Re: PC1800 Front Shovel (1/12)
 

hello
very good job
like other projects , truck and bulldozer
I want to see the excavator to work :)
good luck

Re: PC1800 Front Shovel (1/12)
 

Finished putting the swing bearing together c/w seals and spacers, needed to add spacers to bring the overall height up to what was needed, I didn't have thick enough material to make the bearing tall enough to start with so it will be 4 pcs total instead of two.The total height of bearing c/w spacer is just over 2".

[IMG]http://i1291.photobucket.com/albums/...psh5aby3wn.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...psnh4sin9p.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...pszoddltr1.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...ps8uew7kao.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...psjmgsf1jg.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...psyxwgegiz.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...pszqytzzh8.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...pszy62bolj.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...psg8qplnxq.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...pscc5paidv.jpg[/IMG]

Thats all for now......KP

Re: PC1800 Front Shovel (1/12)
 

Great project, thanks for posting) When able to scratch build a fantastic swivel bearing like that, I was betting you also would be building scale replicas of the original cylinders;) But hey, if there is already some stuff out there on can get hold of that is about the correct size and can take the pressure, one can save time naturally.

Re: PC1800 Front Shovel (1/12)
 

Howdy KP, judging by your dimensional drawing, an electric ac 1/4hp furnace motor might fit. RPM1750 ;)

Re: PC1800 Front Shovel (1/12)
 

Howdy Joe......to bad I dont have any fan motors around like that,would almost fit....LOL....just need a long extention cord and never charge another battery.:D

I did run some red neck, high tech tests using a cordless drill though :p....turns the pump at about 1400 RPM no load, at that RPM the pump is moving about 51cc / sec which is a bit more than I need, could slow it down a bit more.
2.2cc / rev X 1400RPM = 3080cc / min. Rember this is no load very little restriction in the system ( I did need to increase the intake hose to 5/16" ID hose, the pump did not like trying to pull that much oil through the 1/4" OD tubing which is what you see in this picture)

[IMG]http://i1291.photobucket.com/albums/...pscnrnbbcw.jpg[/IMG]

Re: PC1800 Front Shovel (1/12)
 

This was the next test c/w valve and one 1.0625" ID x 6" stroke air cylinder, I have a 40lbs load on the cylinder. I replaced the spring in the RV with a lighter one that I thought would work and with a small adjustment it holds the desired 250PSI very well , really glad this worked :D:D This valve has an open center which means when all the spools are closed the flow is allowed to return to the tank with very little restriction which should help increase run time on the battery.

[IMG]http://i1291.photobucket.com/albums/...psh0mifswq.jpg[/IMG]

Re: PC1800 Front Shovel (1/12)
 

Here is a short video of the high tech test....:)

[IMG]http://i1291.photobucket.com/albums/...ps1nf5zymt.mp4[/IMG]

Re: PC1800 Front Shovel (1/12)
 

I love the testing! It's not too late to build a seat on the counterbalance so that you can sit on it and control it. Why waste money on a remote!

Re: PC1800 Front Shovel (1/12)
 

if you're gonna go that far, why not just go straight for 1:1 scale. Much more space to package everything inside :D

Re: PC1800 Front Shovel (1/12)
 

Is that a furnace oil pump? friend of mine works on oil/gas furnaces and tossed me a few, I've been wanting to make a test on them. He did tell me they can produce some really high pressures. Looks like your redneck testing is not so redneck,,,, lol!! Nothing broke ,, haha. Naa man, stuff looks good!!! This is going to be a monster!!!

Re: PC1800 Front Shovel (1/12)
 

Haha...lets see if I use a furnace fan motor that Joe suggested with a long ext cord and install a reclining seat c/w beverage holder, small screen TV, sound system, small fan for hot days and a cooler this could turn out to be a mans best friend!! :lol:

Re: PC1800 Front Shovel (1/12)
 

Nope, not a furnace pump......got it on sale at Princess auto

http://www.princessauto.com/en/detai...or/A-p1220030e

You might like this thread....

http://www.rctruckandconstruction.co...hydraulic+pump

SURPRISINGLY nothing broke...lol...but things didn't all go as planned.... the return line from the pump to the oil jug decided it didnt like being inside the jug anymore, well ya know the rest...big mess really fast!!! I was so glad the whole thing was working I didn't even swear....much. :D

Re: PC1800 Front Shovel (1/12)
 

Thanks!! Decided to try use some off the shelf air cylinders that are close to the needed sizes instead of building them, time will tell how well they will work and or for how long...lol

Re: PC1800 Front Shovel (1/12)
 

I have a question or two for all you hydraulic fellas on here.....

What type of oil filters are being used in models , are there inline and intank
filters??
How much would these small filters effect the flow if the needed volume is greater than the typical RC system??

How big should the tank be in regards to the total volume of oil in the system, should the tank hold the same amount or more, or can it be less providing the oil temp doesn't get to hot? I can't see the temp of the oil in this model being a problem....there will be about 700cc in the system not including what will end up being in the tank, which is one more thing that still needs to be built. I would think that the longer the model is being used the warmer the oil will get....how warm does the hyd. oil typically get in your machines??

I have limited knowledge in regards to hydraulics and no experience with RC hydraulics...zero...so be patient with me as I hope to learn more from all of you and of coarse the good ole " school of hard knocks"

Re: PC1800 Front Shovel (1/12)
 

Hello Dadsgarage,

In a normal machine, the tank volume is about the same size as the system volume. I would do the same on a model. Maybe a little more to be sure and to have better cooling.
Unfortunately I do not have experience with oil in scale models yet.

Your build is great! I really like the scratch build parts.

Re: PC1800 Front Shovel (1/12)
 

i alway thought it was double the cylinder. 30 gallons in the piston
30 more in the tank. thats how it is on my dump trailer 60 gallons
in the tank when the piston is down 30 left when full lift.

what about a inline carb filter on the return side as long as it not under pressure

Re: PC1800 Front Shovel (1/12)
 

http://www.ebay.com/itm/Inline-Fuel-...pVuezG&vxp=mtr

I wanted to use this (fuel) filter in my stuff but it is too big, probably good for this size model. Oil filter/fuel filter, they both are trapping particles of a certain size, 5~500 microns,,, the ones I use are very small disposable I get from McMaster. I have to drill out ends and thread for m5 fittings. I'm sure they are way too small for this. My opinion on hydro volumes is about same as above, double the system volume and you'll be good. On an hydro guys side, as big of a tank as weight/size/practicality allows. More oil is just better all way around. Temp, contaminants, lifespan of oil, ect. But on 1:1 machines, lifespan, cost of replacing, and available size is what restrictions are. One thing to try is to have tank suction on bottom and tank return line on top (baffle or just opposite side) allows air in oil to migrate to top and not back into pump. That's the frothing of agitated oil, a lot of oil has additives to lessen foaming. I've never had temp come into issue in any of my models. Excavator cylinders get warm after a hour use in summertime, but never hot. (At least that I am aware of:) )

And that school you talk about, one of the best I've ever attended!!! :)

Re: PC1800 Front Shovel (1/12)
 

Love the 777. This build is going to be great. It's going to influence me when I build my excavator. Using regular parts. I like it. Keep up the great work.

Re: PC1800 Front Shovel (1/12)
 

Thanks for all the feed back on the hydraulic questions, now I will have to put it to good use....

Next trick will be getting everything to fit, even though this is a good size model there isn't a lot of extra space left over after all the "big goodies" are in place. Played around with different placements of everything on a plywood template, this seems to be about the best use of the space....the rusty 2"x4" HSS may end up being used as the tank, after getting a good cleaning and cut to proper length it will hold about 1000cc. I dont have the drive motor yet for the pump, it will be belt drive with about 3:1 reduction using a small 2L vbelt. The servos will be mounted on a plate above the motor/pump, the handle shafts on the valve will be cut shorter and then connected to the servos with ball linkage rods. Nothing to exciting but here are some pics....

[IMG]http://i1291.photobucket.com/albums/...psujyoxrty.jpg

[IMG]http://i1291.photobucket.com/albums/...psb8ouoacf.jpg[/IMG]

[IMG]http://i1291.photobucket.com/albums/...psa4lmaspp.jpg[/IMG]

Thanks for looking!!
KP

Re: PC1800 Front Shovel (1/12)
 

How many amps is each battery?