Nylint michigan crane conversion, hopefully

[TRUCKMAKER]

Hey Frizzen you got this done yet? You got 2 of the masters working with you it ought to be close I missed some of the posts on here, don't overlook the fact that the longer you make the boom the larger the counter weight you'll need. If you make it much longer and you do a side swing it will tip it over without lifting anything

[modelman]

Originally Posted by SteinHDan

If you select a 4mm bore, then you can use a gear motor like this one:
- http://www.ebay.com/itm/381486411254

60 RPM / (66 teeth / 12 teeth) = 60rpm / 5.5 = 11 RPM

11 RPM for the swing would be quite ok, I think.


Best regards,
Stein :-)

Nice to see old rigs like this converted. I think on a machine this size-3rpm would be the maximum you want for swing speed and maybe slower. On a dragline with hi-speed swing you will be slinging that bucket around uncontrollably. Also, the longer you make the boom the more boom tip speed you have. You also need a very smooth speed controller for the swing to keep the bucket from swinging wildly. Good luck and have fun.

[frizzen]

SteinHDan, that would work too. I was just planning on running the gearmotor/esc combo units like i'd seen on other cable machines like built by thestuff, smallhaul, rvjimd

Truckmaker, yeah you're right what can i say... i suck at building and having time/money.

I know the longer boom will impart a lot more moment on the machine, i just wanted to see how things change around, and more reach looks really cool. I'm also not above running lead ballast if it needs it.

jim, i greatly appriceate that.
I was thinking something maybe built off one of these:
https://www.servocity.com/standard-hub-horns
Thinking i can have a protrusion to index to the .500 hole and a flange to bolt on the near-side. i wasn't sure if it's worth it to have far-side support on the drums?

I need to break out calipers and think and mock up a bit before i'd be able to do a dimentional sketch for your consideration.

Or depending on the alloy you have, i might be able to just order a spare gearset and just broach the splines into a much simpler drum instead of getting that crazy.

[Rvjimd]

Frizz, do you have the servos already? If not, I highly recommend the hitec 645MG. Especially since I have some of them here already and I can use the round horn to make up a prototype drum.

I would do some off side support, it isn't too much more work and helps support and align the drums.

I'll do something on this today and see what I come up with. I am going to see if I can simply use one of the plastic horns that they come with. I don't think we need the metal spline version for strength. I'll post my progress here.

Jim

[Rvjimd]

How about like this? I'm about to drill the horn to the drum. Then it can be screwed to the servo through the center hole in the drum. The off side can then use a pin to support it.



Jim

[Rvjimd]

[frizzen]

That's pretty much exactly what i had been thinking, i just didn't know how much force the machine uses vs the plastic strenght. I was trying to overcomplicate things.

I'm going to have to send you a pm, that's looking beautiful.

[Rvjimd]

As long as you add a support rack for the off side I think it will work great, I only put two screws in the plastic horn. The screws are about 1/2" of from center so they will have all kinds of torque way out there and they only need to turn the drum. I have two of them made.

Jim

[Rvjimd]

Here is the third one in the lathe, just about to drill the center hole.



Frizz, send me that PM. I can probably send these to you Thursday. I'm think I'll make the mounting bracket for the servos and the off side support as well.

Jim

[Rvjimd]

Frizz,

Here are the three drums. I made a little angle bracket for them and decided to stop there and see what you think? They will need a strap across the opposite end of the servo mount tabs and I used a small 1/4" channel for the off end drum support. The center hole in the off end of the drums could be enlarged a bit at the end to match the head of a #6 cap screw which could be threaded into the channel to support the off side of the drums.



Jim

[frizzen]

At this rate, you'll need to write up a dimensioned spec sheet on the parts or start offering kits.

Those are looking really great!

[frizzen]

As far as i've found, real Clark Michigan cranes seem to be set up with a pair of dead lines off the tip to a sheeve block, cables run from the sheeves back to the house some unknown number of times for mechanical advantage and to reduce the amount of cable.





these are the most helpful images I've been able to find so far

Stock toy just had it route: fixed at house, tip pulley, cable drum. And it works fine as a toy.

Atleast for now, i'm thinking split the difference like jim did: fixed at house, tip, house, tip, house, drum.

[Rvjimd]

Frizz,

Mailed some stuff your way this morning, supposed to arrive Tuesday.

jim

[frizzen]

Mail came right before i had to leave for work. Eventually i got home and got to open this up!



They look awesome, thank you so much!

I'm going to have to study your setup on the C-24 a bit more.

[Rvjimd]

Friz,

once you start messing with it, let me know if you need more detail or have questions.

Oh, and I don't know for sure, but I think the center holes are a bit undersized for 1/8" shaft.

Jim

[frizzen]

Good call on the hs-645 being easy to mod to contious rotation. I had all 4 servos swapped pretty quick.
Verify it works, open up, unscrew pot retainer screw inside, remove the output gear, support the gear on a v-block or pair of pliers and bump pin out. Reassemble, lube gears, verify ops and center pot. I may swap the pots out later for matched set gold band resistors if i'm in there sometime later...

Have they been looked into enough to see if there's a way to open up the deadband a bit wider?

Were the shafts you used made from piano wire, or from a certain donor?

[Rvjimd]

Shafts for the pulleys you mean? I used 1/8" steel round from the "hobby" rack at menards. I think you may need to drill out the center hole, I think they were a bit under size but verify.

Jim

[frizzen]

Build goes slow, lots of life happened...

I know you said 1/8 steel rod is fine to support pulleys, but crazy lives here. Aluminum and steel don't play that nicely together, and i can't remember i'm converting a toy to a better toy. I haven't decided the pulleys need polished and alodined yet, it's probably not far off. Blah blah blah, fretting, types of corrosion, galling...
So finally made it to the hobby shop and got my suppolt rod setup: 1/8 steel rod stock held with 1/8 E-clips, 5/32 brass tube as bushing between pulley and rod.

Also i realized that the back of my cab roof has seperated spotwelds from the right side of the house so that needs cleaned up and braized.

[frizzen]

More boring scratch-build notes:
Picked up the slewing ring gear, an Align trex 500 main gear, 162 teeth, 1/4" tall, 3.986" od. (Thanks again jim)

It seems to mesh ok with a servo spline mount gear i picked up several years ago. Hitech hs-645mg use C1 spline, this gear is 18 teeth, 1/8" tall, 0.426" od. I forgot if it's 32 or 48 pitch.
Gear ratio comes in at 9:1.

[Rvjimd]

Nice to see you working on it! Jim