How to remove Schaffner mains filter that is riveted to panel - Page 1
Forum section: electronics / repair

author: matthuszagh
author_rank: Frequent Contributor
timestamp: October 07, 2022, 01:26:22 am
content: I'm replacing the old Schaffner in my HP 3458A with a modern version (based on this thread:https://www.eevblog.com/forum/repair/hp3458a-schaffner-mains-line-filter-failure/msg1447239/#msg1447239). It seems to be riveted to the rear panel (images attached). How do I remove this without damaging anything?

author: themadhippy
author_rank: Super Contributor
timestamp: October 07, 2022, 01:41:23 am
content: center punch the center of the rivet and drill it out

author: Whales
author_rank: Super Contributor
timestamp: October 07, 2022, 01:42:05 am
content: I normally remove rivets by drilling. Make sure to centre punch first, otherwhise your drill bit will wander. Use a smaller size drill bit than what you need and work your way up afterwards if needed.If you're not confident with drilling then I also suggest putting lots of tape around the rivet in case you slip and scratch other parts. Also don't drill the unit unless you can clamp it well, if it bends when you try and drill it then you will have a hard time.

author: james_s
author_rank: Super Contributor
timestamp: October 07, 2022, 03:03:35 am
content: I've always drilled rivets, the center punch mentioned above is a great idea, as is some tape to protect against scratching. You could also just leave it alone, they rarely fail on 120V.

author: matthuszagh
author_rank: Frequent Contributor
timestamp: October 07, 2022, 03:32:53 am
content: Thanks for the advice everyone! Center-punching, clamping and drilling worked well. Follow-up question. The filter is now out, but the rivets themselves are still there (image attached). How do I deal with those?I have a pair of metal snips, but they can't cut flush to a surface like that. Another thought I had was to pinch the ends down (ends shown in the image) with locking pliers and then they would just pull free. What do people think?

author: matthuszagh
author_rank: Frequent Contributor
timestamp: October 07, 2022, 04:22:28 am
content: Ok I got them. I got one with the snips and the other i got most of the way with the snip and then center punched it out.

author: Ian.M
author_rank: Super Contributor
timestamp: October 07, 2022, 05:38:53 am
content: Next time, if you've managed to drill out the rivets on-center, and have a good selection of bits, its preferable to go up the sizes till the protruding part where the head snapped off panel is very thin walled, but don't go deeper than the panel (to leave a seat for the punch) then take it off down to the panel with a large sharp bit turned by hand (so you can stop before it mars the panel), so you can punch them out cleanly. OTOH if you are significantly off-center, mangling them till they let go may be the only option.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 07, 2022, 06:29:11 am
content: Drilling is kind of rough for a couple reasons:- I'm guessing you can't get this under a drill press, so accuracy will be limited. (All the more reason to centerpunch!)- Once it's pretty loose, or a big enough drill takes a big enough bite... it starts spinning in the panel.- You can still drill out a spinning rivet (handheld is easier, rock it side to side so the drill still cuts in and out a little bit as it's spinning), but it'll make a mess of the panel, and you might lose precious thickness/diameter in the process. This is worse obviously if it's off-center too.So, not great on thin panels or whatever. Looks like it's fine here, no worries.Remember to use star washers on the replacement (assuming you're going to bolt it instead).Tim

author: Haenk
author_rank: Super Contributor
timestamp: October 07, 2022, 08:12:35 am
content: (just two notes: a) Aluminium rivets are great - easy to install and easy to remove; b) for drilling, I'd suggest using a Co5 or Co8 drill - they are way sharper and will cut into steel or stainless steel much better than standard HSS drills...)