Cat 340D Excavator build

[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)

[crueby]

More work on the booms, rough cut the top/bottom pieces and have started forming them. The ends will be solid steel milled to shape.





The pieces were bent using the bench vise, clamped the end in and bent them by hand, the curves took some finessing but came out pretty close. A little filing on the sides will get the seams to close up.

[kerst]

Originally Posted by crueby

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)

Wow! very nice!

Kerst

[crueby]

Thanks guys! I've been getting the plates for the cylinders to attach with patterned out, hope to get enough together soon to test moving the outer boom with the motor.