I suspect it's not about cost, rather more about potential damage to the decoration. A 3.5mm brass nut, set in the plastic, might be all that is needed.
Back box screw
- Thread starter Abyone
- Start date
I suspect it's not about cost, rather more about potential damage to the decoration. A 3.5mm brass nut, set in the plastic, might be all that is needed.
Yes, maybe, by the 'decoration' situation at present looks so far from pristine that that may not be a major issue.
True, but to get an actual nut in would require drilling out the hole to perilously close to the full diameter of that plastic 'pillar' - an exercise which, given the nature of that material, might well not 'end well'
... and, of course, there would again be the question of the cost of the 'minimum available quantity' of 3.5mm nuts (something which I imagine most of us don't have).I found them for 7p apiece but with £ 5.25 p&p from a UK online store. Unless you might need them for something else in the future a new back box would certainly be cheaper. The main advantage of using an insert would be not having to mess with the plaster.
Indeed. I was, of course, thinking of the 'total price to me' (including p&p).
True - although, as I recently implied,. it looks to me as if the plaster would probably benefit from being 'messed with' a bit, no matter what solution is adopted
No, I had not atualy considered that because of the oval only two sides of the hole might fit but the other two woulld be sloppy.
if just doing something like bashing with a ball bearing from the front or back might produce a reasonable result on a large proportion of the ,overall depth thin metal plate - sort of halway or more depth rather than all of it , but in either case a full 360 dgrees of rotaionl thread.
If you could back something hard and solid and a good tight fit behind it and resting on the box back then put a ball bearing on the front and a hard hammer strike then you might stand a good chance on a bench but on a wall with plaster your impact could cause additional damage to decor or plaster. I actually tried waterpumpliers with ball bearings welded onto the jaws and as much hand pressure as possible and it did not made an inroad, I suppose specially making a tool based on the traditional plumbers pipe/tube cutter to give a screw thread pressure and a ling adjusting lever to ramp up the pressure might just do but to fabricate one with enough whooph to send meat into the hole would require awesome pressure compared to a simple hammer strike.
I suppose one could be made but the cost/effort for the odd quick fix or two per lifetime would not be economical really.
Compare to Mr Hughes and his "Yoozy Box" I have used a few but only a few and they were useful but if they are already in production inlarge numbers thanks to Mr Hughes than a box of ten singles and a box of ten twins was probabaly as much as I ever needed - removed after use for next time needed if required.
So if somebody deveoped one and mass produced the tool cheap enough I might have bought one years ago but to make one myself is a different ball o
- Joined
- 7 Sep 2022
- Messages
- 4,879
- Reaction score
- 1,415
- Country
You can pick up wood screws with a very aggressive, self tapping thread, eg Screwfix turbo series. You can also make screws similar by grinding part of the side of the tip off so the threads gain a sharp/flat; handy for driving screws close to the end without splitting and without pre drilling but in this case I was able to drive the screw into a “Bakelite” style plastic back box and have it cut a thread. I used a manual screwdriver rather than a cordless drill so I could feel when it was getting tight and back off/go again. After thread cut, grinder cut the end to the right length, downsized the head (if I’d done that first the head might have been too weak to cut the thread I think it was a 5 and there wasn’t a lot left of the +)
Perhaps a simpler route would be to fill the hole with epoxy adhesive, lubricate a machine screw with wax/grease so it still has some thread presentation, and embed it, then when the epoxy sets wind it out (the wax having prevented the epoxy sticking to the screw), cut it shorter and screw back in
Last edited:
If I see a wood screw in a switch or socket I think 
"here we go" this will be fun....ruff as fek.
"here we go" this will be fun....ruff as fek.All true, and all very reasonable, but it was the plastic material, rather than the screw, that was my concern
Fair enough, and I'm pleased that you succeeded.
Such things do, indeed, have to be done 'manually' - I feel sure that any attempt at 'power-tapping' (e.g. with some sort of electric drill/screwdriver) would be extremely likely to end very badly. Indeed, even when tapping 'fairly small' holes in metal (i.e. fairly small tap), there is a significant risk of the tap snapping if one is not gentle enough with 'manual backwards and forwards' (I have plenty of experience of 'snapped taps'
- and I can but presume that risk would be much greater if a 'power tool' were involved!However, returning to your 'manual' thread-cutting with a screw, on the basis of lots of bitter experience of trying to do things with it, I fear that there would be a very significant risk of the ' "Bakelite" style plastic' (usually urea-formaldehyde resin) material, which is pretty treacherous to work with (brittle and 'unforgiving'), would shatter during even gentle attempts to cut a thread in it. I have, in my time, successfully cut threads in that sort of material, using a 'proper tap', but 'disaster has struck' on a fair proportion of my attempts, wven with my being 'very gentle' - one comes to fear and dread that little 'click' noise
Sure, it's the thread-cutting which is the worrying stage. If/when one has done that successfully, with the box still intact, then the rest is child'splay.
Yep, that would certainly (in my opinion) be 'safer' and is something I've quite often done in similar situations.
Can you tell me where you found them ?Indeed. I was, of course, thinking of the 'total price to me' (including p&p).
True - although, as I recently implied,. it looks to me as if the plaster would probably benefit from being 'messed with' a bit, no matter what solution is adopted
It's not the cost as others have suggested. I really don't want to go hacking at the plaster even if it could be improved. It actually looks ok once the switch is on. It's a tight space to work in, in a cupboard under the boiler with next to no light so really want to get in and out without disconnecting everything if I can.
OK - fair enough.
However, I've nearly always achieved a satisfactory result by (simply/quickly) 'squeezing' the lug (making the hole slightly oval) and then re-tapping. After all, it's not as if the screw is doing anything 'structural' - one just has to try to make sure than no-one is 'over-enthusiastic' in tightening the screw in the future. The same approach would obviously not be appropriate in situations in which a screw were doing anything remotely 'structural'.
If one were concerned, then in the case of a metal lug, I suppose another approach would be to drill out the hole to 'clearance' size and then epoxy a nut onto the back of it (or even solder/braze the nut on, if one could avoid thermal damage to the box) - being careful to avoid/remove and blockage of the thread in the nut with glue (or solder).
Sorry - obviously not since, as I said, I did not realise that one could buy them (easily or at all). However, Ragnar can presumably tell you, since he found the 7pones online
Sorry meant to reply to @Ragnar_AT
for £2.70 you can get 100 delivered on ebay you dont need brass get BZP
Hm I will have to try it sometime John,
by saying I had never considered it I meant that I had never given that one a serious thought.
If I had and had actually tried it I might have been surprised by the result (or I might have still be apprenhensive about the strength or lack of it ) of being able to hold a switch or socket in place to a reasonable practical degree.
I will put it on my bucket list of things to actually try and test, although now retired the opportunity to come across suitable candidates has diminished - a little test run with some metal boxes when I have a couple of hours spare though should suffice.
I possess a "Dremel" type tool, so would cut a slot right at the bottom of that lug, drill a clearance hole all the way through the back for the screw and glue a nut in the slot. If I didn't have a nut I'd salvage a lug from a metal back box (50p from Screwfix).
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
