A super-simple DIY magnetic PCB holder - Page 1
Forum section: electronics / projects

author: ajb
author_rank: Super Contributor
timestamp: December 16, 2016, 02:16:37 am
content: If you haven't seen the PCBite PCB holder crowdfunding project, it's a pretty nice-looking system of spring-loaded posts that stick to a magnetic base:https://www.eevblog.com/forum/crowd-funded-projects/pcbite-the-professional-and-affordable-pcb-holder/msg978495/#msg978495https://www.indiegogo.com/projects/pcbite/reft/13754495/eeI was thinking the other day that something sort of like that, but preferably much shorter, would be useful for a board I was working on. I remembered that I had some rare earth magnets with countersunk holes in the middle, some threaded standoffs, and a healthy assortment of small machine screws on hand, and thus an idea was born.Here are the parts, and the assembled holder. The magnets arethese, purchased from a local hobby story a while ago for some reason or another. The countersunk hole will fit a #8 flat head machine screw, but this would have been too big to fit in the mounting holes of the PCB I was working on. I opted for a 4-40 screw to match the standoffs I had on hand. A #4 flat head screw will slip through the hole in the magnet, but a pan head will not, and will still sit below flush with the bottom of the magnet. These screws are 1/2" long, and with the 3/8" threaded standoffs there's just enough of the screw sticking up. I'm using the base plate from an old solderless breadboard, which was the only suitable piece of ferrous metal I had on hand.Here's a set of four magnetic pillars holding a PCB. This PCB only has two mounting holes, but the far edge rests easily on the top of the standoff, and by pressing the screw thread up against the edge of the PCB, it's firmly held in place. With the metal plate slid underneath of the rubber ESD mat there's plenty of friction to keep and the magnets are plenty strong enough to keep everything firmly in place.There's enough screw thread sticking up to engage a male-female standoff, should some extra height be required. Helpful if you have a massive inductor on the underside of the board that keeps wanting to stick to the magnet, for example.The whole thing worked out very well! It's certainly not as fancy looking as the PCBite, but it was all parts I had on hand, and I think I prefer having the board as low as possible anyway. The main downside of a setup like this is that you can't easily move the board around on the bench to get at different parts of it, so I'm thinking I may get a piece of steel and laminate some other ESD mat onto it as a movable base.

author: lowimpedance
author_rank: Super Contributor
timestamp: December 16, 2016, 05:24:12 am
content: A neat Idea thanks for sharing.

author: cncjerry
author_rank: Unknown
timestamp: December 27, 2016, 07:14:57 pm
content: No, a great idea for double sided boards. Must be much more stable than a typical clamp and vise.

author: SeanB
author_rank: Super Contributor
timestamp: December 27, 2016, 07:29:03 pm
content: Think I must give that a go, I have a lot of standoffs, and a good number of very clean ( soaked for a week in MEK to get them off the plates) hard drive magnets to stick them to as well, using some thick superglue.