Mb146 Unscrews Itself From Cap

[CS388]

Hello all.

 

Have seen this problem mentioned in other posts on this forum - but usually as a side issue in another thread and have never seen a solution offered. So I thought I'd ask about it.

 

Of all my pens, my 146 (c1970s) is the only pen which will unscrew itself from the cap, while clipped into my pocket or bag. The cap and section threads are good, there are no cracks in the cap and it tightens up and fits snug, like the other pens.

 

Yet I will often find the cap clipped in place (on the pocket) and the pen lying in the bottom of the pocket (or bag partition). I've never found the cause of this quirk, or a cure for it - and, as I said, this is the only pen I own which exhibits this behaviour.

 

In the past, it has ruined a suit jacket (the uncapped pen wicking ink into the pocket/lining/suit etc) - and last week I opened my bag, found the cap clipped in place (with 2 other Meisterstucks) and the pen was nowhere to be found. (I knew this day would come!)

Unbelievably, it turned up in a friend's studio - which I had visited on the day of the loss. Phew!

 

But the event/close shave has got me thinking about this problem, again. I was lucky to get my pen back, but it will inevitably happen again and not come back - and I can't afford to lose an expensive working tool.

I'd be grateful for suggestions to remedy this, or to know if anyone else has this issue.

 

I once tried a light smear of beeswax on the threads - but it made no difference.

 

Thanks, CS

[EclecticCollector]

I have this issue with a few of my vintage pens, caused by the plastic threads of the cap and body shrinking at different rates. They are still able to be tightened, but will come apart very easily due to the stresses of the now not-quite-matching threads. The only fix I'm aware of involves rebuilding the threads using solvents and epoxy, which is not something I'm willing to risk.

[Dr.Grace]

Until you find a better solution, you could try keeping it in a pen case.

[CS388]

I have this issue with a few of my vintage pens, caused by the plastic threads of the cap and body shrinking at different rates. They are still able to be tightened, but will come apart very easily due to the stresses of the now not-quite-matching threads. The only fix I'm aware of involves rebuilding the threads using solvents and epoxy, which is not something I'm willing to risk.

 

Ah. Yes, that explanation makes sense.

But, like yourself, I don't think I'd be willing to undertake that remedy.

Thanks.

 

Until you find a better solution, you could try keeping it in a pen case.

 

I've always tried to avoid pen cases, I like having the freedom and ease of simply using the pocket clip in a pocket, or bag partition.

But your suggestion makes great sense and would be far preferable to losing a pen, so I'll keep it in mind.

Thanks.

[fountainbel]

Could be caused by the fact the section front does not positively back-up against the collar inside the cap.

When the thread fit between section and cap is rather tight, one can think the cap is firmly locked.

However without the axial back up the cap can still come off

Just my 2 Euro cents...

Francis

[Hooker56]

All,

 

I have a '50's vintage Pelikan 140. Delightful writer, but exhibits the same behavior. doesn't happen often, but about the time my confidence builds that it won't happen, I find it at the bottom of my shirt pocket in a pool of ink! I don't have any ideas for a fix either.

 

But FWIW, I used Amodex on my silk and cotton dress shirts that were blotched. With patience ALL of the ink came out thus saving about $250 worth of apparel. Most recently, it happened to a nylon shirt that cleaned up very easily. Amodex is rather expensive for the small quantity, but it doesn't take much. I talked with the dry cleaner about using it on a wool suit (the Amodex label swears it's safe for fine apparel), he assured me by saying that's what he uses on wool suits and sweaters for ink, then dry cleans as usual. Even old ink stains!

Edited September 4, 2014 by Hooker56

[EclecticCollector]

I don't know how effective it is, but Montblanc boutiques will give you an ink cleaner sample if you just ask for it. My local boutique throws one into the bag every time I buy some ink or have a pen serviced.

[CS388]

Thank you, Francis. That sounds feasible.

I dismantled the cap to check the internal collar, but have no way of checking whether it meets the front of the section.

I cleaned out both sets of threads to see if they could pull the section further into the cap - but, again, I have no real way to check this. I am also wary of cracking the cap by overtightening or forcing it too far!

I did see a thread once which instructed us how to use infra-red photography on our pens. This could be a useful way to check if the section and internal collar are meeting, as the Meisterstucks become transparent in the images.

I will post back any results. (But photography is not my strong suit!)

 

Thanks for the tips Hooker56 and EclecticCollector. Definitely worth a shot, if I suffer the clothing mishap again.

 

Many thanks again to all, for your replies. They have given me food for thought and encourage further investigation.

Much appreciated. CS

[hari317]

Tighten the cap nicely finger tight.

 

i have never faced this problem with my MBs, happens with some of my Pelikans however, I have to slightly creak the cap while closing and then they remain snug.

[SteveE]

I'm not sure how I would deal with this if it was one of my MB's, but an idea I've seen presented regarding other brands was to brush a very small dab of shellac onto the threads of either the cap or the barrel and let it dry most of the way. Then screw the cap on and immediately remove it and set the pen and cap aside separately to dry. Once dry, the threads will become what machinists call an "interference fit" and may have just enough drag to stay together in your pocket.

[Algester]

when in doubt plumber's tape/teflon tape or what ever you guys call it... it may not be the most beautiful fix but I have a feeling the cap thread and the barrel thread (where ca cap meets the barrel) get loose by friction (can also mean thread wear and tear considering the pen's age) this happens to my Lamy Logo and F-C Ambition

Edited September 6, 2014 by Algester

[CS388]

Thanks, Hari. Hope you're well.

Always glad to take your advice - but, in this case: Yeah, tried that one. Often use the 'creak' on older pens. Still, this one pen plays this trick.

 

SteveE: Thanks. That's great. I get the interference-fit ideaology. Going to go for this one, I think.

 

Algester: I actually did that! The cosmetic appearance of my pens doesn't bother me, in the least. But I must admit that it looked a bit 'bodged' - white tape on a black pen. But, more importantly, it didn't work. I think PTFE tape must be designed for a more permanent junction - and removing and replacing the cap countless times, every day, soon turned the tape into lumps and tears and it became a hinderance, rather than a help. Does it work on your Lamy and FC?

I totally buy your thread-wear logic. Thanks.

 

Francis. In conclusion of the axial meeting of section and inner collar: I 'botched up' an infra-red cheat on an old camcorder. Terrible quality, but useful for technical explanation.

First, infra red of the 146 cap, clearly showing inner collar (146 section in background):

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146capinnercollarinfrared_zps78acddfe.jpg

 

Now, the pen capped. The section meets the collar. (This stop point can be clearly felt, when capping.)

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146capmountedinfrared_zpsde73516d.jpg

 

Took a shot of celluloid 146, but the infra red didn't affect it all:

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146andcelluloid146infrared_zps42df57ec.jpg

 

Again, thank you all for your contributions. They are much appreciated.

 

Enjoy.

 

 

[Algester]

Thanks, Hari. Hope you're well.

Always glad to take your advice - but, in this case: Yeah, tried that one. Often use the 'creak' on older pens. Still, this one pen plays this trick.

 

SteveE: Thanks. That's great. I get the interference-fit ideaology. Going to go for this one, I think.

 

Algester: I actually did that! The cosmetic appearance of my pens doesn't bother me, in the least. But I must admit that it looked a bit 'bodged' - white tape on a black pen. But, more importantly, it didn't work. I think PTFE tape must be designed for a more permanent junction - and removing and replacing the cap countless times, every day, soon turned the tape into lumps and tears and it became a hinderance, rather than a help. Does it work on your Lamy and FC?

I totally buy your thread-wear logic. Thanks.

 

Francis. In conclusion of the axial meeting of section and inner collar: I 'botched up' an infra-red cheat on an old camcorder. Terrible quality, but useful for technical explanation.

First, infra red of the 146 cap, clearly showing inner collar (146 section in background):

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146capinnercollarinfrared_zps78acddfe.jpg

 

Now, the pen capped. The section meets the collar. (This stop point can be clearly felt, when capping.)

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146capmountedinfrared_zpsde73516d.jpg

 

Took a shot of celluloid 146, but the infra red didn't affect it all:

 

http://i1023.photobucket.com/albums/af351/shoulderhead/146andcelluloid146infrared_zps42df57ec.jpg

 

Again, thank you all for your contributions. They are much appreciated.

 

Enjoy.

 

 

yes it works on my Logo and Ambition but the tape is slowly wearing down so I apply it from time to time but since these pens have a push type cap the tape is on the section and barrel threads the inner threads so to speak

Edited September 7, 2014 by Algester

[CS388]

Brief resurrection of this thread, just to report:

 

Tried the shellac on threads suggestion. Didn't work.

Tried it again, building up a thicker layer. Still didn't work.

Found the 146 in the bottom of my pocket again, today - cap still neatly clipped in place.

 

Ah, well. You can't win 'em all.

If I do come up with a solution, I'll add it to this thread.

 

Thanks.

[fountainbel]

Brief resurrection of this thread, just to report:

 

Tried the shellac on threads suggestion. Didn't work.

Tried it again, building up a thicker layer. Still didn't work.

Found the 146 in the bottom of my pocket again, today - cap still neatly clipped in place.

 

Ah, well. You can't win 'em all.

If I do come up with a solution, I'll add it to this thread.

 

Thanks.

 

Looks to me the cap threads are partly stripped, thermally shrinking the cap radially a few tenths of a millimeter could restore a proper thread fit .

Francis

 

 

 

[CS388]

 

Looks to me the cap threads are partly stripped, thermally shrinking the cap radially a few tenths of a millimeter could restore a proper thread fit .

Francis

 

 

Thanks, Francis.

I think you may be right.

But the remedy is slightly beyond my hack capabilities.

 

Also:

This old pen has other issues and - rather than pursuing the cap fix - I think it's time it went back to Germany for a service from the manufacturer.

It'll be a shame to lose all the old parts (except nib), but, all things considered, it's the quickest way to get it back into the everyday workhorse stable. (I'd like to keep the old W GERMANY clip, though.)

 

So, it's off to the 'boutique', when funds allow.

 

Thank you all again for your thoughts and suggestions. Very much appreciated.

 

Enjoy.

Edited October 18, 2014 by CS388

[empty]

I have a 149 that does this, I haven't found any solution but what I have observed is that even when tightly capped I can wiggle the pen from side to side and it moves within the cap. My other 146/9s don't move nearly as much if at all. I think while its in a pocket or hanging in a bag it gets jostled enough to loosen the cap.