Unit Cable Hoe

[doodlebug]

Hey Scott, now you know why the bucket has side board's on it.
Later, Neil#2 aka doodlebug

[Stuff]

lol. cant go wider, then go higher!

[RCTech9]

Any updates Scott?

[SmallHaul]

Originally Posted by RCTech9

Any updates Scott?

Not much new really. Ordering & quality of parts is causing delays. I ordered the servo city sprockets that have the servo splines built in and they don't work at all because they are made wrong...when the chain wraps around the sprocket it grabs the chain and won't let go. They were supposed to send me "better" replacement sprockets a week ago and they never showed. I'll call Monday and talk to management there... So, I took 9 tooth metal sprockets and modified it to work on a servo. They run very smoothly and don't grab the sprocket at all. I'll probably make some progress on it this week though.

[9W Monighan]

Maybe the small diameter is causing the grabbing. Anything smaller than 12t is not recommended at certain speeds but for your intermittent use you should be ok. Did you grind the teeth open some?

[SmallHaul]

Originally Posted by 9W Monighan

Maybe the small diameter is causing the grabbing. Anything smaller than 12t is not recommended at certain speeds but for your intermittent use you should be ok. Did you grind the teeth open some?

The servo city sprockets are 10 tooth and the metal sprockets that I modified are 9 tooth and work great. The metal 9 tooth sprockets work so smoothly that I can drape an 8 inch loop of chain over it and run it just hanging there and it runs the chain fine, never grabs at all... The servo city sprockets have tall square teeth and I think that is the problem.

[SmallHaul]

I made a quick vid of the chain drive working. I'll have to make a jig for drilling the track pads because the few that I made aren't consistent enough for my liking.

http://www.youtube.com/watch?v=8Lj4c_IDNAI

[fhhhstix]

Looks like you have made some good progress Scott keep up the great work.

Travis

[doodlebug]

Hey Scott, Jig's are alway's nice to have for repetition. Sure helped when I was running an iron worker 25 year's ago. Later, Neil#2 aka doodlebug.

[SmallHaul]

Thanks Travis!

Agreed Neil.

Well, I called Servo City and they were very helpful. Turns out the #25 chain I am using has a smaller roller diameter (.120) than they use (.127) which would explain why my chain binds up when you wrap it around more than 100 degrees or so. They are sending me some of there #25 chain to rectify this. That is really good customer service! Even most good companies would say just send the parts back for a refund but, these guys want people to get there projects running.

[modelman]

SmallHaul-I used the servo city sprockets on my shovel and they worked great but I did also use their chain so I guess that explains the problem you had. Their servo sprockets were the only ones I could find that were small enough to get the ratio correct. Enjoying watching this build.

[D8R]

Nice solutions on the drive. Wish I built smaller so servo could be used. Maybee some day....
Servo city, is that a supplier??
Dan

[SmallHaul]

Originally Posted by modelman

SmallHaul-I used the servo city sprockets on my shovel and they worked great but I did also use their chain so I guess that explains the problem you had. Their servo sprockets were the only ones I could find that were small enough to get the ratio correct. Enjoying watching this build.

Thanks Modelman, I believe there chain will fix it.

Originally Posted by D8R

Nice solutions on the drive. Wish I built smaller so servo could be used. Maybee some day....
Servo city, is that a supplier??
Dan

I only used the servos because the hoe is small & light (probably less than 6 lbs when complete). If I had the room and needed more power I would use a 200:1 geared motor on each track and esc's. But, I am making the undercarriage all one rc unit...meaning there will be a (4 cell 500mah) battery pack and a separate receiver just to run the drive. That way there is no electrical connection between the crane/house and the undercarriage.

Yes, Servo City has some nice unique servo related items that you can't get/find anywhere else. Adapters, sprockets, reduction units, aluminum arms...

[RCLogger]

Looks very good Scott, you will have more than enough power there. Do you need a speed control , as the servo has it already ?

greg

[SmallHaul]

Thanks Greg.

You are correct there are no esc's needed, all of the servos just plug into the receiver. The undercarriage electronics will consist of 2 servos, one receiver and a battery. The cranes main electronics will consist of 4 servos, one receiver and a battery.

[SmallHaul]

Well, since I am waiting for parts to build the undercarriage I made a large bucket so that I could load trucks faster at the meets when we use ground up rubber.



Its really too big for actual dirt but, I had to load the Mack up a couple of times just for the fun of it.

http://www.youtube.com/watch?v=xtjl5kGhRhc

[modelman]

SmallHaul-looks to my like it handles that bigger bucket pretty good!

[Roadmasters]

I like the quick change system on the backet. Cant wait for more!

[Stuff]

hehe one for show and one for GO GO GO! lol

[SmallHaul]

Originally Posted by modelman

SmallHaul-looks to my like it handles that bigger bucket pretty good!

It is fun to use the large bucket because it forces you to operate it more efficiently. If you just reach out over the pile and drag the bucket all the way back and lift it out of the dirt the crane really stresses to lift the bucket but, if you smoothly lift the bucket just as it is filling up, the crane lifts it well.

Originally Posted by Roadmasters

I like the quick change system on the backet. Cant wait for more!

Thanks.

Originally Posted by Stuff

hehe one for show and one for GO GO GO! lol

Yep, it seems like we can never load all the dump trucks fast enough at the meets.