#1 Repairing a Classic Tonearm
Posted: Sat Dec 12, 2020 6:15 pm
My SME 3009 Series II Improved arm had been bothering me after I noticed a couple of weeks ago, that the way rod carrying the tracking force scale and rider weight, was not level with the armtube. It was pointing slightly upwards.
Further examination revealed that the counterweight was sagging, the cause being, that the two bottom rubber bushes, of the three that make up the decoupling arrangements on the spider carrying the threaded counterweight stub had become compressed over the years.
You can read plenty of stuff about saggy counterweights on the older Series I tonearms, and places like Peak Hi-Fi sell the rubber insert for the rear of the armtube and provide fitting instructions, so the older arms can be kept going.
The Series II Improved arm does not seem to have an easy solution to the saggy counterweight issue, and nobody seems to talk about it much - probably because the Series II improved is not as desirable an artefact. Replacement spiders are available on ebay but they are invariably used and I wouldn’t want to take a chance on one. Also the rubbers in the SME spider, even if you could get a NOS one, are going to be knocking on forty years old and could be either hardened or perished.
It is easy to remanufacture the rubber insert for the Series I arm, but the triple bush spider on the Series II is another matter altogether, requiring a clockmakers bush press to push out the tiny retaining pins, so that the rubbers could be changed.
So for me, it was either, take a chance on a used spider off ebay, or get creative. As I’m a tight b’stard, I decided to get creative.
I have a reel of black waxed wire loom, lacing twine, from my BT days and I can do clove hitches, so with a magnifying light and a lot of care, I put a clove hitch of the waxed twine around each of the bottom two spider pins. This had the effect of forcing the tiny rubber bushes away from the rear plate holding the counterweight stub, the two turns of twine filling the resulting gap.
This little bodge, straightened up the counterweight stub plate and made the sixteenth-inch gap between it and its opposing armtube plate, nice and parallel. Fitting it all back together resulted in a perfectly level wayrod and the counterweight was no longer saggy.
The improvement in the sound quality of the arm was quite something, and the repair is completely invisible and keeps the arm original.
A good result all round. Sometimes with these classic products, one has to do a bit of thinking outside the box to keep them going. I suppose the same is true of classic bikes and cars.
Further examination revealed that the counterweight was sagging, the cause being, that the two bottom rubber bushes, of the three that make up the decoupling arrangements on the spider carrying the threaded counterweight stub had become compressed over the years.
You can read plenty of stuff about saggy counterweights on the older Series I tonearms, and places like Peak Hi-Fi sell the rubber insert for the rear of the armtube and provide fitting instructions, so the older arms can be kept going.
The Series II Improved arm does not seem to have an easy solution to the saggy counterweight issue, and nobody seems to talk about it much - probably because the Series II improved is not as desirable an artefact. Replacement spiders are available on ebay but they are invariably used and I wouldn’t want to take a chance on one. Also the rubbers in the SME spider, even if you could get a NOS one, are going to be knocking on forty years old and could be either hardened or perished.
It is easy to remanufacture the rubber insert for the Series I arm, but the triple bush spider on the Series II is another matter altogether, requiring a clockmakers bush press to push out the tiny retaining pins, so that the rubbers could be changed.
So for me, it was either, take a chance on a used spider off ebay, or get creative. As I’m a tight b’stard, I decided to get creative.
I have a reel of black waxed wire loom, lacing twine, from my BT days and I can do clove hitches, so with a magnifying light and a lot of care, I put a clove hitch of the waxed twine around each of the bottom two spider pins. This had the effect of forcing the tiny rubber bushes away from the rear plate holding the counterweight stub, the two turns of twine filling the resulting gap.
This little bodge, straightened up the counterweight stub plate and made the sixteenth-inch gap between it and its opposing armtube plate, nice and parallel. Fitting it all back together resulted in a perfectly level wayrod and the counterweight was no longer saggy.
The improvement in the sound quality of the arm was quite something, and the repair is completely invisible and keeps the arm original.
A good result all round. Sometimes with these classic products, one has to do a bit of thinking outside the box to keep them going. I suppose the same is true of classic bikes and cars.
