Drilling a self tapping screw on a rad that won't bleed

gebbel · 21-11-2015 09:05AM #1

I've a radiator that needs bleeding but the nut is worn and can't be opened. Last year I had the same issue with another rad and ended up replacing it. This time the plumber has suggested the self tapping screw. He's very competent but I'm asking myself....if these fail with nobody around then the consequences are dire. Can anyone who has drilled one these comment? Thanks.

Wearb · 21-11-2015 09:24AM

Some of the bleed screw units can be replaced. That would best. I have seen a tek screw with a felt washer used, but I would be nervous of using it too often. Post a pic, resized if possible, to spare my data allowance.

iwillhtfu · 21-11-2015 09:34AM

gebbel wrote: »

He's very competent but I'm asking myself....if these fail with nobody around then the consequences are dire. Can anyone who has drilled one these comment? Thanks.

There's unlikely to be a catastrophic failure resulting in a flood.

The likely scenario is that it will work for what you want and in the event it does fail it will be more of a drip than the deluge you're imagining.

I'd use a small self drilling screw similar to the ones the lads use for building metal studs. approx 5-10mm long rather than using one of the roofing ones.

Keep in mind if the screw isn't galvanised it will more than likely snap the next time you try to remove it.

DublinDilbert · 21-11-2015 09:47AM

The first thing I would try to do would be to replace the bleed screw, if the outside can be unscrewed from the rad. Failing that I'd pick up a cheap tapping set with drill bits in lidl/aldi. Drill out the brass bleed screw with say a 4mm bit and put an M5 tread into it. Then put in an M5 button head screw with a rubber washer or even covered in PTFE. The brass will be very easy to drill/tap.

Wearb · 21-11-2015 01:15PM

There used to be a lad on here from cork that had a good tip for removing old worn bleed screws (don't reuse it if you get it out) You file off about 2mm SQUARELY, (don't end up with a high side) off a new rad bleed key and hold it tightly against the valve while turning it.
That way you might just get a grip on the furthest in part of the valve. Worth a try. Don't forget to have a replacement valve ready, to turn off rad valves and have lots of towels in cast the rad valves don't fully seal. Also have a plan worked out in your head, in case everything goes pear shaped.

gebbel · 22-11-2015 11:36AM

The rad is a double, and the screw is facing the wall so access is difficult without dropping the rad. The nut is circular, no wonder it can't be gripped.

Dtp1979 · 22-11-2015 03:00PM

gebbel wrote: »

The rad is a double, and the screw is facing the wall so access is difficult without dropping the rad. The nut is circular, no wonder it can't be gripped.

Aldi do a small socket set. One of the guys on here used to post about it. I think the 5.5 head was good for this sort of thing

cruiser202006 · 22-11-2015 05:34PM

+1 on the 5.5 socket you mite need a pump pliers to force socket in on it. Works 9 times out of 10

Drilling a self tapping screw on a rad that won't bleed

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