Dragline Rebuild
 

I thought this might be a good time to post my project. I built this dragline many years ago and it needs some work now so I guess this is a good time. It originally was powered by a computer power supply that a friend gave me and told me which wires to use to get the voltages I needed. After adding some components to help with the electrical noise from the motors it worked good for several years but now the P.S. will not turn on. It will be replaced with a linear P.S. for the hoist and swing. The swing motor is also not working and never has worked like I wanted it to so it will also be replaced.
http://i305.photobucket.com/albums/n...ps0710c537.jpg
http://i305.photobucket.com/albums/n...psac7e06e7.jpg
I made the mechanical joy-sticks using old R/C car throttle resistors as a speed controller. Here is the drag control-
http://i305.photobucket.com/albums/n...pscd64faf0.jpg They are crude but they work.

Re: Dragline Rebuild
 

I have had this project started a long time (I work slow) and I'm not sure when it will be finished but I work a little every day. The drag controller will be replaced with a variac control that plugs into 110 v. ac. I will probably use the swing & hoist joystick that I made until I can get an electronic joystick. Starting the teardown-
http://i305.photobucket.com/albums/n...psf4bfe967.jpg
The swing motor has already been removed in this picture-
http://i305.photobucket.com/albums/n...psf3194063.jpg
Next I have to turn the base over and remove the bearings that hold the swing rotation plate. I am working on the new swing gearcase and I will post more later.

Re: Dragline Rebuild
 

I enjoy seeing the pictures! Keep em coming, fun to see the unit come apart and go back together.

Jim

Re: Dragline Rebuild
 

Here is one for you jim- I found this old picture showing the original swing motor and drive.
http://i305.photobucket.com/albums/n...ps71affe2b.png
This unit is big! The motor is really hi-RPM so I had to use a planetary and many more gears to get the RPM down. It also draws 3.5 amps and that is more than the model should use on all-3-functions. I am really struggling with the new gearcase but hopefully I can make it work-more later.

Re: Dragline Rebuild
 

Very nice dragline Tom , been kicking around the idea of building one ,one of these days.

Re: Dragline Rebuild
 

Hey Tom there's a old dragline out from Tuscaloosa in Brookwood , last I heard it was being restored .The name of the dragline is Mr Tom found a few pics on the web , search for Drummonds mr tom dragline

Re: Dragline Rebuild
 

Thanks pumptech-this is the 1st. construction model that I built. Didn't know anything about dragline then and have learned a little since. I think I could make a really nice one now if I were not so old:(.

Re: Dragline Rebuild
 

I think that dragline has been restored and moved. I drove down there twice to watch it cross the road. Missed it the 1st. time but got to see the crossing the 2nd. time but the weather was lousy. Here is-1-of the pictures I took-
http://i305.photobucket.com/albums/n...ctures/003.jpg

Re: Dragline Rebuild
 

Hey Tom, Nice to see you have been working at your hobby again. I like the control you built. I see what looks like small electrolyte capacitors ( I think) on the rear. What is all that about?
Let see some pictures of you swing gear box.

Re: Dragline Rebuild
 

Yes indeed, good to see you tinkering again Tom. :cool:

Re: Dragline Rebuild
 

Tom,

What is the size and composition of the angle iron use in the boom?

Jim

Re: Dragline Rebuild
 

Hi steve-I am trying to stay busy and this is what I like. That is capacitors on the controller. The computer P.S. would shut down as soon as I moved the sticks (electric motor noise) and the capacitors added in series (6-pcs.) solved the problem. I will post some pics. of the swing gear-case when I get further along. Now I am just trying to design something that will work in the space I have. I need lots of gear reduction and the gears I am trying to use are actually too big.
Lil giants joe-thanks-I would say tinkering is a good description of what I am doing :D. Just trying to stay active and I still really like the model building but find it very hard to do what I want to do.

Re: Dragline Rebuild
 

Jim-the material is .025" thick sheet metal (a.c. and heating duct material) and I bent it into 1/4"x1/4" angles for the main boom rails and 3/16"x3/16" for some of the bracing.

Re: Dragline Rebuild
 

I found this double-shafted motor that I felt would be a good size for my swing drive and easy to add a flywheel-
http://i305.photobucket.com/albums/n...ps68e37a35.jpg
The seller didn't know the RPM so I put together a quick test stand. I decided to use the square drive plastic gears from vex thinking they would save me some machining time. They work good for testing but are a bit large and take up a lot of space. I used these extra large gears to find the RPM of the motor-
http://i305.photobucket.com/albums/n...ps078bb524.jpg
The motor runs at 4950-5000 RPM on 12 volts. Now I have to make the swing gear-case that will reduce down to approx. 9 RPM and the swing gear and pinion will reduce it to 1.5-1.6 RPM.

Re: Dragline Rebuild
 

This segment is lesson #1 in what NOT TO DO!!! I had some small sprockets and I decided to make my own swing gear to match the pitch. I had to make it in-4- pcs. because at the time I didn't have a pcs. of alum. that big. After a lot of machining I got it to work but it is a bit "jerky". and not smooth at all. So now I have ordered the proper gear and pinion and while I am waiting I can work on the swing gear-case. Lesson learned-
http://i305.photobucket.com/albums/n...pse0238bb6.jpg
More later-

Re: Dragline Rebuild
 

Still very interesting to look at! What exactly do you think made it not smooth? Pitch not perfectly matched? Not enough teeth?

Very nice looking, keep the updates coming!

Jim

Re: Dragline Rebuild
 

Jim-the pitch is good. The sides of the teeth on the main gear are not cut on the correct angle. I had no way to do that. I think that is causing the jerky motion since the pinion is not engaging smoothly as it rotates. The way this model is designed I cannot use a larger main gear. The one I have ordered is a 32-p-128T x 24T and I hope that will solve the problem. The swing gear-case is driving me nuts but I will keep working at it.

Re: Dragline Rebuild
 

I have some work done on the swing assembly. I got the holes drilled and reamed so that is the critical part. I still have a little milling to do on the plates and another set-up on the other-6-bushings.-
http://i305.photobucket.com/albums/n...psc2f09b98.jpg
I probably didn't save any work by using the square drive parts. I tried running the square shafts in nylon and brass bushings but the drag was way to much and caused the motor to lag and draw to much current. I had to get a 4-jaw chuck and turn round ends on the .125" shafts and now they work really smooth. This is the gears I have to pack into these frames to get the pinion speed down to 9-RPM.-
http://i305.photobucket.com/albums/n...ps3f960363.jpg
I am still waiting on the pinion and swing gear and also a 1/4" shaft for the pinion. I'm getting closer.

Re: Dragline Rebuild
 

That is a bunch of gears, huh? I'm sure you have already considered a low rpm gear motor? Going to be cool getting all those gears turning!

Jim

Re: Dragline Rebuild
 

Your right jim-it took awhile to work this out but I think I got it. Here is a couple of pictures showing all the gears in place-
http://i305.photobucket.com/albums/n...ps89ab1c51.jpg

http://i305.photobucket.com/albums/n...ps4f8401c1.jpg
The 1/4" bushing is for the pinion shaft and that will be another reduction. I would consider this a low rpm motor -5000 rpm-12v. but a gear-motor will not work. It would start & stop instantly and that would cause the bucket to swing side to side. That is why I use a flywheel. It starts slowly and smoothly and does the same when stopping. I probably would not need the flywheel with an electronic speed controller but for now this will work.

Re: Dragline Rebuild
 

I have the swing assembly finished and it works good so I am ready to install it on the model. Here is a few pictures-
http://i305.photobucket.com/albums/n...ps3b39d0d5.jpg

http://i305.photobucket.com/albums/n...ps8a675361.jpg

http://i305.photobucket.com/albums/n...psaa103119.jpg
This is a short test video-
https://www.youtube.com/watch?v=XTuLGUQFbJg
Now to put everything together and hopefully it will work.

Re: Dragline Rebuild
 

Wow that works nice, a lot of hard work right there, but for me that's the fun part! great job!

Re: Dragline Rebuild
 

So the purpose of the brass counterweight is to smooth out the start/stops? And it kinda looks like you even balanced the counterweight to offset the grub screws of it and the gear below too? What tool do you have to measure that?

Re: Dragline Rebuild
 

Thanks for your kind words. I agree, building is the fun part!!
That is correct joe-if I were using an electronic s.c. the flywheel probably wouldn't be needed. I have a balancer that I used to balance my props when I was racing R/C boats but the flywheel is not balanced perfectly. To do that I would need a polished stainless shaft .080" dia. about 3" long and that I do not have. I just drilled a hole opposite the set screw and there is also-2-holes drilled in the top (for extra weight if needed) but I did that with the rotary table so they are drilled and spaced correctly. The balance is close and there is no vibration.

Re: Dragline Rebuild
 

Very intuitive, would be very cool if you could figure out or design the shoes that could move it from place to place.

Re: Dragline Rebuild
 

I know how to make a walking system but if you look at the 1st. picture on page 1, this is the only place I have to work this model. There is no place to walk it. A scale step for this machine would be 2-1/2-2-3/4". No room for even one step. I have thought about making it a walker just for the fun of making the parts but it would be time and money wasted so it probably won't happen.

Re: Dragline Rebuild
 

I love that gear box. Once again, quality work upfront.

I would not have thought to use the flywheel.

Re: Dragline Rebuild
 

Lots of fooling around getting that gear train right eh?
I never needed the flywheel because I can program the ramp up on the motor with the settings on my motor drive boards. They can be set from 0-20sec. to ramp up to full rpm then down, "regen to stop" or, "coast to stop" Without, you get a big pendulum swinging back and forth :o I also have my radio sticks set up on a curve to ramp up. I may try the flywheel someday just to see how that would work.

Re: Dragline Rebuild
 

I used one of those doohickeys that slow down servo speeds. It gives the same slow acceleration/deceleration with a continuous rotation servo and it tamed my crane down nicely for much more scale operation.

Re: Dragline Rebuild
 

Do you get much backlash with all those gears?

Re: Dragline Rebuild
 

Thanks a lot-this is the 1st. construction model I built and it is not engineered very well but I think I have learned a little since this old model was built.

Re: Dragline Rebuild
 

Yes steve-it took some time to get those gears right. The flywheel works well for me but you are doing the same thing with electronics. Todays electronics work so good that I thought about getting a radio and-3-esc's and be done with it but I am going to try to keep it the old-style manual controls.

Re: Dragline Rebuild
 

I have no servos or radio on this model.
There is no backlash. The gear mesh is close to perfect.

Re: Dragline Rebuild
 

Just a small update-I got the dragline back together and with this new swing motor I found the swing speed controller doesn't work. :confused: Now I have to sort out this problem and fix or replace things until it works. The flat wound resistor I am using on the controller is only 35-40 years old so I can't imagine why it would go bad. :rolleyes: More later.

Re: Dragline Rebuild
 

Would like to see all the details from your controls but maybe we covered that already. Shouldn't be a big deal to replace a resistor or two. I am getting ready to acquire some swing pedals for my machine. I will give an update when it happens.:D

Re: Dragline Rebuild
 

ive always wanted one of these sized draglines. the mines here used to have one they took to shows but i think it wondered home with someone.

Re: Dragline Rebuild
 

Hi steve-Here is a couple of pictures of the hoist and swing control. The first one is the hoist which works good on the resistor set-up-
http://i305.photobucket.com/albums/n...ps60f28f1d.jpg
This is the swing control which I am rebuilding now-
http://i305.photobucket.com/albums/n...ps7ddae04c.jpg
I don't think it is a matter of replacing resistors. These cannot be found anymore. They were made for hi-performance car motors which turned hi RPM and drew lots of current. The swing motor I am now using only draws .125 ma. and I think that is why the resistor doesn't work-(not sure). Anyway I am reworking the swing portion and will post pictures as I go.

Re: Dragline Rebuild
 

You should build one. That's what I did after watching my grandson play in a dirt pile out behind my house. I thought we could have fun with the dragline together and we did for several years but now he is 15 and no longer cares about this but I guess I am still the kid at heart so I still enjoy running the drag.

Re: Dragline Rebuild
 

oh i might build one some day!

Re: Dragline Rebuild
 

I am re-building my hoist and swing controller with a different device used for the swing. Here is a picture of the frame with electrics removed-
http://i305.photobucket.com/albums/n...psd5a81dfc.jpg
In this picture you can see the left to right motion (swing) axis is off center.
http://i305.photobucket.com/albums/n...pscf362ff3.jpg
This was okay the way it worked before but now it has to be changed to have the axis on center since there will be gears on this. These pcs. are all chopped up since I had to change things a lot to get it to work originally but I am going to re-use the parts and cut on them some more. Here is a little quiz- does anyone know what this is-
http://i305.photobucket.com/albums/n...ps2f87a396.jpg
More coming later