I got my drill press in place to hopefully use a boring head to repair the upper swing pivot. Welding up the bore turned out pretty good and I ground most of it with a plug wheel on an angle grinder. It was slow going. The skid steer worked good for getting it in place and I'm just glad it was the right height I could even consider the drill press. I thought about using a hole saw and then a flap wheel to get final size but some members on the Welding Web suggested the boring head could work in a drill press if I took slow shallow cuts. I bolted some square tubing with leveling bolts to the base of the drill press and then made a simple wood frame to set it on. I had some 2' square indoor/outdoor carpet samples a friend gave me and put 4 of them down on the gravel floor under the wood frame. I figured they'd let the wood frame slide a little to align the drill press. Would have teen terrible on just the gravel. I have it pretty close but still needs a little fine tuning. I have a digital torpedo level to help line things up. It doesn't have to be perfect but has to be as close as possible. I'll try to get some pics. up in the near future. I sure hope it works. I can't afford line boring right now. Thankfully the bottom pivot is fine and it's only 1 bore to repair. Wish me luck.
You may want to try a long (beefy if possible to eliminate droop cause by gravity) rod chucked in the drill press to sweep/Center the lower pivot with a dial indicator. You can rotate it to find center and also run it up and down to make sure they are on the same plane.
I might be able to use the drill press table with a dial indicator. It won't necessarily have to be perfectly square with the spindle for lining up the center of the bore.
I'm not sure what a boring head is. Does it center itself in a hole and the drill press runs a flexible coupling?
This is a micrometer adjustable boring head. There are 3 different holes to put different length's of boring bars in. I'm really hoping it works as line boring is too expensive for me right now. Magnum 2" Adjustable Boring Head (kmstools.com)
I posted this on another forum. It may help someone on here. I'll try to get a bunch of pics. up in the next day or 2. Well I can finally report on my progress. Hoping to get some pics. up tomorrow. There is a definite learning curve but seems 3 times is the charm. First time I ground too much as part of the bore near the bottom was angled out from the bore and had about 3/32" gap. Preheated again and figured I'd weld up about 1/4 of the bore so I can have a nice straight hole. Nope, the weld is definitely a little harder than the base metal and caused the boring bar to cut too much opposite the 1/4 that had the weld applied. Ok, preheat and weld up the bore again. Seemed like everything was lined up good but getting near the correct size noticed that it was cutting too much off in part of the bore. It might have worked but bothered me so figured I'd start from scratch again. Welded the hole back up realizing that the boring bar works much better cutting the same material (weld). The US brazed carbide boring bar worked better but still chips way too easily. I was running out of boring bars and sick of trying to regrind them. I bought a small bench grinder and a silicon carbide wheel on sale. I was thinking I need to get some HSS blank to make a boring bar or get a carbide insert boring bar. As luck would have it a guy came to ride my track on Sat. that was a machinist and did some small jobs at home. He suggested I weld the drill press table to the backhoe frame to make it even more rigid but looking at it I figured I could put a block in-between the table and the swing pivot I was working on and bolt them together. I put a 4" block of wood in and turned the table up tight on the block. Then I bolted from the table to a piece of heavier rectangular tube I had. This did make it as rigid as possible. He said he had some lathe tools he could bring by on Sunday. They were all square but I read somewhere that 3/8" square will fit in a 1/2" hole if you grind the corners off a little. I tried to use a new 1/4" bit with a piece of welding rod for a spacer but didn't work. I tried a 3/8" brazed carbide with a much bigger carbide but it didn't work either. He had a broken piece of 3/8" square HSS so I ground probably the crudest cutting tool ever made. I made the point at the back so it was behind center when turning. Much to my delight it worked! And it wasn't chipping like the carbide. Not as nice a finish but it was cutting if I took pretty small bites. I went out today to hopefully finish. I got the bore close but the very top was a little oversize so I preheated again and put 2 beads around the top of the bore. I ground most of it with the plug wheel and finished with the HSS boring bar. The morse taper held for the most part. It came loose a couple times near the end but part way through the cutter jammed (the belts slipped) and it didn't come loose. I did a final finishing with a flap wheel. For some reason my caliper was reading different than before even when I zeroed it but the bore seemed about the right size for the hardened bushing. I heated my newly made bore to 400 or so deg's., put the bushing on an ice pack I had in my lunch pail and then applied Loctite 660 to the bushing. I very slightly rounded the top edge of the bore to help guide the bushing in. I put the bushing on top and a piece of plate on top of the bushing. I was going to use a C clamp to put the bushing in but decided I'd try to pound it in. It pounded in pretty good with a med. size ball pein hammer till about the last 1/4" or 5/16". Then I panicked a bit thinking if it doesn't go, I'll never get it back out. I grabbed my long handle sledge hammer, I think only 6lb. but after about 5 good hits the bushing was in! I am so darn glad this swing mount didn't get the best of me. The pin is slightly snug at the bottom where the bushing is tighter in the bore but is easily tapped in/out with a hammer. I can live with that. Broke a couple drill bits trying to drill through the weld for the grease hole but got er done. Might need to tap for a larger grease fitting but that's minor. If you ever have to try this with a drill press or even a mag drill, don't bother with brazed carbide and just use HSS. It will save you tons of frustration. My back is killing me but I'm a very happy camper!
Well after knocking the hoe off the hyd. jack I was lucky the skid steer bucket tilt was able to lift the hoe boom by the swing post. Lift cylinders wouldn't lift it but after it was snug, the bucket cylinders lifted it. I got the hoe mounted back on the Cat. Had to fiddle around a bit to get the bottom pin lined up because it has big washers that go on either side swing pivot on the frame. Had to pull the Cat ahead a bit with the tractor and then push it back to line the pin up but got it done. On the top pivot I repaired, the pin was a little tight in the bottom of the hardened bushing but I cleaned it up with a flap wheel so it slid right in. I was worried it might cause problems being so tight it had to be tapped in place. I was even able to clean up the threads and put the small size grease fitting back in. I thought I might have to go to a larger thread size zerk because I had to drill through the weld in the grease fitting hole. I was delighted I just had to take a come-a-long to pull the top of the swing post back and it lined right up with my repaired bushing. Was a little worried there too that it might be at a bit of angle and the pin wouldn't go in easy but it went perfect. Thrilled I was able to fix it myself. I'm having some good luck lately. 2 of the set screws on the boring head vibrated out onto the ground and I thought I'd never find them. I looked with a bright flashlight a few times and couldn't see them. Today I found 1 while I was moving the carpet pieces away from the Cat and for some reason after I had moved the 4 pieces of carpet I saw the other one. I was shocked I found both them on the gravel floor. Must have been a good sign. What wasn't so good was when I knocked the hoe off the jack, a bunch of oil came shooting out from a couple hoses. It blew the threaded plastic caps I had on them right out. Oh well, ***** happens. Anyway I'm glad it went back together without too much trouble and didn't leak when I started the Cat up. I'm going to pressure wash it before I put the floor boards and side covers on. It's amazing how much dirt collects on top of the trans. and bevel gear cases. I'll need some help putting the belly pan on though. Kneeling down and especially crawling under the Cat to get the 2 back bolts on the bottom in I have extreme trouble with. When I took the 2 bolts out I almost got stuck under the Cat because my right arm doesn't pivot like it should. I have bursitis and getting a cortisone shot on Tuesday.
Here's some pics. of my repaired swing pivot. The tubing bolted to the drill press table held everything as rigid as possible. I had to weld it up 3 times to get it right but so glad I was able to fix it. My homemade HSS boring bar was night and day better than the brazed carbide boring bars I got. The brazed left a nicer finish but they kept chipping which was a real PIA. Kind of hard to tell but it's centered pretty close. I cleaned it up some with a flap wheel. So glad I didn't have to call someone out to line bore it. Hopefully I'll never have to worry about it again.
Thanks for the advice