My Mruder (bruder cat320 something look alike)

[cdm]

This will be a quick and disorganized run down since i have about 400 things on the honey do list for today alone.. hard to find me time lately.

This is a pooper scooper. Its job is to go in the reptile cage and turn over the soil. Not as hardcore as digging a basement ( i love that thread!), but it allows me to get away with building it less than milspec tough. Besides its all red clay out where i live; you aren't digging through that regardless.

At first i thought about simply converting the bruder cat but the thing is a joke and so I opted to make a lot of my own parts, just using the body canopy at the end. I thought about extending this as well to make it into a 40 or 60ton but I dont want another super long project to drag on. So it will stay as a 20 ton with a custom long reach arm, which is what i really need.

Initially i extended the lower arm on the stock cat, but it was still too small and the geometry was wrong as far as cyllinder and bucket control angles. So i machined one out of reinforced plastic stock. Drilled and tapped with 6mm sleeves and the shafts are 3mm hardened ss stock.

There are 2 of those holding the bucket itself, the epoxy is there to help keep it all centered as i mounted it and what not. most if not all of that will be cut away. The range of motion is phenomenal with the 172mm cylinder and the longer than scale bucket oscilting links.

To give you a size idea of mine vs the stock lower arm:



The long arm is custom extended bruder one (3 extensions to get the proper geometry). I could cut that too out of plastic stock but i already invested a lot in the stock extension. Pics of that later when im done prettying it up. I still might cut one, depending on how much power i get out of the system - that solid plastic is heavy!

Quick test of the tracks section. This is weighted with lead (epoxy is a good bonding agent for that, again that will be machined away, prettied up and painted and hidden with top attached) and it weighs as it stands at close to 5lbs. I can make it 10lbs easy if i ballast it all. So there is room to play with that if COG is off down the road. Right now i left it as is since i have a few lbs in the top floor ballast. Also there will be a battery in the lower body for the turn table motor (it gets it's own battery yes - fewer wires to run between the 2 sections this way)

The servos are factory modified robotic servo motors producing over 100oz of torque each at 6v. This test is with an almost dead 4.8v pack and the throttle didn't go over 20% even here. Of course, friction on the floor was pretty slim so im quite i'll use all of the 200+oz down the road. If i really wanted to i could have made it a quad sprocket for over 400oz of power, but that's an overkill.. Could have also gone with direct motor drive (have them here) but i just WANTED to play with these awesome servo blocks. As you can see quite easy to mount and adjust height and position to get the perfect mesh with track and ground level. The tracks have also been extended a few links over stock. Width is the same; see comments above about making the body scale bigger.


I have the base plate, the turntable main floor - all that ready -1/8 and 1/4 t6 alum plate that was interesting cutting to shape. Waiting for some hardware to attach the bottom floor to the main beams. Then it's time to tinker with the hydraulics. I decided to stay brushed for now, using a cool new motor over the stock 540 can. It's shorter to boot.

The drive section will not be as scale as other's but this isn't a conversion per say. I will opt for function over realism any day when it comes to something like that. I will probably lose the H pattern the tracks section has but it's ok.


http://www.youtube.com/watch?v=0fB9vQ8YkWk

[Lil Giants]

Cleaning the reptile cage..? That should make for an interesting video.. titled Cat vs Snake should get you some views!

Red clay.. would that put you in the midwest somewhere between southern Kansas & Texas?

[cdm]

further down, southern red clay. slippery as ice when wet, hard as a rock when dry. there is a bit in between where it is mallable but our seasons have been either dry or monsoon the past few years.

took the cab out and i'll use that to store the electrics. The stock cab had no detail so no point in preserving it. I'll cut some lexan and make windows but that's about it.





drilled the holes and mounted the main components. I have plenty of space for batteries and what not now. My valves came with the straight fittings and i ordered none first time around of the 90d ones. So i just put in another order for the swivel ones tonight. The good news is i can run the system with the straight ones so i can at least test it before the new ones arrive. Filter is hooked to the valve which is the shortest and weirdest connection i had to make so far. No kinks in the line or any real strain points.

The filter should be connected to the pressure line, right? P on pump > top of filter, bottom of filter to P on valve block?

Servos are in the mail. Ill try the 3153 futaba digital and see if that will fit. The HS55 is too short on the horn area and too long on the mount holes (which can be fixed). Futaba is slightly different sized, by a mm or so.

Next up, the boom.

[cdm]

the s3153 digital is a direct fit in the control valve! the 4 way default horn takes 30 seconds to cut and grind to size.

no reason to not use it over the 4.8v limited analog version.

mounted the turntable to the tracks today. still need to lower the rear sprockets about 1mm down to the ground.

[Lil Giants]

Originally Posted by cdm

The filter should be connected to the pressure line, right? P on pump > top of filter, bottom of filter to P on valve block?

Correct, filter the oil before entering the valve block.

[cdm]

Decided to test the rc4 cyllinders today since they are very stiff so i had some doubts about what it will take to get them to move. With your instructions from the other thread servo setup on the valve took less than 10 seconds, including remounting the horn. Thanks! So easy to zero it in i was surprised actually. Response is amazing with the digital unit. Not sure if the video shows it but i can feather the stick for instant response all along the range. I have mixes off but can turn those back on after the pump is broken in to further modulate the speed and power depending on stick pos.

http://www.youtube.com/watch?v=5wHPCyrJkvg

12bar stock on this pump @ 29% power on the motor (can go all the way to 125% if i want to). Tried to hand grab the bucket and no dice. it kept moving so power is awesome from what i can see so far. Took it easy as the pump is still new but from what i can tell, no leaks on the leimbach gear.

Going to go test the other cyllinders now but i expect no leaks there either. If you can live with the 6mm mounting holes and the sizes they are in, they seem a great unit that you can get stateside. So far.


Back to working on the main boom now.

[dabears]

Your conversion is coming along nicely! I have a bruder excavator i plan on doing as well i just havnt decided hydrolic or not yet

[caterpillar]

great work, i will be following this build!

[cdm]

Lower boom after its first primer. Lots of little things left to smooth out. I should have just cut it out of solid stock. There is now enough metal (alum angles, u channels, threaded rods) in it to say that weight savings are nil.

The only weak point i can think of are the mounting ears for the short section. If those break though (can't see why unless i push it) i can make the whole part out of 1/4 stock. But for now i'll just carry on with the reinforced bruder ears, which i still need to trim out to get max travel. If they break i'll make a new part. If they dont, less work for me.



started working on the boom to chassis mounts. then i wore out my blades. waiting on the new one to get in, should be in tomorrow. i really have no tools to cut stainless. even aluminum destroys what i have in no time. hmmm.

also ordered a new esc to handle the voltage. the one i was using was only up to 8.6v and it didn't like the heat. good brushed escs are hard to come by it seems. but china to the rescue. got one up to 18v with built in cooling so i should be covered.

[td9clyde]

2x12 sabertooth from robot market place or a 2x25 those are good up to 24 volt lol

[cdm]

too expensive, laughable amps.

Sabertooth 50HV Dual Motor

is nice but for that price i can go so many better routes. robotic escs are really way behind hobby ones for some reason.

they are still stuck in the 80s

[cdm]

Began working on mounting the main boom (which will use another detail over before the paint goes on)



had to chop up the cyllinders a bit at the base and replace a few 13mm orings. 1 due to my fault, the other chipped from the factory and leaking. anyhow, i couldnt mount the boom today because I decided to go with 5mm shaft vs the original 6mm. the outer collar for the 6mm is way too thick requiring too much material removal for my taste (less material = less strenght). 5mm i can go down to 8mm OD or 10mm OD vs 13mm OD for the 6mm shaft which is used for the cyllinders themselves.

parts are on order for that part. as soon as i mount the base of the boom i'll be able to begin cutting and bracing the little "ears" to shape and make them all pretty along with any other metal pieces i need to pretty up. i wont leave them square

in other news, the body is getting extended. why, you'll see later. simple version: its too small. but i'll cheat! i'll extend the upper canopy and just add solid material to the base plastic on the outside.

so much for a quick and fast build eh. you know, you double the boom and go with 14mm bore hydraulics, and expect to keep the stock bruder. im such a noob..

in other other news... leimbach uses 4mm holes on the pump and filter, 3mm on the valve and reservoir.

my last batch of 90d connectors only fit half the joints. but at ~7euros for 1 of the 4mm ones, i might just ignore them.

[cdm]

it was a busy night.

as soon as i mount the lower boom and machine the mounts to shape i'll be able to drop down the guts and begin wiring it up.



i love the hitachi orange. never cared for the puke cat yellow.........

[Lil Giants]

Gosh!! that's quite a reach.. you using a block of lead for a counterweight?

[ihbuilder]

1st thing I thought was an old 6644 Koehring .

[RCP57]

Probably out reach my Volvo! It will be more fun to play with having a longer reach though IMO.

[cdm]

Originally Posted by Lil Giants

Gosh!! that's quite a reach.. you using a block of lead for a counterweight?

Oh there is lead.. and more can be added if needed. I didnt go overboard since the tracks are well.. plastic. But i figure with the batteries (3 of those) et al in there it should be more than enough.

1st thing I thought was an old 6644 Koehring

I googled that. the boom is eerily similar. Thing is i still have to fiddle with the body since the twin cyllinders can't fit in the space of the stock clearance width wise. I might just make a new smaller cab for it. 1/2 the cab = 2x the tonnage. Will deal with this when i get there. It just might turn into a koehring by the time im done with the styrene.

Probably out reach my Volvo! It will be more fun to play with having a longer reach though IMO.

big booms are bigger fun and imo just looks better.

And speaking of booms, i got it mounted tonight.



i think it can go higher, not sure if this was the max position when i took the photo. i took the turntable pinion out so im using a tool to hold it from spinning



sideways balances just fine. empty deck.

i was copying the geometry of this thing: http://www.youtube.com/watch?v=Rchz0ob8sAk

hopefully the angles arent too crazy for the model version and the boom doesn't stall. if it does, well i'll just have to recut new ears and remount in another position. we will know soon enough

[cdm]

bolted the hyds in and tested the tracks and turntable. tracks have loads of power and turntable could use a slower motor (i was trying to calculate it but i overshot a bit). instead of 27rpm final its more like 40. it works fine as long as you dont go all the way on the stick, but like i said, just a matter of swapping the motor unit for a lower rpm one. overal im very happy


now, initially i planned on using 1 battery in the chassis to power the turntable and feed the rest of wires between the 2 halves. that would of course give me a limit to the numbers of turns you can make before wires get twisted.

tonight after some beers i had the stupid idea of trying 2 receivers to 1 radio at the same time. lucky for me (hitec is my deity now!), that actually worked (some dont).

so i have optima 9 upper deck, optima 6 lower deck. 0 cables between body and chassis. i can spin it round for hours

lower receiver is channels 1 (track1),2(track2) and 6(turntable esc) and upper is 3 4 5 (valve block) 7 (pump esc). perfect. still have 8, 9 on the upper as spares for whatever i might add.

no videos etc as it is 4am and i just got out of bed to test that theory.

[cdm]

trying to see the best way to get it all in there. i ended up with more space than i thought would be. ignore my sloppy dremel grind marks. that's what the hood is for.

ordered the styrene and will fiddle with the canopy. as if i needed another styrene project, but it has to be done.

[cdm]

mounted and wired everything up today, began working on the underside skirt (just to make things pretty on the undercarriage).

i have 1 leaking cyllinder.. could be my fault since when i took them apart i might have nicked the oring in the process.. the one i didnt replace. so new orings in that size are in order.

the good news is the geometry is perfect on everything and no other leaks.

got one air lock up the main boom due to not bleeding it properly but took care of that.

video after i fix my leak