Made these up for an AMT flatbed trailer, used measurements of a strap winder on the 5-ton truck at my work. These were scaled down to 1/25 and converted to thousandths of an inch. Evergreen .030 x .156 styrene strip for the side & top plates, 3/32 styrene tube for the winder itself. Top plate cut .330 long, side plate blanks .275 long, 3/32 tube .475 long.
.010 brass shim & 1/32 square bar jig is used for making the two side plates. The blank is inserted and the 3/32 hole drilled. Then the excess material is trimmed off, filed & sanded flush with the jig.
Jig for assembly made from piece of scrap 1 x 2 pine with Northeastern scale lumber ("HO 4x8/N8x16")
Top plate goes in first, then side plates, then winder is inserted into the side plate holes. Stop on right side of jig to set winder in proper location. Apply cement sparingly! Once cement has set #61 hole drilled in winder - I line this one up "by eye".
Tricky part is the ratchet itself. Disassembly of an old Model Power GP-38-2 turned up 12 small Delrin gears, 6 in each truck assembly. 8 were a suitable size for the ratchet, 4 were slightly larger. Being plastic they were quite easy to rework, pictured are an original gear, gear as modified, and final assembly.
Stub axles are cut off and gear sanded smooth on both sides. Centre hole drilled out, working up to 3/32" in 3 steps. Delrin is pretty tough stuff but slow and careful is still key here. Gear is slipped over the 3/32 styrene tube, it's a snug fit but a small amount of ACC or epoxy (I prefer epoxy) provides good "insurance".
.030 x .030 styrene strip .100 long cemented in place provides the lock ("pawl" for correct terminology)
The gears are just slightly oversize but as they have 9 teeth vs the 12 on the protoype they look "right". I added an extra top plate (.030 x .156 styrene) to compensate for the oversize gear so the strap winders will look correct when cemented to the styrene channel track on board the trailer.
BTW, the donor locomotive was one I had in my "junk" box, it's one of the older N scale locomotives (from the era when they didn't run well ). They can be had cheap at swap meets so it isn't necessary to chop up expensive locomotives just to get a handful of gears!
Hooks modelled were the bent flat bar style here, haven't yet figured out how to do the other type which uses a grab hook on a short length of chain.
A strip of .010 shim brass was cut .180 wide, each hook consists of a bent lip .075 long with the main body of the hook .150 long. To attach them to the strap protoype hooks have a slot in them, in model form I bent .010 brass wire in a [ shape to match hook width & trimmed the legs to .125 long. This was soldered to the inside of the hook leaving about .030 gap.
Strap itself is good old masking tape cut to .156 wide (I used a strip of styrene as a gauge) slipped through the hook and stuck back onto itself. Pictured is a short piece of strap that will be used to simulate one of the rolled-up ones that isn't in use. Also shown are the "bits" for one hook and a completed hook:
Excellent how-to! As soon as possible I am using this and making a bunch just because it is cool and I have everything but the gears, which I will likely fabricate gears with "slanted" teeth and make a mold to make epoxy copies.
I'm going to sticky this thread. It's an awesome tutorial and this is something we'd love to see more of here. If anyone has any tricks, how-to's or what-have-you, feel free to post them and we'll sticky the thread so everyone can have a place to come to see how to do these things for their own projects! Thanks for sharing this how-to!!!
"Build what you want, how you want, but most importantly, build for the FUN of it!"
Well,this is how a forum should be.Everybody has some special tricks and things i think. Anyway,i post such things always so that all truckies in the forum can use that tricks and tips. Building means learning and as long we live we learn!!!
Very nice work and excellent tutorial. This is what I was talking about in another thread. Sharing your ideas and tricks. There are things we all do that we think are not that big a deal but to someone else, it could mean so much more. For me, I'm stalled on my next project because I'm trying to figure how to make the tracks for a crawer crane. But your so right Truckmaniac and I have learned from you.
Truck, no there is not a thread on the crawler crane, I am in the process of designing it in a cad program at the moment and as I said the tracks for this thing is kinda stumping me. I see what needs to be done but I'm not sure on how to go about it. ha ha. I did see a thread on the "how to's" on a guy making a jig to make each piece of the track. I am sharing a pic of the crane in question so as you can see and I'm just trying to figure the best way to attack this is all.