Wahl Coronet Repair

[lcoldfield]

I wonder if it is generally appreciated that the early transparent plastics are very delicate?

 

I have been persuaded to repair a Wahl Coronet which was dropped - I think with the cap on. The Coronet has a transparent top to the barrel to enable observation of ink level, and this had broken into many pieces. There was no alternative to replacement. This part in the original Wahl repair catalogue was priced at 25 cents, but the Wahl phone number no longer works!

 

The first step was to remove the remnants of the broken pieces. The piece screwed on to the back of the section came off easily enough, but the piece stuck in the barrel was more of a problem and had to be machined out. This joint on the Coronet (according to the Wahl manual) has to be glued, and it is also splined so that it cannot be rotated. This is so that the action of unscrewing the cap – which screws to this transparent part - does not result in the filler assembly coming out of the barrel. It is worth being aware of this when a simple sac replacement job is needed on a Coronet. The Wahl manual says to tap it with a mallet and then pull straight out – I do not recommend the first bit, but it may be the only thing that works.

 

The replacement part was made in clear acrylic (the cast stuff, NOT the cheap extruded variant which can degenerate into millions of micro cracks when machined). The external threads which mate with the cap threads are 36 tpi 3-start. The internal threads which mate with the back of the section are 48 tpi. This latter joint contains a ‘belt and braces’ rubber seal which you could buy from Wahl for 5 cents. (I enjoy working on Wahls, they are surely the top brand of the period when it comes to quality of design and implementation!) The inner and outer surfaces of the part were polished and it was made to be a tight fit in the barrel. It was hoped that omitting the splines would not be a problem as the spline gaps in the barrel will fill with shellac and thereby make glue splines on the part.

 

Moral – Don’t drop your Coronet or any other pen with 20’s/30’s transparent plastic (I had a similar challenge with a Dunn), it will cost you a lot more than 25 cents!

 

[Bibliophage]

Nice looking pen. Good job getting it back in business.

[pen lady]

I'm gobsmacked Mr. Oldfield!

[eckiethump]

Wonderful to see that pen working again, I knew it could be done, but take the skill and knowledge of Laurence to do it in timeous fashion.

[Addertooth]

Wow, that was a nice restoral. It is something not to be attempted unless you have an engine lathe, and a lot of patience.

[eckiethump]

Laurence will perhaps not thank me for this, he's retired from general pen service/repair. But give him something like this, few people could, or be motivated to do the work required, thankfully Laurence is.

[markiv]

Wonderful work as usual.

Now the user needs to stain the clear acrylic with a stubborn orange ink to complete the vintage look 😎

[lcoldfield]

Yes, I agree that it would have been better with an orange tinted acrylic. I have blue and red tinted acrylic, but could not obtain orange. There is certainly a need for orange tinted material - for Watermans 100year, Ford ink chambers, Dunn, Onoto demonstrator etc. does anyone know of a source?

[Addertooth]

IColdField,

It is out there, it is simply one word which kept you from finding it... don't use "orange" in your search... use "amber". "amber acrylic rod"

I find that an amber color is a better match for aged acrylic than true orange... which seems too harsh.

 

https://www.google.com/search?sxsrf=ACYBGNTAO89PmF0saYs4kAUfqIj2GG7_Dg%3A1571835622612&source=hp&ei=5k6wXcjlItP59APEiKbgAw&q=amber+acrylic+rod&oq=amber+acrylic+rod&gs_l=psy-ab.3..0i22i30.3169.8089..8972...0.0..0.139.1946.3j15....2..0....1..gws-wiz.....10..35i362i39j35i39j0i131j0j0i22i10i30.tjNrjJIdVFk&ved=0ahUKEwjI8Lb_t7LlAhXTPH0KHUSECTwQ4dUDCAc&uact=5

 

or... to cut to the chase...

 

https://www.ebay.com/i/291676484626?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=291676484626&targetid=595232443429&device=c&mktype=pla&googleloc=1013487&poi=&campaignid=2086088130&mkgroupid=77632104192&rlsatarget=aud-622524043118:pla-595232443429&abcId=1141016&merchantid=112321395&gclid=CjwKCAjw9L_tBRBXEiwAOWVVCW6oRdFjv0kBWOWeGPGMkTvrRBRb1bn9oXzhm366y9dXbxvv1oeIRBoCZ-sQAvD_BwE

Edited October 23, 2019 by Addertooth

[FredRydr]

Wonderful work as usual.

Now the user needs to stain the clear acrylic with a stubborn orange ink to complete the vintage look 😎

 

I love these pens. Brad Torelli rebuilt mine years ago, and thankfully he used amber acrylic from the get-go.

 

[lcoldfield]

Thank you for the references to coloured acrylics. However, the problem was not obtaining the right shade of amber discolouration, but of obtaining it in cast acrylic. The references I found all said it was extruded acrylic or did not say which it was. I have found by experience that extruded acrylic is problematic for this type of application. The extrusion process locks in stresses which are affected by drilling - even when drilling slowly with cooling fluid. The material can appear to be unaffected by the machining operation, but later, perhaps after some weeks, develop a network of micro cracks that can result in fractures following some impact. Perhaps this is why the pen broke in the first place. This does not happen with cast acrylic. For this repair I considered it most important to prevent a further breakage.

Incidentally, who knows what the clear section looked like when new? I have seen many shades of amber ranging from nearly clear to nearly opaque and I had one pen that significantly darkened following the fitting of a new sac.

[FarmBoy]

Based on extremely clean examples the celluloid was clear and not tinted any color.

[Addertooth]

Heat cycle and cool Acrylics to eliminate stresses... i.e. take up to the point where it starts to get soft... and cool very slowly.... don't heat so hot you get bubbles.

I am sorry I missed the fact you specified cast.... but this limitation can be mitigated.

 

With your tooling, I would be tempted to make a rough mold, and simply cast it from liquid acrylic casting kits.. then do the final machining and polish....

Edited October 24, 2019 by Addertooth

[FarmBoy]

I’ve had good luck finding cast acrylic. No luck finding clear celluloid

 

https://www.eplastics.com/ACRCAR1-000_2?gclid=EAIaIQobChMIwIPF-JK05QIVxkXVCh0gKAywEAQYAyABEgJCnvD_BwE

 

And

 

http://www.delviesplastics.com/c/Cast_Acrylic_Rod.html

[judo]

Fantastic piece of engineering skill that you can bring this wonderful old pen back into service. The transparent plastic has done well to last so long before shattering and hopefully it'll last another 100 years without further major surgery.

[joss]

Incidentally, who knows what the clear section looked like when new? I have seen many shades of amber ranging from nearly clear to nearly opaque and I had one pen that significantly darkened following the fitting of a new sac.

 

That is an impressive repair, thank you for showing the pictures and for sharing essential details (eg the splined section) on the repair itself.

 

As to the colour of the ink window: some period advertisements show the Coronet without cap and although these ads are black & white, they do suggest that the Coronet's ink window was clear transparant indeed.