FERROGRAPH FACT SHEET

   Three sad looking idlers wheels

Two unfit pinch wheels

Either the rubber goes very hard and disintegrates, or it softens until eventually it becomes

soft and sticky like tarmac on a hot summers day. The softening seems to happen quite quickly (6-12 months or so) relative to the life of the machine.

You could always buy old wheels recovered from scrapped machines (what a crime!) but they could turn to mush just as quickly if they are taken from a series 7 machine.

I saw so much written about the problem with Series 7 idler wheels, but no one (or at least no one in the UK) seemed to be getting very far with it, so in a moment of madness, and with a rush of blood to the head I decided to see what I could do.

After searching in vain for a supplier of new Ferrograph idler wheels, I contacted a local

manufacturer of high quality rubber mouldings to the aerospace, defence, maritime, medical, auto-sport & motor industry. Their product range includes rubber mouldings and rubber to metal bonding.

I was very lucky as this company manufactures only custom parts, and is very involved

in restoration work. Using the latest technologies, they can produce components which have been long out of production.

I visited them taking along three idler wheels from a Series 7 model 722H which were in various stages of decaying into liquorice, and one idler wheel from a Vortexion WVA, with a series 5 deck, which was in fine condition.

Their technical experts examined and tested the compounds and concluded

a)     the Series 5 idler wheel is made from Neoprene

b)    the Series 7 wheels seem to be based on natural rubber

Regarding the Series 7 wheel they commented “it is possible that it was not fully cured. This would be consistent with the stickiness and the marks left on one’s fingers etc.

It doesn’t make much sense unless someone was cutting corners to save money.”

So the outcome of this visit is that I asked them to manufacture a custom mould to re-cast neoprene rims on existing wheels. The process involves removal of the existing compound, ultrasonic cleaning and degreasing and then hot bonding the new rubber to the metal wheel. The bonding takes place under pressures up to 170 tons at temperatures up to 200°C depending on material. This ensures the best possible bond.

After the casting the wheels are de-flashed and bead blasted to give a quality finish as shown below

Above: Cleaned up wheels ready for moulding

Above: New idlers. These look better don’t they.

Above: Pinch wheels with a new lease of life

My aim is not to make a fortune, but to save otherwise good Ferrograph machines from the scrap heap. The turnaround time is in the region of four weeks as I need to fit my small requirement into the factory schedule.

Remove the idlers from your recorder,taking care to retain the circlips etc in a very safe place.  Send the idlers to me, preferably recorded delivery, and I will make them "better" than new again.