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View Full Version : what steel for pinion puller



darryl
08-04-2008, 05:58 PM
Shortly I'll be making up a pinion puller for these slot car motors. I have a puller which works, providing there's enough room behind the pinion for the 'jaws' to fit. In many cases there isn't enough room. Sometimes all I have is about .020 between the pinion and the motor bearing or case. I'm considering using music wire to make three jaws from, grinding away enough material to leave a small 'foot' at the end. Maybe I'll use four of these 'pins with feet' to spread the load as much as possible. I don't know how badly I'll be affecting the tempering of the music wire during the grinding, or even if there's a readily available alternate material which might be better. I'm really just looking for the best material to use which I can easily get and hopefully won't require a heat treatment process.

With the music wire, I might just make up a copper holder which I'd chuck in the lathe to hold the pin and keep some of the heat out of the material while I grind with the tp grinder. Now I'm wondering if maybe there's a more suitable material, possibly even some particular welding rod- tungsten, titanium, or other?

I don't imagine there's too much torque to overcome to move a pinion off a 2.5 mm shaft, but it sure does seem a bit of a chore for the ready-made pullers designed for this (when they can be used). I'm looking to make the 'cat's meow of pullers', as they would say, whoever they are. I plan to make a sliding collar of sorts to slip over the pins once around the pinion so they can't slide out and damage the pinion when the pulling 'gets tough'. The rest of the construction of the thing I'm not concerned about, just that I can make the jaws as tough as possible since there will be so little thickness at the 'business end'.

Any ideas?

Thomas Staubo
08-04-2008, 07:13 PM
Maybe you can use a clock hand removal tool? Like this one (http://www.jewelerssupplies.com/product981.html).

http://www.jewelerssupplies.com/media/241581.jpg

If you don't want to spend $21.05 on this, you can surely make one yourself.




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darryl
08-04-2008, 08:09 PM
That's not far from what I had in mind. My conception has the fingers arranged around a circular body and keyed onto an annular ring, so it will take as many fingers as you can fit around the shaft. An outer ring keeps them all in place. I like the method shown to force the fingers together- maybe I'll do exactly that. Thanks for the photo and the idea.