360* Rotating Back Blade Project

[scott_vt]

Mornin Larry,
Looks like you have come up with a great idea ! And with Robs help Im sure it will turn into reality ! Glad to see you guys hooked up and put your collective minds to work together !

Reading through the thread, I thought I was serving my apprenticeship allover again

One question on the keyway you broached. Couldnt you find anyone with a hydraulic press ? All you really needed to do was make a plug to fit the bore on your lathe, mill a keyway through the plug and use a keyway broach with shim stock for progressively deeper cuts !

Great thread, and I will be following along!

 

[GuglioLS]

....."One question on the keyway you broached. Couldnt you find anyone with a hydraulic press ? All you really needed to do was make a plug to fit the bore on your lathe, mill a keyway through the plug and use a keyway broach with shim stock for progressively deeper cuts !

Great thread, and I will be following along!

Thanks Scott! -
Re the Keyway fiasco - your right - just goes to show you what I know At least I've learned something and know better now.

Rob's made incredible progress since my last post - He's letting me compile all his efforts for posting here - I can barely keep up with him.

Larry

 

[Cidertom]

I am humbled by the machine work.

WOW!

 

[montejw]

I guess I bored everyone ? no replies yet

Larry

No, not bored here, just found the thread. Very cool project. I want to be a machinist when I grow up and I'm running out of time

Monte

 

[JoeL4330]

A masterpiece in the making ...but, there is one thing on which I am unclear. When you started the design, as I understand it, you had planned to use your pto, which drives "horizontal" so the worm gear is the cat's pajamas...but, once you switched concepts and decided on a hydraulic motor, couldn't you just mount it vertically and use rotary gears--your "flywheel" idea? or, perhaps sprocket and chain drive ...of course, it would have to be enclosed for safety, but might not need to be in an oil bath ...(naive questions, I'm sure... perhaps the issue then would be making sure ground forces couldn't change the angle of the blade?)

 

[montejw]

A masterpiece in the making ...but, there is one thing on which I am unclear. When you started the design, as I understand it, you had planned to use your pto, which drives "horizontal" so the worm gear is the cat's pajamas...but, once you switched concepts and decided on a hydraulic motor, couldn't you just mount it vertically and use rotary gears--your "flywheel" idea? or, perhaps sprocket and chain drive ...of course, it would have to be enclosed for safety, but might not need to be in an oil bath ...(naive questions, I'm sure... perhaps the issue then would be making sure ground forces couldn't change the angle of the blade?)

A worm gear (with the right worm angle) won't let the blade drive the motor. Once the motor has stopped turning, the blade can't move. No pins or other locking device needed to hold the blade angle. The motor doesn't even need to be locked.

Monte

 

[3RRL]

A worm gear (with the right worm angle) won't let the blade drive the motor. Once the motor has stopped turning, the blade can't move. No pins or other locking device needed to hold the blade angle. The motor doesn't even need to be locked.

Monte

That's right Monte,
The worm which drives the worm gear has a helical angle of 4°-16' which is considered a "self locking angle" (generally under 5°). So the worm gear (attached to the blade) will not rotate the worm ... which is attached to the hydraulic motor. It locks there until the motor starts to drive it again.

 

[3RRL]

I got the side plates tapped 1/2-13 for the bolts that will hold the hydraulic cylinder on. This is a bottom tap and the holes are shallow so I started them by power tapping in the mill for a couple threads only. Then finished off by hand with a tap handle and a tap guide to keep it on location. The tap guide is spring loaded and keeps pressure on the end of the tap to keep it straight.



Next, I set up the bottom plate so I could rotary table out the counter bores for the bushing that hold the thrust bearings. I had to add 2 more holes to both top and bottom plates because I had no way to clamp the large plates to my 12" rotary table. ??? So I tapped them 1/4 NPT for additional fill and drain holes.

Here you can see how the plate hangs out over the rotary table. This is what we call a "knuckle buster" set-up, where when you rotate the handle, you get to smash your hands on the plate.

 

[3RRL]

A couple more shots beginning the rotary table work for the counter bores.



I will switch cutters when I near the diameters (on all the RT work) to establish a nice flat bottom and cut the OD within .010" of finished size. Then I will re-indicate the original bored hole to be sure it is on center of the quill, and use the boring head to finish the OD right on size. I am shooting for a light press fit for the collar. Then I will TIG (heliarc) weld it permanently.



I'll have to do this to both sides of the top and bottom plates for collars and oil seals and also to the side plates for the worm collars and seals. I'll post more when I wake up.

 

[Renze]

The photos leave no doubt about the workmanship... Not to be the salt in your beer or something, but if i ever make a gearbox like that, i think i'd just weld up a box and then surface mill the mounting surfaces and drill the mounting holes... Off course that is a bit low tech compared to what you guys are making, but if it does the job, it's fine for me.

I assume it's all depending on the trade you work in. If you work daily at a precision machine shop, this is the most likely approach. If you work in the trailer fabricating industry (like myself) where tolerances are to the few mm, instead of to the nanometer, the approach gets a totally different reference point.