3D-Printing Replacement Parts

[WestLothian]

Hopefully this will be of interest for those wanting to "repair" by replacement the unrepairable components of vintage pens.

 

This Conway Stewart from around 1950 has cross-linked changes to the polymer causing severe distortions and embritlement (see photograph). The lever-fill mechanism was completely unusable depite all the parts still being inside the barrel.

 

 

I have had a basic level 3D printer for a couple of moths now and I have been impressed with the fine details that can be generated when the slower speeds and layer heights are used rather than the standard settings. This encouraged me to measure the complicated elements and print test parts to see if the cap threads and the jewel threads would be sufficiently accurate to work.

 

The cap has a 4-start thread that secures it to the barrel with a simple twist. This has a lead of 2.5 mm per turn and, with 4-starts, the effective pitch is 2.5/4 = 0.625 mm. I then used the standard thread forms for ISO metric or Unified to prepare small test parts 1/2" or 12 mm long. The first attempt was far too tight so I kept the same thread form but put the 4 helical cuts deeper into the cap to give a greater than standard clearance. It only took this second test part to get a free running thread that was still very secure when tight.

 

The barrel needs to hold a "J" shaped spring for the filler and has a fine groove to retain a 2-coil helical spring that positions the gold-plated lever in its socket. I printed the barrel first and persuaded the original springs to seat correctly in the new part. This let me fit an ink-sac and get writing.

 

 

The cap required the female thread to be printed in the same way and had a simple single thread for the cap jewel. It seemed to be close to the dimensions for M4 x0.7p but again required the hole to have a more generous clearance than the metal standard. This cap jewel tightened well using some silicone gloves for grip and holds the gold-plated clip securely. 

 

The surface finish shows a texture which is a bit like a silky fabric. I decided to leave this texture rather than trying to sand smooth and polish to a finish. 

 

 

 

I will need to experiment with the best method to add a decorative gold-plated capring and possibly a printed securing band rather than a groove.

 

The project was worthwhile, if only for the learning and process familiarisation.

 

 

 

 

 

[mizgeorge]

Fantastic! When you say low-level, how low-level do you mean? Something genuinely affordable?

[ajoe]

@WestLothian, that is really amazing. I'm vaguely familiar with 3D-printing, but that is really impressive.

 

Do you think that entry level printer could make a pen body and cap if a person had a suitable nib and feed unit?

[WestLothian]

The model is Voxelab Aquila X2  like here https://www.voxelab3dp.com/product/aquila-x2-fdm-3d-printer so about $170. The software was all open-source, free for personal use. FreeCAD for design models and Cura for the printer G-code. You can print out other useful items like coat-hooks and even a full-size descant recorder that plays at the correct orchestra pitch. I was more interested in fountain pen applications. The layers are down as low as 0.1 mm or 0.004".

 

The body and cap for any cartrige/replacement feed section was really easy especially with a click-to-close cap. The more technically demanding features were the cap threads and the lever filler details.

[es9]

This is awesome. I assume that level of detail makes fine threaded parts possible. For example, sheaffer triumph nib collars or sheaffer vacuum filler packing units—things that are not necessarily visible or all that expensive, but that can be a pain to harvest and require a parts pen. 

[IThinkIHaveAProblem]

Very cool

[mizgeorge]

5 hours ago, WestLothian said:

The model is Voxelab Aquila X2  like here https://www.voxelab3dp.com/product/aquila-x2-fdm-3d-printer so about $170. The software was all open-source, free for personal use. FreeCAD for design models and Cura for the printer G-code. You can print out other useful items like coat-hooks and even a full-size descant recorder that plays at the correct orchestra pitch. I was more interested in fountain pen applications. The layers are down as low as 0.1 mm or 0.004".

 

The body and cap for any cartrige/replacement feed section was really easy especially with a click-to-close cap. The more technically demanding features were the cap threads and the lever filler details.

Thank you! It's one of the ones I've been looking at, and at a really sensible price.

[WestLothian]

In this 2019 post the thread dimensions for the Sheaffer have been kindly measured for us by Hari317 and tested in a machined part. This appears to be the identical threadform generated onto the slightly smaller diameter (approx 7.6mm) rather than diameter 9.4mm.

 

I measured the cap thread on a couple of my Sheaffers and they are 3-start , 10 TPI. That should get me a temporary cap for this sad, old specimen.

[IThinkIHaveAProblem]

On 1/27/2023 at 5:13 AM, WestLothian said:

In this 2019 post the thread dimensions for the Sheaffer have been kindly measured for us by Hari317 and tested in a machined part. This appears to be the identical threadform generated onto the slightly smaller diameter (approx 7.6mm) rather than diameter 9.4mm.

 

I measured the cap thread on a couple of my Sheaffers and they are 3-start , 10 TPI. That should get me a temporary cap for this sad, old specimen.

Touchdown TM?… 

[WestLothian]

It is an old touchdown pre-snorkel, so it could be TM. There is no sac protector and the cap was missing when I found it. The plunger cap seems to have been glued in to the gold filled part at a wonky angle that resists a squeeze in the vice.. It now has a 3D-printed black plastic cap that fits and makes it functional.

[IThinkIHaveAProblem]

still likely a great pen!

betcha the nib is nice

 

here's how I know:

 

 

the triumph nibbed pens I have restored hardly ever need any adjusting at all, they just write, and usually beautifully, right off the bat  

[WestLothian]

Yours is a really nice example, and it's nice to see the correct cap. I only have three very diverse Sheaffers to experiment.

 

 

 

[IThinkIHaveAProblem]

42 minutes ago, WestLothian said:

Yours is a really nice example, and it's nice to see the correct cap. I only have three very diverse Sheaffers to experiment.

 

 

Thanks, i am very happy with it. (I have it and both gold snorkel triumphs, but not a masterpiece…)

 

wrt the correct cap: you seem to have done ok with your printed cap, the correct cap is just about the same as the snorkel cap  
 

that second writing sample is insane!  I wish mine was that wet!  That’s amazing and would be worth trolling eBay for a cap… even if you just found a “crest” cap, the lines wouldn’t match but at least it would be gold. 
 

yeah. That pen looks like it was made for signing paperwork!

 

[judo]

On 1/26/2023 at 12:58 PM, WestLothian said:

Hopefully this will be of interest for those wanting to "repair" by replacement the unrepairable components of vintage pens.

 

This Conway Stewart from around 1950 has cross-linked changes to the polymer causing severe distortions and embritlement (see photograph). The lever-fill mechanism was completely unusable depite all the parts still being inside the barrel.

 

 

I have had a basic level 3D printer for a couple of moths now and I have been impressed with the fine details that can be generated when the slower speeds and layer heights are used rather than the standard settings. This encouraged me to measure the complicated elements and print test parts to see if the cap threads and the jewel threads would be sufficiently accurate to work.

 

The cap has a 4-start thread that secures it to the barrel with a simple twist. This has a lead of 2.5 mm per turn and, with 4-starts, the effective pitch is 2.5/4 = 0.625 mm. I then used the standard thread forms for ISO metric or Unified to prepare small test parts 1/2" or 12 mm long. The first attempt was far too tight so I kept the same thread form but put the 4 helical cuts deeper into the cap to give a greater than standard clearance. It only took this second test part to get a free running thread that was still very secure when tight.

 

The barrel needs to hold a "J" shaped spring for the filler and has a fine groove to retain a 2-coil helical spring that positions the gold-plated lever in its socket. I printed the barrel first and persuaded the original springs to seat correctly in the new part. This let me fit an ink-sac and get writing.

 

 

The cap required the female thread to be printed in the same way and had a simple single thread for the cap jewel. It seemed to be close to the dimensions for M4 x0.7p but again required the hole to have a more generous clearance than the metal standard. This cap jewel tightened well using some silicone gloves for grip and holds the gold-plated clip securely. 

 

The surface finish shows a texture which is a bit like a silky fabric. I decided to leave this texture rather than trying to sand smooth and polish to a finish. 

 

 

 

I will need to experiment with the best method to add a decorative gold-plated capring and possibly a printed securing band rather than a groove.

 

The project was worthwhile, if only for the learning and process familiarisation.

 

 

 

 

 

Just spotted your post. That's a tremendous 3D print and I agree the finish looks better than smooth and highly polished. Can you print in a transparent resin on the Voxelab Aquila X2? There are a number of pen parts I can't get hold of and would purchase if they can be 3D printed.

[mhwombat]

I would love to be able to buy or 3D print a modern pen body (whether it uses a standard converter, or a piston, or even an eyedropper) that can take certain vintage nibs. I love the feel of a vintage nib, but I don't like the fiddly-ness of pens with ink sacs. Vintage eyedropper/safety pens are usually too skinny for me to find them comfortable, and there aren't that many vintage pens that have piston fillers.

[Lamy4life]

Oooo, Very fun. I have been thinking about retro fitting vintage nibs using a 3d printer. I tried to 3d print ink sacks but it was a struggle to get them air tight. I am eying some SLA machines to get much better detail tho. 

 

[Lamy4life]

5 hours ago, judo said:

. Can you print in a transparent resin on the Voxelab Aquila X2? There are a number of pen parts I can't get hold of and would purchase if they can be 3D printed.

Nope, The Voxel Lab uses filament and not resin sadly. Tho you might be able to get translucent to clear 3d prints on the machine depending on fillament and printer settings. 

[WestLothian]

On 2/10/2023 at 5:05 PM, judo said:

Just spotted your post. That's a tremendous 3D print and I agree the finish looks better than smooth and highly polished. Can you print in a transparent resin on the Voxelab Aquila X2? There are a number of pen parts I can't get hold of and would purchase if they can be 3D printed.

There are transparent filaments available. This Geeetech PETG Filament 1.75 mm Transparent has very good reviews.

[WestLothian]

On 2/10/2023 at 10:21 PM, Lamy4life said:

Nope, The Voxel Lab uses filament and not resin sadly. Tho you might be able to get translucent to clear 3d prints on the machine depending on fillament and printer settings. 

There is an interesting comparison of transparent prints here https://3dprintguides.com/2020/04/transparent-clear-3d-printing-petg-vs-pla/

All the temperatures and speeds are within the capability of this Aquila X2,

[Lamy4life]

1 hour ago, WestLothian said:

There is an interesting comparison of transparent prints here https://3dprintguides.com/2020/04/transparent-clear-3d-printing-petg-vs-pla/

All the temperatures and speeds are within the capability of this Aquila X2,

 CNC kitchen has a fun video about it too. Good luck, It can be quite a challenge from what I heard. 

 https://youtu.be/9qb25Gi4Jv0