Hello guys. The rear most driver side rod screw backed out and was lost. The parts manual shows part number M8. It is a hex head screw with an unthreaded shoulder. Does anyone know where I can get a replacement screw or know what size and thread pitch it is? Any help would be much appriciated.
Funny you should ask. The exact same thing happened to me. Walthers is completely out of the steam engine business including repair and spare parts. There are still some helpful folks there but their stock of parts is close to zero. I inquired about the M8 screw and was told they had none but a very helpful guy (name since lost) did send me a couple he thought might help.
You can probably forget finding the shoulder screw. That's a specially machined part for that engine by that manufacturor. I measured the substitute screw he sent me:
Diameter=1.4mm, Thread length=4mm, Hex head=3mm across flats.
The most common thread pitch for M1.4 appears to be 0.3mm but I have no way to measure that. I would guess you are looking for an M1.4-0.3x4 metric screw. I did a quick Google search and found hex socket head versions which would work but look funny. I also found a hex flat head but in 12mm length. That would require cutting to length. The lack of a shoulder doesn't seem to affect the operation of the loco though it might cause some extra wear.
Good luck on your search and please report back if you're successful.
Charlie
Note that you can 'shoulder' one of these screws comparatively readily (if not easily) by sleeving or thread filling, followed by chucking in a small tool or even pin vise and sanding or filing to diameter.
One of the functions of a shoulder on a screw is to allow the screw to be tightened while still providing a space below the head for the rod to turn. The 4mm length appears to provide this by bottoming out in the hole in the driver. The extra slop between rod and screw don't seem to have any detrimental effect. The hardest part of finding a replacement screw will be finding a hex flat head.
This isn't exactly what you're looking for, Charlie, but maybe it will help, or give you another avenue to search. Watchmaker's screw sets, or in this case, eyeglass repair kit. Amazon has both, and you'd be well off taking a look at both:
Jinlaili 1000pcs Eyeglass Repair Kit, Glasses Repair Kit Spectacles Repair Screws Nuts Tool Set,Glass Repair Tool with Screwdrive and Tweezers for Glasses, Eye Glass, Sunglass and Watch Repair : Amazon.ca: Health & Personal Care
This took care of me pretty well. I then got a tap set for $13 . Also got a larger assortment of 1.4to 2.0 sizes For about $13. Now I can handle just about every screw on a brass loco. I think it's important on the driver screws (1.4 x 5, or so) to use lock tight. Only problem I have now is finding king pin screws. May have to fabricate them from longer 1.4 stock screws.
https://www.amazon.com/HVAZI-Kinds-Small-Screws-Assortment/dp/B071DXG8D4?pd_rd_w=S1byo&pf_rd_p=5bc65336-a8b0-4888-9e70-4d4ce2f6bd59&pf_rd_r=97KHRQ8RW8XQFX0GTYNM&pd_rd_r=3821be67-12fb-4e6a-9bf7-d6d31deaa191&pd_rd_wg=0ueFz&pd_rd_i=B071DXG8D4&psc=1&ref_=pd_bap_d_rp_1_i
Thanks for the inf guys. I ordered the screw assortment kit. I think I can add a shoulder by using a tiny bushing or washer. I'll let y know if it works
Ii bought the same sets. What a nice change. Now I can handle any screw on a brass loco except, as has been said, the long king pin. May have to fabricate it.
i have a number of locos apart putting sound and doc and new motors in. I suspect my friendly local pack rat got into my stuff. Wow! I had left candy out for him, but I think he liked my glittery stuff better. Can't find his nest.