Production of new EMG swan-neck tonearms.

[emgcr]

The most unobtainable, difficult to make and expensive part of any EMG gramophone has always been the tonearm. I believe
this item has not been manufactured since 1939 and it is thought that the very limited post WW2 production of acoustic gramophones used up pre-war items.

Some years ago I made a batch of Xb aluminium conduits (yet to be polished---see attached photos) most of which have been utilised to bring incomplete base units back into fully operating condition. The surplus is of little use unless matching tonearms can be found to complete the unique EMG technology, thus I resolved to produce a matching number of eleven new swan-neck tonearms. Many of these have now been employed in the completion of machines/instruments and I have a few surplus to immediate requirements.

At the outset of the project I went hunting for the correct encapsulated ball-bearing set and was disappointed to find that it was discontinued and therefore unobtainable. This would not have created an insurmountable problem as new manufacture could have incorporated different internal measurements to allow use of another bearing with slightly different coordinates. However, I then heard of a wonderful firm by the name of “The Vintage Bearing Company” in Burton-on-Trent---email : vintagebearing@aol.com ---which had the correct specification items immediately in stock—hallelujah ! The project has taken over two years and, during this time, I somehow managed to lose this first batch of eleven bearings so had to buy all again ! The problems of getting older……!!

The next part of the investigation was to establish how the original items had been made. A special “X-ray” showed that the main cast brass/bronze arm was produced in two pieces. I wondered if it could be done in one and the very clever foundry---Harling Foundries Ltd, Hastings---email : sue@harlingfoundry.co.uk--- managed to achieve success after a protracted and frustrating period of experimentation resulting in the manufacture of a single traditional wooden pattern. The same brilliant foundry produced the castings for the initial part of the Xb horns some years ago---also a difficult task.

Maintenance of the position of the core and therefore wall-thickness was the main concern, thus the first sand casting was sacrificially drilled in several places to prove requirements. Machining was the next phase which, again, was tricky in view of the awkward shapes involved. Silver-soldered additions of previously machined items could then be made to both ends of the arm. The swinging section of the swan-neck was made and bent in copper tube with brass additions at both ends. It is worth noting that cast brass/bronze was not used for these items so as to allow flexibility of fine-tuning when setting individual “offset” of the finished item---prior to nickel plating. This is absolutely vital for accurate tracking purposes. A jig had to be made to achieve this.

Machining of the bearing housing complete with knurling and threaded section to allow connection to the conduit was relatively straightforward. I am always at pains to avoid plagiarism and have thus stamped my initials and the production number out of eleven which can be seen on the underside of the bearing flange to avoid confusion for posterity---see photo No.5.

The final process was carefully to polish all items to obliterate and even-out casting marks thus making ready for polished nickel plating whilst having carefully masked off critical areas where plating is prohibited. Bearings/spigots etc are lubricated with fine grease. The thread for the machine screw retaining the swinging swan-neck section is 4BA.

A final point of note is that EMG improved the swan-neck tonearm over the years, in particular with reference to the joint between the underside of the ball bearing and its mating housing. Originally this was merely a butt-joint and the bearing was secured by a narrow threaded collar but this design did not allow for air-tightness. The final well thought out modification involved a long threaded spigot (seen in photo No.3) which, when lubricated with grease, ensured no escape of air and thus safeguarded/promoted the reproduction of the all-important bass frequencies.

Previous posts have given details of new tonearm rests and tonearm stops of which I still have a few spares. The various nickel-plated collars connecting to the veneered casings can be made to order.

[Loudbass]

Another magnificent achievement Graham. Your attention to detail is exemplary. What a way to start 2023.

[Orchorsol]

No words are sufficient to express appreciation for this stupendous achievement... Extreme awe... Congratulations Graham!

[Inigo]

Hats off to Graham!
What a project! Congratulations!

[JerryVan]

Beautiful work!

Photo #8 must have been choreographed by Busby Berkeley.

[Marco Gilardetti]

Terrific work, all parts look awesome! How I wish that quality spares like this would be available for all gramophones...

[CarlosV]

Excellent work! Congratulations!

[BassetHoundTrio]

What an achievement! Really astounding - many thanks for sharing the photos.

[Ahmed]

The amount of work that's gone into these is truly astounding, hats off to you Graham! What an incredible achievement

[Hoodoo]

Wonderful work Graham.
I see the tags on the pieces in photo 6 have numbers that range from 3 ¼ to 4 ¼. What do those numbers signify? The pieces look too similar in the photo to have such a wide variation.
Is the fine tuning of the assembly done by setting the position of the pivot barrel along the tonearm to give the ideal 3 ¾” offset?