Cat 340D Excavator build

[Originalrob]

Hi Chris

Excellent idea on the lead screws and workmanship. I’ll be following your build with interest as I think an excavator will be my next project.

Good luck

Rob

[crueby]

Thanks guys, glad to have you along for the ride on this one.

[crueby]

Getting the rest of the cylinders assembled, couple more set screws to go...

[crueby]

Got the last bits on the cylinders done, time to start working on the booms. This morning got the side panels cut from some 1/8" aluminum plate:

[crueby]

And started riveting on the angle stock to hold the top/bottom panels. Those will be screwed on, with screw blocks inside the angles since the angles are just aluminum. This will let me access the insides to get at the gearmotors.

[Originalrob]

Its coming along nicely!

any reason for using aluminium?

how do you know your rams will act fast enough? can you speed them up if required with more voltage?

keep up the good work !

Rob

[crueby]

Originally Posted by Originalrob

Its coming along nicely!

any reason for using aluminium?

how do you know your rams will act fast enough? can you speed them up if required with more voltage?

keep up the good work !

Rob

Thanks Rob!



I am using aluminum for ease of working plus cost, plus I already had a couple sheets left over from some fixtures we built before I retired. Normally I use 303 stainless on most of my steam engines and such, but for these booms the ali will work out fine - at 1/8" thick its pretty solid, especially once made up into the box. I'll be putting in some strengthening parts of steel around the cylinder bases and the ends with the pivots will be steel on the inside.


I timed the rams at different voltages, should be good but if too fast or slow I have other gear ratio motors. These are 176 rpm at 12v, also have some 90-some and 56rpm motors that are the same size. Servo City has a whole range of different gear ratios in the same motors, all swappable. I'll be running speed controls on the motors, and can always tune them back for lower speed too. There will be limit switches on the pivots to keep from over-running the travel and locking them up.


These will not be as powerful as hydraulics, but should work out okay, good way to get into this branch of the hobby (I hope) at lower cost to start. I've been in RC boats forever, have plenty of radios, speed controls, and batteries already.


FYI - here are some pics of my last big build (year of research plus two of building), the Marion 91 steam shovel over in Leroy NY, all live steam and working engines (not RC though)