Great Dane excavating co.

[Cooper]

Question for you guys, the differential I'm using has x number of teeth on pinion and x number on the big gear. Is that a reduction I should consider into wheel rpm? Like if pinion has 25 teeth and gear has 100 is that a 4:1 reduction? After thinking about this beast and weights wanting to haul, I may be putting motor under cab like 1:1 machines using the reduction gearbox same as the 1:1 machines. Gives me more room in front of axle. Yes over engineering this heavyweight. I've been crunching the numbers and just thought of the differential aspect, I did not figure that into the final rpm. I'll go and count teeth on differential pinion and spur gear and find out numbers. Thanks guys.

[doodlebug]

Originally Posted by Cooper

Question for you guys, the differential I'm using has x number of teeth on pinion and x number on the big gear. Is that a reduction I should consider into wheel rpm? Like if pinion has 25 teeth and gear has 100 is that a 4:1 reduction? After thinking about this beast and weights wanting to haul, I may be putting motor under cab like 1:1 machines using the reduction gearbox same as the 1:1 machines. Gives me more room in front of axle. Yes over engineering this heavyweight. I've been crunching the numbers and just thought of the differential aspect, I did not figure that into the final rpm. I'll go and count teeth on differential pinion and spur gear and find out numbers. Thanks guys.

Yes that's 4:1 ratio.
Cheers!

[DADSGARAGE]

Originally Posted by Cooper

Question for you guys, the differential I'm using has x number of teeth on pinion and x number on the big gear. Is that a reduction I should consider into wheel rpm? Like if pinion has 25 teeth and gear has 100 is that a 4:1 reduction? After thinking about this beast and weights wanting to haul, I may be putting motor under cab like 1:1 machines using the reduction gearbox same as the 1:1 machines. Gives me more room in front of axle. Yes over engineering this heavyweight. I've been crunching the numbers and just thought of the differential aspect, I did not figure that into the final rpm. I'll go and count teeth on differential pinion and spur gear and find out numbers. Thanks guys.

Hey Cooper....great job on the axle and susp. cylinders look great!! If you use a very small vent hole in the cylinders it might act a bit like a shock restricting the movement while the suspension is unloading...just a thought...

Something to remember/consider is the diameter of the tires when trying to figure out the ratio....my truck also has 8.5" tires and it is geared to turn the wheels at about 38rpm, 8.5 x 3.14159 = 26.7" circumference , 38x26.7=1014.7 inches per minute or 84.5 ft per minute. The banebots motor gear box actually turns at about 65-70rpm not the stated 90, at least the one I have turns at that speed, the 540 motor turns at 16800 divide that by 256 which is 65.6rpm on the output shaft. Here is a link that might also be helpful on calculating the needed power/torque....

http://www.robotshop.com/blog/en/dri...zing-tool-9698

Putting the motor up front and using a drive shaft will make it more like the real deal...should look great!!! I used chain drive for two reasons....easy to change gear ratios and the linear actuator is right in the middle of the frame rails so there was no way to run a drive shaft to the rear end. Did you do any more work/testing on the telescopic cylinders??? We have one in the shop at work, I think it's off a 789 not a 785 , one reason for the double acting telescopic cylinder is to decrease the time it takes to lower the box instead of just letting it drop under its own weight (time is money) , the other reason is it help hold the box down tight to the frame shims which helps add overall rigidity.
Looking forward to seeing the progress on this build...keep up the great work!!!

KP