How Thin Can It Go?

Ron-

It you haven't post this question on sci.engr.mech

The answer depends on the alloy & the heat treatment as well as the wall thickness.

I would suggest that you use an extruded tube of 6061-T6 or 6063-T6 rather than machining from a solid rod.

You could easily go down to ~.030 wall (or thinner) depending on the length of the tube & the operating environment.

1" OD x .035 wall x 3' $9ea

anyone

the wall

6063-T6 rather than

Thanks for the skinny on this, but I have to start with a solid rod as one end of this piece is pipe threaded to fit into another cylinder and at the other end there's a semi-hollow cone-- the whole thing being no longer than three inches in length and with an OD of 0.500 inches.

Ron

I carry reading glasses in my pocket in an aluminum tube case. The case is about 0.9 inches in diameter and the thin wall is on the order of

0.02 inches thick (0.5 mm by cheap measuring device).

There are a few dents in the tube, so I would suggest you take 1 mm (0.040 inches) as a rough guide.

Jim

Ron-

There are other ways to make the connection to the threaded piece; adhesive on a slip fit, a press fit or a shrink fit. Machining to a thin wall is possible but not first choice of a production system.

If you want something that works & can be made in production you need an experienced designer.

If you're just prototyping continue to iterate.

Bob

Another thought - does it _have_ to be aluminum?

you could possibly get good results with steel / stainless steel.

If you go this route, you could do tons of prototypes with 1" bolts for not much money.

My bad. Make that 1/2" bolts, and even less money.

cone--

Bob, it's just a silly project, a sophisticated toy. Ten years ago I first saw the BBC show Doctor Who and fell in love with it. It was campy and cheap, but it had charm. I was particularly fascinated by the good Doctor's sonic screwdriver and I set out to build one. It took two years me two years working out the acoustics end, but when it was done it could produce

143 dB of sound that could turn screws from a few inches or keys in a door from about a foot away (the door has a bigger surface area)..

It was a brilliant piece of engineering that nobody else has done before or since. But things happened and I lost it; lost the screwdriver and all of the files on it were either corrupted or lost as well. Ten years later the electronics have improved, piezo-ceramic materials have improved, and I decided to reconstruct the screwdriver from memory and while I'm at, make a few improvements.

There have been enough companies and people who have made mock-up versions of the screwdriver, lathed out of a single piece of aluminum; but since this version houses batteries and electronics, there are four main pieces that screw together via pipe threads. The pipe threads add a degree of ruggedness plus the finished project looked better, being constructed out of different sections rather than one long cut piece. Most of it was schedule 40 aluminum pipe or 1" aluminum rod, but there were also sections made out of copper tubing and brass.

It was a neat little toy. If it was ever marketed it would be sold by The Sharper Image people for an incredibly high amount. And it will probably cost me an arm and a leg to build it again given the cost of machine works these days,

Ron

Bob;

A picture of one design for the screwdriver is at:

I only made a few slight modifications to the basic design.

--rh

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lost

Thanks for the tip, Jim.

anyone

You said something about threads. The tube wall needs to be 3X the depth of the thread root as a minimum (and that is still not sound engineering practice). Cute idea though. Dr. K

Well, in this case the threads are external. But I will keep your information in mind when it comes to joining the other pieces together.

Ron

engineering

anyone

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