Rondo Pen Fault - Looking for a solution

[Mike O'Pray]

I won the above on e-bay. It is a 1960s( I think but might be even earlier) piece of equipment. It acts like a pen in that when you make contact with paper it lights up and send a very narrow beam of light onto the paper and "writes" so signatures, words and a black penline is possible.

Given its age and the number of times batteries( two AAs) must have been changed the "female" thread on the metal barrel seems to have become worn or possibly( but maybe unlikely)the top of the metal barrel has opened slightly so while the male thread which is plastic does still screw in, it is delicate to say the least and may jump out. It needs to be able to stay tight as the male plastic thread sandwiches the metal contact from the bulb onto the barrel and completes the circuit when you press the pen tip on the paper and it pushes the bulb to make contact with the battery.

So to summarise: The plastic thread looks to be in good condition but I think the receiving metal female thread is worn.

Any ideas as to how I improve things? What sprung to mind is applying a die to the inside of the metal barrel to either re-thread it or at least slightly deepen the thread

However friendly engineering workshops that would take on that kind of a job for anything less than a king's ransom are about as scarce as hen's teeth around here.

Sorry to have to rule out the obvious but I just don't think there is any access to such workshops around my location.

Any ideas? Feel free to brainstorm. Nothing excluded at this stage

If any of this is confusing( quite likely ) feel free to ask questions

Thanks for any help

Mike

[robinb]

hi mike

if its anything to do with these
http://www.ballograf.com/Page.asp?PageId=53
then it has a lifetime guarantee !

robin

[Mike O'Pray]

Well the name is the same but these are all "real" pens, not torch pens to "write" on darkroom paper.

Mike

[Terry S]

Hi Mike,

I presume this is the pen that you bought?

http://www.ebay.co.uk/itm/RARE-VINTA...p2047675.l2557

Lucky that I never spotted it, otherwise we may have had a bit of a bidding war on our hands, as I do like old and unusual photographic items!

Anyway, as mentioned, personally I would enquire with the company just in case = especially if there is a lifetime guarantee on all their pens!

In the past, I remember having the same problem with things like pens that I like (usually cheap but I loathe to throw them away when there is loads of ink still in them) and I have wrapped a little bit of not so wide sellotape around the male thread and then screw the top on and that generally holds the top in place...?

Either that or keep an eye out for something of a similar size that might just screw on. I'd check out any junk boxes or tit bit boxes that most of us have.

Hope these suggestions are of some help.

Terry S

[Mike O'Pray]

Terry,yes that's the very pen you link to. I'll have to check with Rondo to see if it is the same company. Even if it is, it clearly doesn't sell these pens any longer and I'd be surprised if it had any spare bodies left, given its age but you never know.

Your suggestion has given me an idea. PTFE plumber's tape might do the job but please do not let this put off any other FADUer from making suggestions.

Only by a form of brainstorming might I get to the best idea

Thanks all

Mike

[MPerson]

PTFE tape is a good idea. You could also try clear nail varnish. I have used that before with success on pen barrels but you may need to test how much due to the pressure applied through the barrel.
Another thought is the Locktite thread sealant.

[Mike O'Pray]

Andy, at some point I'd have to unscrew the top to replace the batteries so my worry about nail varnish and Locktite would be the damage unscrewing could then do or is it your experience that both adhesives can be broken without damage to the plastic thread?

Mike

[Mike O'Pray]

I forgot to add that I have contacted Rondo pens which is a Swedish company and it has no knowledge of ever producing a light pen.

I now recall vaguely, having given it some thought, that the seller mentioned that the pen had Japanese origins

It would appear that no custom-made narrow beam light pens are now made. Understandable as there would never to a big enough demand.

Mike

[Terry S]

Originally Posted by Mike O'Pray

PTFE plumber's tape might do the job...

But of course! I've used the stuff on numerous occassions and it would be much better than sellotape!

I agree with there being no demand for the pens = I mean I WOULDN'T want one (or two...)

Terry S

[MPerson]

They both give easily when required.