4mm is a (not very common) standard for shafts on electronic controls volume controls, rotary switches etc. Have a look for collet type knobs which give a very high grip on these shafts. hth
Bob
Camping Gaz knob
Mar 27, 2011
2 Replies
Anyone have any bright ideas on how to re-fix the gas control knob on a Camping Gaz luminare?
The knob is plastic the shaft splined brass (no split). The plastic is too soft or splines not big enough to take the torque so the knob is now more or less round inside. I've tried araldite which worked until SWMBO'd turned it off too hard... Investigation shows that the araldite has stuck to the brass OK but failed with the plastic knob.
The shaft is only about 4mm dia, and fully recessed into a housing. The small dia would make cross drilling it for a pin will be tricky. The knob is very soft plastic so a simple grub screw onto a flat filed onto the shaft probably won't work either.
I would be inclined to make a new knob entirely out of epoxy. Rest the shaft vertically on a piece of flat plastic.Cut a ring from a plastic pipe and put that around the shaft. Pour epoxy resin inside the ring and allow to set.
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