Conway Stewart 70 Cap Problem

[mariom]

I've picked up a CS 70 in green marble which, from the imprint, is a later variant according to the book. It's all in nice condition except for worn gold plating, but it does have a loose clip.

 

Try as I might, I can't loosen or tighten the cap screw using a rubber jar opener for traction. Are there any tricks which might help, or alternatively is this pen made of a plastic I can soak to help loosen things up?

 

Thanks

 

Mario

[Cob]

I soak celluloid caps to clean them and also when I wish to free up the clip screw. And judicious heat is an excellent help; I use a powerful hair dryer, checking with my fingers - it's amazing how much damage one can do with heat, but it will often help shift stubborn parts.

 

The best solution would be an ultra-sonic cleaner.

 

A word of warning though: first, if you are absolutely sure that the pen is made from celluloid and not casein, you should be OK. Water and casein are a disastrous combination. Second, if the clip screw is black hard rubber, then you can expect discolouration as a consequence of soaking; this can usually be polished out however.

 

Cob

Edited May 15, 2015 by Cob

[johnmc2]

Clean the inside of the cap out, then shine a torch into it and see if there is a slotted nut holding the cap-screw on. If there is, you can loosen this with a spanning screwdriver. You can make this tool yourself by grinding a 3 - 4mm square out of the middle of the blade of an ordinary flat-blade screwdriver.

If there is no nut the cap screw is secured in a threaded plastic plug and you will have to use friction to turn it. I recently sold my only CS70 so I'm sorry I can't be sure which type they are.

[northlodge]

I think the CS70 is the Aussie market version of the CS75. If correct then I think John.s solution with eth DIY screwdriver tool will work. Worst case scenario you could grind off the jewel (carefully, slowly, and avoiding any heat build up) and then fit a new one.

[mariom]

Clean the inside of the cap out, then shine a torch into it and see if there is a slotted nut holding the cap-screw on. If there is, you can loosen this with a spanning screwdriver. You can make this tool yourself by grinding a 3 - 4mm square out of the middle of the blade of an ordinary flat-blade screwdriver.

If there is no nut the cap screw is secured in a threaded plastic plug and you will have to use friction to turn it. I recently sold my only CS70 so I'm sorry I can't be sure which type they are.

 

Thanks John, and to the other responders. There is a nut in there, so now it's just a matter of concocting or obtaining a spanning screwdriver which will fit inside the inner cap.

 

Any ideas on the celluloid vs casein question so that I can possibly give it a good soak to help the process along?

 

Mario

[Cob]

 

Thanks John, and to the other responders. There is a nut in there, so now it's just a matter of concocting or obtaining a spanning screwdriver which will fit inside the inner cap.

 

Any ideas on the celluloid vs casein question so that I can possibly give it a good soak to help the process along?

 

Mario

I cannot help on the casein question: I do not even know if CS ever made pens from Casein; Burnham certainly did and I have a Mentmore bulb filler that is too - I also had a Macniven & Cameron Waverley "Stainless" that was casein. I made the mistake of soaking the Mentmore's cap with disastrous results: it now wears an American Swan one!

 

Good luck

 

Cob

[johnmc2]

Conway Stewart certainly did make pens from casein, Dinkies and 15s, for example.

As your pen is coloured it is possible it is casein, There are several supposed tests for casein: a milky smell when rubbed rigorously; a faint smell of formaldehyde; surface crazing etc

The only definitive test I have used is to take a small shaving from inside the barrel or cap and place it in acetone. If it is celluloid it will dissolve.

It is good practice to assume it may be casein in which case you should try the screwdriver without adding water. If it is stuck, a few drops of water could be placed on the nut as long as you dried it afterwards.

[johnmc2]

I just noticed that you described the trim on your pen as gold plated. My 70 had chrome trim (or nickel plated, some white metal anyway), as did the 75 which was the "home" version. Interesting.

[mariom]

I just noticed that you described the trim on your pen as gold plated. My 70 had chrome trim (or nickel plated, some white metal anyway), as did the 75 which was the "home" version. Interesting.

 

On closer inspection John, you're probably right - the nickel plating, if that's what it is, appears intact. I just assumed that it had been originally gold plated like most pens, and had lost it.

 

I've had the Dremel out and converted an old flat blade into spanning screwdriver. I had a lot of trouble stopping the cap screw turning with the nut, but eventually managed to it out. You probably don't want to know what I had to do to get there, but let's say the original pointed dome on the screw is now somewhat flat. In any case, it looks OK, and the clip is tight, firm and straight.

 

The pen is a nice writer - medium-broad, wet and with a bit of flex. It's a bit on the small side, but balances well when posted.

 

Thanks for your input.

 

Mario

Edited May 17, 2015 by mariom

[johnmc2]

Cheers Mario, I'm pleased it worked out OK for you.

John