

Best,

BW

[widgitmaster]

Originally Posted by BobWarfield That's a beauty! You've a good eye for proportion on that one. Widgit, what are your preferences for boring bars? I'm curious about this project, but also for your mill's boring head. Best, BW

Thanks!
All I used were cheapo 3/4 shank brazed carbide bars, the shorter the better! Having a diamond wheel on my surface grinder does make a world of difference tho!
Eric

[brianklein]

Excellent Work!!!

[Mcgyver]

Eric, those look great, bet you could sell them.

I'd always thought a turners cube, as the English apprentices were taught, had undercuts so that the cubes separated, cube inside a cube that can't come out. Lautard in one of his books walks through how. here's a three cube one i made years ago, its 1" sq. Lot of fun just having it sit on the desk because all the non technical people would pick it up and hurt their brains trying to figure it out. lol. its the machinist's equivalent of worry beads so the edges have long since been rounded.

http://i20.photobucket.com/albums/b2...urnerscube.jpg