How To Tighten Loose Cap's Rings ?

[fabri00]

In many vintage fountain pens celluloid tend to shrink with the age, and the rings of the cap become loose.

 

I'm not interested in solutions like using a drop of glue, and I machined a tool a year ago to tighten rings, but I'm not happy with it. It works, but only for very thin rings.

 

On the other hand, a couple of years ago I sent back to Stipula a Nettuno pen, not that old as I think I bought it 20/25 years ago, because of this problem, and the pen came back to me with rings perfectly tightened to the cap. For sure Stipula has no spare parts for this old pen, therefore it is possible to do this, and also with very good results.

 

I've not found any idea about how to do that on the web: anybody has an idea of what kind of tool can do that ?

 

Thanks.

 

[hari317]

Look up Franciss technique of swaging the cap rings. IIRC he uses a collet chuck with a protective liner for this. HTH.

Edited December 26, 2017 by hari317

[fabri00]

Thanks Hari.

Is a complicated method because several collet chucks are needed, of different siameters. And those chucks are also quite expansive.

I was thinking more to make some metal rings of different diameters, something like one every 0,20 mm., and mount them in a kind of pliers, and then clamp the rings. I the meantime i think to make also some pins to inserts in the cap to not break it while clamping.

But before to loose time to turn those tools, I was wondering if someone had any better idea than me.

[hari317]

Thanks Hari.

Is a complicated method because several collet chucks are needed, of different siameters. And those chucks are also quite expansive.

I was thinking more to make some metal rings of different diameters, something like one every 0,20 mm., and mount them in a kind of pliers, and then clamp the rings. I the meantime i think to make also some pins to inserts in the cap to not break it while clamping.

But before to loose time to turn those tools, I was wondering if someone had any better idea than me.

once you have clamped, how do you plan to release the ring? also the clamping force has to be radially uniform. Pliers will provide discrete points of contact, not continuous.

 

The appropriate mandrel(pin) to hold the cap and prevent from from getting crushed while swaging is compulsory.

 

wishing you good luck.

 

I have some Omas 360 with loose cap rings. Given the triangular shape, I am still waiting for some ideas to strike.

[Chrissy]

Would a cap mandrel be better to use while clamping?

[Inkling13]

I think you can do this, watching Conid Bulkfiller, it seems that the cap ring is tightened with a collet. You might want to ask fountainbel.

[Glenn Atkins]

There might be something that could be fashioned to use these.

 

Glenn

 

https://www.amazon.com/Loggerhead-Tools-BW6-01R-01-Adjustable-6-Inch/dp/B000JPN2QK

[fabri00]

once you have clamped, how do you plan to release the ring? also the clamping force has to be radially uniform. Pliers will provide discrete points of contact, not continuous.

 

The appropriate mandrel(pin) to hold the cap and prevent from from getting crushed while swaging is compulsory.

 

wishing you good luck.

 

I have some Omas 360 with loose cap rings. Given the triangular shape, I am still waiting for some ideas to strike.

Hari, sorry but I said something different from that.

I want to try to make several metal blocks with a bore decreasing in diameter of 0,1 or 0,2 mm one from the other.

It should be something like this:

 

 

Then the cap will be inserted inside the 2 parts, and the 2 parts will be pressed with plyiers and will press the rings.

The force will be radially very uniform.

Edited December 27, 2017 by fabri00

[fabri00]

There might be something that could be fashioned to use these.

 

Glenn

 

https://www.amazon.com/Loggerhead-Tools-BW6-01R-01-Adjustable-6-Inch/dp/B000JPN2QK

This is interesting, not far from the tool I did.

Thanks Glenn.

[fabri00]

This is the tool I did already some time ago:

 

The 3 wheels shrink the ring, while the cap is turned by hand. the pressure is slowly increased turning the knob with the screw.

The body of the pen should be tigthly screwed in the cap, in order to not break it while increasing the pressure.

It works well but only with thin rings, and not too loose.

Edited December 27, 2017 by fabri00

[Glenn Atkins]

This is interesting, not far from the tool I did.

Thanks Glenn.

 

Except I think your block idea would stop at the exact right place, for example .1mm.

 

Glenn

[Ron Z]

This is the tool I did already some time ago:

 

 

The 3 wheels shrink the ring, while the cap is turned by hand. the pressure is slowly increased turning the knob with the screw.

The body of the pen should be tigthly screwed in the cap, in order to not break it while increasing the pressure.

It works well but only with thin rings, and not too loose.

 

I can see where that might work but I would be nervous about the cap plastic flexing as you turn it rather than the band diameter being reduced. A modified tubing cutter work for a hand knurling tool as well.

 

The design farther up with the two pieces will not work. It is too much like a standard crimping tool. The band will pinch out on both sides when you squeeze it closed. You have to compress the band over the full 360 degrees at the same time, or you'll end up with a piece sticking out and getting crimped.

[fabri00]

 

i can see where that might work but I would be nervous about the cap plastic flexing as you turn it rather than the band diameter being reduced. A modified tubing cutter work for a hand knurling tool as well.

 

The design farther up with the two pieces will not work. It is too much like a standard crimping tool. The band will pinch out on both sides when you squeeze it closed. You have to compress the band over the full 360 degrees at the same time, or you'll end up with a piece sticking out and getting crimped.

Because of that I was thinking at the "2C" system, which is not far from using a collet chuck

[fountainbel]

Hi Fabricio,

I wish you good luck in your search for an alternative method for tighten loose cap bands, but I expect you finally will end using the ER25 or ER32 collets swaging approach.

I 've looked on the internet and actually a set of these collets and a holder cost approximately $ 80.00.

Quiet a reasonable investment In case you are regularly doing this kind of repairs , at least in my opinion !

Below the link to an earlier post in which I've explained how I use the tools.

Please look at my last reply in this post were I show my latest improvement.

Francis

https://www.fountainpennetwork.com/forum/topic/68596-shearing-my-method-for-capring-swaging/page-2?hl=+fountainbel%20+swaging%20+cap%20+rings

 

http://i62.photobucket.com/albums/h89/fountainbel/Repair%20suggestions%20to%20forum/P1010303.jpg

[siamackz]

Would a bionic wrench be a cheap and more crude substitute https://www.amazon.com/gp/aw/d/B000JPN2QK/ref=mp_s_a_1_2?ie=UTF8&qid=1514686032&sr=8-2&pi=AC_SX236_SY340_QL65&keywords=bionic+wrench&dpPl=1&dpID=41aWzx6fbqL&ref=plSrch

[FarmBoy]

Would a bionic wrench be a cheap and more crude substitute https://www.amazon.com/gp/aw/d/B000JPN2QK/ref=mp_s_a_1_2?ie=UTF8&qid=1514686032&sr=8-2&pi=AC_SX236_SY340_QL65&keywords=bionic+wrench&dpPl=1&dpID=41aWzx6fbqL&ref=plSrch

short cuts are rarely shorter.

[siamackz]

short cuts are rarely shorter.

Is this that 'rare' occasion then?

[FarmBoy]

Is this that 'rare' occasion then?

I'd follow Francis ...

[praxim]

Having a bionic wrench to hand, I can add that the surfaces (pressure points) on one sized appropriately for a pen cap are about 3 mm while the gaps between are nearer 5 mm. This will not swage well.

[siamackz]

Having a bionic wrench to hand, I can add that the surfaces (pressure points) on one sized appropriately for a pen cap are about 3 mm while the gaps between are nearer 5 mm. This will not swage well.

Thanks for explaining.