Weldable Backhoe Pin Bushings

[gdutson]

Hey guys,

I am converting an older Kubota cleanup bucket to fit my New Holland BH. Because the pin mount width and diameter is different I am starting over with new 1/2" thick flanges.

The New Holland pin diameter is 1.25". Does anyone know where I can source weldable bushings that I can weld into my new flanges?

Thanks,

Greg

 

[GPintheMitten]

Try DOM tube (drawn over mandrel). You can get pretty much whatever thickness and inside diameter you want. Probably want to go a about 10 thousands over the pin size. Still may have to ream them a little to be sure they are smooth inside but there is no internal weld seam.

Here's where I plan on getting mine for a loader build.

http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube&LimAcc=$LimAcc

 

[gdutson]

Try DOM tube (drawn over mandrel). You can get pretty much whatever thickness and inside diameter you want. Probably want to go a about 10 thousands over the pin size. Still may have to ream them a little to be sure they are smooth inside but there is no internal weld seam.

Here's where I plan on getting mine for a loader build.

http://www.metalsdepot.com/products/hrsteel2.phtml?page=rndtube&LimAcc=$LimAcc

Hmmm. Good call...I can try and source that locally. I guess I will take my pins with me and check the fit. 10 thousands isn't much. Is that enough to keep grease in there?

I wonder what the OEM clearances are? Anybody know?

~G

 

[GE222]

Do you need to have bushings? Most buckets don't use them, as the pin doesn't rotate in the bucket ears. I had the same issue, except that I bought a used 9" bucket for trenching electrical lines, and I did the same thing you want to do.

I torched off the old ears, then welded a new 1/2" plate to the back of the bucket for a nice mounting surface.

Then, "Here is where I am fortunate", I drew up the new ear design in Auto CAD, gave the file to a co-worker, and it was loaded into a water saw - yes it cuts with a high pressure jet. I had 3-pair of ears cut, 2-pair were for future use.

I then cut 3/16" disks to go on the inside of the ears for spacers - I was matching the profile of my existing bucket, allowing the dipperstick to be offset from the inside of the bucket ear. The disks holes were milled to match the holes in the ears. The finished bucket is pretty tight when mounted.

I also made a jig to match the dipperstick profile to keep the ears parallel when welding.

The pins I also made new which will stay with the bucket.

I will upload up some pics this weekend of the finished bucket this weekend.


As an option for you, if you really want to go the bushing route, in another application for bushings, I used sprocket hubs. These are the kind that get welded to a sprocket, but are bored to closely match a shaft size. A pocket could be milled to fit the bucket ear, then weld the bushing on both sides. One drawback of using them is having a keyway cut in them. In my application I rotated the keyway in the direction that wouldn't receive any major force on it. After many years of use, they are as tight as ever.

 

[GPintheMitten]

Hmmm. Good call...I can try and source that locally. I guess I will take my pins with me and check the fit. 10 thousands isn't much. Is that enough to keep grease in there?

I wonder what the OEM clearances are? Anybody know?

~G

Well, you got me second guessing the clearance. Maybe it should be a bit more. I'm trying to find where I read that. As you can see I'm learning too.
I'm confident the DOM tube will be a good bushing but maybe not so confident about the clearances. Try to get other opinions.

 

[Sam Mac]

You could try something like this from McMaster Carr

McMaster-Carr

or give them a call and see what else they have that would work.

 

[true temper]

McMaster bushings won't work they are real hard, can't get a good weld. DOM tubing is what you want. .010 clearance might not be enough, when you weld them on the bushing shrinks some and you can't get your pin in. Plus when you weld them in they will draw some, make sure you have them lined up best you can.

 

[gdutson]

McMaster bushings won't work they are real hard, can't get a good weld. DOM tubing is what you want. .010 clearance might not be enough, when you weld them on the bushing shrinks some and you can't get your pin in. Plus when you weld them in they will draw some, make sure you have them lined up best you can.

The DOM tubing sounds like the way to go. It is softer metal than the pins which is appropriate. The pins mic out at 1.250". I have found some DOM tubing with 1.260" ID so I might go that route and figure on honing them out after I weld them into the brackets.

My thought was to put the pins into the bushings and then spot weld the bushings to the brackets, remove the pins and then do the final welding with the pins removed. I am a little concerned though hearing that the bushings will shrink during the weld.

 

[charlz]

If it looks like it is gonna be too close look for a local guy with a lathe to take a few thousands out of the bushing/DOM. I did this for one of my projects.

 

[jmc]

It is softer metal than the pins which is appropriate.

I would make sure that if it is going to wear, that the pin wears instead of the bushings.

As far as maintaining clearance during welding, one thing that worked for me was to wrap the pin in the thickest shim stock that will fit in the prewelded clearance, then weld the bushings while the pin/shim stock is in place. That way, after you hammer the pin out, you have clearance where the shim stock used to be.

 

[Iplayfarmer]

I would make sure that if it is going to wear, that the pin wears instead of the bushings.

The other option is to line the bushing with another bronze or softer metal bushing that is replaceable. They are easy to put in if you soak them in some dry ice and alcohol for a while. They'll slip right in and then expand to a pressed in fit.

I know McMaster.com has bushing stock. I'm sure other places have it too.

 

[gdutson]

After re-reading the earlier response by GE22 (his 2nd sentence) and watching the movement of the bucket curl, it donned on me that these pins don't rotate in the bucket flanges. The only parts that rotate around the pins are the bucket curl ram-to-pin connection and the dipper stick-to-pin connection The pins themselves do not rotate in the bucket flange.

This would indicate that the bucket flanges don't need bushings. The flanges just need to be reinforced in the area where the pins slide through and the hole diameter in the flanges just needs to be snug enough to not allow free play between the pins and the flanges.

Much simpler than I thought...

 

[dfkrug]

The DOM tubing sounds like the way to go. It is softer metal than the pins which is appropriate. The pins mic out at 1.250". I have found some DOM tubing with 1.260" ID so I might go that route and figure on honing them out after I weld them into the brackets.

My thought was to put the pins into the bushings and then spot weld the bushings to the brackets, remove the pins and then do the final welding with the pins removed. I am a little concerned though hearing that the bushings will shrink during the weld.

I have done lots of these, and I am much better at it than the first ones
I did. Back then, I used a long hand reamer to clean up the pin/bushing
alignment.

I always use DOM, usually 1.000" ID, paired up with 25mm rod stock for
pins. That gives me a .015" clearance, which works great. Your .010"
clearance is a bit tight, but it should work if you are very accurate in your
welding. I prefer softer pins, but many off-the-shelf pins are hard....like
Kubota's. If you use mild steel pins, you can knock a couple of thousanths
off them in a drill press with sand paper, if you do not have a lathe.

The way I do my welding is to use a temporary pin with very tight clearance
to hold everything in place. I preheat the steel that the bushings weld into,
then do the complete weld. The bushing will shrink and clamp onto the
pin, but it will expand when it cools. There is no way to get it out until it
cools. Works great, and no more reaming.

 

[GE222]

Gdutson,

Yes that is correct. In most cases, the pin does not rotate in the bucket ears.

Often times the pin has a plate on the end with a bolt hole for keeping it in place, (bolting it to the bucket ear) instead of a cap at one end and a keeper pin on the other.

I will be close to my bucket this weekend so I will get a couple of pics for you.

I made up a jig to hold my ears in place for welding. I also kept the pins in the holes as well. My pins had a very close fit. So close that the surface rust from me handling them made them tight. A very light touch with emery cloth and oil made them turn freely again.

I was very careful to tack the ears all over, and periodically rotating the pins to verify alignment. Then I welded longer beads, stopping again to check the alignment. There were times when the pins got tight. I would add a partial bead on one side of the ear or the other to straighten them back again.

I used a stick welder, as I have been welding with one for over 25 years. I wasn't as comfortable with my wire welder yet.

Did they need to be so tight? I'm sure over time they will loosen.

You also might this curious. On my older New Holland skid steer, the bucket has a quick release mount. The 4 pins for the mount are in nylon or teflon bushings, and are grease less. After 2000+ hours, the bushings have almost no free play.

 

[GE222]

Pictures of the almost finished bucket.
All that remains is to drill and tap the ear for the pin retainer bolt.

 

[gdutson]

Pictures of the almost finished bucket.
All that remains is to drill and tap the ear for the pin retainer bolt.

GE222...looks good. Nice job.

Even though it eventually wears off, paint always gives things that finishing touch too.

I may try and take some pictures of mine for the benefit of the group as I put it back together.

~Greg

 

[GE222]

I will curious as to how much trouble I have with material sticking in the bucket, as it is only 9" wide. I bought it for shallow trenching of electrical lines.

 

[spo307]

Pictures of the almost finished bucket.
All that remains is to drill and tap the ear for the pin retainer bolt.View attachment 151708

View attachment 151709

View attachment 151710

what size steel did you use on the curved ( bottom ) part of the bucket, and how did you get it to form the radius to weld it?

 

[schmism]

an adjustable reamer will make the 5 thou clearance you need in no time.

 

[GE222]

spo307,

My bucket was originally a Bobcat brand mini excavator bucket. I adapted it to fit my Gehl mini excavator. The pins and ear spacing didn't match.