Troubles with 7mm Transmissions

[turn4fun]

Over the last 2 to 3 years, I haven't been really happy with any of the 7mm transmissions used in slimline, Trimlines, Euros,etc.. They are often hard to twist. This is specially true if the pen hasn't been used for a while. Sometimes they slip a little in the upper blank. When they do this, it becomes a pen that I don't want to sell or even give away.

Has anyone else had these kind of experiences with 7mm transmissions? If you have, what do you do about it? Is there anyway to loosen up the transmission? Is there anyway to stop it from slipping in the upper blank? Have you found the transmissions to be better or worse from any particular vendors? Or is this the just the way they are?

Thanks.. Larry

 

[GColeman]

I think most transmissions have a corrosion preventive on them. It is sticky and will cause a transmission to be hard to turn. I use a little mineral spirits to clean them off and lubricate with a tiny amount of 3 in 1 oil. I have only had trouble with a loose fit between the upper barrel and the tranny on a 7mm euro. I roughed up the surface of the tranny with 120 grit and it seems to work fine now,

 

[Sylvanite]

Larry,

I go through lots of 7mm transmissions making bullet pen kits, and have seen several problems with them over the years. The issues seem to come and go, and are not limited to any particular vendor.

Stiff operation is pretty common, espeically when the transmission is new. I check every one before installation. I work it back and forth several times to smooth it out. If that doesn't fix the problem, the transmission goes in the trash.

At one time, I was salvaging them by putting a drop of oil in the transmission. I never used them in a kit, so now I have a bag of oiled 7mm transmissions that are all very easy to operate (almost rattling). Most any oil seems to work -- I've tried way oil, spindle oil, and 3-in-1 oil. I wouldn't recommend WD-40 as it tends to evaporate over time, leaving a gummy residue behind.

Regards,
Eric

 

[turn4fun]

Greg and Eric.. thanks for your inputs.

Greg.. I'm going to try wiping the trannies down with mineral spirits before I rub a drop of oil on the outside. I have been just rubbing off the sticky protective coating with a dry paper towel and then applying a drop of oil. I was unsure about using mineral spirits because I was afraid if it got inside the tranny, it might mess up the operation. I didn't really want to rough up the outsides of the upper half of it to prevent slipping. It sounds like it could stop the slipping, but it could mess up the cosmetics when the pen is pulled apart to replace the re3fill. I have tried to rough up the brass tube in the upper blank with limited success. On trannies that slip a lot, I've sometimes noticed that the small ears embossed in the chrome of the tranny aren't large enough.

Eric.. I'll try putting a little oil or something similar into the tranny and see what that does to the stiffness. Like you, I'm not sure if I want to sell it that way because I don't know what the long term effect on the tranny might be. Maybe I'll do this to one pen and use it myself for a year and see what happens. You mentioned that you go through a lot of trannies in order to get good ones in your pens. That helps me realize that these trannies are far from perfect. I sure wish someone would invent a better 7mm tranny.

Anyway you guys, thanks again for your help. If anyone else has any thoughts or experiences with the 7 mm trannies they'd like to share, please chime in. It'd be nice to hear from more folks on this and see what the common issues are and what's being done to work around them.

Regards.. Larry

 

[Smitty37]

Stiff

I have notice that 7mm transmissions do tend to stiffen up after sitting for awhile. I've found that working them back and forth a few times seems to clear it up. I believe it's probably caused by the grease that's used inside.

Being a little loose fit is probably more of a tube than transmission problem. I've seen it a couple of times and usually if I try a different upper barrel it works ok which points to the tube. I've always been able to find a way to fix the problem.

 

[wouldentu2?]

I find the stiff transmission in the streamline feels "richer" than the easy transmission in the trimline.

 

[thostorey]

Anyone thought of using a little graphite to lube the transmissions? I mean the stuff you can buy to lube entrance locks, car door locks and the like. Seems to me that it should work just fine...oil could be a messy business...fwiw