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Here is a Caution when Drilling the Axel Nut Cotter Pin Hole

bacstabber

Well Known Member
Friend
I just wanted to share with you my experience with making the hole in the gear leg axel for the cotter pin that secures the axel nut. Once you have the axel nut tightened just enough to stop any wheel play and yet the wheel rolls freely, the instructions tell you to use a center punch, through a hole in the axel nut, to mark the axel for drilling the cotter pin hole. I followed the instructions but after center punching, the axel nut that was easy to put on was now very hard to turn. To make a long story short, I had to go buy a 1.5"/38mm deep socket to use with a breaker bar to remove the nut. All the while, I was thinking that the axel threads were being damaged and I was going to have to replace my gear leg. I did get the nut off and inspection of the axel threads showed that the punch deformed one adjacent thread enough to cause the problem. When I drilled the hole to size, that thread was removed but I had to lightly use a deburring bit to remove the holes jagged edges before I could get the axel nut back on the axel past the hole. Several times of exercising the nut on the threads resulted in easy turning of the axel nut. For the other axel nut,instead of using the center punch, I lightly drilled the axel with a #30 bit to mark the axel for drilling. This worked much better then using the center punch method. The axel nut did need some massaging to get free nut threading but nothing like the other axel nut.
 
Jack it looks like first axle was for EDUCATION and second one for RECREATION :) fits the purpose of experimenting.

On mine I marked the spot with torque seal, then removed the nut, dremeled the spot threads free and flat, then center punched and drilled. Cleaned the other end using dremel too. Looked like too many operations but it was easy and enjoyable.


cotterpinhole.jpg
 
That is very funny Vlad! Many of my building tasks are exactly that, Education. Next time I might have the sense to do something as smart as what you did. Thank you for your feedback. It is appreciated by me and I'm sure it will help someone like me in the future.
 
It's easier to tighten the axelnut in place and just use your angle drill to drill through the hole in the nut and through the axle.
Put a pin in the hole to steady it and repeat on the opposite side of the nut.
 
Now that I am so smart, I agree with you 100%. That is the way that I would do it if I had to do it again. I did think of doing that way but I decided to just follow the instructions. That was not the right choice. I did use the nut and the hole that I drilled in the axel to help me to line up the drill for the exit hole on the other side. This worked well.
 
What we did: Tightened the nut on the axle and measured the angle from the gear leg to the flat of the nut where we wanted the cotter pin (forward and up), marking the flat. Then we removed the axle nut, counting the number of full revolutions. To be sure, we re-tightened and recounted a couple of times. Then we removed the wheel and put the nut back in place, counting and then adjusting until the marked flat was at the angle we had previously measured.

Now to the Bridgeport. Clamp the leg in place and position the tool so it goes cleanly through the hole in the nut. Then remove the nut and cut the hole in the gear leg. Use a file to clean up the threads, replace the nut, turn the leg over to position it to cut the other side, and repeat.

I used an angle drill on the -6A and went through several bit and got an ugly hole, taking a long time to get it done. The mill was cheaper and more accurate, but even a drill press would be better than hand drilling these. You can apply more pressure and control the speed better. It's even better if you have a cutting bit rather than a drill, because they are too long and can wander slightly.

Another thing, I notice that there is potential interference between the cotter pin and the valve stem on my RV-10 mains. I will be counter-sinking the holes in the nut slightly to allow the cotter pin to fit closer; we also enlarged the cotter pin holes very slightly to allow an easy slide fit (but not loose).
 
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