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Hi, am I missing something obvious about Delrin. Nobody seems to make rear wheels out of Delrin. Does it deform under load, will it not take a strong enough thread in the boss. Any ideas, guesses or facts would be apreciated before I buy some Delrin/acetal rod.

John
 

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Tony
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Hi John
SCD make delrin front wheels and I had some recently and stripped the hole for the grub screw without using too much pressure
 

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Discussion Starter · #6 ·
just been on milans site and his wheels are the same as ab,s. just a plastic tube with an ally boss inserted in it. Big T if you turn down the boss you could glue an ally ring onto the small boss thats left and drill and tap that. john
 

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Discussion Starter · #8 ·
just dave, i,ve been on pendle,s site and looked at the delrin wheels. i think their front wheels, from the size and i cant see any grubscrew fitting, as they only show the fronts. but its exactly what i,m trying to find. cheers. john
 

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Hi

We use delrin rear wheels in HO and given the amount of magnet we use in the top classes can report no isseues regarding deformation under load.

It has to be said though our wheels are push fit and all non metallic wheels and gears I have encountered in other scales tend to have a metal boss.
 

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Rich Dumas
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The material commonly referred to as delrin is actually a type of nylon. Delrin is a trade name for a different type of plastic that is softer and more flexible than nylon. Both types have been used on slot cars, especially for gears, bearings and HO car chassis. Delrin is too soft to use for wheels, nylon works well for press-on wheels. If you make a set screw wheel out of nylon it will distort when you tighten the screw.
 

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Sorry RichD, but Delrin is an Acetal Homopolymer, not a type of nylon and is harder and stiffer than nylon, to quote Wiki:-

"Polyoxymethylene (POM), also known as acetal, polyacetal and polyformaldehyde is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. As many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and is therefore sold under many commercial names like Delrin, Celcon, Hostaform, etc."

Delrin is a homopolymer, whilst Celcon & hostaform are copolymers, the difference being the polymer chain linkages. The reason for the two types being the need to circumnavigate patents held by the original inventing company. Whilst it is an excellent material, it's inability to take high torque on small threads does limit it to front wheels only, as with most other plastics.

Mike T
 

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As stated by Mike above .......................

Delrin is not really a suitable material for tapping M2 or 4/40 threads ( NSR grub screws ) and then expecting those grub screws to hold the wheels on ! !
If you can design another method for holding the wheels on, that does not rely on grub screws, then, in my opinion, Delrin is a suitable material, mechanical strength OK, for making rear wheels.

Mechanical design engineer ( retired )
 

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Obviously the likes of DH71Tiger and Mike T know exactly what Delrin is - not so sure all the other contributors do.
Lots of people don't know the difference between the different sorts of plastic, so when they use names like Delrin and Nylon it really means little more specific than some sort of plastic. Pity they don't stick to words like plastic if that's all they mean!

DH71Tiger is right when he says Delrin is not really a suitable material for tapping M2 or 4/40 threads and then expecting those grub screws to hold the wheels on - the same could be said for just about any other plastic! !
 

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the tapping is easily sorted. when i turn the boss i,ll take it down to 1mm allround the axle hole then turn an ally boss that just fits over the spigot and glue it in place. when i drill and tap it 2mm i shouldent have any problems with distortion or thread stripping. john
 

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Rich Dumas
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I stand corrected, as a retired chemist I was aware that there are many varities of both nylon and delrin. While I was still working I had some "delrin" analyzed by FTIR and found that it was actually nylon. In any case a member of my club that runs an online business wanted to have wheels made of delrin and ran into the distortion problem, even with a hubless wheel design. The distortion was not severe, however he decided to go with aluminum wheels and those have sold fairly well.
 

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QUOTE (stoner @ 30 Aug 2012, 14:56) <{POST_SNAPBACK}>the tapping is easily sorted. when i turn the boss i,ll take it down to 1mm allround the axle hole then turn an ally boss that just fits over the spigot and glue it in place. when i drill and tap it 2mm i shouldent have any problems with distortion or thread stripping. john

That's a very good idea .................. I might try that myself
 

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Tony Condon
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The first time i encountered Delrin was when cox gears came on the market 40 odd years ago
They were advertised as being made of delrin which was a fall out from the space race
However all cox gears had alloy hubs whether they were sidewinder or inline as /cox quite rightly thought that delrin wasn,t a suitable material to tap for grubscrews

Cheers tony
 

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Hi Tony................

I remember as them being specified as Coxalloy ...................... or something like that. LOL

Andrew
 

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Tony
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As far as I am aware any plastic/nlylon/delrin/whatever gears or rear hubs have an alloy boss for the grub screw
 
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