On Thu, 23 Feb 2017 17:10:26 +0000 (GMT+00:00), jim k wrote:

bar shower developed a continuous drip from the 1/4 turn flow
valve. Got a tuit so pulled out the old to measure & get a
new.

Oh dear. No online source had the same spec. Nearest was very
close but the splined head of the spindle was 7.6mm, diameter of
my original dud was 9.8mm....

For 7 quid posted I ordered one yesterday & it arrived today (tap
magician, eBay).

So out with the polymorph

https://www.amazon.co.uk/gp/aw/d/B017SA92O4

and ten minutes later I had moulded myself a bush to enable the
smaller replacement spindle to fit snugly & exactly into the the
shower control knob.

All back together & job done! Assuming the shower doesn't get
above 60deg all should be ok :-)

Result IMHO.

Anything that works and lasts can be considered 'a result' I'd say.
;-)

Had the relative diameters had a slightly bigger I think I would have
3D printed a converter collar [1] and PLA is probably good for 150
DegC (it's extruded at 200 DegC).

That said, if these were splined (rather than with flats / D section)
I'm not sure you would get sufficient detail to print the splines
without going down to a very vine nozzle (currently .5mm).

A metal spindle would probably cut it's own into the inside of the
collar but the collar to plastic knob might need gluing (or melt
tacking) in to be sure.

You could print a complete new knob of course. ;-)

Cheers, T i m

[1] For those interested in what it would take to design and print an
adaptor (and assuming you have access to a 3D printer of course), it
typically takes the following steps.

Open (free) Sketchup (Windows and Mac only I'm afraid), open a new
template and use the circle tool to draw a circle to the inner
diameter (spindle OD). Draw another circle over the first to the OD.
Select the inner circle and erase it. Use the drag tool to drag the
washer shape into a tube of your desired length (about 20 seconds so
far). 'Export STL' to filesystem.

Open RepetiorHost (free Win / Lin / Mac), load the .stl file and
'slice' the object to generate the .gcode file (another couple of
seconds). Hit print and watch while your adaptor appears in a few
minutes. ;-)

Yesterday I did very similar in that I designed and printed 30 off
very small (12 mm OD x 3mm thick) plastic 'feet' to screw underneath
our daughters large rabbit cage / run so it can stand just out of the
water where it sits on the concrete (hoping it will then wood will
last longer).

Cheers, T i m