Rex Edgar Posted December 1, 2016 Report Share Posted December 1, 2016 I am looking to build a small (4"X10") keepsake box. I want to incorporate a secret compartment. I need to use a pre-loaded spring to pop the compartment open when the key is released. Springs are difficult to get in the dimensions needed, especially in small quantities. What are the thoughts as far as using small rare earth magnets with the polarity reversed? There is not enough physics in my background..... Quote Link to comment Share on other sites More sharing options...
wtnhighlander Posted December 2, 2016 Report Share Posted December 2, 2016 I think that will work, you can control the strength of the 'spring' by varying the distance between the faces with the compartment closed, until it works the way you want. Magnetic field strength follows the inverse square law, so the travel distance will be short, but you shouldn't need much for a secret compartment latch. Quote Link to comment Share on other sites More sharing options...
wdwerker Posted December 2, 2016 Report Share Posted December 2, 2016 K&J MAGNETICS has all sorts of data on the pull strength of magnets and charts that show the drop over distance. They also have an incredible selection of magnet sizes, shapes and strengths . Quote Link to comment Share on other sites More sharing options...
Rex Edgar Posted December 2, 2016 Author Report Share Posted December 2, 2016 I recently found K&J for a specially size R/E magnet for a project. They have much stuff that I didn't know about. Good info, Quote Link to comment Share on other sites More sharing options...
chrisphr Posted December 2, 2016 Report Share Posted December 2, 2016 What are the thoughts as far as using small rare earth magnets with the polarity reversed? That is a really clever solution! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Coop Posted December 3, 2016 Report Share Posted December 3, 2016 But won't they be terribly pissed at each other until you turn that key? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.