1920s-30s RCA lathe/cutter – what is this?

[jlhowland]

Hello all. I was happy to recently discover the Lathe Troll community. I’m music professor by profession and a vintage music tech hobbyist on the side. While I usually work on vintage amp, electric guitar, and Hammond organ rebuild and build projects, several years ago I picked up a reasonably priced set of 1920s or early 1930s US RCA record cutter parts off of UK Ebay. These were cobbled together in a Frankenstein cutter arrangement that I received some percentage of. Thus far, I have found nothing resembling this cutter online. Based on the home-cut discs I received, as well as the odd assortment of parts, the last owner (not the original owner) had worked with this in the 1950s and 1960s. I’ve now started the tinkering process. I’d like to cobble together a working record cutter system for in-class production-history lectures at my job. I’m not expecting high quality, but “working” is the key here.

I’m hoping that the older-vintage-interested cutter enthusiasts here can help me simply identify what it is I have, hence not posting this simply to the newbie list (which I will use later). But, yes, I’m an official “newbie” – new to cutting and rebuilding this area of music technology, so I know there will be a learning curve.

Copied below are images of some of the parts. The RCA cutter head is marked as MI-4840/MI-4841 (see inside head image). This is Camden, NJ, era RCA equipment. (I have ten years in NJ, so I appreciate that!) The measured output impedance is 12.5 ohms, so if this works like speakers, then it is rated 16 ohms, correct? Also copied here are shots of the iron lathe and a shot from the case of the massive iron turntable motor. The markings (shown) list this as model no. R53787QJ, if that is of any use. I haven’t included the bakelite playback arm and pickup, the turntable platter (ten-inch), and other original parts. (And then there are the newer elements.)

Is there any historical knowledge that members can share about this equipment? And what of the cutter head? Am I correct on the impedance? What amp output should go into this? Thanks for any and all information, wisdom, and speculation that can be shared.

John

[TonyD]

Ive never seen one if these but it looks so cool!!! The carraige definetly looks RCA to me though. I couldnt tell you the exact model or anything though. Good luck and welcome!!

[piaptk]

The overhead design also looks a little like a very early version of the Radiotone style as well.