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 Post subject: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 3:06 pm 
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Victor Jr
Joined: Sat Apr 07, 2018 9:15 am
Posts: 6
Hi everyone! I'm new here, but have some experience with collecting. I have a few questions about a recent purchase.

I just received a portable Grafonola 100 (my first Columbia) from ebay, which is in pretty good shape, though I plan on replacing the sound box gaskets and cleaning the motor.

As you will see in the pictures I've attached, I discovered a problem with the tone arm. It sits very loose in its attachment to the body (does this have a term?) Basically, it's jiggly, and rests on the record when I lower the needle, stopping the motor in it's tracks. It appears there are ball bearings in there.

So before I open it up, does anyone have any thoughts/opinions/solutions to my dillema? I think the tone arm is made from pot metal, so I'm afraid of cracking it if I'm not careful.

Thank you :)


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File comment: Nice looking machine
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File comment: :'(
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File comment: Me holding it up in what I beleive would its proper position
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File comment: Tonearm in resting position
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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 5:43 pm 
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Victor III
Joined: Sun Mar 15, 2009 6:18 am
Posts: 766
This arm is held in place by a screw on the back of the base that holds it tighly. This screw may be loose in your case. The problem is that its base and the arm are all made of pot metal, so be very careful when handling it or it will crack. It has ball bearings, but to remove them you would have to manually push apart the sides of the retaining cylinder of the base, which I never tried as it would risk cracking it in two. Another alternative, if you don't want to risk fiddling with the pot metal, is to unscrew the arm with its base from the motor board and make a pad with the the shape of the base, in plastic or other material, and install it under the base. This would lift the arm and allow it to play records, and would not be very noticeable if done with the same shape as the base. The Columbia 100 is a nice machine, but it has a minimal margin between the arm and the disc, and even with properly aligned tone arms it will scrape over warped records.


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 7:03 pm 
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Victor Jr
Joined: Sat Apr 07, 2018 9:15 am
Posts: 6
Thank you! I definitely do not want to fiddle around too much with the pot metal!

So I removed the tone arm from the case, and I don't think I am missing any screws (my first suspicion). I'm assuming the notch in the tone arm is to oil the bearings?

Is the screw you are talking about the long bolt secured with two nuts? If you see in the picture, there seems to have been some kind if washer there, which may have corroded or broke down?

There is a think cork pad on there already, so I'm also measuring to see if I could make a thicker cork pad.

On an unrelated note, do you notice how the threaded tube has separated from the soumd box portion of the tone arm? The ends are knuckled, so what would be a good solution for securing these pieces, other than sheer pressure?


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 7:53 pm 
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Victor Jr
Joined: Sat Apr 07, 2018 9:15 am
Posts: 6
Ok, so small update!

It turns out that corrosion was a bit of solder which was preventing me from tightening the bolt. I picked it out and tightened the bolt. Still wiggles, but, success--clearence! I'm wondering if a previous owner soldered it. How tight is too tight for pot metal?

After doing this, I was able to play a disc all the way through, though the motor struggled (which I expected--haven't looked at it yet). Could you look at the attached photo and tell if the needle is resting in the groove properly? I'm a little concerned.

Sorry for all the questions!


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 9:42 pm 
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Victor V
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Joined: Tue Dec 14, 2010 1:17 am
Posts: 2770
Location: Where there's "hamburger ALL OVER the highway"...
The soundbox does look a little bit off the perpendicular from this angle. Did you replace the cork gasket? One side looks a bit thicker than the other, which may explain the slight tilt.

It is definitely a good idea to go over the motor thoroughly: hardened grease and gummy oil can rob power.

Bill


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sat Apr 07, 2018 10:22 pm 
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Victor Jr
Joined: Sat Apr 07, 2018 9:15 am
Posts: 6
Besides examining the tonearm, I haven't touched anything. Probably wont be ready to open up the sound box for a while. I do plan on replacing the gaskets and what not(I think the diaphragm is ok).

Dumb question, but what cork gaskets are you referring to?


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sun Apr 08, 2018 9:32 am 
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Victor III
Joined: Sun Mar 15, 2009 6:18 am
Posts: 766
tesch1932 wrote:
Thank you! I definitely do not want to fiddle around too much with the pot metal!

So I removed the tone arm from the case, and I don't think I am missing any screws (my first suspicion). I'm assuming the notch in the tone arm is to oil the bearings?

Is the screw you are talking about the long bolt secured with two nuts? If you see in the picture, there seems to have been some kind if washer there, which may have corroded or broke down?

There is a think cork pad on there already, so I'm also measuring to see if I could make a thicker cork pad.

On an unrelated note, do you notice how the threaded tube has separated from the soumd box portion of the tone arm? The ends are knuckled, so what would be a good solution for securing these pieces, other than sheer pressure?


You could make another thicker cork pad, it is easy, and from the photo the original one looks damaged.
The screw I mentioned is the bolt you found, as you can see, it is the tightening of that bolt that keeps the pressure on the retaining cylinder. The little hole, I believe, is for lubricating the bearings, and probably was used to install them originally by forcing the cylinder apart and dropping the bearings on their track. You could try to carefully tighten the bolt to reseat the arm.

I cannot help you with the threaded tube, I never disassembled mine. Just be aware that the whole arm is made of pot metal, so be careful when exerting pressure.

My recommendation is to leave it alone, now that you made it work. You could add a new cork pad and that's it. Fiddling with pot metal is very risky. Clean the motor, relube it, replace gaskets on the soundbox and you will end up with a nice gramophone!


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sun Apr 08, 2018 5:19 pm 
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Victor III
Joined: Sun May 27, 2012 2:38 pm
Posts: 608
Location: United Kingdom
I think you have done all you can with the arm on this machine. I have only once, in fifty years of collecting gramophones, come across a 100 with an arm had had no "sloppiness". Until recently I had four of these machines sitting on a shelf in my workshop, all waiting for replacement arms. It became obvious after a few years that I was waiting in vain, so reluctantly, I scrapped the machines. The arm on yours should be sitting a lot higher, so that the soundbox sits at right angles to the record, but don't be tempted to turn that nut any further in an attempt to tighten the base, I guarantee you it will split. What causes the "sloppiness" is the weight of the arm hanging off the base when the machine is stored on it's side for a long time, in some cases, years. This results in the base becoming oval in shape, rather than round, so even if you did manage to tighten the nut, it would make the narrowest part of the oval so tight that the arm wouldn't turn. Been there, done that!


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sun Apr 08, 2018 7:41 pm 
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Victor Jr
Joined: Sat Apr 07, 2018 9:15 am
Posts: 6
Thank you all for the words of sound advice! I tend to get carried away too soon, so what I needed most was a firm "don't do it!"

Just one more concern about the tone arm and then I'll leave it be is the part which attaches to the soundbox which has come loose from the piece of threaded tube. On the one hand, it appears that it is meant to come off, on the other, I think that joint has a part to play in the soundbox not sitting as it should. Is there some kind of gasket that should go there. I'm thinking of maybe cleaning it carefully, and then using locktite or something to attach it?

I was very excited to get this machine, and it's my first portable. And the price was a no brainer. So, 1. Clean and grease motor, 2. Make a cork pad for the tone arm holder 3, replace gaskets on soundbox. (I'm assuming it's a #15? I plan on dollowing the instructions form the late Graham Barber), and 4, don't try and mess with the bearings on the tone arm!


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 Post subject: Re: Columbia Grafonola 100 tonearm, help!!
PostPosted: Sun Apr 08, 2018 11:40 pm 
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Victor V
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Joined: Tue Dec 14, 2010 1:17 am
Posts: 2770
Location: Where there's "hamburger ALL OVER the highway"...
tesch1932 wrote:
Besides examining the tonearm, I haven't touched anything. Probably wont be ready to open up the sound box for a while. I do plan on replacing the gaskets and what not(I think the diaphragm is ok).

Dumb question, but what cork gaskets are you referring to?


The 'cork washer' on the bottom of the tone arm. As mentioned, you could make a thicker one to raise the tone arm, and possibly help it to sit straighter.

Bill


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