Leadscrew

[FatFreddie]

I have a question, what type of bearing are you going to use for the turntable. It will need to be supported over the whole surface and have extremely low noise levels, so low in fact that you may have trouble engineering it. Forgive me if i'm reading too much into this, but to cut a record involves physically cutting a groove in a disc. So the turntable have to be rigid to avoid any deflection when cutting and have no bearing noise (wow and flutter).

I suspect the cutting forces will be quite low (is any data available?) so you can, to some extent, substitute mass for rigidity.

For the turntable I'd think that a spindle supported on some decent quality bearings with a platform above it and then the turntable itself above that supported by some noise absorbing material would work quite well. Most of the mass should obviously be in the top part.

Drive could then be to the spindle via a belt to isolate motor noise. A bit of tuning of the feedback loop should give you good wow (low frequency speed variation) response and the mass should sort the flutter (high (relatively) frequency speed variation) out.

Sounds easy :lol:

[fusionkid]

For the turntable, I have found a complete direct drive "pro" turntable it has 5kg of torque which beats anything else available these days. Technics 1210s have been used successfully but at 1.5kg torque wow/flutter does manifest itself. What i have found should suit my purpose, but if i get to the stage of building my own i would look at using an precision lapped thrust bearing, oil bearings/drives have been used but they prob. too complicated or expensive for my purpose. The use of heavy platter reduces wow/flutter too. Whatever - i will be looking at pro turntable designs old and new, i don't feel it's necessary at this time to personally further development in this field! Most of the lathe parts should be off the shelf.

Cutting heads - There are a couple available, i intend to build my own, there have been successfull heads made from a pair of tweeter (speakers)

On the feedscrew again, i would prefer as many off the shelf parts as possible including the nut, i am now going to look again at what's available

Neumann lathes start at around £10 000 these days for a VMS66 upto maybe £45 000 for a VMS80 (DMM lathe) setup. It's extremely unlikely that any studio would put a lathe in the skip, they're too rare and valuable. An pro audio broker would bite your hand off, the last few i've seen were sold rapidly!

I haven't seen a lathe driven by gravity! But i know one of the first portable disc recorders (during WW2) had a turntable driven by a wound spring like a gramaphone, and a battery operated electrical cutting head, they were used in the trenches!