Miniature Rack and Pinion sets

[KL7AJ]

I want to build a bunch of permeability tuned inductors for some low power antenna tuners, and I think using rack and pinion sets would be perfect. Does anyone know where I can get some small rack and pinion sets that I don't have to order in quantities of 95,000 from Guangzhou?

Eric

[K4PP]

Maybe try Mcmaster Carr, PIC Design, WM Berg, Stock Drive Products/Sterling Instruments SDP/SI.

K4PP

[KL7AJ]

Thanks! I'd prefer to buy American if possible. Not that the Chinese products wouldn't work fine...I just don't need 95,000 of them......yet. HI!
eric

[K4PP]

Didn't you just dump a printer? Might have checked it for a miniature rack and pinion.

[G0CWA]

I want to build a bunch of permeability tuned inductors for some low power antenna tuners, and I think using rack and pinion sets would be perfect. Does anyone know where I can get some small rack and pinion sets that I don't have to order in quantities of 95,000 from Guangzhou?

Eric

Hi Eric

Just a thought any particular reason why are you thinking of using a rack and pinion system ? an alternative approach would be to use a setscrew arrangement made of a small piece of threaded rod mounted in small bearings with a threaded bush (or nut)on it. The bush could be attached to a plastic rod holding the core or even the bush and rod could be made of ali or brass they could then be used as the core as well! The deeper the core is "driven" in the lower the inductace would be.

If you still want to go via the rack and pinion method why not try model shops small ones are around for steering radio controlled model cars.

Failing that have a browse on ebay, constructional toys like lego and meccano include small rack and pinion sets.

Hope this helps Nick G0CWA

[KL7AJ]

But I need more than 1. My requirements fall in the category known as several...which means greater than one and lest than 95,000.

[KF5FEI]

There have been a number of small motorized linear actuators showing up on the surplus sites like Marlin P Jones and Electronics Goldmine. Might be a cool alternative.

[KL7AJ]

I already have a lot of these...and this might be my second option. I just want to do this on the cheap.

[KL7AJ]

Hi Nick:

I've built setscrew PTOs (acutally using all-thread rod) and they aren't as stable as one might suspect. If the slug rotates in the core, if there's any wobble at all, it can actually tune BACKWARDS over small regions. I learned this the hard way. Any useful setscrew arrangement will turn the NUT, allowing the screw to perform a pure linear motion. The rack and pinion seems to be the simplest way of doing this...I've also looked at "slug rack" mechanisms, a-la Collins R-590, but they are all pretty complicated mechanically.

ERic

[KB4QAA]

Have you looked at RC radio control modeling supplies?