Broken truck mounting screw

[Trainman203]

A brass screw into the under frame bolster of an old "zamac" die cast underframe broke off inside.  Any ideas how to get that out?   

[jbrock27]

Drill it out, tap for a new screw that will fit the hole and the truck and put in the new screw.  Or, drill it out and use a self tapping sheet metal screw that is just a little bigger than the hole and will still fit through the truck hole.

[richardl]

This will require a steady hand and sharp drill bit. I use kerosene for lubricant.
A vise would be a great help and maybe even a drill press. As a former mechanic, I was able to do this where I worked.
I finally bought a Dremel drill press and a vise to fit on it for at home projects.

I do remember tapping for a 2-56 machine screw.

Rich

[jbrock27]

I should ask, are you able to take things apart to get at whatever may be left of the screw on the inside.  My first response was based on my first thought you were asking about a freight car.  Are you?

[richardl]

Yeah. Can you see the other end of the screw?

Rich

[electrical whiz kid]

That screw will be harder than the zamac floor.  If it were me, I might do some prep work.  Using a flat bit, grind the bolster area with screw down to flat-won't take much.  THEN (Now the going gets tricky) take a small enough punch and at center of screw-punch a dimple into the flat face of the screw.  That done, try drilling out the screw; just go easy-this is a job where I hope you aren't prioritizing time-TAKE YOUR TIME!  ONE SLIP OF THE DRILL BIT, AND IT IS GOING TO PROBABLY MEAN KAPUT-NIK!!.  Once the screw is drilled out, take an easy-out that size and insert it COUNTERCLOCKISE into the screw, (hopefully) taking the screw out.  If not, just DRILL out to the tap size, and re-tap it.  2-56 is the usual size.  Kerosene or lard is good-Richardl said kerosene.
There are other alternatives, such as getting a new underframe and using that in place of the old one.  Keep in mind that one metal is harder than the other-in this case, it is the screw!

RIch C.
SGT C. 

[Trainman203]

It's an old crummy 50 year old tank car, maybe Mantua, I was trying to upgrade for someone.  Took the "talgo" trucks off and was trying to put some better ones on, then do the body mounted couplers.

If it was my car I'd pitch it but since it's someone else's I need to fix it.  Maybe it would just be easier to buy them a new one.  And make a branchline water tank out of the old one.

[Len]

Take the underframe off and see if there's enough screw coming through on the inside to grab with a pair of vice-grips. If so, you should be able to turn it so it backs out on the side you were putting it in from. Then you can grab it from that side and take it the rest of the way out.

If not, all you can do is drill it out and retap the hole. Use a drill press if you have one, and clamp the car in place while drilling. if not, use one of those "egg beater" type hand drills to take it out. There's a lot less chance of overheating anything, or tearing up the car the way an electric hand drill can. Especially if the bit jams.

Len

[jbrock27]

Thanks Len, this is where I was coming from in my Post #2.  However, I would suggest that the screw be turned in the direction of the tank and not toward the bottom of the car as it should be a lesser distance for the threads to travel and it will be less likely to damage the threads on the car body bc you are not trying to push the screw down with threads that may very well get marred by holding them with vice grips or needle nose pliers or whatever he uses to hold and turn what remains of the screw.

[electrical whiz kid]

I was not aware what type of car it was.  A tank car...  Can I recommend going to Tichy site.  Don has a good set of parts, including a great underframe for  a tank car.   Go to www.tichytraingroup.com 
On experience with them; I recently did a Mantua "conversion" (Gulf Oil) and found it to be an interesting challenge.  You will do some extensive work, but you will also find that the detail in the assembled model will far surpass anything you had before. 
While you're at it, take a look at Don's tank car kit.  I think if you like model making, you will be impressed enough to try one.  I can't speak for them, but I think possibly Jeff and Roger might also endorse them.

Rich C.
SGT C.   

[jbrock27]

You giving up Sargent Major on the prospect the remaining threads can successfully be removed?

[electrical whiz kid]

Jim...You aiming that at me?  Oh, by the way; I wasn't a "Sargent Major'.  I was just a Staff Sargeant  in the Air Force-nothing fancy.
RIch C.

[jbrock27]

Yes Sarge, I am addressing you, I certainly am not aiming at you.  So, are you giving up on the prospect of the remaining threads being successfully removed??