360* Rotating Back Blade Project

[3RRL]

I have quite a lot of progress to report today. I started work on the shafts and there are three that need to be made or modified. Each one entailed a lot of work to custom fit them to work in Larry's gear box ... more than the eye meets.

I started on the big worm gear shaft. Larry had given me hollow splines that needed to be connected so they would be long enough to run through the top and bottom of the box. That way he could not only plug in a PTO type shaft into the bottom such as his tilt blade, but also into the top if he wanted. This represented some problems because connecting the two hollow shafts and keeping straight as well as strong and lined up in the center was tricky.
I put the long spline inside the shaft to line them up. Indicated several times in the "V" block.



I found the outside did not run true to the inside so I had to position the shaft several times so the OD ran true to the ID. Then I clamped them in position to TIG weld them together. This took several hours to straighten out after welding each time until I was finally able to arc weld the shafts completely.

 

[3RRL]

Next was to turn down the weld and blend the two shafts together. Total run out over the entire length was .002" ... not too bad for that super slow turning worm gear. Even better is that I will not use the total length but a shorter length for the box.



After that I figured out where to cut the key slot. Larry wants a 1/2" protrusion on the bottom and 1/4" sticking out of the top. I had to work the key stock a little to get it to fit the worm gear since there was a lot of taper in the broached slot. But after some massaging, I got it all in there neatly and fit together.

 

[3RRL]

Here it is now all turned down and machined with the key fitted to it.



And fit to the big worm gear. It has been cut and chamfered to the correct OAL for what Larry wanted. So now this big worm gear and shaft are ready to be installed.



Next was to get started on the shaft for the worm itself. First thing was to measure how deep the hydraulic motor would clamp inside the side plate couter bore. This has to be fairly close so the shaft end is still inside the oil seal. I had to saw off about 2" to get it to this point.

 

[3RRL]

Not only did I have to get the length right, but I had to figure out how to attach the hydraulic motor to the shaft to drive the worm. I decided to make a 3/4" square drive pocket in the end of the shaft, like on a 3/4" drive ratchet wrench. I set the shaft up in the milling machine again this time inside a big "V" block held by my vise. Then started to drill out the corners of the pocket.



Here is the pocket all finished machined. It is .002" per side larger than 3/4" square for an easy fit. I had to be very careful because it was standing way up in the air and use a small endmill for this work. Notice the end of the shaft still has the lathe finish and also how the keyway was cut all the way through the shaft.

 

[3RRL]

I mentioned that keyway because Larry was kind enough to machine that at his home for me. He was kind enough to cut it all the way through so now I had to plug it up where the oil seal has to ride around it.
Here is a close up of the pocket work and the keyway slot.



Oops, in this photo the keyway slot has miraculously disappeared!! Fixed by magic...
Can you tell where it was? I'll bet Larry is relieved because he was fretting about this for a month now. If you look at the right side of the shaft you can see where the rest of the slot still is. The end and the diameter look pretty good now. Larry is going to owe me for life.

 

[3RRL]

I'm not done yet because I still had to modify the hydraulic motor shaft itself....another easy job.

Here is a photo of the motor Larry sent me. It is a European "Meta" brand and originally came with a Ø1" keyed shaft which I could not use.



I quickly took it apart and removed the drive shaft noting how all the gizmos went into it. It had "O" rings, bearings and a bunch of other stuff. Hope I remember what order they go to put it all back together again?

 

[3RRL]

I chucked up the shaft (which is harder than a wedding night peter) into the "V" block and set it up on the surface grinder. I had to plunge grind the hardened shaft to get the flats on it. Then rotated the shaft inside the "V" block and indicated each square side to get it perpendicular to the others and on center of the shaft.
This is starting the first flat.



This is it all finished and cut off to length. It is all surface ground and chamfered, ready to re-assemble the hydraulic motor. Grinding all these surfaces took a very long time. It is also .002" under 3/4" square for the same reason... ease of assembly. Total engagement of shaft to pocket is .800".

 

[3RRL]

Shown here are the completed worm shaft and hydraulic motor with it's modified end.



This is how they mate up.



What's left now? Well, I have to tack weld the collars to the plates so they don't come off during assembly. I will also add radii to the top and bottom plates so they are not sharp and Larry will not bust his knees on them. Then I will assemble the box with one end left out so I can inspect how everything fits and runs together ... maybe even take a video of it like that running. Then take it all apart again for final assembly with sealer on the side and bottom plates. Larry can get his own gasket for the top. Larry, get a thin paper gasket so you don't lose the pre-load for the thrust bearings! I'll include a couple shims for you.
For now, I'm going to take a break after all this hard work.
I'm very pleased as to how it's all turning out.

 

[tlbuser]

Ever heard the term "artistry in motion" ? Some people pay big bucks for that type of stuff and here, we're getting a freebie
Very impressive !

 

[3RRL]

Thanks TL,
It's nice that this thread has been of interest to you. BTW, in our trade we always "mark" our tools so they don't end up accidentally in someone else's box. Most of mine I've had for many, many years. Dating back to when I worked on the bench for others, so they are all marked. But yes, my underwear is marked too. ... just a habit I guess.