Wanted: LA650 loader wedge bolts

[oregontrail]

I bought a Kubota LA650 loader that is missing the wedge bolts needed for mounting it to my tractor (L3450DT); the part number is 75540-56810. Messicks wants a fortune for them. I'm in the Pacific NW and would appreciate suggestions of any salvage yard that might have something like that (if it's even conceivable that they might).

I'm also rebuilding the loader hydraulics, and would love to know what the length measurements are for the hoses from the hydraulic block on the tractor to the loader control valve, if anyone knows.

Thanks,
John

 

[North Idaho Wolfman]

The chances of you finding a good used set is going to be near to impossible.
You could have someone make you a set, as they are a pretty simple design.
I would make them if it was mine.
I have a Woods loader on my L3450 so I can't help with the line measurement.

 

[oregontrail]

The chances of you finding a good used set is going to be near to impossible.
You could have someone make you a set, as they are a pretty simple design.
I would make them if it was mine.
I have a Woods loader on my L3450 so I can't help with the line measurement.

Thanks for your response, I was afraid of that. Looks like it should be only moderately hard to make, but I wish I had the specs.

 

[North Idaho Wolfman]

Thanks for your response, I was afraid of that. Looks like it should be only moderately hard to make, but I wish I had the specs.

Total length 10", 5" for the wedge and 5" for the bolt.
Measure width and height of the pocket in the front of the loader frame that will give you the 2 other dimensions.
Measure the diameter of the bolt hole, this should be the same as the width of the wedge.
The wedge is the height of the bolt angled back 2" to the height of the total width.
Use a grade 8 fine thread bolt and 2 nuts each
Steel should be mild steel then after welding heated then quench hardened in oil.

 

[Lil Foot]

Anybody got a pic of this wedge bolt?
I've never seen one.

 

[Russell King]

I was also wondering what they look like so found this on Messick’s. Look at the price of that thing!

 

[torch]

Steel should be mild steel then after welding heated then quench hardened in oil.

Random mild steel alone cannot be quench hardened in oil -- by definition "mild" steel has a low carbon content.

There are alloys designed to be quench hardened. O1 tool steel is probably the most ubiquitous for home shop applications. It's not as sensitive as alloys designed for water or saline hardening. Heating the part evenly with a carborizing flame to cherry red before quenching in a coffee can filled with used motor oil will be successful -- but "draw it back" by reheating to a straw colour and allowing to air cool. This will make it less brittle.

One can case-harden mild steel -- but it requires adding carbon to the outermost skin of the part, effectively turning that thin layer into a medium carbon steel. There are a number of ways of adding the carbon but the simplest is to use a product such as "Kasenit" or "Cherry Red" (available through gunsmith suppliers). Heat the part to cherry red, coat with the powder, reheat the part, quench in water (Kasenit) or oil (Cherry Red) then remove the resulting scale. This leaves the toughness of the mild steel inside but with a hard outer wear surface.

NOTE: ventilation and breathing protection required!!! Do not breath the fumes coming off the Kasinit!!!! They are real nasty. Also, quenching involves immersing the part completely as rapidly as possible, then swirl around in the oil until it stops smoking to ensure even cooling and prevent warping.

 

[MapleLeafFarmer]

I was also wondering what they look like so found this on Messick’s. Look at the price of that thing!
View attachment 169462

Ouch.... I guess that's the price of being rare

 

[oregontrail]

Thank you all for sharing your knowledge. The bolt is 5/8-18, I think. The hardening process sounds non-trivial -- for a "carborizing flame" can you use an oxyacetylene torch with an excess of acetylene? And if I looked for a machine shop or fabricator to make it for me, would it make more sense to start with mild steel or 01 tool steel?

 

[torch]

Thank you all for sharing your knowledge. The bolt is 5/8-18, I think. The hardening process sounds non-trivial -- for a "carborizing flame" can you use an oxyacetylene torch with an excess of acetylene?
{/quote}

That's exactly right. Not so much acetylene as to produce huge clouds of black smoke, but enough excess that the flame is on the yellow side rather than blue. (The same method works well with case hardening powders too).

And if I looked for a machine shop or fabricator to make it for me, would it make more sense to start with mild steel or 01 tool steel?

I would go with their recommendations based on their abilities and available materials. There's no point in case-hardening anything but mild steel -- hardenable steels just need the correct heat treatment. O1 is just one such example, the easiest and most forgiving so that's the one favoured by farmers and home hobbyists (like me): All you need is an Oxy-acetylene torch and a bucket of oil.

But a proper shop may have an actual oven and a stock of water- or saline- quenchable alloys. Those are trickier and more prone to cracking if not done just right but can produce even harder wear surfaces in the hands of professionals.

 

[JohnDB]

... The bolt is 5/8-18, I think.

Why not use M16x1.5 instead? (For consistency, assuming that the rest of the loader/tractor is metric). Its a common enough thread used on Kubotas. If it is grade 8.8 I believe that it is more weldable/heat treatable than some ANSI higher tensile bolts (subject to confirmation by @torch whose info about heat treating seems spot-on)

 

[oregontrail]

The loader uses mostly SAE hardware (fractions of an inch); however, anything bolted to the tractor itself in the subframe uses metric bolts. I imagine that the wedge bolt is subject to heavy shearing and possibly hammering forces as the end of the loader tries to move up and down, but only moderate tension. @torch I'm a novice when it comes to heat-treating and machining. Do you have any advice about whether to start with mild steel, grade 8.8 steel as @JohnDB suggested, or 01 tool steel?

 

[oregontrail]

Oh sorry @torch, I missed your in-line reply above. Thanks!