Re: Cordless screwdriver innards?

From: Ian Stirling (root_at_mauve.demon.co.uk)
Date: 07/06/04 

Date: Tue, 06 Jul 2004 11:50:10 GMT

In sci.electronics.design Terry Pinnell <terrypinDELETE@thesedial.pipex.com> wrote:
> "John Jardine" <john@jjdesigns.fsnet.co.uk> wrote:
>
>>I've scrapped 3 of them. The leccy bits are all within the trigger mech.
>>Speed control via a tiny linear pot moulded with the trigger. I found the PM
>>motors are OK but the electronics are magnificently designed and constructed
>>to do just the job in hand and very awkward to cannabalise for other uses.
>>Good luck with the curtain openers :-).
>
>>Tried it once with a windscreen wiper motor. This apparently simple project
>>to do a useful simple job, escalated over a 2 week period into a screaming
>>nightmare of electronic controls, timers, limit switches, wires, cords,
>>pulleys and mechanical hardware. The dynamics never 'felt' right and the
>>eventual size weight and complexity of this monster caused it (thankfully!)
>>to fall off the wall. A version #2 a couple of years later. worked but
>>wasn't really worth the effort.
>>Learnt at that point that some things are better off being industrially
>>manufactured.
>
> Thanks, very helpful. All I'm hoping for is to be able to (a) open it
> up without bits flying off in all directions, and (b) solder thin
> wires to the F/off/B switch contacts and still be able to close the
> thing up again.

Generally no problem.
However, you'll probably need thick wires.
IIRC, the minimum starting current of one I tested was 3A or so.
(2 cell screwdriver)
I've bought 10* very, very cheap (1 pound 99) screwdrivers (about US $3.5)
for use in various projects.