Getting back in the pen saddle...

[sfurini]

What holds the pen body on the mandrel?
Seen all kinds of mandrels for kitless pens but can't work this one out.

It's a very crude pin mandrel that needs a little more work. It's git a very rough flat filed onto it and a shortened nail acts as the pin.

Sent from my SM-G900F using Tapatalk

 

[Macaronytony]

Thanks for the explanation, if I had seen a flat area I would have guessed that.
Just thought you had come up with some super easy way.

 

[sfurini]

Well I got home from work much earlier than expected today so got out to the workshop. In terns of work flow I'm pretty much showing my method step by step...not because I think it's the best way to do it but just because this is how I do it. This is only my 6th kitless pen.

First step with the nib is a piece of blank about 5mm long on which a tenon is turned for the M9 x 0.75 thread.

Next a thin parting tool is used to clear up the back of the threads so that the nib section will screw fully into the barrel.

Then comes the drilling for the refill. Centre drilled first and then drilled 33mm deep with a 1/4 inch drill bit.

Then a 3/16 bit for another 3mm (love using imperial and metric at the same time...)

I then reverse the nib section in the collet and drill through with a 7/64 bit.

Finally for this post a test fit of the nib in the barrel with a refill in...perhaps the nib section is a tiny bit short. I'd have preferred less nib sticking out...

Sent from my SM-G900F using Tapatalk

 

[sfurini]

Thanks for the explanation, if I had seen a flat area I would have guessed that.
Just thought you had come up with some super easy way.

Nope. But my first one was turned too small so I didn't bother with a flat. Just wrapped masking tape round it and jammed the barrel on!

Your pen ideas look great in the sketches!

Sent from my SM-G900F using Tapatalk

 

[sfurini]

The nib continued...

Back in the collet and turned down to just shy of the barrel threads...about 11.6 mm.

Then reversed again and the front of the nib roughly shaped.

Here's the test fit photo that should have been at the end of my last post...

Then final shaping on a delrin mandrel...threaded for the nib section to screw onto. Cuts have to be very gentle...

Sanded and micromeshed and fitted to barrel...

Just the lid and final buffing to go!

Sent from my SM-G900F using Tapatalk

 

[Macaronytony]

Stunning Stewart, I'm learning so much from you..
Cant wait for the next episode.

 

[Les ELm]

Looks well done from here.

Les

 

[sfurini]

And finally onto the cap...no clip on this...

Face off and centre drill. Then drill for cap threads and to full depth of cap. I think it's an 11.4mm drill bit but I can't make out the size anymore! Then a very shallow drilling with 31/64 bit so that the cap will thread up snugly to the body...

Next turn down the barrel to final width and then reverse in a smaller collet and do top end of barrel...

Then using a jam chuck mandrel final shaping and sanding...

Sent from my SM-G900F using Tapatalk

 

[sfurini]

Then buffing. ..

I use supplies from the polishingshop. Pictures after each compound in order...

Lastly some ren wax which is then buffed off with a soft cloth...

...and left it too late to photograph the completed pen...need better light so that will have to wait until tomorrow!



Sent from my SM-G900F using Tapatalk

 

[Macaronytony]

Stunning job Stewart.. Came out beautiful.
Didn't realise how exacting you have to be with these.

 

[sfurini]

Thanks for sticking with it through the whole thread, Tony. I made another pen today - only took about 40 minutes, mainly because I had gone through making this one so painstakingly. Made a shorter nib section on this one as the cap on the purple pen does look a bit long. Oddly, the new pen today came out shorter when I was intending to make the body longer! It needs final sanding and buffing...

 

[wm460]

Beautiful work Stewart, you have done well.

 

[wm460]

Just wondering why you used a 9 X 0.75 thread?

Sent from my D6683 using Tapatalk

 

[sfurini]

Just wondering why you used a 9 X 0.75 thread?

Sent from my D6683 using Tapatalk

Hi
Probably because I read about someone using it! The margins between all the threads are quite fine. The cap thread reduces the diameter of the barrel tenon to 11.2mm. The nib thread in the barrel gives an inner diameter at the maximum thread depth of 9.75mm. This leaves a wall thickness between the threads of 1.45mm divided by 2 if I've understood taps and dies correctly. I realise that sounds thin but in practice it hasn't caused any issues.

With the nib section itself the wall is even thinner. The tenon is turned to about 8.8mm and the 9 X .75 die is used on it. This gives a diameter of 8.25mm. The hole for the refill is 6.4mm. This gives a maximum wall thickness between the inner wall and the bottom of the thread of 1.75mm divided by 2.

Overall the threads part of the barrel has a thickness of about 1.8mm and the nib section one of 1.3mm. My thinking is that it's better to have he thicker tenon on the barrel as this gets more use than the nib section thread.

Here's a shot of the two tenons....

 

[Macaronytony]

Be a while before i'm knocking them out in 40 minutes Stewart.
I purchased 9,10,11,12 x 0.75 taps and dies after reading something somewhere, just never had the bottle to try them till I followed your post.
Thanks again for all the great info and pictures...

 

[sfurini]

I'm glad it's been a useful thread, Tony.

I would say, that I've not had much success with threading polyester resin that I've cast at home but homecast polyurethane resin which I used on this pen is lovely to thread!

 

[Macaronytony]

Where do you get the Alumilite blanks from, Stewart?

Managed to turn and thread some clear Acrylic, that went ok. Just got some ebonite blanks off Phil at Beaufort Ink so playing with that next.

 

[sfurini]

Where do you get the Alumilite blanks from, Stewart?

Managed to turn and thread some clear Acrylic, that went ok. Just got some ebonite blanks off Phil at Beaufort Ink so playing with that next.

The alumlite is from www.metalclay.co.uk but I've also used polyurethane resin from mb fibreglass. Will see if I can find a link.

This is my casting mould...

 

[sfurini]

https://www.ebay.co.uk/ulk/itm/321410325676 This is the resin I used. It works just the same as alumlite. With alumlite dy so you can can get some nice effects...

Sent from my iPad using Tapatalk

 

[Phil Dart]

What a great how to Stewart.

Yourself and others may or may not find this drawing of use for future rollerballs, for the internal geometry of the section. It will allow the refill to protude by 3.5mm. The element that is 3.4 i/d is not a critical diameter - you could just as easily make that whole 11.5mm the same diameter at 2.6, but its presence makes it easier to insert the refill.