1:50 Dragline

[modelman]

Rvjimd-I think you got! It looks good to me. Enjoyed the video loading the barge. As I said before-Great Job!!

[Rvjimd]

I like the barges that are half loaded, sitting all out of wack, high on one end and about to sink the loaded end...



Real quick video of two more scoops, the last one sends water over the lower corner.

http://youtu.be/rMwlLP2CIX4

Jim

[Rvjimd]

Got started on motorizing the tracks on the crane. Going to see how far it can rotate using the kidney shaped holes in the base and cab. I have not yet figured out how to secure the top to the base without the center screw. Not enough stub poking down onto the base for threads, or I would be all over that, using a audio plug in the screw hole.



Crown gear and pinion on shaft of the drive servo. Drilled out the hole in the frame and bushed it with 1/8" brass to make a better fit for the axel shaft.



Switch to a smaller crown, and added a lock nut as a jam nut on the threaded rod, up against the spline of the servo.



I'm going to try the single servo and drive parallel and see how that works first. I have started the second servo setup, but I will need to cut the shaft on the other end as well to isolate the left from right.

Jim

[SmallHaul]

Jim,

i did a quick search for 1/48 rc tanks to find a gearbox for you and found this:

http://www.ebay.com/itm/ACADEMY-1-48...item4ac350585e

RC tanks are such a large hobby segment that you could probably find a tiny twin motor metal gearbox in 1/48 too for your dozer.

[Rvjimd]

Great minds must think alike. A buddy of mine that does RC airplanes and slot cars and 1/18 scale sprint cars with me said the same thing. "You need to find a small motorized tank and use the base from that for your crane"

I already feel like a cheater by simply converting a diecast, instead of scratching it like the rest of you guys!

That dozer I bought is gona be tough though, boy is it small. I may look for a D11, there has got to be more space to work with in the high drive model.

Jim

[SmallHaul]

The Acadamy tank gearbox looks to be well made.

http://www.rcgroups.com/forums/showthread.php?t=1355256

Your idea of using a slot.it crown gear and a shaft off the servo is clever.

[Rvjimd]

Well, I got it going, what a project... Lot of little details that seem like they took all day to iron out, oh wait, it DID take all day!

Don't remember if I posted this one, this was the FIRST location of the servo.



I wasn't happy with that spot. It hid the center mounting screw and was in the way for other reasons.

So, I moved it back to where the potential second servo was going to go.



Here is a shot of the center hole mod to allow the wire up the center instead of my initial plan of the kidney holes. Had to drill the center of a 8-24 rod and then drill and tap the center hole on the crane body. Won't be able to spin but good enough, just need to keep the revs down to about 1 each way. There was no way an audio jack was going to fit, I bought some 1/8 sets at radio shack and it just was to tight to get that to work.



And here is a short bench test. I had it on the loading wall, but it got cold an rainy again so no job site video today.

http://youtu.be/2osu07_ULxg

Jim