Let The Build Begin! Update Dec 14,2011
 

Well I am finally getting around to building my first piece of construction equipment, and even better; it is my shop class project for the year! I started designing it early May 2011 and after a few versions, screw ups, long nights and errors I have finally got the design finished! I roughly based it off a CAT 930H to get the general shape right:

http://www.usateq.com/images/inv2499big.jpg

I did change some aspects of the design for RC convenience and if push comes to shove there will be no copy write infringement. But it is roughly 12:5 scale +/- 10mm. Each wheel will be independently driven by a planetary gearhead motor and all motors will be driven by a Sabertooth 12RC ESC rated at 25A Peak. The hydraulic system will be powered by a RC4WD 4200XL Pump, I will be making the cylinders and Bi-directional Spool valves and the hose will be from a place in Germany. It will be approx. 60cm long with the boom parallel to the ground , 20cm wide and weigh in at about 23-25lbs. For most of the construction I will be using 6061 Plate aluminium, Standard Carbon Steel, 7075 Aluminium for the boom, and a little bit of styrene here and there. The model will have approximately 350 parts, welded, brazed and bolted together/ I luckily will have full access to a Tormach PCNC 1100 that our school just bought and luckily :cool: I am the only one who currently knows how to run it :D so my teacher has basically given me full access as long as i don't ruin the new machine. I hope to have the model some what perfect but with it being my first construction model i'll try to keep my hopes a little lower. I think I've got most things figured out but I'm sure I am going to learn lots. One question I have is how big of hydraulic fluid reservoir should I have? Anyways here's a few renders of my design:



Version 2:

http://i345.photobucket.com/albums/p...30Hpainted.jpg

I liked it but it was WAY to wide (30cm!!!) and to short (50cm) to be scale.

Version 3:

http://i345.photobucket.com/albums/p...ct/CAT930H.jpg

http://i345.photobucket.com/albums/p...DarkRender.jpg

http://i345.photobucket.com/albums/p...wingCAT930.jpg

Bi-directional Spool Valve - Servo Operated:

http://i345.photobucket.com/albums/p...SpoolValve.png

-Chris

Re: Let The Build Begin!
 

Looks good, is the underhood area big enough for the pump and motor and valves?

Re: Let The Build Begin!
 

Thanks, yea the area under the hood was designed to have pretty of room for a 540 sized pump motor, 2/3 spool valves, dual esc's reciever and room for lights modules, PMW switches, and much more. Heres a picture of it:

http://i345.photobucket.com/albums/p...hotRearEnd.jpg

All the parts in there are the exact size from there dimensions sheet.

And i added some mirrors, grab handles, fire extinguishers and reworked the bucket linkage and quick release bucket.

http://i345.photobucket.com/albums/p...NiceRender.jpg

Chris

Re: Let The Build Begin!
 

looks good Chris ;) I wish I had a shop like that when I went to school :( . I see 1 issue , how long is your servo arm for the steering ? IDK what your using for a servo , but you loose torque the farther away from the servo you go .

Re: Let The Build Begin!
 

nice CAD work - inventor or solid works?

Re: Let The Build Begin!
 

Thanks everybody!

ihbuilder - Yes having a shop like this is nice but there is a big downfall it it all. About 2/3 years ago the school district thought they had a surplus in funding so all the schools in my district spent lots of money. Then when the spending was done they readlized that they never had the money to begin with so now our district is in $11.2million debt :eek: So we got a nice mill out of it but we got stuck with terrible lathes :( Thanks for letting me know about the torque issue i never really thought about it. Ill go back in the design and see what i can do.

Izzy - I'm using Solidworks 2010 with the in-software rendering software

Chris

Re: Let The Build Begin!
 

Well I was able to get in the shop for 3hr's between a math test and physics test :) and i started on a hydraulic cylinder for the bucket tilt. I have only done the roughing passes and have not honed the cylinder or cleaned up the outside. Heres some pics of today's work.

http://i345.photobucket.com/albums/p...t/IMG_5821.jpg

http://i345.photobucket.com/albums/p...t/IMG_5822.jpg

http://i345.photobucket.com/albums/p...t/IMG_5823.jpg

http://i345.photobucket.com/albums/p...t/IMG_5824.jpg

*still needs to be parted off stock
http://i345.photobucket.com/albums/p...t/IMG_5825.jpg

http://i345.photobucket.com/albums/p...t/IMG_5827.jpg

http://i345.photobucket.com/albums/p...t/IMG_5828.jpg

http://i345.photobucket.com/albums/p...t/IMG_5829.jpg

http://i345.photobucket.com/albums/p...t/IMG_5831.jpg

Any comments would be greatly appreciated as i only kinda know what i'm doing with the hydraulics. ;)

Chris

Re: Let The Build Begin!
 

Chris , you can use 2 servos , 1 on each side y'd together . But , you have to mount 1 reverse of the other . solidworks looks nice , I'll have to try it sometime ;) I did try Autocad2012 :D but my cam dosen't support it ( to new :confused:) and runs 5-6000.00 usd :(

Re: Let The Build Begin!
 

You're installing hyds anyway, why wouldn't you make the steering hyd too? :confused:

And with a motor at each wheel, that's almost like two locked axles, it'll take alot of power to steer. Hyds is way smoother action & stronger. 9mm bore with 2mm plumbing, it'll steer plenty quick & save you alot space.

Make your cyl housings from brass, then you can solder most of it together & bolt the rod cap on to change seals when a leak develops. Are your pushrods stainless steel?

12mm bores for loader/bucket & 9mm for steering, 2mm plumbing throughout & belt drive with reduction between your pump & motor... should be quite a hardy working loader. :cool:

Re: Let The Build Begin!
 

ihbuilder - thanks for the idea! I think im gonna bo with Lil Giants idea and run another valve and some cylinders versus a servo. I think from what you guys have told me it will be better off. Yea solidworks is awesome and the student discount is even better!! $150 :D. What CAM software are you using? Is there a plug-in available for it? When i first got my cam program i was having all sorts of problems even to where i couldn't import a part :confused: then i got the Solidworks Plugin and i have not had a problem yet :D :D

Lil Giants - I originally didn't run hydro's because i didn't know how easy or hard the valves where gonna be to machine but for one reason or another i never really thought about the torque needed to turn this machine (brain fart :confused: ) Okay i'll if i can get some brass tomorrow when i head to out local metal shop. Right now they are 1/4in carbon steel as that is all i had. When i get near completion i think i will get some stainless but for now ill settle with this steel so if i ruin a shaft by accident i can just go grab another piece. Any recommendation on a reduction rate? I am planning on running the same hydro pump as the RC4WD 4200xl Earth digger and the same motor it has.

Thanks for the advice I really appreciate it as I don't exactly know how to make these hydraulics work perfectly :o Just one more question though how much friction should there be for the shaft to move up and down? My piston seals seam to be very tight and im just wondering how tight is to tight?

Thanks!
Chris

Re: Let The Build Begin!
 

I was gonna try 2.5:1 belt reduction for my rc4wd motor/pump, I think that's what's in the 850. You fashion up the mounting plates with bearings on the pump shaft, get two sets of pulleys & belts to send me one. :D (ofcourse I'll pay you for your work, as well as parts)

Did you lubricate your seals before putting the cyl together? Lithium white grease is what I use, the grease will help to prevent any nicks to the seals during assembly. Should be a reasonable amount of resistance there, you want tight seal.

Re: Let The Build Begin!
 

Okay I think I might try that out once I get my pump and motor using these http://www.robotmarketplace.com/prod...ingertech.html

Yea if I can get some spare time and if it works out ill let you know.

I used some motor oil that we had in the shop but that's about it. But I got some brass today so ill start on some new cylinders. On my existing cylinder there is quite a bit or resistance but i guess ill just need the pump to test and see if it is to little or to much resistance.

Thanks!
Chris

Re: Let The Build Begin!
 

motor oil works too . there should be some resistance but you should not have to work up a sweat to move the ram in or out with a vise grip locking pliers . there's a formula or chart for figuring your o-ring grooves I'll have to look it up . I think it's in the machinery hand book . do you have 1 or access to 1 ?

Re: Let The Build Begin!
 

Steve are these the chart's you where thinking of ? http://www.marcorubber.com/gd-directory.htm

Later, Neil.

Re: Let The Build Begin!
 

that should help him

Re: Let The Build Begin!
 

One example of a motor/pump mounting hardware.

http://www.vario-earthmovers.com/bau...70-teil-8.html

Re: Let The Build Begin!
 

Thanks for the charts guys! those will come in lots of handy, as i'll have to admit i didn't really know what i was doing in the beginning. :confused:

Lil Giants - Thanks for the picture I should be getting my pump within a few weeks so I will keep you updated.


Just a little update, I got some 2.5" aluminium stock for some wheels and ordered some tires, some 2" aluminium stock for some axle cases and some 3/4" brass round stock for some hydraulics. As well as ordered some tires and taps so I can get back to work now that i've got an idea of what to do :D

-Chris

Re: Let The Build Begin!
 

Some Pictures of today's work:

http://i345.photobucket.com/albums/p...7/IMG_5838.jpghttp://i345.photobucket.com/albums/p...7/IMG_5835.jpg
http://i345.photobucket.com/albums/p...7/IMG_5833.jpg

Chris

Re: Let The Build Begin!
 

Got a cylinder 90% done just need to attach the caps, drill mounting hole and attach the hydraulic lines.

http://i345.photobucket.com/albums/p...t/IMG_5840.jpg

http://i345.photobucket.com/albums/p...t/IMG_5841.jpg

Chris

Who can tell the radio in the back that i'll be using?
http://www.autonerdz.com/yabbfiles/S...tch-head02.gif

Re: Let The Build Begin!
 

Update!

Well I was able to get some time on our bigger engine lathes and got some hubs made. They are now ready for the CNC to drill out the final mounting holes. They have a finished OD of 25mm, ID of 4mm and length of 15mm.

http://i345.photobucket.com/albums/p...t/IMG_5884.jpg
http://i345.photobucket.com/albums/p...t/IMG_5886.jpg
http://i345.photobucket.com/albums/p...t/IMG_5887.jpg

I was also able to test out turning steel :eek: Jeez is that ever harder than Brass or Aluminium (no pun intended) I started by making the rotator ring that the model will rivot/rotate upon.

http://i345.photobucket.com/albums/p...t/IMG_5888.jpg

Then I tried to make the spool for a valve. And thats where it all went bad, first i accidentally ran my tool into the chuck and snapped my carbide insert (luckily it was only the insert). Then our very high end lathes (1950's engine lathes that cannot even cut straight) slipped while grooving a slot for some o-ring and bent the spool :mad:.

So I said screw it and made one out of aluminium :p

http://i345.photobucket.com/albums/p...t/IMG_5890.jpg
http://i345.photobucket.com/albums/p...t/IMG_5891.jpg

I am not really happy with it so I may remake it out of brass. Anyways I should be getting a pump soon so I should be starting to make something move by end of January!!

Also I just picked up some 16GA Hot Rolled sheet steel and will be running it through the mill to construct the rear of the chassis.

Here's an exploded view so you can get an idea of how many plates are just on the back:

http://i345.photobucket.com/albums/p...plodedView.jpg

-Chris

Re: Let The Build Begin!
 

Update!

I got the CNC running yesterday after filing the dam coolant up :rolleyes: the tank is in the bottum of the enclosed stand our school build and i had to pour it through a 3/4'' hole through a 2sqft door. Not exactly the best design but it works. Anyways i got some plates cut out of the 16ga steel and started to tack weld the rear end together.

http://i345.photobucket.com/albums/p...t/IMG_5892.jpg

http://i345.photobucket.com/albums/p...t/IMG_5894.jpg

http://i345.photobucket.com/albums/p...t/IMG_5896.jpg

http://i345.photobucket.com/albums/p...t/IMG_5897.jpg

http://i345.photobucket.com/albums/p...t/IMG_5899.jpg

http://i345.photobucket.com/albums/p...t/IMG_5898.jpg

And a shot to show the size of the model:

http://i345.photobucket.com/albums/p...t/IMG_5900.jpg

Should be a nice size, and will look good behind a semi as its only a few cm wider :D mabye a lowboy will be next. :D

Tonight i should be getting my tires and pump!! so hopfully in January when i get back to school you will see some nice machined wheels! This may be the last update for the year as my school closes on friday for Christmas and I am not to sure if the shops will be open or if we will be cleaning.

Thanks,
Chris

Re: Let The Build Begin!
 

Very nice progress, looking forward to see the wheels!

Re: Let The Build Begin!
 

nice work on the cylinder

Re: Let The Build Begin!
 

very nice work. one thing to think about when you are using AL for your spoos is that the oil and AL can have a negtive chemical reaction and make the oil really dark and a bit acid. but i don't think it a big problum just to let you know.

Re: Let The Build Begin!
 

Thanks for the nice comments everybody!

mog - thanks for letting me know! I think I will be doing the majority of the system out of brass because of how easy it is to work with. And i can solder to it.

Also i got some parts in!!

http://i345.photobucket.com/albums/p...t/IMG_5912.jpg
http://i345.photobucket.com/albums/p...t/IMG_5916.jpg
http://i345.photobucket.com/albums/p...t/IMG_5914.jpg



Chris

Re: Let The Build Begin!
 

CAD Update!

Finally got everything perfectly (I hope) designed on the axles. It was a real pain trying to have a motor connecting to a hub that passes through a brass pushing and finding a way to turn the set screw on the hub. And having it all fit in the diamater of the axle for looks :D (sounds really confusing so i can post a pic if you guys want) Heres a CAD render of the axle: (For those who haven't noticed, I love CAD! I can make tons of bad parts until I find the perfect design and it doesn't cost me money in wasted material!!)

Anyways heres the pic:

http://i345.photobucket.com/albums/p...oject/Axle.jpg

Believe it or not one axle has 85 Parts in including the 54 bolts :blink: And that doesn't include the mounting hardware.

-Chris

Re: Let The Build Begin!
 

I don't seem to have the correct detail shot on file of how Stahl locks their wheels to the output shaft of the gearhead motors, hopefully this one will be sufficeint?

There's an approximate 2.5 or 3mm hole drilled through the gh motor shaft, inward about 5mm of the end for a 10mm length steel pin to pass through. You can see the slot in the wheel of the pic. The entire wheel slides past the hole on the gh output shaft so you can install the steel pin.

Pull the wheel outward to set the pin into the wheel & it's all held in place by bolting on the simulated planetary hub cover.

This is the best method I've ever seen of locking a wheel to a driveshaft, no chance of any set screw(s) coming loose. ;)

The TLT axles in my 6wd semies work on much the same as this principal, but have a big ugly nut showing.

http://img.photobucket.com/albums/v1...7/IMG_1854.jpg

http://img.photobucket.com/albums/v1...7/IMG_1864.jpg

Re: Let The Build Begin!
 

Ah I see, looks like I may have to go back to the drawing board. My original design in the picture below uses a single set screw pushing onto a 4mm D shaft on the gear head. It is designed to support a heavy vertical load but I never really thought about how easy they would come off. Heres what Originally done:

http://i345.photobucket.com/albums/p...eelDiagram.jpg

Basically a hub rides inside a brass bushing which is inside an aluminium axle end cap bolted to the axle case (not shown) to support vertical load and a single M3 set screw on the hub presses against the D-shaft.

Thanks for the pics! I'll start working on new design, mabye something build right into the rims :cool:

-Chris

Re: Let The Build Begin!
 

Well that was nice and quick, rather than redo the whole mounting system I just put a 2mm hole running through the motor shaft and run a set screw with a step i believe its called. This will replace the original pressure fit set screw I originally had. Now it can take a heavy load without falling off! Thanks for the idea Lil Giants! I probably would of never changed it and had problems in the future. Now I just need this Christmas Break thing to hurry up so I can get back in the shop :p,

Chris

Re: Let The Build Begin!
 

Will that be a set screw with a long rod that will reach through into the other side of the hub for support on both sides of the motor shaft?

Something else while looking at your CAD from the vertical view... is your hub/wheel flush to the face of the gear head, as in a flat solid wall of material?

The reason why I ask is that there should be some recess area so dirt/sand is free to fall out of the inner wheel, and not cause any unnecessary wear or binding. I hope that makes sense.

Re: Let The Build Begin!
 

seeing that your using a bushing you want to avoid any dirt/dust getting in between the hub and bushing that could cause premature ware or binding . You prob. be OK with what Joe is saying depending how and where you will use it . for me , I would at least have some kind of seal or use a sealed stainless steel bearing with a space between for dirt/dust to fall through . OTOH , your doing a great job :) yes , cad is a great tool :D

Re: Let The Build Begin!
 

New Years Update!

Since I don't have any access to a lathe or our mill during the christmas break I decided to get some parts together and start doing some styrene work. Wow i dont give enough credit to the guys who work with styrene to make beautiful bodies. My design was simple and straight forward yet i still had a heck of a time putting all the pieces together.. I also got the chuck of aluminium for the boom, it measures a whopping 30mm x 60mm x 250mm. I just hope it wont be to heavy. And i also got the wheel blanks cut out. Now i just need to face and center drill them, then they are off the the CNC and drill press. Any way, on to the pics:

http://i345.photobucket.com/albums/p...t/IMG_5923.jpg

http://i345.photobucket.com/albums/p...t/IMG_5924.jpg

http://i345.photobucket.com/albums/p...t/IMG_5925.jpg

http://i345.photobucket.com/albums/p...t/IMG_5926.jpg

http://i345.photobucket.com/albums/p...t/IMG_5928.jpg

http://i345.photobucket.com/albums/p...t/IMG_5929.jpg

http://i345.photobucket.com/albums/p...t/IMG_5933.jpg

http://i345.photobucket.com/albums/p...t/IMG_5921.jpg

http://i345.photobucket.com/albums/p...t/IMG_5922.jpg

http://i345.photobucket.com/albums/p...t/IMG_5920.jpg

And since my old Digital caliper died i picked up a new one at KMS :D

http://i345.photobucket.com/albums/p...t/IMG_5918.jpg

Thanks for looking,
Chris

Re: Let The Build Begin!
 

Hey Chris, I didn't realize you were close by until you made the KMS comment. I'm guessing that you will have this done by the end of the school year so will you be able to join us at the truck show in Duncan this summer?

Keep up the good work!

Reg

Re: Let The Build Begin!
 

Outstanding work! Cant wait to see this one done
Scott

Re: Let The Build Begin!
 

That's coming along nicely Chris, looks as though your a natural at this hobby.

Re: Let The Build Begin!
 

Nice work and nice pump can't wait to see you loading some dirt

Re: Let The Build Begin!
 

Thanks for the comments!

RCP57 - Yea I plan to be finished by June but I have got tons of work ahead of me. I'll have to see if I can make it out there as I need to work the summer for university in the fall.

I'll be back in the shop tomorrow and start on the wheels, I'll try to get an update up depending on how much i get done.

Chris

Re: Let The Build Begin!
 

Very nice and clean build!

Re: Let The Build Begin!
 

Thanks!

Well turns out the co-axial indicator i need to set my offsets for the mill hasn`t been ordered yet so I decided to get as much done on them as i could on the manual lathe. I was able to turn the final OD, drill the 4mm center hole, turn down the wheel lip and do a final finishing pass to clean it up and get all the final dimensions. Luckily I was able to turn them to within 0.4mm of my plans, which is pretty good considering how worn out our lathes are. For example the cross slide knob can be turned a full revolution before moving the actual table. :rolleyes: Each part took 30-40 mins to machine and I had to make 8 of em. So i was pretty busy in the shop!! Now they are really ready for the mill as they only need to be bored out and have the mounting holes drilled. We are going to try and get the co-axial indicator by next week so I hope to finish the rims next week. Anyways heres the pics:

http://i345.photobucket.com/albums/p...7/IMG_5934.jpg

How they look until final machining:

http://i345.photobucket.com/albums/p...7/IMG_5935.jpg

http://i345.photobucket.com/albums/p...7/IMG_5938.jpg

http://i345.photobucket.com/albums/p...7/IMG_5939.jpg

Thanks for lookin!
Chris

Re: Let The Build Begin!
 

Looking good.

The tech college I went to, we had a bridgeport mill with 1/2 turn backlash in x and y handles. One of the required projects was an internal square pocket milled to +-0.0002" and it had to be done on that mill. Lots of guys struggled with that one, but it is doable. You learn how to work around the backlash.