Just to update on this.
While I was in talks with a local fellow to get a winder printed, Rob dived in and had a couple printed via 3D hubs. They look like this...
They were printed in ABS @ 200 micron resolution. Rob sent them to me to try on my speedo.
Sadly they did not fit the shaft, and turned out to be about 0.5mm undersize all round.
I carefully drilled out one of them with a new 4mm bit, and that fitted the trip shaft perfectly (except for not having a flat anymore.)
So the model was right at 4mm but 200 micron resolution was not good enough.
I sent out email enquiries to a few 3D printers and was either getting no replies or quotes for single prints in the region of £60.
Just when I had given up, my local fellow dropped me a mail to ask how I was getting on with the trip winder, and btw he has a new SLA machine he wants to try out.
No sooner had I explained the problems I was having than he says he has printed one already and if it doesn't fit he won't charge me...
His rates are £10 for the first one and £5 for subsequent ones.
So I dashed over and tried the winder on my shaft.. It fit perfik!..Needless to say I bunged him a tenner.
This is printed in resin using SLA @25 micron resolution and the result is like an injection moulding... A very nice product. unfortunately he only has grey resin at the moment, but it can be done in black just the same.
So we now have a CAD model and printing regime that works, and also a good contact who can do them at a good price.
As it stands, I can email you the CAD model and/or my printer chappies details.
Hopefully this will all appear on a future post if I can find out how to post details of the STL file for the model.