Hello, first timer here looking for help to build sling to go with RFM M1A1/M1A2 Abrams kit No. RM-5007.
I’d like to build the sling to lift the engine, but I’m really bad at estimating dimensions from photos and it doesn’t even have nice simple 90 degree angles. Best references so far has been these two:
They’re different versions. I’m looking to build the one behind the upper link. I’ve so far tried to combine the measurements on behind the second link to the design of the first but if anyone would have good knowledge, drawings or excellent photos, they’d be very welcome!
I would use the dimensions from your second link as a guide and build it close to them and so it fits the Rye Field engine. I doubt anyone is going to pull out a ruler and the TM and compare them. Sometimes close enough is good enough.
Like Gino said I would convert “ As-shown in standing position, it is 71" tall and base is 50" wide. Beam is 6 thick” values into 1/35 and call it close enough.
I am using them as reference and building the sling close enough. It’s just always easier If you don’t have to use your brain and can just go with existing measurements or instructions.
I guess it’s just me, but when I see that someone has taken the time to write a post asking for “good knowledge, drawings or excellent photos” they aren’t asking for “permission” to stop trying to find out, or to hear what other modelers consider to be acceptable approximations.
If you’ve compared most of the 3D models out there today to the objects they supposedly represent you’d agree that the hobby has far too much “close enough” already.
Well said. I MAY be able to get you exact measurements within eight weeks either at Fort Carson or Fort Cervezas. I have access to maintenance at both facilities.
The top beam looks like it could be made from two “C” channels of Evergreen cemented back to back. The closest sizes are .156 and .188. Personally, I wouldn’t use either. I’d just make it from strips and get the exact dimensions. I had to make my “C” channel for a crane I’m building. It’s not that hard and this project doesn’t require nearly the amount I had to make.
There are two construction methods, one with two wide flange beams welded together and one with channels riveted to plates. I think the second one is easier to estimate.
The base is 50 wide, the overall length is 71, and the stem is a 6-inches deep. Looking at the construction, that means the base is also 6 inches tall.
The connection is slightly off-center. By proportions, it looks like the centerlines of the base and stem intersect 27 inches from the end, with the stem tilted toward the short end.
It has to fit an M1 powerpack. If you have the RFM powerpack, measure the lift point locations. The tool was almost certainly designed such that the chain connection holes are the same as the lift points so that the chains hang vertically. Note that means the holes are at those dimensions, not the ends of the beams.
The parts list shows the shackle is a 4-ton capacity with a 7/8 diameter pin, IAW RR-C-271. That’s the standard specification for chains and attachments. Looking there the width between eyes is 1.438 +/- .125, so 1.313 minimum. That says to me that the plate sandwiched between the channels for the stem is 1.25 thick to insure that the shackle fits.
Now for assumptions:
The plate backing up the channel in the base is also 1.25 thick.
The channels are standard American rolled sections, C 6 x 10.5, with flanges 2.03 wide. The ends of the flanges look square so these might be an MC section, say, MC 6 x 3 x 1/4, with 3 inch wide flanges.
The rest can be estimated by looking at the pictures and taking proportions.
I’ve just started to learn 3D modeling. I don’t have printer myself, so I can’t print prototypes. I’d need to get it right the first time or in this case good enough. But here’s where I am so far. The angle between those two beams is probably the most difficult part with this sling.
No. Only one for the M88A2 which is similar but not suitable. But in my travels in April I may be able to get photos and measurements. Usually it depends on whether someone is working or not. As a lot of my travels are on a Friday, I sometimes arrive after everyone has left the shop to “do PT,” in which case I can’t get in.
And no one I know actually says “Fort Cavazos.”
Edit: As for the rivets, I use round head quite a bit, and to a lesser extent conical heads. I don’t know if anyone makes flat head rivets in that scale. Rather than trying to slice off pieces of rod, now would be a great time to invest in a punch set of you don’t already have one. You’ll wonder how you ever got by without it.
Oops. I misunderstood you. The crane I’m building? Do a search on this forum for “SS 249 Flasher in 1/72”
