How To Fiх Looseness Of A Retractable Nib Carrier In Safety Filler?

March 23, 2017

Hi!

Can't find myself information about how to fiх looseness of a retractable nib carrier in safety filler from Montblanc. When retracted, nib and feed dangle inside barrel/section. Please, could someone advise me on it.

Edited March 23, 2017 by alexro

March 25, 2017

I think the problem is that the turning knob is not tight enough with ribbed part (Packing?), therefore when the nib carrier is retracted, it still has a backlash in longitudinal axis. I think to place a washer (spacer) between the parts. Is it OK?

http://static2.keep4u.ru/2017/03/24/IMG_20170324_18590898412.jpg

March 25, 2017

Although I'm not a particular fan of using O rings for piston fillers, I prefer using O rings in safeties.

The friction factor being considerably higher at an equal radial pretension, a well chosen O ring ensures much better the nib will not slide in the barrel during writing.

This is the main reason why i always prefer using O rings in safeties.

As you already suggested, you could alternatively install a complementary axial spacer ring between the actuating knob and the cork seal to compress the cork seal more , hence creating a tighter fit of the cork on the shaft.

Francis

March 26, 2017

Thank you Francis for your response!

March 29, 2017

Of course original cork sealing had to be replaced (see photo). Finally I have ground an o-ring with the closest dimensions (the exact size inner 5mm, outer 7mm). And the other part I have just filled with silicone sealer, because couldn't make it from cork so thin. I am not sure if it will work, have to wait little bit until it fasten.

March 30, 2017

Of course original cork sealing had to be replaced (see photo). Finally I have ground an o-ring with the closest dimensions (the exact size inner 5mm, outer 7mm). And the other part I have just filled with silicone sealer, because couldn't make it from cork so thin. I am not sure if it will work, have to wait little bit until it fasten.

I expect a standard O ring diameter 5 x 1.2mm or - when too tight - 4x 1.2mm would have been OK

A radial O ring pretension of 0.2-0.3 mm is recommended.

Although not paramount, l mostly install a spacer bushing to compensate for the cork /O ring length difference.

However the spacer bushing should not press on the O ring after assembling, best leave a gap of 0.5 mm

Francis