Making a Rotring pen body

Odd question-

I'm fed up with the cheap plastic body on my Rotring Isograph pens being broken by colleagues in the office, so considering turning aluminium or possibly brass replicas, that I can then mount the standard isograph nibs in, for which I will need to cut relatively fine threads into, as well as deeply bore a long hole with a thin wall.

The threads look around 10.25mm (13/32"?) and approximately 0.67mm pitch (measured by eye and ruler at desk..) and will be cut into the ends of thin tube (11.5mm OD, 10mm ID, approx. 75mm long).

Does anyone have any comments about how they would go about producing these - I'm thinking that turning a tap from tool steel would be easier to reproduce multiple threads from (rather than thread cutting from a ground tool), and with minimal cutting depth from such a fine thread this wouldn't need anything too fancy by way of cutting geometry. probably cheaper and easier to start from some tube rather than solid bar and boring from scratch, but with such a thin tube- how do I prevent crushing it when holding- turn a wood blank to sit inside to resist compression- but the blank inside would then obstruct the final boring of the tube?

Simple split bush will stop you crushing the tube - just bore a hole in say a bit of 20mm scrap to a nice fit on teh tube then saw a slit in teh side so that when you put it back in the chuck the bush will close on the tube.

I would have thought you need a smaller bore for that size thread in the region of 9.5mm as typical tapping siz ewould be 10.25 less pitch 0.67. Something like 3/8" (9.53mm) bore tube would do nicely.

Just measured a metal Rotring thread and it came out at 10.05 OD and a M4 screw dropped into the thread quite well so could well be 0.7mm pitch. If that is the case you could use the old trick of holding a smaller tap eg M4x0.7 in the toolpost with one flute on ctr height and using that as a threading tool just engage 0.7mm pitch screwcutting.

Thanks for the responses Jason- hadn't thought of using a split collet externally to surround the piece to avoid crushing it- but somewhat obvious now...

And thanks for the measurements and the thread guestimate- also a neat trick using a tap like that, which would avoid quite a lot of effort too!

It's going to be held in the part of your body that has the most nerves. You will feel it if it's not concentric. If you don't have a suitable collet chuck, you need to make as much of the barrel as possible in one go, working from the tailstock end and then parting off and facing the top end of the barrel in a different operation. Concentricity needs to be as good as you can manage, exact dimensions are OK to 0.1mm.

Probably wise to make a tap for the barrel threads,otherwise you'll need a really tiny threading tool. Just noticed Jason's bit on using a tap. Clever.

Material: Aluminium will make your hands black unless anodised. Brass feels surprisingly heavy in the hand. If more than 50grams, you really will feel it at the end of the day if you do a lot of drawing. Do you have 'Delrin'? Might be tough enough to survive your colleagues.

Regards

Richard

(www.chestnutpens.co.uk)

Edited By richardandtracy on 16/06/2017 17:08:54

Unless things have changed from a few years ago I would not have thought Rotring would use cheap plastic, seems more like your office workmates are heavy handed!

IanP

I tend to use hex brass bodied automatic and propelling pencils on a daily basis, so I do appreciate the comment on weight- I like the solidity and heft, but that there are limits as you say, Richard. I have got some black Delrin as it happens, but a shiny metal pen has a bit of added charm- now thinking of copper, letting it start to pattinate then lacquering...

I fear things have changed- the bodies are quite delicate and tend to get brittle when clumsy people overtighten them after use- but only the newer bodies have broken, the older pens I still have going are still fine!

I'm surprised you let them use your pens!

Neil

I'm surprised that you still use Rotring pens. Mine were shelved years ago when CAD was introduced. It is a lost art form that can look better than the computer generated version.

Paul.

I dug out from the loft, a bunch of Mifa square leaded pencils with many different lead hardness`s. Took me back 50+ years. Put them back and got on with Fusion 360??

I may be 30 and fluent in most CAD software an architect should be, but as someone said pen drawings do look far nicer- since only about half the people in the office have the ability to use a pen, and CAD is used for most things, the nibs tend to dry out so pens get shared round...

(And no-one said we're not allowed to model things in CAD then trace over a printout to create a sexy drawing without having to redraw designs dozens of times by hand!)

Edited By RichardN on 17/06/2017 06:38:59

Even better than the old hand drawn ink drawings were those that were produced with a pencil only. These were a true art form which reflected the skill of the draftsman (sorry meant draftsperson to be more correct). A bit like a painting, you could tell who made it by their technique and style.

Never let anyone else use your pen. The end gets worn to your angle and will not be good for someone else, or you when next used. Just the same with nibbed pens. Modern drawing pens have some fancy materials for the tube but still wear.

A couple of years ago, maybe 8-10 I suppose, Both Parker Pens and Rotring were bought by Gillette. Then 4 years ago the pens business of Gillette was bought by Newell-Rubbermaid and much of the Rotring designs became Parkers before being dropped from the Parker range. The Rotring brand has disappeared entirely except for draughting equipment. Newell-Rubbermaid also owns the Waterman and Durex brands.

Regards

Richard

I must admit I delight in Ashley Best's tram drawings in Model Engineer, they take me back to pre-war MEs let alone those from the 50-s.

Neil

Rotring seem to be still very much alive in several fields. Apart from the Rapidograph pens they do mechanical pencils and lots of other drawing instruments.

No connection but I have used Tigerpens.co.uk who carry a vast range of finger held drawing implements

Ian P

The issue of not lending your pen to someone else because it will damage the tip is a myth I'm afraid. Firstly, the tips of fountain pens are made from an extremely hard alloy (often not containing iridium despite being described as such) and it takes years of regular writing to produce detectable wear. I know this to be the case. As I collect vintage fountain pens (currently about 1000 in the collection) and it is extremely unusual to find even a very early one with wear to the tip, unless it's an untipped steel one.Secondly, the myth just doesn't make sense, if allowing someone to use your pen for a few lines of writing wears away the tip, then you could restore it by writing a few lines yourself, anf if the tip really did wear so quickly it wouldn't last a week, which they obviously do. My pen of choice is either an extra fine point Parker 51 or a broad stub nib Sheaffer Snorkel, I've used both of these pens just about every day for the last 20 years and neither shows any detectable wear, even under the microscope.

I'm happy to let anyone try one of my pens - even the £1000+ examples - my major concern not being wear to any part of it, but the chance that they'll drop it, which is why I tend to hover nearby!

Re nibs wearing - I was talking about using the pens for production drawing, sorry if not made clear. Even the nibs/ tubes with hardened tips wore to suit the user. Some of the plastic film used was very abrasive. Just for interest would you allow a left hander to use your nibbed pens ?