# Delrin flashlight body



## series8217 (Jan 13, 2009)

Delrin machines very nicely and is dimensionally stable.
Seems like it would make a great lightweight and durable flashlight body assuming the design of the electronics are such that electrical paths through the body are not required.
How well would threads (for an endcap for example) hold up in this material? The endcap would be removed often to replace the batteries. Would stainless steel inserts be required?


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## gadget_lover (Jan 14, 2009)

The threads will not hold up well unless you make them very coarse. I have done some fine threading in delrin and it tends to be somewhat fragile.

Dan


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## RyanA (Jan 14, 2009)

What if the endcap functioned similarly to a prescription pill canister cap? I dunno if or how that would allow for a switch though.:thinking:


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## ToddK (Jan 14, 2009)

Delrin is used for some of the high end backup flashlights for cave/technical diving. For example: http://www.halcyon.net/lights/scout.shtml
I have two of these at home, and agree the pitch is somewhat coarse. I can measure the pitch tonight. EDIT: the pitch is 16 threads per inch.


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## Sgt. LED (Jan 14, 2009)

Sounds great to me!


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## Mick (Jan 14, 2009)

Black delrin is my favorite material but it has it's place. I have made flashlights with aluminum heads and delrin tubes. I use a double O-ring to hold them together. Put about 90% of the O-ring groove in the aluminum and a chamfer on the outside edge of the delrin grooves. This allows you to pull it apart without too much effort. A big plus for the delrin tube is you can use the new capacitive sensing technology and have a 100% sealed light.


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## series8217 (Jan 14, 2009)

Mick said:


> Black delrin is my favorite material but it has it's place. I have made flashlights with aluminum heads and delrin tubes. I use a double O-ring to hold them together. Put about 90% of the O-ring groove in the aluminum and a chamfer on the outside edge of the delrin grooves. This allows you to pull it apart without too much effort. A big plus for the delrin tube is you can use the new capacitive sensing technology and have a 100% sealed light.



That's an interesting idea. So the endcaps just push/snap into place? Have you done any dunk test to see how well it seals?



ToddK said:


> Delrin is used for some of the high end backup flashlights for cave/technical diving. For example: http://www.halcyon.net/lights/scout.shtml
> I have two of these at home, and agree the pitch is somewhat coarse. I can measure the pitch tonight. EDIT: the pitch is 16 threads per inch.



Very cool! Thanks for the info and link.


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## kaichu dento (Jan 15, 2009)

If we can trust our lives to delrin ski bindings and boots, I'm sure they can apply SF style square threads to solve that problem and any others that should arise.


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## Mick (Jan 15, 2009)

I just did a quick dunk test of a IR laser light with a single O_ring in a water pitcher for 10 minutes ... no bubbles, no water inside. Not a good test but better than nothing!
One thing to remember about using delrin with aluminum is the vast difference in coefficient of expansion.
Another thing; I get a beautiful knurl on the delrin.
I'll post a picture later; my camera battery was dead.


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## Mick (Jan 15, 2009)

This shows the O_ring joint on a battery tube. You can also see the knurling on the rear section. (with lint)


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## Axkiker (Jan 15, 2009)

delrin does machine very nicely. I machine alot of it on my milling machine. Its wonderful for making prototypes and molds for casting materials.


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## 65535 (Jan 16, 2009)

An idea could be to use close fitting grooved mating parts where the body is delrin and a metallic insert is epoxied in place (grooves to help improve hold) where the metallic insert is threaded

A proper design would be strong and if don't right very clean.


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## wquiles (Jan 16, 2009)

Mick said:


> This shows the O_ring joint on a battery tube. You can also see the knurling on the rear section. (with lint)



Very nice 

Will


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## will (Jan 17, 2009)

65535 said:


> An idea could be to use close fitting grooved mating parts where the body is delrin and a metallic insert is epoxied in place (grooves to help improve hold) where the metallic insert is threaded




Delrin is like teflon, very few adhesives will work. You have to get the correct adhesive to have anything stick. I have tried epoxy and gorilla glue, neither worked..


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## Mick (Jan 17, 2009)

Very true Will; also the difference in expansion rates will break any bond you get. You could try a roughened metal surface with a heavy interference fit.


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