Help bending Bucket pin straight

[ThomasH]

If it were my backhoe, I would 1) read about steel properties to determine what I thought I need; 2) cut the pin and remove it; 3) measure the old pin to determine the exact size needed and either make one with the correct materials or get someone to make it; 4) work on straightening the old parts or cutting out bent material and replacing it; 5) paint the repaired area.

Steel is measured in hardness, toughness, and tensile strength. Many hard steels fracture much more easily than softer steels, you want to a tougher steel with good tensile strength.

Here is a thread that discusses this.
http://www.tractorbynet.com/forums/.../240092-best-steel-backhoe-pins-bushings.html

All steels, no matter how hard, can be drilled, but may require a carbide drill bit or annealing to soften the steel.

Of course, once the pin is out there is the matter of straightening the parts that the pin went through, and probably reinforcing those areas with fish plates and new bushings made from DOM tubing as appropriate. All of this to say to properly do these repairs so that your time and money isn't wasted doing it 2 or 3 times, requires either learning the materials that should be used and the stresses involved or getting someone that has knowledge of these repairs to do it.

 

[Sodo]

GP That helps a lot! Great idea to search for a thumb kit.

TH I'll goof around for a couple hours trying to bend it straighter with the hydraulics. If no quick satisfaction, the process you wrote will be necessary. Had to tow this eqpt. on slushy salted highways, then parked it in a barn where the waterpipe is frozen. No opportunity to rinse it until weather warms up. :thumbdown:

 

[GPintheMitten]

GP That helps a lot! Great idea to search for a thumb kit.

TH I'll goof around for a couple hours trying to bend it straighter with the hydraulics. If no quick satisfaction, the process you wrote will be necessary. Had to tow this eqpt. on slushy salted highways, then parked it in a barn where the waterpipe is frozen. No opportunity to rinse it until weather warms up. :thumbdown:

You're welcome. Wash your tractor? I thought it rained everyday in Seattle. Park it outside.

 

[the old grind]

I would caution against using drill rod or other hardened steel. Pins should be allowed to wear rather than have them gouge their bores out of round. (easier to replace pin than to re-bore/sleeve the holes.)

Ask your steel supplier for/about 'stress-proof' round stock, a low cost 'free-machining' steel (tools easily) with smooth finish and precise, uniform diameter. My guy says that most all that he sells is to replace equipment pins. Understand that it does not weld well but keepers can be bolted on. (drill/tap mount holes) This stuff machines like few other ferrous metals (very well) and wears reasonably well too (ie: just short of galling pin holes.) I'm told it's 'all the rage' nowadays for this purpose. :2cents:

 

[Sodo]

Very interesting. Thx very much grind, for this timely info!

 

[namyessam]

Agreed on the shims.

Really hoping I can get it mostly bent back by tractor hydraulics or other shadetree methods. I won't know pin diameter until its all apart and all disabled. Just bending it back fits my schedule better, because if it's bent back then at least it will come apart so I can plan the repair.

Agreed what bent this pin is the guy lost the collar (and bolt and shims) then replaced it with just a bolt, which "lengthened" the pin allowing the thumb 'clevis' to spread (what chvfrk98 said). Thus bending the pin further along with the clevis. I can't live with that. Ideally, I get it bent back, then squeeze the thumb clevis back and add proper shims and collar. I'm not thinking this will be easy, but after an hour or so fooling with the hydraulics I'm bound to know "something".

I don't see that clevis bending back on its own. If I can get that thumb off the those collar bores somehow must be re-aligned, maybe to an eqpt. repair shop with a big press.

I don't think it has shims in the 'middle', there is no rotation there because the pin has an anti-rotation tab. A shim or shims under the end cross-bolt collar is likely.

Heres the pic again.

Doing a little research on replacing the parts with new. I found O1 Drill Rod in 1.875 size at Victor Machinery in NY for $61.25. I dont know the size of the dipperstick hole but the pin end (where I test-drilled) is 1.18".

Is O1 drill rod drillable? How much stronger is drill rod than CRS (for example)? Is there a functional difference that I should know about (between O1 and W1) drill rod when used for a "pivot pin"?

I will need a collar for the bolt, to maintain the clevis width and clearances agains the shims. It's like a shaft collar but rather than clamping is has a cross-bolt. And it needs to have inner diameter 1.875"+. What's a search term for this item, I can't find them on the interweb. Does anybody know of a pic already how this joint SHOULD look (so I don't have to draw one)?

Got about a 1/4day invested in replacement already and I bet I'm about 10% there. Finding replacement parts for custom-built machinery ALWAYS SEEMS to takes --->me<--- more time than fixing what I have. I guess time flies when you're having fun. Lucky you guys who know where to find stuff quickly (and without paying thru the nose too)!

The pin may have been either induction or case hardened meaning the outer surface, maybe 1/32 deep was carburized and hardened to anywhere from Rockwell 50 to 60. This process provides a hard wear resistant surface and a soft tough core that resists breaking. Bending would be possible. This is a point above using standard HHS cutting tools. Since you have drilled it, I doubt that it is hardened at all since the carburizing process usually covers all surfaces unless protected from carbon absorption. Induction hardening may leave the end soft. O1 you mentioned can be hardened since the O refers to oil hardening. It would have to be turned on a lathe to what I guess is 30MM which is 1.181 inches. The cross hole drilled and heated cherry red through out then quenched in oil until cool. Then the surface should be shined up and reheated to a straw color to temper it and reduce the brittleness. Stress proof would be machinable and somewhat more tougher than a straight cold rolled steel. W1 should be hardened and quenched in water I believe. I have never used it. Both steels would be about the same strenght as cold rolled unless hardened and tempered. Hope this helps somewhat.

 

[Sodo]

Induction hardening may leave the end soft?. Both steels would be about the same strenght as cold rolled unless hardened and tempered. Hope this helps somewhat.

And I suppose if the pin was cut after hardening the end would be soft. Seems a guy could nip a little 1/32" deep 'flat' (on O1 drill rod) with a grinder to get thru the carburized layer and drill a hole in the cross bolt with a normal drill. Then avoid re-heat-treat. Thx for the detailed explanation I'll keep that in my bag of tricks.
At this point I am still researching OldGrind's info about 'stress-proof' round stock.

Also need to find a couple cross-bolt collars for the 1 3/16" pin. Whats a searchable name for this part?


========================

So I goofed around with the hydraulics for about 20 minutes then realized that since all the hydraulics available?.ALL pivot around this same pin there isn't much opportunity to put a force on the pin the way I need it to go. (Actually there IS a way, I figured out out what action bent the pin, so it seems I could rotate the pin 180deg then? dang thought of it about 18 hours too late!)

SawZall out and one 18v battery later, the pin was cut. It did NOT cut like hardened steel, the saw was pulling hard and sawdust was flyin'. I was all ready with 4 batteries, and it only took one battery. But it was so bent it still wouldn't come out so I had to cut it again. I changed batteries for the second cut and that one went even faster. Or maybe I have one wicked Sawzall?.or the pin was about as soft as steel gets. The 14" pin was bent about an inch high in the center at 7" (and a surprisingly sharp bend).

With the bucket off, I noticed the quick-release clevis (on the bucket) was spread out almost 1/2 inch! The problem was getting a little worse at this point so I called a buddy in town with a repair shop to ask if he had a hydr press. He said "maybe 40 ton, what do you need?" I explained it and he said bring it in so I loaded the bucket & thumb on the snowmobile (!) & headed to town. Well 50% D.I.Y. Is better than paying for the whole repair.

Pic of the quick-attach lugs on the bucket. The clevis plates are 1" thick steel and are spread 1/2" wider at the top than at the root. I'm quite happy that the whole bucket/thumb area is reasonably simple to tighten up.

That 1" plate was a bit more than I wanted to bend and you can see in my pic with 2 feet of snow theres no place to build a fire.

 

[Sodo]

Bad news is, the new pin is now bent just like the old one.

I think the cylinder on my thumb is oversized. The thumb can overpower the bucket curl. Is there a relief valve that I can put across the cylinder?

 

[powerscol]

I am sure there is - post over in the hydraulics form - more than a few experts over there. Especially J_J - he has helped me out a lot. He also my know a bit of what your up against.

BTW - did you find your locking coller? Most construction equipment dealers carry various ones in stock, from the bolt through to the set screw ones. Seems they get lost when pins break, or rust on and cant get off.