The Talking Machine Forum — For All Antique Phonographs & Recordings

I doubt I'm the first person to think of this, but didn't see any threads about it and figure someone might find it useful.

I was rebuilding a couple Victor reproducers this past weekend, and like to use MicaMonster's method of making bushings/isolators from silicone. I'm also sometimes a perfectionist and am trying to figure out what kind of silicone I like best for this application (a subject for a future thread, maybe). So while the reproducers are ready to go and I want to test them, I don't have the bushings made for them yet. However, I had some 1" OD, ¾" ID surgical tubing on hand. Since that's close to the annular dimensions of a No.2 or No.4 bushing, I grabbed the tubing, a brass mounting collar, and tried it out. I've attached pictures below but it's all pretty straightforward:

Cut a ~¼" long section off some 1" OD, ¾" ID surgical tubing
Stretch the cut-off section of tubing over a brass mounting collar
Stuff it into the throat of the reproducer, align the bayonet pin, and crank down the set screws

It's not a perfect solution - it's ugly and slightly loose - but worked well enough to test and adjust the reproducers to my satisfaction. Wrapping a little electrical tape around the outside might help give a properly snug, airtight fit, but it's still just a stop-gap fix. The useful lives of surgical tubing and electrical tape are pretty short, compared to silicone and synthetic rubbers. This would probably work for Orthophonics too, with some tape and/or slightly larger tubing.

Why bother doing that? Ron Sitko sells these already made. last time I bought one it was $4.00 or $5.00.
Harvey Kravitz

Phonofreak wrote:Why bother doing that? Ron Sitko sells these already made. last time I bought one it was $.0 or $5.00.
Harvey Kravitz

I know, but it was Sunday evening and I had the stuff on hand already. Thought it'd be a fun experiment while waiting on getting some proper bushings ordered or made.

Plus Ron is closed up until January. I think that's a cool idea, even if it's just for experimenting. I completely forgot Ron is unavailable and naturally I'm out of Exhibition micas and flanges. Oh well.

I've been wanting to try doing silicone on a #2, I've got plenty on hand, I just need to rip apart a couple of #2s and chip the old rubber away from the brass fitting.

Sean

One problem I see with the shown solution is that the brass collar is not insulated from the reproducer body at the bottom, which means that metal to metal vibrations will be transferred between tonearm and reproducer. Another narrow piece of tubing should be added at the bottom to avoid that. Also, the protrusions on the outside of the collar are usually embedded in the rubber in order to prevent the collar from rotating inside the insulator. Therefore I could only see this tubing as a temporary stopgap solution.

Andreas

alang wrote:One problem I see with the shown solution is that the brass collar is not insulated from the reproducer body at the bottom, which means that metal to metal vibrations will be transferred between tonearm and reproducer. Another narrow piece of tubing should be added at the bottom to avoid that. Also, the protrusions on the outside of the collar are usually embedded in the rubber in order to prevent the collar from rotating inside the insulator. Therefore I could only see this tubing as a temporary stopgap solution.

Andreas

Neither occurred to me at the time, but you're right on both observations. It's -very- much just a stop-gap fix.

I have a 2 step casting method using silicon rubber. Softer, more flexible, and a tighter seal. The ones sold online are too stiff in my opinion.

Hey Steve,

How about sharing your method with the rest of the class?

Sean

ERG. I consider my method very proprietary. Who knows. Maybe it can be my gift to the world?

MicaMonster wrote:ERG. I consider my method very proprietary. Who knows. Maybe it can be my gift to the world?

I could've worded that statement better, as I meant it only very generally. I first learned about using silicone for bushings/isolators from your posts on the subject some time ago, and wanted to credit you for that. Never intended to actually try to reverse-engineer or copy your work.

I don't post all that much here, and am sorry if I inadvertently stirred up some trouble.