Well, in addition to my X-Y vise project, I've decided to go ahead with a parallel project. I call it a nanomill...a teensy-tiny but highly accurate mill with which I can make tiny but highly accurate parts. The spindle will be the most challenging part, since its runout will have to be equally tiny due to the size of the bits.

The basic specs will be a maximum travel of approximatly 1x1x1". Yes, you read that right...an inch cubed. We're talking TINY parts -- think wristwatch sized mechanisms and gears. Maybe sculpting a cameo...that sort of thing. Very tiny, but of very high quality.

Anyway, as a start to this project, someone has given me some ballscrews and their mating nuts. Beautiful, really...and I think they're precision ground. (How can I tell?) Absolutely no detectable backlash. BUT, there's a problem. Their total travel is only about 1.5", and I have no mounts for the ends. I need ideas.

Is it possible, with a short lead screw, to support only 1 end and leave the other end floating? I have only about 1/2" to work with, here, and don't want to screw up these beautiful ballscrews. Supporting only 1 end would give me the travel I need, barely. Or, are there other creative ways to do this?

I could just scale back my plans and make a smaller machine. What's smaller than nano...pico! Yeah, a pico-mill! Write my name on the head of a pin, using CNC. That's it!

-- Chuck Knight

I am no expert. but all of the ballscrew manufacturers that I have looked at so only one end hase to be supported up to certain lengths and then it is manditory do to screw flop or vibration...

I am pretty sure 1.5" is short enough to qualify for no support! ;)

but again I am no expert.

Michael t.

Where did you find that information? You wouldn't happen to remember the URL, would you?

I'll look for manufacturer's codes or something on the screws/nuts themselves, in the meantime.

-- Chuck Knight

http://www.roton.com

http://www.thomsonindustries.com/default.htm

i bought from roton. but I have the manualls for thomson/danhere although there at work.

both sights are simi complicated to navigate but stick it out and you will find the information your looking for.

Michael t.

You do not need to support both ends of a screw that short.

The reason for supporting both ends of a longer screw are twofold.
-When driving a load, the screw is acting as a beam in compression, and wants to buckle.
-When driving at high speed the screw wants to whip, and bend.

Neither are going to be an issue on your little machine.

Please post photo's as you go.

Pin the screw on its axis, then drive the nut. You will get full travel.

Chuck,

Hi! I've got small slide stuff, but small is relative. Compared to your screws, some of these are LARGE. But I'm thinking in terms of a larger machine. I suppose for what you are wanting to do a single small slide with a one square inch block surface area might do. You could mount the screw directly above the slide and use the top of the block as your "table"!

At any rate, I'm attaching a slew of pictures. The little Thompson bearings are for 4mm rod. I only have one each of the THK and Del-Tron. The goofy-looking camera thingy is off of a CRT inspection unit from MicroVision called a SpotSeeker. I'm going to use the slides, but NOT the camera head and it's associated small Del-Tron Slides, linear actuator, and camera rotation NEMA 17 stepper.

And...the other day I was rumaging through another place's parts bins and found (but didn't get) a small (about 1"-1.5" travel) precision X-Y table. It positioned a camera for for some type of inspection equipment. It's manually operated: each axis has vernier adjustments like on a micrometer. One was rusted stiff. I will go back on Monday and see if I can get it-I think I can wing a deal and get it cheap.

Chuck, these parts are all yours if you want them. No cost for what I have here now. I let you know about the X-Y thingy. PM me with a shipping address if you are interested.

Here are the rest...

Lance

Chuck,

I did manage to get the little X-Y unit. Here it is all cleaned up. One micrometer is frozen-I went to lengths to try and free it up but got nowhere. Actual travel without the micrometers is close to 1" for each axis. With the micrometers, about 13mm. The tables are spring loaded towards the micrometers.

The larger bracket held a tubular CCD camera. It could either hold a small indexer as a fourth axis (basically just a stepper), or perhaps a spindle-I was thinking a collet/bearing assembly driven by a flexible shaft with a remote motor. Lots of ways one might go. Neat, huh?

I don't know that it fits in with your small screws, but it's the best I could come up with.

Lance @ Evodyne :p

I hate to think what this thing cost new. Glad it didn't end up in a tip.