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VPI TNT Bearing question

Trolling the net tonight and ran across a site that showed a MK 5 bearing for the TNT which was attached to the table via a large threaded nut which screwed onto the bearing housing making the housing the equivalent of a giant bolt and nut.

Has anyone done this upgrade? Results? It was suggested that the improvement came from the different attachment method rather than any change in the bearing itself.

Thoughts and experiences?
apbiii
brf
1,715 posts
 
That bearing, and its companion MKV platter is what I have on my TNT. According to Mike at VPI: "they are as good as anything we have ever made; including the Super Platter".

Totally agree 100%. I used both the Super platter and the MkV platter. Kept the MkV platter and returned the Super Plater.
apbiii OP
39 posts
 
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.
brf
1,715 posts
 
Please allow to offer some clarification. The MkV mechanical coupling is vastly superior to that of the 3 bolt coupling. VPI also changed to this type/method of coupling the newer JMW Memorial tone arm bearing; it is basically a mini MKV setup.

My only concern with modifying an older TNT bearing to utilize a single bolt coupling method as deployed in the MkV is that the older bearings are aluminum and I am not sure if your could get the appropriate torque without stripping the soft aluminum threads. If you are interested in my back up MkV bearing, send me a pm.
ketchup
700 posts
 
I am not sure if your could get the appropriate torque without stripping the soft aluminum threads

Does VPI give a torque spec for any of their bearings? If you were to strip aluminum threads tightening any component on a turntable you are applying way to much force.
dgarretson
2,608 posts
 
Whatever VPI has done with subsequent iterations of the platter bearing to improve coupling between the bearing housing and the plinth, my point is that massive brass coupling of the metal bearing housing to the platform below will surpass the acrylic plinth in dissipating parasitic vibration from the system. This is based on several modifications to TNT spindle bearing and suspension I've performed that substitute brass for plastic. If you have access to a machine shop, try it you'll see. The construct can be extended to a brass pedestal that extends from the tonearm pedestal through the plinth to the platform. I've done it and it works. After enough of this the acrylic plinth becomes little more than a means of locating the spindle and tonearm in the horizontal plane.
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