Your wife wants you to get rid of a typewriter? That's not right...

I think it depends on where your tab stops are commonly placed. I rarely use a tabulator, and when I do it's usually just for a paragraph indent, so in that situation where the carriage doesn't travel a signficant distance and consequently doesn't gain a lot of momentum, I can't see the tab stops being damaged. However, if you your tab stops are on the opposite side of the page then they're going to take a good hit.

In reality, what have you got to lose by removing the brake? Worst case is you break a tab stop over time and will have to use one of the others on either side of it instead. If it's an otherwise good machine I would hang onto it (and maybe fresh magnets or parts from a donor will be found in the interim).

Of course now I'm curious about the issue you're experiencing and I'll have to take a look at my SM machines to see what I would do if ever faced with the same problem.  

There are no magnets in the tab brake.  There are 4 aluminium shoes with cork inserts which are thrown outwards by centrifugal force when the axle in the centre is spun.  Would you remove the brakes on your car and just rely on the bumpers to stop you when you hit things ?

thetypewriterman wrote:

There are no magnets in the tab brake.  There are 4 aluminium shoes with cork inserts which are thrown outwards by centrifugal force when the axle in the centre is spun.  Would you remove the brakes on your car and just rely on the bumpers to stop you when you hit things ?

So... I believe you're incorrect, in my case. The most obvious difference between the brake you're describing and the brake I took off is that I have no cork - I have salmon colered bits of rubber.

The inserts are dark, heavy, and clack like magnets.

That would also explain why the gear was so hard to get out of the typewriter - I couldn't get it to just fall out because it would just "hang" on to things.





Moreover, It makes more snese for these to be magnets when one considers the engineering. If they just want friction between cork and metal they could have saved a bunch of money and time and had a much simpler mechanism similar to what was already available on older machines. Just make a cork pad that engages the carriage when pressing the tab key...

This design strongly suggests that it takes advantage of overcoming centripetal force, letting the rotation fling the pieces outward away from the gear when the carriage moves too fast and then they suck back in to the center when it slows down. Otherwise there's no point to making such an elaborate device in this fashion.

This would quite the complex solution to a simple problem if they weren't magnets, is what I'm trying to imply. I'm by no means an authority or have any sort of experience here so if I'm wrong, so be it.

I am inclined to agree with Uwe, though. I rarely use tabs and, if I do, they're never at the end of the line when the carriage gets really cookin'.

Last edited by cjshelley (19-1-2014 13:59:03)

Like I said, If I'm wrong then so be it. I'm willing to accept that they're not magnets but I'm still baffled as to why they would engineer the thing is such a way if these weren't. Furthermore, I see no fix to them slowing the carriage down too drastically. The rubber is still pliable so I don't think I need to replace those. 

The only thing I can think of is to oil the thing. Everything is pretty clean in there. 

I'm wondering if someone made repairs to it prior to my ownership and replaced the parts. Not only do I only see reference to cork tab brakes and none described like mine, I've also noticed that it's weirdly clean for its age (I'm guessing it's seen service because my 8 is not so tidy on the insides), and while investigating my slow tab key response I noticed that the cloth strip that runs from the sprung wheel to the end of the carriage was twisted, which I doubt has been like that since the factory.

I fixed that and I hope I didn't over-wind the spring. It's roughly the same as my 8, currently.

Last edited by cjshelley (19-1-2014 14:18:26)

Glad you're making progress cjshelley; please keep us updated on your repair!

cjshelley/ wrote:

This would quite the complex solution to a simple problem if they weren't magnets, is what I'm trying to imply.

Welcome to the world of German engineering with its long and rich history of coming up with overly complex and elaborate solutions to simple problems. ;-)

@thetypewriterman: We all appreciate the knowledge you bring to the forum, so I hope you don't take any comments that might question your years of experience personally. We all struggle to keep our machines working and sometimes the best way to learn something new is to question things, even if it means challenging an authorative source that happens to be right in the end. It's certainly nothing personal.

I just had a look at one of my SM9s just now, and if anything, I'd say I have the opposite problem. The carriage seems to fly across the rail and crash into the tab stop as hard as anyother machine I have with a tabulator. I verified that the cushion gear is engaging the drawband drum, but that's as far as I'm going to go with this for now. As I mentioned before I rarely use a tabulator and I have other machines with more pressing mechanical issues.

My guess is that in my case the cork has worn away, whereas with cjshelleys machine (given the cork is still there) that maybe it was permanently engaged/seized or the system is otherwise fouled?
If the gear itself doesn't spin freely then it would contribute to extra drag on the drawband drum.

Just for reference, here's what the system looks like when you flip over a SM9:

[img]http://www.vorg.com/typers/Olympia_SM9_Tab_Cushion(1).JPG[/img]

[img]http://www.vorg.com/typers/Olympia_SM9_Tab_Cushion(2).JPG[/img]