1:50 Dragline

[Rvjimd]

MM,

the servos I'm using are labeled as micro servos. The way I have it now, the pinion is running against the ring gear. The only trouble I have is that the ring gear is cast as part of the lower track unit and was never designed to be functional, but the teeth seem to match fairly well with the pinion I'm using. My trouble is getting a good fit to hold the pinion in place. I think i can get it, just wondering if a elastic o ring might reduce the tolerance needed with my current method?

Thought I was going to be filming a test by now but still a few bugs to work out.

Jim

[Rvjimd]

Well, I did manage to get one video of the dragline as I tested out the slew function. I was having trouble with the gear mesh of the pinion and ring gear and you see me help it where the mesh is too loose.

Also the drag servo drum loosened up so I got that to look at this weekend.

http://youtu.be/XH6KNlpnH_c

Jim

[modelman]

Rvjimd-I can see in the picture that the ring gear is not a precision gear and with it cast directly against the lower body that will cause a small problem. Is the ring gear out of round or is the problem holding the pinion in position. The O-ring idea could work but everything will have to be perfectly round and true to keep equal pressure on the gears for 360 degree swing. Keep working at it. I think you have done a great job in a short amount of time. Also I think making the tracks work is a great idea. To have all functions working on a model this small is quite an accomplishment.

[Rvjimd]

Made some really nice progress today on the dragline! I machined down another pinion gear, went up one tooth to 19T to take up some slack in the mesh. I also pinched down the sleeve that the drive shaft runs in to take out some slop. This has completely smoothed out the slewing.

Rewired the battery and plug in socket so I can plug into the RX or unplug and use an adapter to charge. So I won't need to remove the battery for charging. I may still remove it and put back the balance plug that I removed.

The BIG thing I did today to improve operation was went to the hobby shop and bought a new DX6i and a small 4ch RX. The 4ch RX fits really nice in the cab!

I tried the two sticks up and down (throttle and elevator) but was not happy with the throttle stick. There does not seem to be any rate control or centering on the throttle stick.. So, I changed the drag drum to use the rudder channel instead. That way I get centering and can slow down the rate! Sure wish they had rate control on the throttle like all the other channels!

It is supposed to be a bit nicer here Sunday so stand by for some outside video! I practiced on the indoor dirt pile and thought I was doing pretty good work. Can't wait to get outside tomorrow! Gona have to find some material to load!

Here is a picture of the backyard yesterday! The snow did finally melt today from all the rain!



Jim

[Rvjimd]

I still had bit to much slop in the mesh of the pinion and ring gear so took some pics and video of the fancy turning machine I use for this sort of thing. It is not exactly a computer controlled mill, but you get the idea...

Finished gear after turning down



Installed on the crane


With the track assembly in place


And the video of the turning process
http://youtu.be/7-lkVaW3V-I

And the ops test video
http://youtu.be/CSAW4rwGt5M

Loading barge video to follow...

Jim

[Seilbagger]

Hi Jim,

good idea, well done


Wolfgang

[Rvjimd]

Here is the vid of the Menck dragline loading sand onto a hopper barge at the sea wall. Got it working pretty good with the new DX6i.

http://youtu.be/nRH95IXRhQ0

Jim

[SmallHaul]

That is a sharp little crane you rc'd there. Nice work!

i keep looking at 1/48 dozer and cranes to rc. Have you thought of doing a dozer?

The pond is very cool too.

[Rvjimd]

Ya, I am really itching to do a dozer, and a dump truck. Th is is my first conversion of any kind and now they way the crane is working i fell like, no problem... Lets find a few more!

Jim

[Seilbagger]

Hi Jim,

this is a very very good conversion, perfect done.

Its only one little mistake: This is not a M251, its a M260. The difference: M251 has 4 roles on each side for driving, M260 five

For all interested Menck fans, the HP of the Menck archive: http://www.menckundhambrockarchiv.de/ , you can read this in german or english

[Rvjimd]

That is some interesting info. I find a lot of different model numbers when I search on Menck cranes! I wonder why NZG calls it a 251? I'm pretty sure that is the model number on the box...

Thanks for the comments!

Jim

[MattDk]

Really good progress that you have made.

Btw, for getting the tracks moving, I saw a video where someone used a jack connector for transferring the signal and power for the servos for the track, through the center, that was pretty smart, you might find room for a mini jack, you only need 4 wires, ground power and 2 signal, so that would be perfect match.
image.jpg

/Mario

[Jared]

That's great Jim! Ya done good. Certainly sunk the barge down a little. Now you just need another crane with a clam on the other end of the canal to unload it with.

[Rvjimd]

Jared, ya I noticed the barge sink a bit when I watched the video! So, I watched it fast forward, kind of fun watching it sink in as it gets a load!

Mario or anyone, re the video of the phone jack for the slew connection. Do you have a link for me? I want to study this a bit more. I might try to get that done but I'm not sure how to do it. On my crane a single small machine screw goes up from the bottom directly into the center underneath side of the cab. I am guessing I would need to somehow tap this on the outside of that fitting to allow the phone jack to reside in the center hole where the screw is currently?

Jim

[Finster]

Not sure if this is the exact clip they had in mind, but I know this guy used an audio jack as a slip ring for a Bruder mini excavator conversion. Good job on your conversion so far. Hope this helps.
http://www.youtube.com/watch?v=VNd_DcxEh9c

[Rvjimd]

Finster,

Thanks, i did finally find that one a few minutes back. I helps, but I'm still scratching my head a bit. I think I need to study some of the bigger machines to get a better idea, then figure out how I can do it small scale.

Nice thing, if I get this thing moving, I'm planning on a single drive servo on the solid axel. That will require a bit less complexity.

Jim

[MattDk]

Yes that was the video I was referring to.

Here you can find one optionhttp://www.magomhrc.com/en/search?controller=search&orderby=position&orderway =desc&search_query=Ring&submit_search=Search

Another way is this http://www.adafruit.com/products/736

If the mini jack were to work you might have to skip the screw in the middle and just hope the mini jack will keep everything in place.

Doing two servos will not make it that more advanced, it is actually only one more wire, since you share power and ground, between both servos.
You could choose to put the servos in each end instead of next to each other.

If you cut the connector between both sides of the wheels and keep just enough metal to put something like a pinio gear without the gear "cant remember what it is called" to keep the wheel in place. Then you can mount the servos at each end.

I can't figure out how much space you have in the undercarriage, but I have converted a normal servo into driving one of these motors instead, http://www.goodluckbuy.com/micro-dc-...-6v-1-100.html they don't make as much noise as a normal servo.
The conversion is quite easy, I just can't find the link that I followed.
I would also say that if you have the space inside the cabin to use this kind of motor instead, you could have a very powerful low noise setup.

/Mario

[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