Cat 374 Excavator build

[mcCracken15]

Just a detroit diesel. sorry

[supraman]

Got the bucket done .. It was a day of distractions so i made a whoopsy on one of the teeth and another on the back of the bucket - oh well The teeth are mild steel and i still have a few burs that i missed
I have played with the pump , but was only getting about .5 lt per minute ,So too slow without changing motor combos to find the magic number , i was running 2500 rpm to the pump. Although i found that old PC650 thread and noticed he used an industrial pump . It turns out i can get a 1.6cc pump for between 150 - 300 Aus , A 250 kv motor for $100 Aus .So i looked some more and found a 3 spool valve with 1/4 fittings that i could easily mode to take servos instead of the levers , just like the guy with the PC650 - he is a member here , but i can not remember his name . So it looks like i will give up on the home made pump and buy industrial as i have the room . More on that next week .

[supraman]

Going overseas for a few weeks , so i thought i should paint the cyls , to avoid rusting , and i could not help myself and did the boom also . Will continue with the hydraulics when i return .

[supraman]

Wow,, has it been a year ? Oh well
I found some time lately and finally made a new center plate to push the track frames out 50mm wider . Also modified my original center bearing setup as i had too much slop -relying on the deep groove bearings ,,but all sorted now .
Did some wiring today and checked the slip ring was doing the right thing and not getting hot -- purchased off ebay -- 12v 30 amp 6 wires .
Soon i will get the 3 spool valve and then i can move forward again as until that goes in with servos , i can not permanently fix any thing internally until it is all in there .
Yes my hobby room is messy


Also a test vid of electrics working -- Not the smoothest , but i was using a 3 channel receiver and had the controls set up in a strange configuration to avoid removing an 8 channel for the moment

https://youtu.be/tUrzRvzne3I

[Doggy]

Great build!
Did you test the pump from the last photo? A was just looking at pumps like that few days ago, used pump go for really cheap.

[supraman]

No i haven't tested the pump yet .. 1.6 cc pump delivered was around $160 and motor $100 from memory . I had an old speed controller so i will be using throttle mixing on each hydraulic channel - to maintain a constant speed whether one or all 4 cyls are used -- thats the theory anyway
Hoping to get the valve this month if time at work permits.
Cyl volume is about 200ml for all 4 . So if i want to fully extend all 4 in about 5-7 seconds .. Lets say 6 seconds at 200ml means around 2 liters per minute needed = around 1500 rpm at the pump max to give 2.4 liters . Using a 3:1 reduction belt and 12 v at the brushless motor with 560 kv means 6720 divided by 3 =2240 peak pump rpm So really only need 3/4 of the rpm available - wow that was more confusing than what i had in my brain

[liftmys10]

Looks awesome!! Great job!

[supraman]

Since work slowed down this month i decided to continue with the build . Since time costs me nothing i bit the bullet and had a go at making my own valve . I was also worried that a 3 spool industrial valve would take up too much room .
I was also worried that the hydraulic pressure in the rotary valves would push them into the hsg and create too much friction on the back face , so i fitted thrust bearing behind them. Realizing i needed to also seal the stem of the rotary valves i could not be bothered putting a groove in the hsg so i just put a keeper plate on the back with a counterbore to hold the Oring . Next thing is to make a pressure releif valve and the tank ,then test time .

[550166681]

You look beautiful the hydraulic valve

[RCKiwi]

Nice use of the thrust bearing in the valve. I was planning to use a shim of Telfon behind the head, but you've given me food for thought here. Perhaps energise a circuit with out a servo connected and rotate buy hand to give an indication of the effort required with the bearing?
Nice work