My backhoe bucket cam repairs.

[Lu47Dan]

Well, I am mostly over the cold I had and got back out to the shop yesterday.
I managed to get the BMBU milled down and the cylinder hole drilled in it. The pivot pin hole's repair did not have enough material in it to produce a clean hole so it needed built up again. So it was on to the other cam, I set it up in the mill, drill the cylinder hole, then move on to the pivot hole which went well, after drilling it to 1-1/8, I decided to move to the bucket mounting hole. That hole is 3-1/2" and 90° from the pivot hole. I made my count of turns and started the hole with one of my Atrax 1/2" end mills and soon realized the hole had been started at the wrong location. Boy, do I need a DRO for this mill. So I had to weld it shut and will start over on it today.
Once all the holes are in their correct location and I can get the math done I will know how long the 1-1/2" section of the pin needs to be.
I forgot to take any pictures of the work that was done yesterday, I will get some today.
Dan.

[Lu47Dan]

The cams are done and I have the measurements needed to make the pins. After finishing them I set then up on a piece of 1" threaded rod and set the spacing for the mounts on the bucket.
Once the spacing was set I could get the measurement for the length of the 1-1/2" diameter section of the pin. That measurement turned out to be 10-1/4", shoulder to shoulder. Next I checked the width of the end of the dipper where the bucket mounts and it turned out to have been worn back 3/4", so the bushing will have to have a 3/16" thick flange on them.
Once I had all my measurements for the main pin I started getting the lathe cleaned up and ready to start on the pin. I checked the bed for twist and did a minor adjustment. Turned a test bar and had taper to the cut.
After a bit of thought I have come to the conclusion that the tail stock is out of alignment, it is pointed to the rear way of the lathe. So today I have to adjust the tail stock so it is in line with the bore of the spindle and adjust the clamp that locks the tail stock in place.
After doing the tests I came up with a piece of steel slightly smaller then 1" and since I will have to machine in a grease groove in the bushings I decided to use it as a boring bar/internal grooving tool.
That took a little figuring but I got it made.
Dan

[cutter]

This seems to have turned into an pretty complicated affair.

[Lu47Dan]

Originally Posted by cutter

This seems to have turned into an pretty complicated affair.

Cutter, it has. But the complications have made it interesting.
After disassembling the base of the tail stock, cleaning all the mating surfaces, assembling it and adjusting it to dead on center. I went to put a center hole in the end of the bar, and discovered that my drill chuck was now off center. I re-adjusted the tailstock to be on center with the drill chuck.
I did a little more investigating and discovered that the live center is off by about one sixteenth of an inch. I guess it is time for a new live center. This time it won't be a cheap one.
Since I now knew what was going on I made a mark on the live center that gives me my orientation of the live center to the tailstock and the a mark that shows the offset of the tailstock itself.
That whole operation was worth it as the tailstock had been "glued" in place by many years of evaporated oil that formed varnish in the seams.
Once that mystery was solved I set up to turn the new main pivot pin from the a piece of shaft I got at the scrapyard. I had cut a piece of it last week, so it was ready to go.

1. Turning the Major OD.
2. Getting closer.
3. Turning the pin diameter.
4. The new temporary pin bushing.

The "temporary" pin bushings will have to be replaced later with a regular bushing when I do the bushings on the top joint of the dipper stick, I will have to build up the worn off ends of the joint where the bucket mounts and machine it back to the correct width but for now I will keep it greased and hope for the best.
I still need to drill and bore this one to size today, then make another one of them. It took an hour of machine time to get it to this point.
Dan.

[Lu47Dan]

I have one temporary bushing done and one to go, I blank for the second one cut and ready to start machining today.
The first operation yesterday was to make the final cuts on the OD. I measured the Bore on the dipper stick and came up with 2.000" So I made the OD 2.000" and will shrink the bushing to install it. Then it was on to machining the bore for the pin. Drilling out the excess material took longer then I thought it would and then grinding a bit for the new boring bar was an adventure of its own.
Once the drilling was done I set the boring bar up with my first try at grinding a bit for it. As soon as I did a test cut I knew the bit had to be reground. I reshaped the bit and it worked pretty well, a little touch-up and a little more clearance and it was making nice chips.
The pin was used a a gauge to fit the bore, checked with a pin gauge I had about 0.010" clearance between the pin and the bushing.
After the bore was done I chamfered the OD. of the bushing to let it start easier into the bore.
Then I set up to cut the bushing off, I set the parting tool up to leave a 0.250" wide flange on the bushing. I started to part the bushing oil the tool as I went and all went well, the bushing cut off very well.
The flange now needed faced off to 0.187" thick, the extra thickness was for left to allow me to face it to have a flat smooth surface for the cams to ride against.
Next came the machining in the groove for the grease groove, the groove allows the grease to flow around the pin with little resistance. I had to grind a bit for the boring bar, I made the bit about a 1/4" wide with a slight flat on the tip and an angle on each side. I set up the boring bar and set the distance from the end of the bore and made my test cut, no excessive noise or vibration from the bar. I cut the groove about 1/16" deep.
Now it was on to drill the hole to connect the groove to the grease zerk.

1. Cut off.
2. Overall.
3. Grease groove.

The surface finish in the photo#3 looks rough but it is an optical illusion.
Dan.

[Lu47Dan]

These photos are of the drilling of the grease hole and adding an indexing flat to the flange. The flat will allow me to align the hole with the grease fitting.

1. Hole located and drilled.
2. Countersunk.
3. Indexing flat milled.

Dan.

[Lu47Dan]

The last thing I did last evening was to finish cleaning the bore in the dipper stick, it had a few minor dings from having to use a chisel the remove the first bushing. I used my HF pencil grinder, a flap wheel and a few stones to clean up the dings and to polish the bore up.

1. HF Pencil Grinder.
2. Bore on dipper stick.
3. Blank for second bushing.

I have used the HF pencil grinder to do all the internal clean up and grinding that needed done on this project and other then having a slight vibration it has performed very well, it was worth the $40 I spent on it not to have to listen to the air powered die grinder whine.
I cleaned up the bore while the blank for the second bushing was being cut. The left over piece from the bushings will be used on another project. so there will not be a lot of waste.
Dan.

[Lu47Dan]

The bushings are installed, the pins final shoulder to shoulder width is set and the measurements for the pin that connects the cylinder have been determined.

1. Boring the final bushing
2. Final bushing installed.
3. The first bushing installed.
4. Pin with cam to bushing clearance set.
5. The other end of the pin.

I had a few troubles with boring the last bushing, it has a hard spot in it which caused some chatter and the OD turned out to be a little smaller then I wanted but it will work for now. The undersize we cured by applying a liberal coating of sleeve retainer to it before I assembled it. To remove the chatter marks I would have to build a arbor for the TP grinder to do internal grinding. I decided that it would not be worth it right now.
After I finished the lathe operations on the bushing I drilled the grease hole and milled the flat on it to locate the hole, I applied the sleeve retaining compound and pressed it into the bore. Went and retrieved the other bush from the freezer and installed it. Both grease holes had fairly good alignment from the start, but the final alignment was done with a tapered punch.
The pin was then installed into the bore and it spins freely, the pin was then removed and Dykem was painted on the "A" end. Then the pin was installed again and the end clearance (total) was set to the "B" side of the dipper stick. Once the clearance was set I scribed a line on the "A" end and removed the pin. The pin was then set up in the lathe and the cam pin was machined back to the scribed line and to the proper diameter.
The pin was installed so I could install the cam and the arms so I could get the final measurement for the pin that will attach the hydraulic cylinder to the bucket.
That pin turns out to be 1-1/4" in diameter and 11" long, with 2" long 1" pins on each end.
So today I have one pin to make, four holes to locate and drill, and four retaining rings to make and install. I might actually get to dig with it before the days end.
Dan.

[Lu47Dan]

Cams installed.

[Lu47Dan]

All that is left to do is attach the bucket to the dipper stick.
I made the pin that attaches the bucket cylinder to the cam from a piece of steel that I had setting around for many years it started out as a shaft from an old grain binder, it took less time to set up and turn out that shaft then I thought it would.
The retaining rings were going to be drilled for through bolts but time was getting to be a factor yesterday, and I decided to weld the end of the pins to the rings instead.
The retaining rings where made from 2" CRS, I turned it down to 1.875" to remove the rust, the ID of two of them was 1" and the the other two were 1-1/8". I parted them off a little long and after they were all cut, faced off the excess material. They were clamped on the cams and welded in place.
Once all the welding was done it was time to start the tractor and attach the bucket. I had been having trouble starting the tractor for a while and yesterday was no exception. I had bought a carb kit when I bought the new front tire, I had planned to get the ditch dug and then rebuild the carburetor before wood cutting season started. The tractor started and ran long enough for me to get the bucket cylinder retracted all the way and then quit and would not re-start.
Now it was time to rebuild the carburetor, I pulled the carburetor off the tractor and took it apart, I found that the float pin had fallen out of the holes in the stand. So since I had it off the tractor I decided to run it through the carb dip, and give it a good cleaning. Cleaning and rebuilding the carburetor took about 4 hours.
Then the adventure of installing it on the tractor started. With the loader frame on the tractor you have to reach over the frame to work on the carburetor, making it tough to get things lined up. One of the things you have to do is to remove a pin from the governor linkage, when I went to remove the pin I dropped it. Of course it could not stay where I could get a magnet on it to retrieve it, it went to the bottom of the governor housing. that entailed removing the alternator the alternator mount and the plate the seals the governor housing then it was a simple matter to fish out the pin with a magnetic pick up. But before going after the pin I finished installing the carburetor. After retrieving the pin and installing it I installed all the remaining loose parts.
It was now time to try starting the tractor, I turned on the ignition switch and hit the starter button and bingo it started but died, I thought "Now what?". Then I remember I had turned the idle speed screw all the way out. I turned it in to the correct setting and tried it again this time it idled just fine.
Now it was time to stop for the night and pick up my tools.
Dan.