1 - JustAnotherGuy
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- From: Illinois, USA
- Registered: 20-9-2014
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Olympia SM7 Mainspring Trouble
Hi guys! It's been a while since I've been busy with school, but now that it's summer I have loads of time to dedicate to my typewriters. It's nice to be back.
Anyways, let's jump right into this. A few months ago, I purchased an Olympia SM7 cheaply because I was under the impression it needed a new draw band, which is a very common repair I knew I could handle.
Here's the SM7:
As I began to look at it, I realized the draw band was intact and still attached, but the mainspring lacked tension. Easy enough, I thought, I'll just remove the string, wind it up, and attach it again.
No such luck. As you can see from this picture, the string is secured with a pin. The drum had to be wound with the string STILL ATTACHED, which is a much more difficult operation than it sounds. The string was constantly getting tangled and every time that happened I needed to restart. About two hours later, my fingernails torn and sore, it was done. I reattached the band to the carriage and was happily typing away. For about five minutes.
Suddenly, mid-sentence, I heard a loud "sproing!" and the mainspring lost tension. Hours of work, and the only thing I had to show for it were some sore fingers. It was in the same state as when I purchased it - draw band attached, no tension. Evidently this is what happened before I bought it. What's the issue? I don't think the mainspring is broken, because it still holds tension, and enough tension to move the carriage. It just doesn't do it for long. Does anyone know what the problem is and, more importantly, how to fix it?
- Uwe
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Re: Olympia SM7 Mainspring Trouble
After it released tension, was it possible to get the spring to load up again? If so, it sounds like the mainspring is slipping off its drum connection point. You would have to remove the drum and open it to confirm this. The drum on your machine looks to be a sealed unit, so that's not going to be easy. I've repaired a number of sealed units, so it's possible, but it's also a pain.
Maybe I didn't understand your description correctly, but why didn't you disconnect the drawband from the carriage when you wanted to wind it on the drum?
The pronoun I has always been capitalized in the English language for more than 700 years.
- JustAnotherGuy
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Re: Olympia SM7 Mainspring Trouble
Yes, the spring does load up now and yes, I did take the draw band off the carriage to wind the spring.
If I need to get inside the mainspring to fix it, how should I do so if it is sealed, and what specifically am I looking to correct?
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Thread Starter- JustAnotherGuy
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Re: Olympia SM7 Mainspring Trouble
Uwe wrote:
Maybe I didn't understand your description correctly, but why didn't you disconnect the drawband from the carriage when you wanted to wind it on the drum?
I was unclear. I couldn't remove it from the drum, so while I wound the spring I had to keep the string on the drum.
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Thread Starter- Uwe
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Re: Olympia SM7 Mainspring Trouble
If I need to get inside the mainspring to fix it, how should I do so if it is sealed, and what specifically am I looking to correct?
If in fact it's sealed (I can't see the other side of the drum, so maybe it opens from the back, but from your photo it looks very much like the sealed drums that I've worked on), I grind down the tab heads that are holding the two halves together. Some of those tabs are just stays, so you don't need to grind them all down. Once you've done that you can split the drum open and see what the mainspring is doing. There are a few different possible scenarios that you might find, so there's little point in speculating; when you have the drum open the problem should be obvious.
Putting it back together is the challenge. The tabs that act as stays will keep everything in line, but you'll need to figure out a way of keeping the two halves from coming apart. I've done a few different things that have worked well, but they are determined by the situation. You might be able to contort a few of the tab heads enough to bind the case (similar to what was originally done), or you might have to come up with a different solution. I've used extremely small nuts and bolts, but that means working around the mainspring position and making sure they don't interfere with how it moves. Again, once it's apart a solution to your particular case might be more obvious.
The pronoun I has always been capitalized in the English language for more than 700 years.
- JustAnotherGuy
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Re: Olympia SM7 Mainspring Trouble
I've removed the mainspring, and you are correct, it is sealed and I will need to grind down the tabs to get it open. Do you think JB Weld would be enough to hold it together again once I've completed fixing it?
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Thread Starter- JustAnotherGuy
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Re: Olympia SM7 Mainspring Trouble
I meant to say I removed the drum, sorry. I have not taken the mainspring out of the drum.
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Thread Starter- Uwe
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Re: Olympia SM7 Mainspring Trouble
Do you think JB Weld would be enough to hold it together again once I've completed fixing it?
I couldn't tell you as I've never used the stuff (I'm not a fan of glue solutions). My question would be, if it is strong enough, what are you going to do next time (assuming there is a next time of course) you need to open the drum?
The pronoun I has always been capitalized in the English language for more than 700 years.
- JustAnotherGuy
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- From: Illinois, USA
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Re: Olympia SM7 Mainspring Trouble
My question would be, if it is strong enough, what are you going to do next time (assuming there is a next time of course) you need to open the drum?
Good point, especially considering the likelihood of me screwing up once or twice. I'll look for other options.
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Thread Starter- giffer
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Re: Olympia SM7 Mainspring Trouble
I just bought an identical SM7 serial #1880764 (1961-62) for $2.25 plus shipping on eBay, cheap because the mainspring has similarly come undone and, after my amateur effort to sort it out, it now seems tangled inside the machine. Otherwise, it's in beautiful shape. I'm a novice when it comes to repairs. I fear that I'll have to remove the carriage to fix the problem. Does anyone have a simple solution? This is only my first post so I can't upload photos yet, but the photos earlier in this post show what looks to be an identical problem.
Also, to grope about eBayers, the typewriter arrived loose in the box with no padding--not even newspaper--at the top or bottom of the case. The ribbon cover had popped off and the ribbon had unspooled and snared around various mechanisms. I hate that. It's not hard to pack a typewriter, it just takes a little time to do it properly. It's such a shame that so many of these machine survive many decades of use only to suffer damage because of lazy packing. (This typewriter wasn't damaged in shipping, but easily could have been.)
