At least, it looks quite similar to mine. But wasn't able to recognize because of the different case.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1503871;image)
Mine, from school days.
Unfortunately the second one is jammed. Anybody know a good idiot's introduction to repairing them?
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1504414)
Back in the day, when I still used a slide rule, it happened to me a few times. Here's what a remember from fixing them.
What's jammed? The slide or the cursor?
If it's the cursor it's usually because the little bent tension spring has jumped a track - they can often be persuaded back into line by sliding a shim under them.
If it's the slide try soaking the whole thing in a mixture of detergent and water for a few minutes. Enough detergent for the mixture to feel slightly viscous and slippy. 1%? 2%? 5%? 10%? 20%? Not really sure. Then, while immersed, flex the whole rule gently back and forward, and try to repeatedly push and pull the slide. Eventually enough works in to lubricate the thing and free it. Disassemble, rinse and dry, and look for any galling on the bearing surfaces. If you find any, scrape it flat again with a square edged scraper. Reassemble with a little dry lubricant - talc, graphite, ptfe, whatever you have to hand. YMMV.