Author Topic: Making Micro Cotter Pins  (Read 2259 times)

Offline 90LX_Notch

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Making Micro Cotter Pins
« on: March 23, 2017, 04:16:37 PM »
I have a need for a tiny cotter pin.  This is how I made one.  It is .014 diameter by .270 long.

A piece of .014 diameter music wire was clamped taught to a mini pallet.  The wire was then ground .007 thick.  This gave the proper wire contour that cotter pins are made from.

One end of the wire was nipped so that only the .007 half round was left.  The half round was clamped and a piece of .014 wire was layed across it.  The first bend was then made.  A square piece of stock was used to push the 1/2 round over the .014 wire and against the clamp to form the signature loop of a cotter pin.  The half round was then completely unclamped and the other end was nipped to length.

The cotter pin was then moved with the .014 wire in the loop to the mini toolmaker's vise and the loop was further closed upon the .014 wire.


I'm sorry that I didn't take more pictures of the process.  I might make a few more cotter pins.  If I do, I will take more pictures and update this thread.

The picture with the M&M shows the completed cotter pin passing through a .016 diameter hole in one of the "Ultra Tiny" rejects.

-Bob
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Offline b.lindsey

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Re: Making Micro Cotter Pins
« Reply #1 on: March 23, 2017, 04:51:32 PM »
What did you grind it with Bob? Dang...that's a cute little bugger :)

Bill

Offline 10KPete

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Re: Making Micro Cotter Pins
« Reply #2 on: March 23, 2017, 05:44:36 PM »
Gnats' eyelash!!! Good grief!   :o :o

Pete
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Online Doc

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Re: Making Micro Cotter Pins
« Reply #3 on: March 23, 2017, 05:58:02 PM »
WoW! Tell me you used a microscope I know I could not have done it with out  ;)
It dose look really nice! :praise2:

Offline crueby

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Re: Making Micro Cotter Pins
« Reply #4 on: March 23, 2017, 06:19:02 PM »
Thats about a third smaller than the ones I did on my Lombard tracks, and I thought THOSE were too small!

Nicely done!


Offline 90LX_Notch

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Re: Making Micro Cotter Pins
« Reply #5 on: March 23, 2017, 07:07:16 PM »
Bill- A Sanford SG-46 surface grinder.  It was Ray Hasbrouck's.  At one point it was the earliest known serial number according to a fellow who was researching them.  An earlier one did surface later. 

I was very forunate to have had the opportunity to buy it at a very, very reasonable price.  Ray's son was very good to me and really helped me advance my tooling wares.

Pete- The cotter pin is a little bigger.

Doc- No microscope.  I've said this before, but it worth repeating, it's like a pilot flying off of instrumentation.  To go really small you just go off of the dials.  You also need the correct size tooling, but it really does come down to the dials.

Thanks Chris.

-Bob
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Offline Tennessee Whiskey

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Re: Making Micro Cotter Pins
« Reply #6 on: March 23, 2017, 08:23:13 PM »
Awesome jig and die work  :ThumbsUp: :ThumbsUp: and a  :cheers:

Eric

Offline steamer

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Re: Making Micro Cotter Pins
« Reply #7 on: March 23, 2017, 10:43:29 PM »
Thats about a third smaller than the ones I did on my Lombard tracks, and I thought THOSE were too small!

Nicely done!



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Offline Ian S C

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Re: Making Micro Cotter Pins
« Reply #8 on: March 24, 2017, 11:27:17 AM »
The smallest I'v done were for the pins in the links for the governor of a Stuart Turner S9, they were made from steel wire about 1 mm thick. I tensioned the wire in the frame of a fret saw, and used a file to take it down to half diameter, they looked very nice.
Ian S C

Offline 90LX_Notch

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Re: Making Micro Cotter Pins
« Reply #9 on: March 24, 2017, 04:22:49 PM »
Brilliant Ian.  That is the one thing that I worry about when I post something that involves the surface grinder, not everyone has one.   Your method will work for anyone.

-Bob
Proud Member of MEM

My Engine Videos on YouTube-
http://www.youtube.com/user/Notch90usa/videos