My Mruder (bruder cat320 something look alike)

[cdm]

http://www.youtube.com/watch?v=coURIJHQLn8

[Lil Giants]

Quite a wide range of movement! What's the reach @ ground level?

Pump sounds slower than it should be.. what the rpm of the motor you substituted? Batteries full charge?

Now for the vid in the snake tank w/the snake.

[cdm]

I was getting lots of leaks on the 210mm piston. seals kept getting cut and what not. ended up beveling all edges to prevent that upon assembly.

rpm is low as this is my bleeding speed. i need to turn it up. how could you tell tho lol

i'll measure the reach once im done with the tracks section canopy. i don't want to get anything dirty yet because im using the kitchen counters as a table now. all my machinery is on that floor of the house and im not running up and down to my usual RC bunker.

the small arm was designed to level almost horizontally on the pull, but after testing by hand the pull force seemed excessive to get it to that position, so i cut the mount for that cyllinder a little forward, so the arm bends more than it levels. makes sense? otherwise the space is there. i might rework it down the road.

[Lil Giants]

A white lithium grease works well for lube on o rings & sharp edges, and it then dissolves in oil well too.

I've been listening to the whine of that pump for over a decade now, I know how it should sound when running at optium speed. I'm curious to see what your cyl cycle speed is like when you do tune the pump to 6000rpm (est)? I've been thinking for awhile of installing a Leimbach pump & valves into this HK hoe I have with the oem cyls.

No need to get your hoe dirty to measure the ground level reach... while on the kitchen floor, measure from the center point of the house pivot to the very tip of your bucket with the arm fully stretched out along the floor... my 850 is 1400mm, as an example.

I understand what you're saying, and yes it does take alot of hyd power to nearly level the stick, especially with a bucket full of dirt.. it's a negative leverage.

Your custom Mruder is taking shape nicely in just over a month.. your early pics of hacking & wacking & gobbs of expoxy widen my eyes with much WTFism!!! Now I'm looking forward to seeing it in motion. ..especially with the snake in the same area.

[cdm]

I meant dirty as in digging video

The reach is ~2.5ft up, down, across. 1400 comes to 4.5ft. that's insane. i cannot counterbalance that long of a boom on this thing anyway. after i beef up the top side to a scale body, i will be maxing the undercarriage to its "looks small" limit. and i even stretched that 1" over stock as is. i considered making a totally custom bottom out of robotics tracks and what not, but that would push into another realm of expensive and labor intensive




66% rpm
http://www.youtube.com/watch?v=7qxv4-eXdoY


82%
http://www.youtube.com/watch?v=iV4BSQLdaGc

I am getting a lot of foaming in the tank and it sometimes overflows when the main boom is lowered all the way down, then when it's raised, it runs low on fluid as you can hear/see. That leaking piston isn't helping any either im sure.



I need a bigger fluid tank. Any way i can jerry rig one on top of the stock without screwing up the venting system? All bigger capacity pump/tank combos were special order so i didn't go for them.

Epoxy i know.. i have never done that before honestly. Not on such large scale anyway. I have 0 access to CNC, or cad skills to even produce a model for 3rd party machining. The 2 companies in the area that do custom cnc produced a look of utter disbelief so this was a no go. So it's hand tools only and unorthodox approches to everything on this build it seems

[cdm]

ordered another 210mm one. this one i couldn't rescue. i resealed it so many times with all sizes of orings but still not good enough. issue is there is only 1 oring @ shaft and that one is supposed to both seal the shaft and the casing where the shaft goes. if you try to oversize it, it won't fit. if you go smaller to seal shaft tighter, the casing area leaks.

their quality control is pretty bad. 1/4 bit the dust. thats 25% failure rate? i know i know sample size too small to claim that but we will see if replacement is good

[cdm]

Well fixed my leaks and in my attempts to get the reservoir to not overflow (its just too small ) in a fit of brilliance i decided to plug both vent holes. half a second later i blew the cap out and am still mopping up fluid. what a nightmare. pump side seals should be fine. the cap just flew out (its held in by an oring apparently).

anyway doesn't matter because i will have to extend the reservoir. im thinking pipe/spacer stock and some creativity with jbweld. we shall see.

the big leim pump is NLA. id much rather buy the 480ml one with the big tank but what can you. unless somebody can point me where it is available?

[dabears]

Looking pretty good!!!

[Lil Giants]

What does NLA mean?

I'd just put an extention on the exsisting tank, pretty simple lathe job to make a sleeve joint, then epoxy in place.

Those large cyls you have, similar to my 850, the piston rod is quite thick, probably less than half the volume of oil on rod side vs piston side.. greatest reason why the boom drops like rock! I have the EPA set to 70% to go down & even then it's rather sensitive, especially with screener.

[cdm]

No Longer Available.

picked up the perfect 6061 pipe stock i can sleeve over; 1.37id vs 1.36 od for the stock leimbach. jbweld should seal it well. im not even going to attempt to weld that! im glad i live an hour away from a mcmaster warehouse. lifesaver i tell you.

i set programming mixes now. pump idle is at 30 and it goes up to 60 with a single valve use (faster results in no higher speed that i can visually note). then when 2 are activated it runs at close to 90. 3 pushes 100. this gives me enough flow to move all cyllinders at once for short times without killing the pump or pulling massive battery amps constantly. i will likely tweak these down the road. but my experiment was cut short last night as i mentioned

began extending the body as well. more on that later down the road when i have something complete to show. i'll make a whole new canopy and cab, scaling it to at least a 60ton machine. no particular brand on model. i'll also double my counterbalance.

the rod is something like 7.5mm D (odd number i know) at first i thought they were 6mm but that is not the case. 14mm inside diameter of the tube. i am using digital servos @6v so control is more precise than my frame skipping camera shows. although there is grat momentum on the downward swing. i can rock the whole model if i stop the boom suddenly.

[cdm]

Pump is done, even kept the clear plastic cap so you can see the level. Managed to actually bleed the system properly and get no more foam/air/bubbles/goo in there. Capacity is now a little over twice stock, around 2.1 times stock due to the larger bore of the extension.

If i had the space i would run 2 pumps. 1 for the main boom and the other for the bucket and arm, but no space means it isn't happening in that build. I am loving the big bore of the cyls so i am not downgrading those to more leimbach friendly sizes (i guess nothing over 10mm).

I am drawing a lot of power, eatin up 3400mah or so in a few minutes. I will eventually check power draw and see if i have to go to a higher turn motor. I know that without the fan this one overheats... Likely a torque issue. I was trying to go brushless speeds on a brushed but seems i've overdone it a bit. But ive decided to go nuts on battery at 12800mah main and 2800mah for the undercarriage. so ultimately it doesnt matter i suppose......

Started working on the cab.. Got the new counterweight extension and base area completed. I can now scale up the body into at least a 60ton and add a few more lbs of counterweight.

[Lil Giants]

The Leimbach excavator cyls are 14mm, the speed seems slow some times too.

The current draw is about 2.1 amps with no cyl movement, 1.1 amps with cyls moving.

My Stahl track hoe, I had one 2700mAh running just the pump & another 2700mAh to run the rest of the model. The pump batt lasted about 40mins & the other was hours. That's with the Johnson that comes with the pump.

[cdm]

I was drawing something like 5 amps if i am to trust my meter.. After reducing the speed i consumed 1400MAH every 15 minutes on the same motor. But getting the speed up by another 15% tripled the draw.

Got my new torquemaster 45turn in today, haven't tested it yet since i have the thing apart but im hoping to do that tomorrow after i paint the undercarriage. Speaking of that



Some early stages of the cab. It is not supposed to look like anything real in particular. I was experimenting with front windshield angles and this one i liked best.



Here you can see the new scale of the machine. The new counterweight will allow me to add about 8lbs of ballast on top of what i already have (im still deciding how high i want to make it, hence as you see it is not really closed up yet). Side to side i've extended 1/4" each way; total of 1/2" (any bigger will look funny on the carriage after i add the walking ramps) Front is about 1/2" and about the same in the rear. So total about 1" of lenght added. Dimmensions are almost identical to a liebher 944 now.



The undercarriage... 2 3s lipos for the drive servos (~250oz torque @ 6v), a full size ESC with active brakes forward and reverse, a 6ch receiver, the turntable and the BEC all fit in there. Want to finish trimming it up and pulling out the switches and charge plugs tonight so i can paint it tomorrow. It goes down all sides, not just on top.

It cannot look any more scale and support the weight and have the unlimited rotation of the body.. I planned it more scale but decided function over form. It is a small model :\ I have the entire beam support system around the sprocket servos, vs gluing them to the side like everybody else does. It will carry a lot of weight which was the point. Stock bruder buckled so there went that idea.

Turntable and bearing are rated at something stupid like 200lbs distributed weight but with the hollow shaft call it 100lbs. Plenty! I do have a solid shaft too but what's the point. This one ain't bending

[cdm]

Its raining buckets so no painting can take place. Instead if took the boom apart and inspected the joints. No stress damage so it was time to address something that has bugged me.

recut the stick and made a whole new mount to allow for full range of motion in both directions.

Also loving the new motor. Much quieter.

[cdm]

http://www.youtube.com/watch?v=pje467gi0GE

full functions test a success. I walked it out there under its own power (no way to film and operate it at the same time, will have to tripod later).

And found another problem. The incline getting down on the deck from the inside ran the hydro dry despite it being 3/4 full. so now i have to rebleed (hence my limited use of the pump in the video). unfortunately there is no way around that with the leim system. and that's why folks vario has a 50 gallon reservoir in there, to avoid things like that among others. i remember people saying how big theirs was.. well now i personally know why. inclines are bad :i

but that asides, im happy. now i can finish up the bodywork and maybe add some details and i am done.

i am already thinking of my next excavator with a true scale underbody and lots more metal (and a better pump! and maybe valves if i could find any)

[cdm]

Forgot to mention, current weight is 20.08LBs. I expect to top at 25 with the extra ballast. Right on my target of 20-30lbs final weight.

[cdm]

Styrene work last night and some earth box testing. none of that you can see here.

Today it was time to give it a real test

Keep in mind my yard is packed gravel and clay; Not natural earth by any means.. years down i still can't even get grass to grow despite me dumping topsoil and what not on there. Anyway learned a few things today.

I was awkward on the controls because my fingers were freezing and im still a noob as is.

dont care about the tracks..but it made me laugh; yes i was trying to turn it.... yes they are too loose, no i never made a working tensioner. no im not making one now. yes i have spare tracks.

because

new SCALE all metal undercarriage will be coming soon! this one is mainly to just screw around with. its the top side im concerned about and it performed flawlessly. numerous hydro stalls and nothing broke!

yes i remated and rebalanced the motor/pump connection last night. was off center or something resulting in scary sounds. didnt know it was even possible to kink that but i guess it is!

http://www.youtube.com/watch?v=2s6qQYe5w6A

[cdm]

Some better shots of the cab..







Haven't decided if the door will be a slider or a hinge.

As well as other details like window guards (super tedious to make). Interior.. not sure. the floor will be separate and the cab will slide atop the floor piece. Once i put the glass in and see how much visibility is there i'll decide if i will go for the full interior..

It's officially no longer a bruder look alike.. And will use 0 bruder components when im done with the new carriage. I'll change/get the topic changed once it's done. More on that soon enough. Also other things are in the works, such as exchangeable booms. Not buckets, booms. I really want a double articulated one like you can get on the liebherr, just much bigger. STC makes them in real scale

[cdm]

prototype 1 of the track carriers has been sent for milling. no holes for idler and sprocket yet as i'll add these manually (or calculate them later and send for remilling).

2 plates for each track..

and have made my choice. cabin door will be a hinge.

[Lil Giants]

The snowball effect has now begun!