Those Knowledgeable about Ortofon RS212 Tonearms

[adnick]

Have a RS212 coming and have a Bakelite headshell but missing the additional screw in weight.

After some research I’ve found screw weights ranging from 32 to 41g, and believe the early one’s were around 32g (please correct reference the weight).

However the actual weight is not critical to me, but I’d like to know the dimensions….

If I could impose on someone for the actual dimensions of the screw itself I’d greatly appreciate it.

Thanks in advance,

Andy

 

[adnick]

Bumping this up again….

 

[tnsilver]

Hi Andy. No idea about the dimensions and I don't have an RS-212 ATM. but I've found this Korean website where the owner claims to have recreated the original 32g auxiliary weights in 36g and 42g versions. At the very bottom he had left a phone number for inquires. Perhaps... give him a call?

"For inquiries, call 010 8567 3339"

I think you'll need to dial +82 first.

 

[adnick]

Thanks Tom that’s great info, had come across that and It’s a possibility, very expensive considering but an option nonetheless. Have the ability to make a reasonable facsimile once the dimensions and thread size/type is determined.

Was hoping someone could provide the information from an existing one, but I’ll give it a try.


Thanks again,

Andy

 

[tnsilver]

Have the ability to make a reasonable facsimile once the dimensions and thread size/type is determined.

In that case you could probably make a cast using the RS-212 counter weight as a mold. I think the tricky part would be finding the right compound to pour down the hole, so you can later pull it out as a solid in one non-deformed piece. That's slightly out of my league, but I figure dental casting (resin/wax) compound is likely a perfect candidate.

 

[adnick]

I’ve had luck with modeling clay but never tried threads that way, the tonearm is arriving tomorrow so I’ll know more then.
Will try to find a thread to fit, if unsuccessful I’ll look more seriously at trying to make a cast….

Appreciate the thoughts,
Andy

 

[adnick]

Good news is, finding the thread wasn’t difficult, it’s 3/8 fine thread, that alleviates a lot of angst on my part. Making a functional replacement for the additional counter weight won’t be too difficult.

Bad news is, it came with the bearing housing broken in half Looks like one of the previous owners, probably long ago, glued it back together and then passed it along.

It appears the bearing shaft is the same size on most 212 versions 4mm but the counter weight shaft is unique on the RS212

I’ve disassembled the tonearm, it’s clearly a very well designed arm, the quality is self evident. Now it’s time for some deliberation on how to approach this broken bearing housing. My machinist skills are mediocre, especially on something this small, and it would probably take me several tries to succeed. Buying one of the other 212 bearing housing’s is another option, but it’ll require modifications to work, have to remember my mediocre machinist skills

 

[tnsilver]

I'm no machinist but my trick is reinforced epoxying. I drill a 1mm hole in both halves of the broken part, and then snugly epoxy them on top each other with a nail in the hole, through both. If I break the drill bit - I use that for a nail. It's tough, clean, and you'd never guess it's reinforced.

 

[adnick]

Tom:

That’s a very good idea, may try that approach first, really nothing to loose

VR
Andy

 

[adnick]

Ok so it’s completely disassembled….





Put the 2 broken pieces of bearing housing in an indexer drilled 4 tiny holes on each side, and made pins to fit, mixed some mariners epoxy and glued it up.



Now it’s wait and see…

The sliding piece in the photo below is the part that makes the aftermarket AS121 bearing housings unusable without modifications.

 

[adnick]

Some would consider it asinine for anyone to put this much time and effort into this old tonearm, especially since it’s already missing the counter weight …However it’s a piece of music history and it’s challenging.

For the few that are interested in this, I’m at the point of no return, putting it back together

It appears very solid, I’ll probably go ahead and purchase an AS212 bearing housing and see how much work/modifications it’s gonna need for the RS212.

Polished up everything and lubed the bearings while it was apart.

 

[tnsilver]

Some would consider it asinine for anyone to put this much time and effort into this old tonearm

Not me.

It's a very able tonearm. I don't have one ATM but I had a few on the bench before. I do, however, have an AS-212 if you need any comparisons made.

The bearing housing fix is looking good!

 

[adnick]

Not me.

It's a very able tonearm. I don't have one ATM but I had a few on the bench before. I do, however, have an AS-212 if you need any comparisons made.

The bearing housing fix is looking good!

Hey thanks Tom:

As you can see your pin fix was implemented On your AS212 is the counterweight shaft pressed into the bearing housing?

Got the thing together and dropped in a Shure MD3 into the original headshell and wow I’ve only noticed this kind of synergy between cartridge & tonearm a couple of times before. Always thought the old MD3 sounded good for it’s age but now I’d call it excellent.

Already dark, guess it has been for a couple of hours, was focused on getting this done…only a few days worth of time & labor

I’ll post some photos tomorrow.


VR
Andy

 

[tnsilver]

n your AS212 is the counterweight shaft pressed into the bearing housing?

Yes, the stud on which the CW armtube stub is mounted is pressed into the housing like the one pictured at post #11 in this LH thread. Mine is a Mk-II with the 5mm outer diameter bearings (larger than the 4mm Mk-I), and it was broken as well - fixed in the same way with reinforced epoxying. I did not dare pull the stud, or the mounted CW shaft out of the bearing housing fearing the resin housing would crumble away. That resin does not stand the test of time too well.

 

[adnick]

Yes, the stud on which the CW armtube stub is mounted is pressed into the housing like the one pictured at post #11 in this LH thread. Mine is a Mk-II with the 5mm outer diameter bearings (larger than the 4mm Mk-I), and it was broken as well - fixed in the same way with reinforced epoxying. I did not dare pull the stud, or the mounted CW shaft out of the bearing housing fearing the resin housing would crumble away. That resin does not stand the test of time too well.

Thought the same thing about the housing crumbling, that’s why I’m thinking about trying to configure an AS212 4mm housing.

So far it’s holding together and is an extremely pleasing to listen to, I’m impressed. Hopefully it won’t fall apart too quickly

 

[tnsilver]

Oh, wow, She's a beauty! It's such a classic combo with the TD124, it looks natural. The resin housing may crumble if stressed, hence the reluctance to separate any press fit extensions, but once fixed and reinforced, I'm sure it will hold for a very long time. Mine does.

Other than alternative AS-212 bearing housing, I've also seen offerings for RMG 309, RMG 212, SMG 212 and SKG 212 on the auction site. If push comes to shove, I'm sure you'll find a selection of choices for a similar replacement part. So far, however, your fix looks perfect, so you're probably done with it for a very long time.

Nice job!

 

[totem]

Nice work bringing something damaged back to life.

Regarding your original inquiry on the stub weight and being a 3/8 thread, it might be a close substitute
but Ortofon would not have chosen a fine 3/8 SAE in its build.

As noted above ^ the same length RMG 212 was a well designed arm available with an isolated
and non isolated rear stub dependant on date of production.

 

[BillWojo]

Regarding your original inquiry on the stub weight and being a 3/8 thread, it might be a close substitute
but Ortofon would not have chosen a fine 3/8 SAE in its build.

My first guess would have been a metric thread. Isn't that tonearm made in Denmark? What was the prevalent thread standard back in that time period in Denmark?
In any case, Andy is no dummy and if he say's a 3/8-24 screw fits good, I'll let it rest at that. Closest metric would be a 10mm x 1mm pitch thread. Not sure if that is part of the metric fine thread series or not.

BillWojo

 

[adnick]

Nice work bringing something damaged back to life.

Regarding your original inquiry on the stub weight and being a 3/8 thread, it might be a close substitute
but Ortofon would not have chosen a fine 3/8 SAE in its build.

As noted above ^ the same length RMG 212 was a well designed arm available with an isolated
and non isolated rear stub dependant on date of production.

Thanks,

My thought was that it’s metric, guess it could be some pipe thread?

Appreciate Bill’s faith in my abilities but I could certainly be wrong, however the 3/8 24 screws right in, since this will only ever be snug, I’m happy with the results.

VR
Andy

 

[adnick]

Oh, wow, She's a beauty! It's such a classic combo with the TD124, it looks natural. The resin housing may crumble if stressed, hence the reluctance to separate any press fit extensions, but once fixed and reinforced, I'm sure it will hold for a very long time. Mine does.

Other than alternative AS-212 bearing housing, I've also seen offerings for RMG 309, RMG 212, SMG 212 and SKG 212 on the auction site. If push comes to shove, I'm sure you'll find a selection of choices for a similar replacement part. So far, however, your fix looks perfect, so you're probably done with it for a very long time.

Nice job!

Thanks Tom, do like the looks of it and it’s clearly well engineered….my tonearm repair skills aren’t as evolved as yours and certainly not up to your standards but I enjoy the challenge…

That’s a good suggestion, looking at the R &SMGs ….

VR
Andy