Avo Douglas coil winder brake pads

[beery]

Hi all,

just a short post about trying different brake pad materials on my AVO Douglas no. 3 coil winder.
When I purchased the machine it was in poor condition with missing parts and worn out half nuts (that run on the feed leadscrews).

I had some of the missing parts made and others I made myself.

The brake pads seemed to be made from some sort of perished rubber material. Also missing was a small springy tab that was supposed to just lift the end of the brake pad on the static tension brake.

Anyway, when I first rebuilt the machine I fitted gasket cork in place of the rubber pads. It seemed to work ok, but the static tension brake had a tendancy to bind which would cause fine wires to break. Note that I did not replace the missing springy tab, which looks like an afterthought anyway. Perhaps the springy tab was supposed to be there to prevent this kind of brake binding.

Now faced with the prospect of having to work again with 44 or even 45 SWG wire to wind yet another set of frame coils for my HMV 905, I needed to sort out the brake binding issue.
I tried some 1mm acrylic felt and now it works perfectly. I still have the cork in place on the over-run brake, but this does not bind as it works in the other direction relative to the rotation of the brake drum.

The first picture shows the static brake on top and the over-run brake underneath the brake drum. This is with the cork pad in place. The brake drum is supposed to rotate in a clockwise direction.

The second picture shows the felt strip in place. Note the screw that used to hold the springy tab.

The third picture shows the test winding of a scan coil using 44 SWG (0.08mm) wire. The winding was 3800 turns and wound at about 300 RPM. The over-run brake was not used for this winding, so it is opened out of the way.

Cheers
Andy