Homemade drill drive boring bars

[steve loving]

Thank's Tom it looks like you had a busy afternoon working on a jd hoe to darn hot . I ran the overhead on a cummins and half the engine in the cab half out. I cant get in there like i used too.

 

[Old Magnet]

Hi Steve,
Thanks for the response.
Those upper bushings are 1-1/4 in. wide. The lower bosses are 1-1/8 in thick so I'd be looking for the 1-1/8 in width, same 2 in. I.D.

If I have to go special sizes I was considering going to flanged drill bushings. Also the meat is a little thin in this area so was considering some weld build up to offset the bushing hole loss.

Also made my own boring bar from nitride coated shaft, 1-1/2 in dia. with broached holes for 1/2 in. tool bits. Drive will be my Milwaukee mag base drill through a couple of Sunnen 5/8 in. threaded universal joints.

Pretty amazing what you guys tackle for line boring.

 

[steve loving]

530

Hi Steve,
Thanks for the response.
Those upper bushings are 1-1/4 in. wide. The lower bosses are 1-1/8 in thick so I'd be looking for the 1-1/8 in width, same 2 in. I.D.

If I have to go special sizes I was considering going to flanged drill bushings. Also the meat is a little thin in this area so was considering some weld build up to offset the bushing hole loss.

Also made my own boring bar from nitride coated shaft, 1-1/2 in dia. with broached holes for 1/2 in. tool bits. Drive will be my Milwaukee mag base drill through a couple of Sunnen 5/8 in. threaded universal joints.

Pretty amazing what you guys tackle for line boring.

Old Magnet online look at ball bushing warehouse ive used them and i think Tom V has mentioned them also they have bushings listed by size. The hardend ground bushings are hard to machine but grind easy. Do you have enough meat to install the top bushing in the bottom after taking 1/8 off the length. You better double check me but the part number i posted was the case upper bushing. It didnt show the bottom having a bushing am i right on that?

 

[Old Magnet]

Yes, I have been to that site and checked bushings. Correct, the lower swing tower fork, so to speak, is not normally bushed, just the upper pivot has bushing. It's the lower end that I need to either build up and bore back to size or bush. This bottom pivot is a ball bushing affair but if the pivot bolt was not kept tight it wallows out the holes. Didn't help that this bolt had a shoulder that prevented adequate tightening unless ya got creative with shims.
Have you installed flanged bushings in this type application.....maybe it's overkill but I'm concerned that tightening of the pivot bolt would apply side pressure to bushings.

 

[RayF]

I take it that the swing tower is cast iron? If so be wary about welding it as it will go glass hard nd you won't machine it

 

[steve loving]

Old Magnet can you post some pictures of it.

 

[Old Magnet]

Good point, thanks. Pretty sure it is cast steel but will do the spark test to be sure. They do get welded on when replacing worn out boom shafts and bushings with the external welded boss and bushing kits.

 

[Old Magnet]

Old Magnet can you post some pictures of it.

Yes, I can do that, will try and get some today.

 

[Old Magnet]

Ok, here's some pictures....
The original pivot bolt was not long enough and caused the ridge.
The new pivot bolt is actually from a #33 hoe. Fits fine.

The delema is if I straight bush the tightening forces of the pivot bolt are applied to the bushing so I'm thinking flanged bushing such as a slip fit liner drill bushing or.......what's your take? Thanks

 

[RayF]

I reckon a straight bushing would be ok. A Cat bearing with the right ID should work ok. You have enough meat there to bore it

 

[steve loving]

Old magnet i wouldnt weld on that. From what i am seeing the threaded pin is just for keeping the pin from turning in the unbushed casting. Like ray said i would bore and bush the bottom. I dont think the tightening would hurt anything. Is the top pin the same diameter as the bottom if it is you could use top bushings in the bottom.

 

[Old Magnet]

OK, Thanks guys.....will proceed with a straight bore.
Yes, the upper bushings are same I.D. with 1/4 in. wall, just wider at 1-1/4 in. vs the 1-1/8 in. thickness I have to work with on the bottom.

When it's all assembled the space above and below the ball bushing is taken up by the ball bushing receiver, its seat and hardened spacer so that the hole thing is rigid when tightened and rotation is handled by the bushing. All seems good in theory but very difficult to keep tight with not much head on the pivot bolt due to the swing tower cylinder rods running very close. I'm still trying to figure out a better way to anchor it.

 

[OldandWorn]

Would there ever be a chance that the pin could rotate? If that is a problem I would drill and tap a hole in the bottom and install a 1/4" thick plate or whatever against the flat on the pin.

 

[Old Magnet]

Yes, that's one of the options being considered.....or just welding a couple of key stock tabs up against the flats. The tower is cast steel so it would accept the welds. Or a tab welded to the pin flat and bolted to the tower similar to what you describe.

No, I don't see any need for the pivot bolt to rotate, in fact it's better if it doesn't.
Thanks for the suggestion.

 

[steve loving]

Yes, that's one of the options being considered.....or just welding a couple of key stock tabs up against the flats. The tower is cast steel so it would accept the welds. Or a tab welded to the pin flat and bolted to the tower similar to what you describe.

No, I don't see any need for the pivot bolt to rotate, in fact it's better if it doesn't.
Thanks for the suggestion.

How about the pins with a flange like cat uses that takes a 1/2 13 bolt to lock the pin. what is the total length from outside to outside of the bottom ears

 

[Old Magnet]

Not quite sure what you mean by bottom ears.....If you mean from flat to flat on the bottom flange it's just a hair over two inches. The O.D. round diameter is about 2-1/2 in.

I am thinking of making a 1/4 in. plate flange that the I.D. would fit over the 2-1/2 in. diameter and neck down (sort of banjo shape) with a single anchor bolt. I'd weld this (one side) to the pin. I've seen this type used on Cat and other machines....maybe that's what your referring to???

 

[RayF]

If the pin didn't rotate before it won't do it just because its in bearings. And if it did,as the bearings are hardened it won't matter. They will get some grease from the centre bearing. Its a similar thing to what we do with almost all our mining buckets here.We put flanged bearings in the bucket,flanged bearings in the arm.A cap over the end of the bucket bores with a O ring to seal it up. The pin has no tail or lock and its free to turn in the arm or the bucket. No more face wear and everything lasts 4 times as long.

 

[Old Magnet]

I don't think that is quite how it was designed to work....the pin bolt when tightened clamps the whole thing together so that the rotation and wear is on the outside of the ball bushing and within its race. If the pin floats then wear will be between the pin and the I.D. of the ball bushing.....granted movement and rotation that wiped out the bores in the first place would not be an issue with the bushings but I don't think this pin is designed as a wear surface.

Would it be clearer if I add some pictures of the bearing receiver that attaches the tower to the tractor mount?

 

[steve loving]

Old Magnet if i am understanding this your saying the ball bushing inside the swingtower is shimed top or top and bottom with hardend washers. Tightly pinched by the threaded pin you lock up the pin and the ball leaving the race to turn free. I dont think it would hurt to pinch with hardend bushings in there as long as there flush top and bottom with the casting. Ray are you reffering to the oring to the od of the flanges which are radiused i have seen buckets like that and its a good set up also and that would work.

 

[Old Magnet]

Getting closer....The ball bushing, inside that split race which in turn is pressed and held with a retaining ring in the receiver which is welded (not yet) in the hoe tractor mount. The ball bushing seats on a flange/ridge at the bottom of the receiver and a hardened spacer/shim at the top. When all is in place the nut is tightened and the assembly is now rigid with rotation motion transferred to the O.D. of the ball bushing (now fixed) and it's race. The pin bolt just functions to hold things in alignment and hold the assembly in compression.....hell of a thing to explain LOL

As far as the clamping force to the bushings they would just become an extension of the clamped assembly but now totally relying on the press fit of the bushings unless a flange/washer arrangement is used to control vertical position. These would have to have an OD that reached beyond the bushing OD to duplicate the original design. I guess it's up to me to decide if the press fit friction is adequate or to come up with flange arrangement that clamps beyond the bushing diameter. This can work well by combining a flange/anchor bolt for the bottom and I can come up with a large washer affair for the top. Also makes it possible to hold the pin bolt while tightening....something that was near impossible to do originally.

Appreciate your interest and input from both you and RayF.