Need ideas on how to replace crank pin on UP 844

[Bart1701]

I need to replace a crank pin on my UP #844. It popped out while I was doing some work on the locomotive and has disappeared from this universe. I have some coming from Kato, but I could use some advice on how to install this tiny little thing!

My hobby shop thought attaching it to a piece of tape might help me guide it into the hole and keep it from flying away. I also plan on doing this with the locomotive while it is sitting in a plastic shoe box with a paper towel in the bottom of the box - thinking this might help keep it from flying away on me.

Any ideas or suggestions will be appreciated!

Bart

[Lemosteam]

Use one tool to grip, preferably thin, and one tool to push.  Yes working in a container is a good idea but you have to be able to get your hands inside.

Assuming you have the rod holes aligned with the driver hole...

Lightly grip the pin barrel under the head with a good set of tweezers, not too much force on the squeeze or it will shoot. Get the pin into the rods and just inside the driver hole.  Use an allen wrench end, larger than the head, and push the pin down parallel to the hole while still gripping the tweezers, at some point the pin will align, and you will no longer need the tweezers on the pin barrel.  Continue pushing till it seats at the bottom of the hole. 

Same method but a little tougher, add a tiny drop of Red Loctite in the bottom of the driver hole before you align the rods to the hole. Do not risk getting the Loctite on the rod holes, and BY NO MEANS get any Loctite on the pin barrel!

[mmagliaro]

I think this tasks seems a lot more formidable than it really is.  John's notes on tweezers and getting the pin in are good, and I agree with them. 
I would add...
- Get the drivers rotated around so that the crankpin hole is at the bottom of the rotation.
- Put your finger on the pin before you try to pick it up in the tweezers, and keep that finger on the head of the crankpin the whole time as you guide the pin through the rod holes into the driver hole. This one simple thing really goes a long way.  As long as you keep your finger on that pin, it won't go flying.  Get it through the rods and into the driver hole and give a little push with that finger.  That should get it started.
- While holding the pin with the tweezers and pushing with a flat tool should work, I have had better luck with two pairs of
tweezers.  Keep one pair lightly gripped on the pin shank, and use the other pair to push the pin in as follows:
 Get one blade of the tweezer behind the wheel, and the other right on top of the pin, and just squeeze. 
 This is why you need to get the driver hole rotated around to the bottom, so you can get the tweezer
 blade up behind the wheel, right behind the crank hole.  After you get it in at least halfway, you can take away the tweezers that are gripping the pin on top, and just continue squeezing the pin in.

Another trick: On the tweezer pair you use to pick up and hold the pin, put a dab of Walthers Goo on the inner faces of the tweezers, and then wipe most of it off so the blades are just  a little sticky.  You should be able to pick up the pin, let the blades open, and have the pin stick to one
blade or the other.  This really helps keep that pin from going anywhere.  As long as it's just lightly sticky, it won't cause any trouble getting the pin into the hole, and if the pin carries some of that "sticky" with it into the hole, so much the better.

And incidentally, these same techniques are handy for getting other tiny stemmed detail parts into holes, like those slippery handrail stanchions on Kato Mikado body shells, or little tiny nut-bolt-washer castings.