To keep construction simple and convenient I've found couple of easily sourced items which can be easily adapted to serve as the main connectors.
There is also a tips and techniques section which I'd recommend reading before beginning construction especially if you haven't done metalworking previously. I do emphasise though that the making is really simple and that the only care that needs to be taken is to be neat when gluing and to take care that the piston slides very freely in the barrel.
A parts and tools list is below. Clicking on the links on the left will bring you to a supplier for the part or tool whilst clicking on the right will give the part information.
These suppliers are only listed as a matter of convenience and we make no recommendation as to suitability of part, tool or supplier!
- 65mm x 10mm aluminium tube - basic barrel
- 65mm x 10mm steel / brass rod - lathe barrel
- Cap screw M4 x 25 & coin with knurled edge - drive screw for basic barrel
- Cap screw M5 x 25 & coin with knurled edge - drive screw for lathe barrel
- Steel / brass rod 4mm diameter x 75mm - piston
- Steel / brass rod 4mm diameter x 50mm - arm
- Steel / brass rod 4mm diameter x 50mm - needle shaft
- WM12 display fitting (US) - arm / needle shaft connector
- WM12 display fitting (UK) - arm / needle shaft connector
- Ormiston Wire 878-1014 clamp M5 - piston / arm connector
- Large coin, 10mm nut & 5mm grub screw - arm restrainer
- M4 steel nuts x 7 - for basic barrel
- M5 x 8 cap screw x 1 - for arm connector
- 1.20 x 40mm Luer needle - glass needle holder
Tools and materials
- Power drill
- Vice - available very reasonably on eBay (secondhand is good and cheap)
- 4mm / 4.1mm / 4.2mm drill bit depending on actual diameter of rod used
- 4.5mm drill bit for drilling holes for tapping with M5 tap
- M5 tap for threading
- Rapid setting epoxy glue
- File - small round
- Metal polish
- Drop of oil for tapping