In communiqué <(E-Mail Removed)>, Andy Bonwick
<(E-Mail Removed)> cast forth these pearls of wisdom
>On Fri, 19 Nov 2010 18:11:25 +0000, Pete Fisher
><(E-Mail Removed)> wrote:
>
>>In message <(E-Mail Removed)>, Mark Olson
>><(E-Mail Removed)> writes
>>>Pete Fisher wrote:
>>>> So the new M4x70 screws I sourced for the CEV rear light unit are
>>>>exactly right, except that now I remember why one was missing - the
>>>>thread in the mounting has stripped. This is the thread in a plastic
>>>>moulded 'tube' that forms part of the light reflector base. I have a
>>>>spare from the Strada I am breaking, but surprise, surprise that lens
>>>>was also held on by electrical tape and both the threads are stripped.
>>>> No chance of a helicoil or similar and as the lens obviously needs
>>>>to come off to change a bulb occasionally a simple adhesive solution
>>>>isn't practical.
>>>> All I can think of doing is filling the tube completely with bumper
>>>>repair (the two part black stuff which is v. good for repairing well
>>>>bumpers and other plastic parts) and then screwing in a screw
>>>>liberally coated with copper grease. Wait for the goo to have nearly
>>>>set and carefully take out the screw to leave a new 'plastic' thread
>>>>to harden.
>>>> Is this likely to work, or am I going to end up with a permanently
>>>>bonded screw and tube?
>>>
>>>Just fill the hole with JB Weld and drill and tap it afterward.
>>
>>Probably the more elegant solution. Which reminds me that I didn't get
>>to Lidl for that cheap set of taps and dies. I'm not sure if I have an
>>M4 tap, though I think I have an ancient pikey compendium somewhere. Got
>>a set of three (1st cut, 2nd cut and plug) good quality ones for M8, but
>>not much else.
>>
>Fill it and re-tap it properly. If I haven't got an M4 tap I can drop
>in the post to you I'll abuse my power and order a set.
>
I ought to be properly equipped as I now have more time to fettle SO
bikes but the offer is appreciated. Off to Lidl tomorrow and will also
get a drill stand if there are any left.
>Why can't you use a helicoil? The only reason I can think of is if
>it's too badly ****ed and if that's the case then you'll be better
>trying to plastic weld it with a bit of similar plastic and a
>soldering iron before tapping it rather than using a chemical filler.
>
The plastic tubes that stick out from the rest of the back of the light
unit are very thin walled (one is also coming loose from the rest of the
assembly and needs strengthening with JBweld or similar anyway). I can't
see that there is enough meat for a helicoil. Otherwise I might have got
brutal and just drilled and tapped them out to M5 and worried how to
enlarge the hole in the lens without cracking it later. As someone
suggested when I couldn't find long screws, I could use lengths of all
thread right through to the back of the unit with nuts on that end and
dome nuts to hold the lens on. Or just even longer screws and nuts. TBH
that's probably the easiest fix of all if I could find M4 x 80 screws.
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