09-03-2019, 02:48 PM
Welcome to Big Blue, Mark!
According to the instruction sheet for the MDC 4-6-0, the one-piece siderods (brass stampings) need to be cleaned of all burrs, using a file. They are then attached to the front and rear drivers using "small brass shoulder screws".
The threaded portion of the screws, obviously, goes into the hole in each driver, with the shouldered portion of the screw fitting into the hole in the side rod. The hole at the mid-point of each siderod fits onto the extended boss on the main (centre) driver.
The shoulder on these screws is designed to prevent the modeller from over-tightening the screws, which should prevent binding of the siderods.
However, at no place in the instructions, for either the Ten Wheeler or the Consolidation, is the size of those screws mentioned. They're identified only as Part 6L-120, for which I can find no additional information. In the drawing, these screws appear to be roughly twice the length of the known screw, mentioned below.
However, the screw which is to be used to attach the main rod to the centre driver is identified as a 'pan head self-tapping 0-80x1/8" screw'. It's difficult to tell for sure, from the drawing in the assembly instructions, but it appears to also be shouldered, which seems logical in keeping with the others.
There's a pretty good chance, I think, that the 6L-120 screws are also self-tapping, and would likely be 3/16" long, or perhaps a bit longer than that. Again, I'm just guessing, but I can't see any reason why MDC wouldn't use the same diameter screws for the siderods, too, so if you can find some 0-80x3/16" self-tapping screws to use in the siderods, you might be able to get your locomotive assembled.
I also note in the Ten Wheeler instructions, that there's pin connection of the main rods to the crossheads, calling for the pin to be inserted from the back (inside) face of the crosshead, then through the hole in the main rod. The instructions then call for the modeller to use a small screwdriver to "upset" the end of the pin which protrudes through the main rod.
It's been over 40 years since I built mine, and they were sold-off many years ago, and while they ran very well, I don't recall that particular step. Usually, "upsetting" is done to things like rivets...it basically involves fiddling with the end of a pin or rivet to make it big enough to not easily be withdrawn from the hole(s) through which it's been installed - similar to "peening-over".
I seldom see self-tapping screws in hobby shop displays, but you may be able to find them at a really well-stocked hardware store. Otherwise, an on-line search should offer some other options.
EDIT: I doubt very much that the plastic pins would work in lieu of the screws, and I do recall some buyers being less than pleased with the performance of the plastic pins.
Wayne
According to the instruction sheet for the MDC 4-6-0, the one-piece siderods (brass stampings) need to be cleaned of all burrs, using a file. They are then attached to the front and rear drivers using "small brass shoulder screws".
The threaded portion of the screws, obviously, goes into the hole in each driver, with the shouldered portion of the screw fitting into the hole in the side rod. The hole at the mid-point of each siderod fits onto the extended boss on the main (centre) driver.
The shoulder on these screws is designed to prevent the modeller from over-tightening the screws, which should prevent binding of the siderods.
However, at no place in the instructions, for either the Ten Wheeler or the Consolidation, is the size of those screws mentioned. They're identified only as Part 6L-120, for which I can find no additional information. In the drawing, these screws appear to be roughly twice the length of the known screw, mentioned below.
However, the screw which is to be used to attach the main rod to the centre driver is identified as a 'pan head self-tapping 0-80x1/8" screw'. It's difficult to tell for sure, from the drawing in the assembly instructions, but it appears to also be shouldered, which seems logical in keeping with the others.
There's a pretty good chance, I think, that the 6L-120 screws are also self-tapping, and would likely be 3/16" long, or perhaps a bit longer than that. Again, I'm just guessing, but I can't see any reason why MDC wouldn't use the same diameter screws for the siderods, too, so if you can find some 0-80x3/16" self-tapping screws to use in the siderods, you might be able to get your locomotive assembled.
I also note in the Ten Wheeler instructions, that there's pin connection of the main rods to the crossheads, calling for the pin to be inserted from the back (inside) face of the crosshead, then through the hole in the main rod. The instructions then call for the modeller to use a small screwdriver to "upset" the end of the pin which protrudes through the main rod.
It's been over 40 years since I built mine, and they were sold-off many years ago, and while they ran very well, I don't recall that particular step. Usually, "upsetting" is done to things like rivets...it basically involves fiddling with the end of a pin or rivet to make it big enough to not easily be withdrawn from the hole(s) through which it's been installed - similar to "peening-over".
I seldom see self-tapping screws in hobby shop displays, but you may be able to find them at a really well-stocked hardware store. Otherwise, an on-line search should offer some other options.
EDIT: I doubt very much that the plastic pins would work in lieu of the screws, and I do recall some buyers being less than pleased with the performance of the plastic pins.
Wayne