TNT bearing housing info request

TNT bearing housing info request

Postby bdp24 » Thu Feb 15, 2018 7:18 pm

Hi Harry and forum members. HW, I bought an HW-19 MK.1 from Brooks Berdan in the late 80's (miss him a lot, too), and put a MK.2 Delrin platter on it when that platter became available. I loved the table (with a Rega 300 mounted on it), but sold it in the mid-90's (for a reason I won't go into here). I have nothing but fond memories of the table, and recently decided to get another. I found a nice piano black finish MK.2 with acrylic top plates (plinth?), all original except for the slightly enlarged hole for the bearing housing (from 1" to 1-1/4"). The seller told me he had enlarged the hole to be able mount the larger housing of a different VPI platter, the model of which he didn't tell me. He sold that platter and bearing separately, and I received the table with it's original platter and bearing remounted. The larger hole did not compromise the original three little holes through which pass the bolts that secure the stock bearing housing to the plinth.

I started reading the VPI forum, looking into what HW-19 owners had done to improve the table's performance. I did the same on Audiogon. I learned about all the different platters and bearings that VPI has gone through, and read differing opinions of all them. I also read descriptions of the various platters and bearings, some of which contradicted each other, especially in regards to the TNT models. For instance, I read that the TNT-1 through TNT-5 had 1" bearing housings, but also read that in order to mount one of those on an HW-19, the hole in the plinth for the bearing housing would need to be enlarged. But since the HW-19 has a 1" housing, both of those statements can't be true. Question #1: are all TNT-1 through TNT-5 bearing housings 1"?

I know the Aries 1 and TNT-3/4 have a 1" bearing housing. I saw pics of the Aries 1 plinth with it's bearing housing removed, and know that that plinth does not have the 3 little holes for mounting the bearing housing that the HW-19 does. That tells me the Aries 1 must have a 1" stainless steel housing with threads on it's exterior, as the aluminum housing was never made with those threads. And I know the HW-19 has a 1" aluminum housing, with 3 little holes in it's mounting flange for securing it to the plinth. But I've read that early TNT's also had the aluminum version of the housing. Question #2: Are all TNT-1 through TNT-5 bearing housings threaded stainless steel?

I did a Google Images search, and saw a pic of a for sale ad from a few years ago. It was an ad for a TNT-3/4 platter, and included with the platter were three 1" spindle/bearing housings. All three spindles were identical stainless steel, and two of the housings were threaded stainless steel. But the third housing was an aluminum one, with the 3-hole mounting flange. Since VPI spindles/bearing housings come as a set, that tells me the TNT spindle (which is different than the HW-19's spindle) with an aluminum bearing housing was installed on some version of the TNT table. Or, is the aluminum housing I saw with the TNT spindle in it actually an HW-19 housing? Are the interior dimensions of the HW-19 and the TNT housings, and the dimensions of the HW-19 and TNT spindles, identical? Was the TNT spindle/HW-19 housing offered as set?

To get clarification, I called VPI and talked to Marc. I asked him if the 3-hole mounting version of the bearing housing was made in both aluminum and stainless steel, or if all the ss housings had the exterior threading for a retaining nut. He put me on hold to check, and came back to give me the answer: all 3-hole housings are aluminum, none were machined of stainless steel. He also told me all TNT's came with the threaded stainless steel bearing housing. I know the Aries 1 came with the threaded ss housing, but I have not only seen pics of a TNT spindle installed in an aluminum bearing housing (as I just said), but have one on the way to me! I bought a TNT-3/4 platter, and it has the aluminum/3-hole housing. Question #3: If the Aries 1 and all TNT-1 through TNT-5 platters came with the threaded stainless steel bearing housing, where are the TNT spindle/aluminum housing sets coming from, and what table was it mounted on, and with which platters?

Very confusing! Thanks---Eric.
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Re: TNT bearing housing info request

Postby bdp24 » Fri Feb 16, 2018 11:58 am

Never mind, ya'll. I emailed Harry, and he promptly responded, providing me all the information I sought. Most unusual, and greatly appreciated!
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Re: TNT bearing housing info request

Postby Johnny » Fri Feb 16, 2018 1:24 pm

You should post the answer to close out the thread
Last edited by Johnny on Sat Feb 17, 2018 8:42 am, edited 1 time in total.
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Re: TNT bearing housing info request

Postby bdp24 » Fri Feb 16, 2018 10:26 pm

Oops Johnny, my ignorance of proper forum etiquette is showing! I'll provide all the details in the even longer post I did in the Support section of the VPI Forum. My apologies, I didn't want to bore everyone with what I thought would be of interest to very few.
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Re: TNT bearing housing info request

Postby WntrMute » Sat Feb 17, 2018 10:39 am

This is one of my pet peeves. People ask a legitimate, interesting question and then the thread runs amuck for a few weeks/months but the OP never (not never) returns to give feedback or even to say thanks. This isn't addressed to anyone specifically BTW. Just a trend that I find irritating.
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Re: TNT bearing housing info request

Postby bdp24 » Sat Feb 24, 2018 5:48 pm

I have received the TNT-3 platter and bearing I bought to install on my HW-19. I know it's a -3 (rather than a -4) because of the invaluable info I received from Harry in an email, that info available in the Support Forum section in my post entitled "TNT platter/bearing confusion!". I had measured the bearing housing hole in the acrylic plinth on my 19, and found it to be just a hair under 1-1/4". I knew the 19's former owner had enlarged the hole for a bearing he had mounted, but didn't know which bearing that was, and was of the impression that the factory hole had been just big enough for the 1" original bearing. The three little holes around the bearing hole in the plinth are right up against that big hole.

Upon receiving the TNT-3 platter (very cool, much better than the 1" Delrin that came on the 19) and bearing, I measured the housing, and it's exactly 1-1/4". It is the aluminum version with three little holes for securing it to the plinth. I didn't think it was going to slide into the hole, and I was right---it's just a hair too big. Did the HW-19's come with a hole that big, just under 1-1/4"? Anyway, I again emailed Harry with questions about putting the TNT spindle in a 1" HW-19 bearing housing (which I knew wasn't a great idea), and Harry said I could send in the TNT housing and VPI would shave off an eight of an inch, the better solution.

I could do that, or I could take a drill bit or abrasive sanding disc and just enlarge the hole 1/16-1/8". Either way, the three little mounting holes do not line up with those from the stock HW-19 housing, as the TNT mounting collar is much larger in diameter than the 19's. So I will need to drill holes in the acrylic plinth at the locations of the holes in the TNT housing collar. Has anyone drilled acrylic before? I don't imagine it's too hard to do, and I have done some woodworking with drills, routers, sanders, etc. The three holes are far enough apart that they may be over the steel frame under the acrylic, so I'm thinking I'll drill just pilot holes for the three 1/2" screws that came with the TNT-3 housing, rather than try and drill all the way through the steel, in order to use bolts and nuts.

Opinions, experience, anyone? Thanks---Eric.
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Re: TNT bearing housing info request

Postby Johnny » Sun Feb 25, 2018 9:20 am

Where’s Brf?? He could help you out.
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Re: TNT bearing housing info request

Postby Brf » Mon Mar 05, 2018 11:29 am

Sorry for the late response. Your best course of action is the enlarge the hole.

You can use a stepped reamer bit or a Dremel like too with a drum sander attachment. The SS metal plat will offer some resistance, but since you are only enlarging the hole a touch, patience and perseverance will prevail.
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Re: TNT bearing housing info request

Postby bdp24 » Wed Mar 07, 2018 1:17 am

Yep Brf, enlarging the hole 1/16" with a drum sander is exactly what I'm doing. Thanks---Eric.
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