- Fleetwing
- Typewriter Talk Vet
Offline - From: Hartford, CT USA
- Registered: 30-6-2015
- Posts: 1,011
Re: Olympia SM7 Mainspring Trouble
I just got a long stored-away SM-7 exhibiting a lack of mainspring tension and I'm hoping like crazy the root cause isn't the same as what's described in this thread. The drawband was remarkably tangled and wrapped around the sort of star-shaped wheel on the forward-facing side of the spring drum (what purpose does that piece serve, anyway?), but it was intact. I straightened out the drawband and reattached it to the carriage, but I will need to wind the spring up -- and JustAnotherguy is right, you can't remove the drawband so winding the drum is a major PITA. If in fact the mainspring is coming detached inside the drum, that is a job I won't bother with -- will turn it over to a pro if I decide to go further.
- Fleetwing
- Typewriter Talk Vet
Offline
- From: Hartford, CT USA
- Registered: 30-6-2015
- Posts: 1,011
Re: Olympia SM7 Mainspring Trouble
A follow up question -- how many rotations to wind up the mainspring? As mentioned in this thread, the drawband is attached to the mainspring drum, so the conventional approach of winding up the drum and then attaching the drawband doesn't apply. My very rough calculations make me think that I'll only need to prewind it one turn or perhaps two, since extending the drawband out to attach to the carriage will further wind the mainspring 2 or 3 turns. Thoughts? Thanks.
- Fleetwing
- Typewriter Talk Vet
Offline
- From: Hartford, CT USA
- Registered: 30-6-2015
- Posts: 1,011
Re: Olympia SM7 Mainspring Trouble
OK, I got it done. I am rather pleased with myself, I must say. (I will repent of this self-satisfaction at church tomorrow.) One wind of the mainspring drum seemed to be all that was necessary; attaching the drawband to the end of the carriage provided the additional tensioning that was called for.
I will not bore folks with all the details; suffice it to say that with these machines, because you cannot reasonably detach the drawband (as discussed above, and also at Mary Echevarria's blog (myoldtypewriter.com), I had to wind the spring with the strap and the large metal plate that hooks onto the carriage still attached. Getting that plate out of the way while winding up the mainspring is the challenge, since there are a couple of guides around the drum for the drawband that give very tight clearance. I was actually able to use masking tape (painter's tape actually, but it's the same thing essentially) to secure the plate to the side of the drum and thus out of the way. I used part of a coat hanger to hook onto the plate once I'd tensioned the drum to pull the drawband under the carriage. Seems to work fine now -- enough tension to type across the entire platen.
I think the escapement needs cleaning and/or light lubrication still, since it seizes up, but I think that's not a big problem. the machine had clearly sat in its case for years; lots of rusty spots on the innards, along with other corrosion on interior pars. Minor rust in some of the segment slots also, so a few typebars don't seem to make contact with the ribbon. (I need to confirm this; the ribbon is dry.)
And so to bed.
- skywatcher
- Moderator
Offline
- From: The Prairies of Alberta
- Registered: 14-3-2013
- Posts: 737
Re: Olympia SM7 Mainspring Trouble
Greetings All
In situations like this where the main spring has either come disconnected or has broken, for the sake of a reliable repair, it may be worth completely removing the main spring drum assembly from the unit and take it to a clock repair shop, sometimes known as a watchmaker's shop.
I run a small engine repair shop out here in Southern Alberta and I get customers bringing in the rewind starter assembly from their lawn mower, rototiller, chainsaw or what ever because they have taken it apart and can't get it back together. Usually I can have the starter reassembled and working within 5 to 10 minutes for a nominal charge.
A watchmaker will have the experience, knowledge and tools to possibly have your spring assembly repaired in a matter of minutes once he or she can get to it. If nothing else, they would be able to take a look at it and offer a professional opinion on the drum assembly. As I say, this is just a thought that although may cost a little, may save a lot of frustration in the long run. All the best,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)
- Fleetwing
- Typewriter Talk Vet
Offline
- From: Hartford, CT USA
- Registered: 30-6-2015
- Posts: 1,011
Re: Olympia SM7 Mainspring Trouble
Looks like the spring is OK -- still tensioned after a day. So I'm pretty pleased about not having to open up the mainspring drum! Generous application of lighter fluid to the segment and to the ribbon reversing mechanism appears to fixed the seizing problem, and all typebars seem to work properly. Now to load a fresh ribbon to see how it all works.
The tab mechanism still doesn't work; I figure the brake is seized up. I'll attend to that at some point. At least the SM-7 allows removal of the rear panel for access.
- Fleetwing
- Typewriter Talk Vet
Offline
- From: Hartford, CT USA
- Registered: 30-6-2015
- Posts: 1,011
Re: Olympia SM7 Mainspring Trouble
OK, one last update -- as mentioned in another post, the rear panel screws do not budge; I think they got painted in place at the factory so I'll need to think about slipping a razor blade around the base of each screw to try and separate the paint on the screwheads from the rest of the rear panel. I am eager to examine the tab brake and see about fixing it (some good guidance in another thread on this forum).
Also, several keys, notably the period, comma and semicolon/colon, do not print unless I strike those keys very firmly. I thought there might be crud inside the respective segment slots, but instead it appears each of these slugs does not contact the platen when the typebar strikes the ring. The other keys all appear to kiss the platen. I suppose using a backing sheet would help bring the paper closer (and the platen is pretty hard and actually has minor cracks), but I'd love to see what can be done, short of a pro resoldering the slugs.The slugs don't appear to be misaligned compared with the others, so this is puzzling. I don't know how I can bend the slugs forward either -- that seems almost impossible to do, since that's on the longitudinal axis of the typebars, i.e. the strongest axis. Advice?
However, the machine is basically fully operational (the tab notwithstanding), which is darn good considering how it was when I got it a week ago, so I'm pleased. I paid $25 for it.
