hydraulic pump and motor system

[2brains]

I am building lathe to peel pieces of veneer approx 0.160" off of pieces of logs. I sliced pieces off with an arbor press and with some tweaking was very pleased with the results. I have decided that the max torque needed would be 6000inlb. A 3/4hp motor came with the wood lathe. Until I thought of this I was going to buy a 60:1 gear reducer ($272.) and 4 sprockets, 2 chains, and another intermediate shaft with pillow block bearings etc. and reduce the rpm to almost 6 rpm. Then I found I could buy a hydraulic pump with 0.065cu in disp and a hydraulic motor with 5cu in disp and combined with another 2:1 reduction with chain and sprockets have a much simpler setup with a lot more freedom to place the motor etc and get a similar final rpm. The hydraulic approach should cost me a little more, but be much easier and straightforward to put together. The motor should produce at the shaft almost 25inlb and as as I said the final torque could reach 6000inlb. I majored in math and only took a few engineering courses and took fluid mechanics, but we didn't discuss anything like this. After some reasoning here I concluded all I need to do is compare the displacement of the pump to the motor to determine input, output torque. Electric motor rpm is 1800. Am I correct and do you think this will work? If my original experiment wasn't easy I wouldn't be doing it nor would others find it practical.

 

[MikeHalloran]

A common wood lathe may bend rather badly under the force exerted by the peeler.

Consider starting with a metal lathe instead.
It will bend less and store less energy.



Mike Halloran
Pembroke Pines, FL, USA

 

[2brains]

I didn't include all the details. I am planning to mount this all on a 1/4 sheet of steel welded onto a cage of 1 1/4 square tubular steel underneath rather than use the lathe bed that came with it. I am concerned about the spindle which is almost 1" dia but I found it is hollow. It has several steps in dia along its length. I wonder if that makes it stronger. I'll just have to try it. If it twists I'll get a solid one made.

 

[MikeHalloran]

The twist will be accompanied by a radial force, quite a large one.
Chances are the spindle will bend and then fracture.
A replacement solid spindle will cause the spindle support/ housing to bend and then fracture.
... etc.



Mike Halloran
Pembroke Pines, FL, USA

 

[2brains]

I made a mistake: the hydraulic motor I was looking at has a displacement of 12.15 cu in and 12.15/.065=184 which is the ratio I was looking for.

 

[2brains]

The housing of the headstock on this Delta lathe looks to be pretty robust to me and the max torque is when one uses 12"dia pieces of logs and they will be no longer than 11" (what I was using before). Also I could take thinner slices at the beginning and I doubt its really taking as much force as I am estimating.

 

[MikeHalloran]

Then your path ahead is clear.


Mike Halloran
Pembroke Pines, FL, USA

 

[hydtools]

This link will be helpful reference for your calculations.

http://www.engineershandbook.com/Tables/fluidpowerformulas.htm

Ted