Sierra keeps coming apart

[workinforwood]

My wife had an elegant beauty sierra and a regular sierra and they always come apart in her purse too. They bounce around in there I suspect and because the entire engineering of the pen is junk, it doesn't take long for you to have 5 pieces scattered in her purse. Best solution..don't make that.

 

[Smitty37]

Ceenter band

John the nib section unscrews at the centerband and the refill can be replaced from there hence there is no need to ever take the finial off the transmission.

 

[Smitty37]

Dead on

I don't make any sierra types anymore. I know a lot of folks do, but I have had several come back with the exact same problem you describe. My personal opinion is the design is faulty in that you twist the nib end to expose the point. and over time it wears and comes loose. Also, some guys will carry a pen in the front pants pocket and with all the bending and such I think it is just too stressful for that design. I think though I will go look at one and see if I can figure out how to put the locktite and where to put it. If that fixes the problem that would be great. I think some of the sierra type kits are nice looking.

Put the locktite on the transmission...it will work. Since there is no reason to take the barrell off the center coupler (the refill is replaced from the nib it should hold forever.

Either we are talking about 2 different styles or you lost me totally and I make these pens. On the Sierra the nib does not unscrew such as a cigar kit. To replace the refill you need to pull the top half off and unscrew the tranny. The top half is held onto the bottom half by the finial which is pressed into the tube. There is a friction fit at the centerband where it bulges out but this is where it spins so this can not be a tight fit. This also acts to keep the top half in line with the bottom half. The place to put the locktite is either to hold the finial in the tube which seems to not be the case. So there is only one other place and that is the end of the tranny that has the indents on it. That is what the finial turns. I have never had this problem but have had the problem with the tranny get unscrewed. I have gone to the locktite there but don't like it. The customer has to be able to change the refill.

John, I think you are both talking about the same thing. When Smitty says nib, I read that as the nib section which includes the nib and extention all the way up to the centerband looking thingy that unscrews from the tranny. I might be putting words in his mouth but for the Sierra style kit, when you say nib, I think lower section....... I don't think the actual nib piece comes undone on these pens. At least I have never removed it!

Dead on...the tranny does not have to move to change the refill the whole nib section separates from the barrel to replace the refill. Properly operarted the transmission should not move at all with relationship to the finial. I wrote that wrong above ... it should have read "There is no reason to ever take the barrel off the finial.....

 

[jttheclockman]

OK I think I follow what you are saying now. You are taking the top part of the pen off with the tranny inside. You are unscrewing it at the point that I say is a weak point and they seem to always unscrew by themselves. If that be the case then you hope no one forgets to screw it back on and not trys to push it on thus pushing the tranny higher into the top part of the kit. To prevent this yes you can glue or locktite the top of the tranny into the finial. Something would have to be done to secure the tranny into the finial because you can not exert enough tightening force to screw that tranny tight enough to the bottom section. When I put them together I always use a pair of pliar to get that extra effort to secure and it seems to help alot. Wish there were some sort of locking washer that can aide even more so.

The actual design or shape of the pen is such a great look and that is why it has been copied. For those that keep saying don't use it give me a pen that looks like that with that simplicity in making and I wiould gladly switch. So easy to say don't use it. It is my highest selling design pen. It is just a flaw in the design and hopefully there can and will be a change. I think the attempt to put the turning part in the cap was a step in the right direction but not the cure all. Just my opinion.


I now follow but forgot the original question:biggrin:. Hope that person got an answer they liked.

 

[Smitty37]

me too

OK I think I follow what you are saying now. You are taking the top part of the pen off with the tranny inside. You are unscrewing it at the point that I say is a weak point and they seem to always unscrew by themselves. If that be the case then you hope no one forgets to screw it back on and not trys to push it on thus pushing the tranny higher into the top part of the kit. To prevent this yes you can glue or locktite the top of the tranny into the finial. Something would have to be done to secure the tranny into the finial because you can not exert enough tightening force to screw that tranny tight enough to the bottom section. When I put them together I always use a pair of pliar to get that extra effort to secure and it seems to help alot. Wish there were some sort of locking washer that can aide even more so.

The actual design or shape of the pen is such a great look and that is why it has been copied. For those that keep saying don't use it give me a pen that looks like that with that simplicity in making and I wiould gladly switch. So easy to say don't use it. It is my highest selling design pen. It is just a flaw in the design and hopefully there can and will be a change. I think the attempt to put the turning part in the cap was a step in the right direction but not the cure all. Just my opinion.


I now follow but forgot the original question:biggrin:. Hope that person got an answer they liked.

Me Too

 

[PTownSubbie]

It's all good. This discussion helped me come up with my band-aid..... I tried loctite and we will see how long that lasts....

 

[KenV]

I have not been blessed with the failures and have been working a "naked Berea Sierra" parker style for several minutes. This is a chrome version that I have had for about a hear and has yet to be assembled with a finished barrell.

The finial piece fits snuggly over the top of the transmission with a fairly wide range of tube lengths possible -- +/- about an 8th of an inch. If there was a problem with the friction fit at the finial end fitting around the top of the transmission, it would be easily and (for me) pretty noticeable.

The other spot where I think I heard qutestions is the connection between the transmission and the lower section (nib end) - the threads are few (3) and appear to be tapered. Unless the transmission is securly tightened the lower section is "rattling and wobbly" It only took less than 1/8 turn to make it feel insecure.

I suspect those who are having sierra pen come apart are having the threads loose and the pen becomes top, bottom, refill, spring.

I went back and looked in stock and have about a dozen finished ones in stock with the double twist action. When I assures the threads were firmly set with the finial turned clockwise to a firm set, they all worked the tranny with a counterclockwise turn but with a noticable extra twist, the transmission would unthread.

I do not doubt that those who are having problems, are having problems, but it does look more torwards tolerances than a general design flaw.

 

[Smitty37]

Inherent in design

Not necessarily a design flaw but what you described says that it is inherent in the design. Tolerance build-up and operator error can both be the actual cause of a specific failure but it is in the design that they can.

 

[bruce119]

I like the lock tight fix. I think this is the best solution although I never encountered a problem I can see it arising from someone not understanding how the pen functions.

By using lock tight on the end of the trany when pressed into the final would help a few issues. First I wouldn't use glue especially CA for a couple reasons you may need to disassemble the pen at some time and CA if not left to air out and fully cure sometimes a week the gasses will corrode and fog some enclosed parts and platings. Now advantages of lock tight you can get the NIB section screwed on nice and tight to hold so it will not unscrew as easily. With out lock tight as the kit is made you can only tighten it so much then the whole NIB/trany assembly spins. With the lock tight you solve the push the trany in to far and it is out of reach of the NIB to screw on. This is a common mistake people do. I did it my self unscrew the NIB section to replace the refill then not thinking having used slimlines just push the NIB section back on. Now the have pushed the trany back into the final out of reach of the NIB section a BIG pain in the but to fix the first time you encounter this. Lock tight would solve that problem also a piece of something like a small short dowel to act like a stopper glued into the final to prevent the tranny from going in too far is a fix. Finally I believe if the need ever arose to disassemble the pen you can break the grip of the lock tight without destroying the pen. Now I admit I don't have much experience with lock tight so I can't recommend which one to use. Could someone with more experience chime in on what would be the best to use. I know there is blue and red I think and I think red has more holding power. But I am just guessing on memory and that is not reliable these days. So let's hear from you guys that know your lock tight what would have the best hold almost as good as glue but still break before the components do.

These are good kits if for the only reason the signal barrel design. And a there are a LOT of custom made blanks for this kit.

that's my in-put
.

 

[sbell111]

... Now I admit I don't have much experience with lock tight so I can't recommend which one to use. Could someone with more experience chime in on what would be the best to use. I know there is blue and red I think and I think red has more holding power.

You are correct. Red is stronger. That being said, I'm not happy with the idea of using loctite on a part that the buyer will need to remove to change a refill.

I always use loctite on cigar (and similar) mechanisms because the refill is easily changed by unscrewing the nib. However, a sierra's refill cannot be similarly changed. Even blue loctite holds strong enough that the connection may not be broken without tools. This can lead to disaster and unhappy customers.

 

[ed4copies]

If you do this correctly, the adhesive will not interfere with dis-assembling the pen, if needed.

All our kits will have instructions, with pictures to make it easy, in about a week.

 

[bruce119]

... Now I admit I don't have much experience with lock tight so I can't recommend which one to use. Could someone with more experience chime in on what would be the best to use. I know there is blue and red I think and I think red has more holding power.

You are correct. Red is stronger. That being said, I'm not happy with the idea of using loctite on a part that the buyer will need to remove to change a refill.

I always use loctite on cigar (and similar) mechanisms because the refill is easily changed by unscrewing the nib. However, a sierra's refill cannot be similarly changed. Even blue loctite holds strong enough that the connection may not be broken without tools. This can lead to disaster and unhappy customers.

A standard Sierra operated by twisting the NIB NOT the final. The customer has no reason to pull out the tranny to refill simply unscrew the NIB section and the tranny stays in the barrel & final. In fact that is how I show my customers to change the refill. In fact it would make this kit much simpler for the customer if they didn't even know the tranny came out and was unable to remove it. My only concern is me as the maker if I had reason to repair I must be able to remove it. So I my experiment with different lock tights to find just the rite amount and type. I would want it strong enough so the customer wouldn't break it loose by twisting it a little hard. Yet I would still be able to break the adhesion with some force like a tap with a punch and not destroy the pen.

Who uses lock tight what type do you use what are your experiences with disassembly. I think lock tight is a good idea with kit. I think you would only need a drop also too much would probably get you in trouble real fast.
.

 

[Smitty37]

Agree

... Now I admit I don't have much experience with lock tight so I can't recommend which one to use. Could someone with more experience chime in on what would be the best to use. I know there is blue and red I think and I think red has more holding power.

You are correct. Red is stronger. That being said, I'm not happy with the idea of using loctite on a part that the buyer will need to remove to change a refill.

I always use loctite on cigar (and similar) mechanisms because the refill is easily changed by unscrewing the nib. However, a sierra's refill cannot be similarly changed. Even blue loctite holds strong enough that the connection may not be broken without tools. This can lead to disaster and unhappy customers.

A standard Sierra operated by twisting the NIB NOT the final. The customer has no reason to pull out the tranny to refill simply unscrew the NIB section and the tranny stays in the barrel & final. In fact that is how I show my customers to change the refill. In fact it would make this kit much simpler for the customer if they didn't even know the tranny came out and was unable to remove it. My only concern is me as the maker if I had reason to repair I must be able to remove it. So I my experiment with different lock tights to find just the rite amount and type. I would want it strong enough so the customer wouldn't break it loose by twisting it a little hard. Yet I would still be able to break the adhesion with some force like a tap with a punch and not destroy the pen.

Who uses lock tight what type do you use what are your experiences with disassembly. I think lock tight is a good idea with kit. I think you would only need a drop also too much would probably get you in trouble real fast.
.

I never pulled the barrel on my own sierra until this discussion started. I had changed the refill once and then substituted one of Ed's easy flow refills. Both times I unscrewed the nib end, you just need to be careful that you don't lose the spring.

 

[jttheclockman]

Here is the thing I found with these. As mentioned the tranny has a tendency to unscrew itself. Even if you locktite the tranny into the top portion you did not stop the possibility of the tranny unscrewing from the lower section. I am not calling this a nib because to me it confused me when people started calling it that. To me the nib is the small metal piece where the ink refill tip protrudes.

What I do is when puttting the kit together and explaining to the customes I show them to pull the top off and unscrew the tranny and sometimes they need a pair of pliers to do it because I use them to install it. If you do not locktite the tranny in and explain to the customer to just unscrew the top portion, when they go to reinstall the refill and screw the top section back on they will never be able to get it tight enough because after it snugs up the tranny now spins in the top portion because the only thing holding it on is the indents in the end of the tranny and they are not secure enough to hold back the twisting force. So now the tranny is just snug but not tight.

You may be able to get away with locktite but one forceful twist and you are back in the same boat. It is a desgn flaw in my opinion in spite of what Smitty says.

What is the answer I am not sure but you probably would have a fighting chamce if the nib would be able to unscrew such as in a cigar and that is how you can instruct the operators how to change it. You then can locktite the tranny on both ends.