Tractor loader rebuild

[Pete O]

Thanks for the encouraging comments. The problem solving is what makes the process interesting I think, unfortunately it also means that I tend to work pretty slowly. I'd hate to be paying me by the hour. Plenty of satisfaction in nutting things out though.

[Pete O]

I actually made a start on the line boring today, might even have got the front bores finished if we hadn't had a power failure. A few more photos of the setup:
I made up some plates to mount the flange-mount bearing housings, there's enough slop in the bolt holes for some aligning once they're tacked down to the bench
   
the bearing carrier plates were hung from the shaft while I got it aligned where I wanted it, then a few pieces of scrap offcuts used to suspend them in position. The feed rod slides through the gap underneath
   
To explain what may or may not be obvious, the shaft is free to slide back and forth through the four flange-mount bearings, which allows for the feed. The one pillow-block bearing is fixed to the shaft with grub screws, one of which is located in a hole in the shaft to provide a positive position.
The pillow block bearing is moved by a long rod (cobbled together from offcuts), the other end of which is in the lathe toolpost
   
so the lathe provides both rotation and feed.
I had to add some more bracing from the front of the loader arms to the bench, the bench itself is not really rigid enough for the task- the top is only 5mm thick and there's no diagonal bracing in the frame. I bored the one nearest to the lathe first, it had much less twist than the other so there were only a couple of passes with an interrupted cut, once it was cutting continuously it was nice and smooth and I got a good finish in the bore. The other end has a fair bit of misalignment so I've made several passes with an interrupted cut and it was setting up a fair bit of wobble in the bench. I might add some temporary bracing to the bench frame if I can find suitable scrap lengths.
I took a video of the contraption in action but I don't think I can post it. a photo will have to do.
   

[Highpower]

(02-01-2020, 07:15 AM)Pete O Wrote: To explain what may or may not be obvious, the shaft is free to slide back and forth through the four flange-mount bearings, which allows for the feed. The one pillow-block bearing is fixed to the shaft with grub screws, one of which is located in a hole in the shaft to provide a positive position.
The pillow block bearing is moved by a long rod (cobbled together from offcuts), the other end of which is in the lathe toolpost so the lathe provides both rotation and feed.

That is brilliant Pete.

Brian Block recently did a video on line-boring a John Deer front axle using a similar setup with the bearing block for support on the far end of his boring bar. His biggest advantage though is having a horizontal boring mill to supply the rotation and feed. Cheater....

[f350ca]

Thats brilliant Pete !
Couldn't vision how you were going to get the feed from the lathe, thats ingenious.

[Dr Stan]

I'll probably PO some people, but that's OK.  Pete what you have demonstrated is the big difference between manual all around machinists and button pushers (CNC).  Your skill set goes way beyond what CNC machinists can deliver.  Fantastic work especially the problem solving.

[Pete O]

Very kind remarks, thankyou. I guess the fact that I have not really had exposure to the 'normal' ways of doing this stuff means that I have to come up with my own solutions, so they are always somewhat 'outside the box'. There are probably plenty of better ways to go about this but I don't know them. It sure is nice when a plan works.

[EdK]

(02-01-2020, 09:30 PM)Dr Stan Wrote: I'll probably PO some people

Why would you say that? Especially on this forum. 

Ed

[Dr Stan]

(02-02-2020, 12:07 AM)EdK Wrote:

(02-01-2020, 09:30 PM)Dr Stan Wrote: I'll probably PO some people

Why would you say that? Especially on this forum. 

Ed

Members here are much more civilized than a certain other site that is owned and operated by a control freak with a very thin skin.

[Pete O]

G'day fellas, sorry I haven't been around much over the past month or so, haven't been in the shed much either for that matter. 2020 has not been a good year for us so far. I did finally get the line-boring part of this job finished though. A few photos of the rest of the process...
The end that I had welded back onto the right-hand loader arm was quite a bit out of alignment by the time I had welded all the fish plates on. That made for an interrupted cut for a fair depth before I got the bore round, and the cutting forces in the line-boring process were setting up a lot of wobble in the bench. I attached a temporary brace to the legs of the bench to stiffen it up, part of my tractor splitting stands tacked on as a diagonal member..
   

That helped a lot but there was still some movement in the job so I added some more scrap metal braces to the bearing carriers...
   

and that made the setup rigid enough to get the bores done and get a good finish. I had to take the bores out bigger than planned because of the misalignment, the worst of them came out to 1.75" by the time it was round and in line, so I matched them all to that size.

The next challenge was facing the ends of the barrels at 90 degrees to the bore. The proper line-boring setups have a tool for this where the cutter is mounted to a right-angled arrangement on the bar and feeds out like a lathe tool. A bit complex for me. I puzzled over this for a while and came up with the idea of using the surface grinder to put a straight, long cutting edge on the side of a piece of HSS to sweep the face. I put a bit of top rake and a bit of side clearance on the cutter with a flat on the top for the grub screw..
   

Mounted it in the boring bar..
   

and promptly snapped it off in the first cut.
   

I had more success with the second trial but forgot to take photos. Essentially a slightly shorter version of the same tool form, but I cut the face in several steps of around 0.150" each, blending the cut as I went. Came up ok, fit for purpose.
   

The outer diameter of each barrel has been hardened by the welding, I got out so far with the cutter but then could not cut the stuff around the perimeter. I decided to bevel the outer part away with an angle grinder once I have the job dismounted from the bench.

This setup all worked very well, I guess the next time I have a line-boring job to do it'll be quicker cos I already have all the stuff made for the task.

[Pete O]

Looking at the dates on these posts it seems my visits here are about a month apart at the moment. Can't be good. I hope you guys are all keeping well, it's a strange world we're living in at present.
Anyway I got some time to start installing the bushes in the bores on the loader project.
I made a puller that consists of a 1' length of 1" 20tpi UNEF thread on a piece of unknownium bar, and a nut turned from 2" 4140 bar stock with a full 2" of thread and a couple of flats. The threads were single-pointed with a HSS tool. The end of the male part was cross-drilled to take a piece of bar to apply the rotation. This pic is after some use- the 16mm bar was straight when I started.
   
The bushes (4140, OD of each is matched to it's bore plus .0025" interference) have been sitting in the freezer since I hardened them a couple of weeks ago- heated to cherry red in the furnace and quenched in clean oil, they all are hard enough to resist filing.
The insertion of the first candidate was commenced after grinding the perimeter of both faces of the barrel, so the bore was warm and the bush cold. Things started off well enough but predictably got more difficult to turn the screw as the bush went in. It got to the point where I could not turn the handle any more, with the bush only half-way in. Obviously by this time any advantage from the temp difference was history.
   
The puller threads were holding up ok at this stage but I needed a way of applying more torque to the screw. I contemplated setting it up behind the lathe again and using the PTO that I made for the line-boring, but I could see the possibility of damaging the lathe gearbox. Eventually I came up with the crazy idea of using the tractor to do the rotating. I cobbled together a gadget that attached to the tractor wheel hub with a protruding drive shaft made from an offcut of PTO driveshaft, i.e. a telescopic triangular section. I think Ben Hur's chariot had something similar.
   
Maneouvered the tractor alongside the loader frame and jacked up both back wheels, slid the drive shaft over the puller. Low range, 1st gear, diff lock engaged, slow idle. Probably making something like 2 RPM.
   
Amazingly the threads held up. The cast-iron gear I was using as a spacer (first thing I found with the right bore size) didn't hold up so well and had to be swapped out halfway through the task but the bush gradually made it's way into the bore. There was a lot of shuddering and complaining as it got close to home and I lost my nerve when it got to about .030 from the finish line- I think I was pulling some concavity into the disc on the outer end so it had made contact there. I'll call that good for this one, have to make a proper cupped spacer before attempting the others so I can get them all the way home.
   
   
   
I used reverse gear to relieve the pressure from the puller but all that achieved was destroying the end of the slding shaft. Some modification required there also.
   

So the 65 horsepower bush insertion tool seems to be a proven concept. A little more development required before I tackle the rest of the bushes.