EMG Mk X tonearm advice sought

IainW · Post by **IainW** » Sun Dec 29, 2024 1:55 pm

Hope you all had a good Christmas. I am seeking advice as to what I can expect when unscrewing the Mk X gooseneck tonearm from the cabinet. Will I be confronted with a load of loose balls, some of which may drop into the U tube while others roll down and disappear between the floorboards, or will I find a caged race as per Grahams Xb tonearms?
Thought it a good idea to ask before I blithely unscrew the bearing cap and end up cursing.
Thanks
Iain

kirtley2012 · Post by **kirtley2012** » Sun Dec 29, 2024 2:12 pm

Earlier Mk X's will have loose ball bearings, I think mine does, if there's enough grease on there they won't go rolling all over the place, but you may still have a nice evening filled with fishing ball bearings out of the conduit

Post by **emgcr** » Sun Dec 29, 2024 6:00 pm

Iain, Happy Christmas and Hogmanay !

Alex is quite right and I hope these photos will give you certainty as to which type you have. The early type has loose ball bearings whilst the later type has a fully enclosed ball-race which will be removable in one piece without any danger of individual balls falling out. In the case of removal of the early type I would always unscrew the entire bearing housing first which can be done by taking out the three flange wood screws and unscrewing the whole assembly in an anti-clock direction thus separating the complete tonearm from the internal conduit (remove soundbox first !). If the assembly has been in place for many years it might be necessary to start the process by gently tapping one of the flange holes with a nylon or perhaps aluminium drift of suitable diameter. It is then easy to dismantle the housing over a large tin to contain wandering balls. Note there is a grub/locking screw in the side of the cap which also needs to be slackened/removed to allow uninterrupted movement.

Please be extremely careful upon reassembly not to overtighten the cap thus indenting the brass tracks. Having introduced light grease, just nip up the threads to eliminate any play whilst still allowing unimpeded movement. If previous owners have not done this and you find indentations, and thus notchy movement, I am afraid it will be necessary to remachine the track(s). Retighten the grub screw but, again, without too much pressure to avoid distortion of the fragile brass threads.

Whilst on the subject it might be worth noting that the early type EMG bearing was current for all goose-neck and some swan-neck tonearms until the improved design arrived. Expert gramophones (unfortunately) used the early type with loose ball bearings throughout their production run and with goose-neck tonearms exclusively.

I hope this is helpful.

IainW · Post by **IainW** » Mon Dec 30, 2024 5:10 am

Alex, Graham, Thanks very much, that's really useful. From the photos mine is the early version however no locking grub screw so maybe this was a later refinement. Anyway I will proceed with caution and remove unit from cabinet complete before disassembly.

IainW · Post by **IainW** » Mon Dec 30, 2024 6:00 am

Well that was easier than I thought. Removed tone arm and taken apart as per attached photos. There are 23 of 3/16" loose balls which are probably worth replacing as some feel quite rough and there is a bit of muck in with the thick oil. Only marking seen is the number 3 on the underside of flange. Will clean up and reassemble with steering box lube.

Post by **emgcr** » Mon Dec 30, 2024 8:32 am

Well done Iain and it is always very interesting to see the progress of the original development on the technical detail front such as the locking screw. The latter does seem to be a worthwhile idea to maintain the "set" of the critical adjustment but these days I suppose a dab of Loctite would probably be better. Your use of steering box lube is a good idea. The number 3 is also interesting and would seem to point to a pretty early machine although nobody has yet discovered any definitive dating records (please excuse the pun !).

IainW · Post by **IainW** » Mon Dec 30, 2024 2:55 pm

Graham, I notice there is an annular groove half way down the bush where the tonearm spigot fits. Would there have been some sort of 'O' ring seal here or is it just to retain the lubricant?

Post by **emgcr** » Mon Dec 30, 2024 6:43 pm

Like you I suspect, I have always assumed that the groove is there to contain lubricant which is why I use a light grease at that point which also acts as an air seal---desirable to maximise bass frequencies. However, I cannot argue with your thoughts of a viscous oil at the higher level to promote free-running although a light grease does aid assembly ! I have never come across or heard of an "O" ring at that lower point---indeed I think they were a pretty new invention in the early nineteen-thirties ? Felt certainly (not suitable in this narrow groove ?) but I am not sure about rubber/neoprene etc. I think slightly increased friction might have interfered with the required free movement ? Interesting question. Thank you.