With the violin apart I realised that I only had half enough spool clamps – so before proceeding with the repair I made another 15 clamps bringing the total to 30 – which should be more than enough to reassemble the violin.
I know I’ve shown you before, but I thought a step by step view might be useful. Here’s how I made them
First get some threaded rod – I used 3/16″ whitworth – as that was standard at Bunnings®. I also bought nyloc® nuts, washers (double the quantity of the nuts) and wingnuts. I also had some 1″ dowel – like the sort used for broom handles.
Tools
hacksaw
saw
grinder (or file)
vice
8mm wrench (for the nyloc nuts)
I used nyloc® nuts as they have a nylon insert that grips the thread so it won’t unwind with vibration – you can use normal nuts but it’s best to imobilise it on the thread eg by using Loctite®
First cut the threaded rod to length – in this case about 100mm/4″ with a hacksaw
spool clamp
Next I smoothed the ends on the grinder – you can use a file – this will take the sharp edges off the ends. Just rotate so you have a light chamfer on the ends.
spool clamp
Next I cut the dowel into approximately 1.5-2.0 cm (about 1/2″) slices – two per clamp.
spool clamp
Now drill a centred hole through each pair of dowel rounds to fit as a close but sliding fit over teh threaded rod sections.
spool clamp
Now take the threaded rod and add one nyloc nut to one end. Using the wrench, make sure the nyloc nut is on tight so that the ed of the threaded rod just emerges through the nut. Then add a washer.
Luthier's spool clamp
Now add the two dowel rounds
Luthier's spool clamp
The washer will keep the pressure even across the dowel so it won’t break when you tension the clamp – of course you don’t want to over-tighten either. Now add another washer and the wingnut and the clamp is complete
Luthier's spool clamp
And you can add that clamp to all the ones you made earlier!
Luthier's spool clamp
Total cost was about AU$16.00 – making them actually less than AU$1.00 per clamp because I have enough material left over to make several more.
