The yoke screw on older and on pre war hand ejectors is not a special screw, same as the other side plate screws (except the bug screw at the top), It's only special once the length has been fitted to the groove in the yoke at the factory. So as in the other thread, just swap with one of the other two screws and fit for proper length to the yoke.
The issue with your gun is usually caused because most people don't realize that the screw is fitted to the yoke. They remove the side plate screws and mix them up. One of the other side plate screws likely properly fits the yoke already. You just need to examine the yoke button for damage.
If you do need a replacement screw, you'll want a pre war screw.
A specification change on March 4, 1942: a specification change in the standardization of tolerances for screw diameter. A change from old S&W 'smaller minimum diameter' tolerance to the larger minimum standardized tolerance of the #5 x 44 National Fine (N.F.) screw diameter (no, the threads per inch did not change). It refers specifically to the sideplate screws in this discussion (but excluding the bug screw or upper sideplate screw which is a 4-48 pre and post war) but also the #5 N.F. grip screws. Therefore, there CAN BE a difference between 'pre-change' and 'post-change' screws and they CAN measure differently.
In March of this year, I purchased sideplate screws from three sources: Numrich, Brownell's, and Gun Garage. The domed screws from Numrich were in a dull finish and incorrect thread size - they wouldn't fit. The domed screws from Brownell's were a high-polish finish and the correct thread size (5 x44) - however, the diameter of the head was just the slightest bit small. This showed up visually when installed but I did not measure them. The screws received from Gun Garage were high-polish, correct thread-size, and fit beautifully. They are gorgeous and look exactly like OEM screws.
Sources for proper screws:
GUN GARAGE on Ebay (for screws)
gungarage | eBay Stores
"Aonepawninc"
aonepawninc | eBay Stores
has a bunch of old S&W parts for sale. I just ordered a complete hammer for my pre model 30 from them. They are very customer oriented and have very reasonable prices. 1/10/16
Dave Bennett: Parts and guns from 1900 up to 1970's.
e-Mail:
[email protected]
Web Site:
www.22ammobox.com