Stuffed pcb and angle grinder
« on: April 25, 2016, 02:47:48 AM »

I need to trim down some pots on my stuffed pcb,
thought of using an angle grinder.

But, can the sparks damage the board in any way?
HJFP2, ssl9k, Harrison Ford Filters
My music


Re: Stuffed pcb and angle grinder
« Reply #1 on: April 27, 2016, 10:12:00 PM »
I use an abrasive cutoff wheel for that. I mount the pot shaft in a vice. I put a piece of tape around the bushing to keep any debris out.  By putting the part of the shaft you wan to remove in the vice keeps pressure  off the pot element. If you have a stuffed PCB I'd do it the same way but support the PCB so it doesn't fall. I would also cover the PCB with something to be safe.


Re: Stuffed pcb and angle grinder
« Reply #2 on: April 28, 2016, 02:09:42 PM »

I'm not sure what abrasive cutoff wheel is.
I used one for metal.

I left the pots in the frontpanel, and put the lid on.
Seemed to have worked ok.

But, I see quite some heat build up (metal glowing)

Will clean well, and hopefully all is fine :)
HJFP2, ssl9k, Harrison Ford Filters
My music


Re: Stuffed pcb and angle grinder
« Reply #3 on: April 28, 2016, 07:15:25 PM »
An abrasive cutoff wheel is what the wheel in the angle grinder is called. I use a Foredom rotary shaft tool with an abrasive cutoff wheel for this.  A 4.5" angle grinder is oversized for a 4mm shaft but will work.

A grinding wheel (like on a bench top grinder for sharpening)  is thick and a cutoff  wheel is thin. Cutoff wheels are made for different materials. I've seen ones for all ferrous metals, ones for stainless steel and ones for aluminum. The ones for aluminum work better on aluminum than the ones for ferrous metals. No surprise.

I use 14" abrasive cutoff wheels in a metal chop saw when I have to do cuts in large metal stock. I use extruded T slot framing for all sorts of things.   I cut 8020.net with a  Metabo CS23-355

I have gone though a lot of stuff to cut metal. I bought a table top horizontal band saw which I hate. I don't think it's me. I want to move to a saw blade instead of a cutoff wheel for a cleaner cut. The problem is that a saw blade for metal wants to run slower than the cutoff wheel. I can't just put a blade in the 4800 RPM chop saw. A slower 14' blade based chop saw for metal is $450 which is more than I can spend at the moment.
« Last Edit: April 28, 2016, 07:21:58 PM by Gold »


Re: Stuffed pcb and angle grinder
« Reply #4 on: May 23, 2016, 01:22:58 PM »
while trimming; its very easy to damage those pots once they are soldered to PCB!
I'd secure the pots firmly... best is to mount them to the enclosure...
or make a small jig ( small aluminium that u can hand held, or vice ) , and use the pot's nuts to secure them, and hold from the jig, (make sure PCB is on flat bed too)
when u start cutting, u actually putting a  lot of force on pots, u can damage PCB legs, or even break the
pot very easy!

Re: Stuffed pcb and angle grinder
« Reply #5 on: August 03, 2016, 10:20:05 AM »
In our car bodyshop we use these flexible back pads for fibre discs with our Makita angle grinders. They seem to go forever which saves a fair bit of aggravation of re ordering and replacing etc. -  http://www.dtc-uk.com/products/100mm-back-pads-for-fibre-discs/114/