Insulated shaft extension

[Pamphonica]

Dismantling some homebrew gear from a box of assorted stuff I came across this.
I wonder why I never thought of it myself.
A blown ceramic mains fuse fits nicely on a knob and into a coupler.
In this case it's just a short shaft extension, as the coupler was insulating, but the idea is a reasonable one.
Unusual!
- Jeremy

[Radio Wrangler]

The trick works the other way too... the entire live rock music industry is founded on the fact that the barrel from a dismantled quarter inch jack plug will fit in place of a 13A fuse.

David

[Pamphonica]

Ah yes, the old 1000A fuse trick in another guise. Better than a nail, some cigarette box foil or a bit of chinese takeaway carton.

[Herald1360]

At least fag packet foil might blow at <1000A!

I've been guilty in the past of soldering a strand or two of 0076 across a plug fuse to get something going in a hurry. The fusing value is reasonable but there's no guarantee that the arc will stop

I like that shaft extension- creative reuse that is. Just so long as nobody replaces the fuse

[ColinTheAmpMan1]

Hi,
Ages ago, when I was trying to make a 'scope, I wanted something to isolate the "brightness" and "focus" controls from the front panel. I found that there was a particular size of plastic knitting-needle that fitted nice and snugly in standard pot knobs and the like. I can't remember what the identity of the knitting-needles was, but they were obviously as close to quarter-inch in diameter as makes no difference.
Regards, Colin.

[Herald1360]

A size 3 knitting needle is 6.5mm apparently. I suspect it used to be 6.35mm

[ColinTheAmpMan1]

Hi,
Another thought (it came to me as I was sorting through a tool-box and came across said bits of junk) is to use the plastic bits which you saw off long shafts. These are, of course, exactly the right size and material. Ok, you have to be a bit of a hoarder like me to keep "discarded" stuff like that, but I reckon I'm probably not alone.
Regards, Colin.

[Kala_12]

No, You're not!
Stuart

[G6Tanuki]

If you can get the brass end-caps off 13A fuses, they make good ceramic stand-off spacers. A 6BA nylon bolt will usually fit down the hole of a 13A fuse; some of the bigger 15A fuses you find in consumer-units will happily take a 1/4-inch bolt.

Only thing to be wary of is whether - when the fuse blew - the sand caught all the vapourisation-products of the fusewire.

--G6Tanuki

[Anthony Thomas]

Lots of good suggestions here

I was looking through our local gardening centre a while back and noticed some wooden stakes that are used to keep plants straight up in their pots, they were perfectly round and over a foot long. Wood is a reasonably good insulator and I used a short section of rubber petrol hose to join on to the potentiometer spindle.

Purfikk as Larkin would say

Tony

[threeseven]

Careful with the fuel hose or any rubber hose or tube, some of it is designed to be anti-static, so conductive to some degree.

[Outrun_uk]

Outer insulation from thick 3-core flex filled with hot-melt glue, used this a couple of times for semi-rigid spacing but enough flexibilty so the PCB had a degree of shock protection.

[Anthony Thomas]

Originally Posted by threeseven

Careful with the fuel hose or any rubber hose or tube, some of it is designed to be anti-static, so conductive to some degree.

Oh I agree there threeseven, the wooden sticks more than make up for that conductivity but I heed your wrning if joining two metal shafts for example.

Tony

[Radio Wrangler]

Plastic knitting needles are good. I've also used sections of plastic chopsticks when desperate. They have the advantage of being covered in ideograms wishing you great success and happiness. They make great spacers for 70cm helical antennae.

David