Coupler Screw Size?

[NH Mike]

Anyone know what size screw is used to hold the coupler pockets on a Proto 2000 SD60, HO scale? No doubt its metric but I don't have anything here to use. I thought about drilling and retapping the frame for a standard 2-56 screw but the head of the screw won't clear the back side of the pilot. As a matter of fact a 2-56 screw won't go through the hole in the coupler pocket although a drill would have fixed that as well.

Whatever metric size it is smaller than a 2-56 but larger than a 0-80. I appreciate any info you can help me with as to the size.

 

[kenw]

M2 ?. Can't remember the diameter of the 2-56, but the metrics are,, well, metric. An m2 is 2mm, a m2.5 is 2.5 mm. Next is m3, m4, etc.
Edit http://www.engineersedge.com/screw_threads_chart.htm

 

[Iron Horseman]

Whatever metric size it is smaller than a 2-56 but larger than a 0-80. I appreciate any info you can help me with as to the size.

Are you sure it isn't a 1-72?

 

[NH Mike]

Are you sure it isn't a 1-72?

Thats possible but the thing is made in China so I'm guessing it might be metric. You could be right about the 1-72 but I don't have one here to try.

Tomorrow I'll take it to the LHS and see what fits. Instruction sheet isn't much help as it simply says screws come with the coupler replacement parts set. Not even a hint of size.

 

[NH Mike]

Problem solved. Whatever size it originally was, it was larger than a 1-72 but smaller than a 2-56 so most likely some lovely metric size. Retapped the holes for a 2-56 and opened up the holes in the coupler pockets to clear that size screw. Next issue was the head of a standard 2-56 screw was too big diameter and hit the back of the pilot and the screw would not go in straight. Used a Kadee nylon screw that happened to have a smaller diameter head. Life(like) is good again.