M42 lens conversion

Dear all
I have picked up a few cheap m42 praktica lenses with a pin in the base.push the pin in and the lens will shut down to whichever stop you pick.Without pushing pin the lens is wide open and cannot adjust the stop.I was thinking of pushing pin down and glueing or soldering in place so that I can use all of the f stops.
Anyone have any experience of doing this or any other way around this.
Replies much appreciated
thanks

Yes. Remove the back of the lens, slip a piece of electric insulation cable sheath over the pin (so there's only about 1mm showing at the end) and reassemble.

The plastic sheath from the cable will prevent the pin from popping up so the lens will act as a manual one. If you ever want to use it in "auto" mode (or sell it on) then the process is completely reversable.

Are we talking Helios 44M's here by chance? They tend to be auto only and I've converted lots of them now - only takes a minute or two at most.

Thanks
I knew I would get an answer here!
I will try that.
one of them is the helios but curiously this works without the pin depressed!
where have you get good qaulity kit to take lenses apart from? ie small posi screwdrivers/lens spanners,etc
I have tried with what must have been a cheap screwdriver size 00 ,but it sheared off

Cheap screwdrivers have a habit of doing that, that's why they're a bit of a false economy. I use Wiha brand screwdrivers which I've bought from Micro-Tools, although I've recently been informed you can buy them cheaper direct from the manufacturer. You can get all the other lens tools you could ever want from Micro-Tools too.

Have you got a Helios 44 with an auto/manual switch? I'm actually selling one on eBay at the moment and they're quite rare - I've only ever seen them bundled with the "Moscow 1980" special edition Zenits. Earlier ones tended to be either preset (like my personal copy), then manual only, then auto only for the later ones. They're all good though - mighty sharp little lenses.

There are adapters available which have an inner flange that engages the pin and pushes it up turning the lens into a pre set. I have one but they can be expensive, try looking for a post on MFlenses forum, there is a guy called Alex (hk300) that sells good quality but cheap adapters like this from Hong Kong that still go to infinity. Otherwise what Hefty1 says is fine I've done ti myself its relatively easy and reversible