VPI TNT Bearing question

Thanks for all the responses. My thought was not in finding a MK 5 bearing but in modifying the mount of the bearing I have. There are a couple of options that come to mind but the housing appears to be thick enough to thread and attach like the MK 5.

Interesting to learn of the material change for the housing. If I understand correctly from Brf the method of mounting makes no difference so the gain would appear to come from the stainless housing and or different rulon inserts.

It is interesting to note that my TNT mounts the bearing with three screws tapped into the acrylic but I see there are another set of holes with what appears to be a broken tap or screw in one. Perhaps that is why they went to through fasteners on the later models.

Very interesting and thought provoking responses.

I am not worried about aluminum threads stripping and suspect you could shear of the top collar of the bearing housing if you apply enough torque (consider the amount of material engaged in the threads compared to the amount of material in the flange).

Dgarretson has done some very nice mods. As I read more about turntables I had begun to wonder if more mass on the bearing housing would be beneficial and I think he is saying it is.

The feet are pretty slick also. Do I understand that the flex provided by the fingers of the cup which holds the ceramic balls is enough to give a bit of vertical compliance as the four balls on the bottom move in and out allowing the top ball to move up and down? Some more details on the foot construction would be nice.

Your AC supply for the turntable bears some research as I have been looking for something that would do that.

As to machinist, while I am not a pro I do have pretty good skills and a very well equipped shop in my garage so I can fabricate a lot of this sort of stuff.

Lots of food for thought...

Yes it is a bit of a crap shoot but you really would not have much invested except time unless you use some super exotic bearing material such as rulon and even then you don't need much of it for a TT bearing.

I think making a turntable bearing for a one off is a bit easier than manufacturing them. On a one off you only need to get the clearance right, the absolute dimensions don't matter that much.

You would need a decent lathe with a tool post grinder and someway to ream or hone the bearing to fit.

I have not seen anyone attempting this task. As I understand it Dgarretson only made a weight to attach to his bearing, not the complete bearing.

I'm not sure what sort of clearance is involved but I have two VPI bearing / spindle sets and they are both pretty tight.