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The ART of disc-cutting lathe repair

Dave Robinson 30 May 2017
The ART of disc-cutting lathe repair

ART (Audio Related Technology) Ltd, the repair and technical services business based in Chesham, has just restored – and sold! – a unique, original Neumann VMS-70 disc-cutting lathe. The machine is believed to have been left, unloved, in a Nigerian studio for around 20 years, reports ART’s Simon Griffett.

“During this time it saw little use as far we know. It just sat, unused, in the country’s hot, humid and dusty conditions.”

Proprietor of rare and secondhand gear supplier Funky Junk, Mark Thompson came across the lathe while looking for a Neve 8086 MkII console. Knowing the importance of his find, he Thompson contacted Griffett to see if the machine could be brought back into service.

“With only two photos to go on, the condition could not be judged with any accuracy,” says Griffett, “but after speaking to fellow ART director Duncan Crimmins and long-time friend and associate Sean Davies, we decided we had to give it go.”

Thompson arranged for his Neve (when he found it), a Studer A80 multitrack and the VMS-70 to be shipped back to the UK. “After opening the shipping crates, on first glance, it looked like we had got lucky,” continues Griffett.

However, first impressions can be deceptive: “The electronics rack containing the amps and signal conditioning processors all appeared to be in good condition, with the exception of the power supply.

“Then it dawned on us, the two signal processing modules and the limiter were completely missing!”

One option was to find another rack and, luckily, ART knew where to locate one – it was just a matter of fixing it.

In the meantime, the team started to dig a little deeper into the mechanics of the lathe: then things grew steadily worse…

“Thirty years of hot humid conditions by day and cooling at night meant the condensation on the screw joints and the ferrous metals had really taken its toll. The switch contacts, mounting points, even the aluminium pulleys had becomes pitted and flaky.” (Original lather in situ in Nigeria shown right.)

A project such as this requires a variety of different skills some of which need the help of a real specialist. One such was Peter Knott, a semi-retired toolmaker, who re-skimmed and balanced the vacuum plate and disc platter, “exceeding Neumann’s original specification,” says Griffett.

“The other specialism we required was someone to rebuild the cutter head. We knew that one feedback and one drive coil were broken, so we sent it off to one the few people in the world who can fix it. However it wasn’t long before we got a call saying it was not possible to repair because the corrosion around the tiny screw mounts was so bad they could not be worked loose.”

This was potentially a major problem: “A vinyl lathe without a cutter head is very big paper weight!” jokes Griffett. On return of the head to ART, Griffett’s colleague Duncan Crimmins set about testing various penetrating oils to see what effect each would have on the metal components (in order to loosen the screws without causing further damage). One product was chosen and delicately applied to each screw in turn to soak overnight. “With some modification of standard size screwdrivers, the screws were coaxed out of their housing. The whole process took two weeks but we did get them all out!”

Back went the cutter head to the specialist to have the coils replaced, this time with a bag of screws. “It came back beautifully restored,” reports Griffett.

Trouble with the head wasn’t the only surprise the African treasure delivered: “When we opened the wooden housing containing the vacuum pump, we found (right) the remains of a termite nest! It was solid and required a hammer and chisel to remove it…”

Griffett notes that the audio and control rack had to be completely recapped, and all transistors replaced, many of which had to be sourced from small suppliers from all over the world. “In all approximately, that was 1,000 caps and transistors replaced,” says Griffett.

Then there was a genuinely shocking moment: “When we first applied power we found the chassis was live with 240V – that certainly woke me up when I leaned against it!” The culprit? The insulation in the turntable motor had broken down to such a extent it was leaking 240V direct to earth: “Not a good idea,” warns Griffett.

Eventually, the ART crew were in a position to measure and, finally, test the machine in action.

“When we measured the head against its manufactured specifications we found [the numbers] were significantly improved, so much praise must go the Roberto at cutterheadrepair.com, a great source of lathe facts and info for anyone interested in learning more.”

And the test cuts? “They went really well, with only some minor adjustments required.”

So well in fact, at the end of March, a closed auction for all those interested saw an Argentinian company called Morellosa SA ­ – a printer wishing to move into vinyl mastering – make a successful bid for the completely restored lathe. (Sean Davies and Duncan Crimmins shown here with the finished machine.)

The project had taken a total of 11 months of problem-solving and ingenuity, but ultimately, perseverance saw the team come good.

Back in April when Mark Thompson first approached ART with the broken lathe, Griffett told him it would take that a year to complete: “With luck, maybe 8-10 months. I don’t think he believed it would take so long!”

www.audiorelated.com

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