Drill rod question

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namonllor

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Hello again,
I'm looking at the wrist pin I have to make and it's dimensioned at .094" and made from drill rod. The peice is to be hardened and polished...should I get some 3/32" drill rod or go with a #40 or #41 peice of rod?
I feel like a putz not knowing, but I don't know, so any reply will be appreciated.
Thank you ,
Ren
 
Ren,
If you are going to use drill rod, I would use 3/32. Remember to temper it after hardening or it will break on an compression ignition engine like the NGEZ-1.

Two other alternatives that I use more often for wrist pins in this size engine.

1. Music wire from the local hobby shop in straight 3 foot lengths. It is drawn and has a very hard skin with a relatively soft tough core. I take a micrometer to the store when shopping. I generally check for roundness and size. I polish the OD and cut it to approximate length with a rotary tool, like a Dremel, and cut off disc. Then finish to length on a bench grinder with a fine wheel while holding the pin in a portable electric drill. Keep it cool. No hardening needed.

2. Dowel pins also work very well. Fractional sizes in this range are generally 0.0002 oversize, but I have a reamer that cuts about that much oversize anyway. Like music wire, very hard surface and tough core. Being polished and hardened already, no finishing needed except to cut to length and polish the ends. Cut and finish the same way as music wire.

Gail in NM,USA

 
Ren, have you considered a 3/32 dowel pin. They are case hardened and have worked very well for me, although most of my engines run at considerably less RPM than yours will.
 
Hah, I love it. Post a question....get an answer.
Thank you , thank you , thank you. I have music wire here in the house I could use, just didn't know I could use it for this application. Also Dowel pins are a doable option as there is an "ol timey" hardware store in town where I got some 1/4' pins last year.
EXCELLENT!!!
Thank you all,
Ren
 

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