30mm Rams on Kubota FEL or BH cylinders?

[Lil Foot]

Does anyone know if Kubota uses (or used) 30mm (1.181") diameter rams on any of their cylinders?

I am having a devil of a time finding 30mm stock to make new pins for the mini excavator, and hit upon the idea of using old hydraulic rams from rebuilt cylinders to fabricate new pins. Trouble is, I can't find any old ram stock in 30mm: everyone has SAE sizes.
So before I go talk to my local Kubota dealer, (shudder) I thought I'd ask here.

I know my FEL & BH cylinders are SAE sizes, because they were made in the US.

Anybody out there have any 30mm steel stock, or old 30mm cylinder rams?

 

[PoTreeBoy]

Does anyone know if Kubota uses (or used) 30mm (1.81") diameter rams on any of their cylinders?

I am having a devil of a time finding 30mm stock to make new pins for the mini excavator, and hit upon the idea of using old hydraulic rams from rebuilt cylinders to fabricate new pins. Trouble is, I can't find any old ram stock in 30mm: everyone has SAE sizes.
So before I go talk to my local Kubota dealer, (shudder) I thought I'd ask here.

I know my FEL & BH cylinders are SAE sizes, because they were made in the US.

Anybody out there have any 30mm steel stock, or old 30mm cylinder rams?

Both my loader and hoe cylinders are imperial, even though it was presumably made in Japan. The TL720 has 31.75 rods (1.25", I think you slipped a digit). McMaster, eBay, Amazon have 30 mm, but it's special use and $$$$$. You may be better off visiting a machine shop and having it turned. What are you doing for bushings?

 

[Lil Foot]

I think you slipped a digit

You're right, good catch, corrected. (getting old )

McMaster, eBay, Amazon have 30 mm, but it's special use and $$$$$.

You are correct, very pricy.

You may be better off visiting a machine shop and having it turned.

What are you doing for bushings?

I can turn it from larger stock myself in my shop, but I was hoping to avoid all that work, seeing as I am probably have to machine custom bushings to take up the wear in some of the bushing holes.

Beginning to look like I'm just going to have to bite the bullet and machine everything from scratch.
Starting with on-size pin material would have saved me a lot of time & work.

 

[PoTreeBoy]

While we're on the subject, I've seen this discussed but set me straight. Are the bushings or pins harder material? Seems it would be easier to replace worn pins than bushings. Why are bronze bushings not used? And, if you're going to have to machine new bushings, couldn't you size them to use 1.25" pins? I'm sure I'm missing something, just curious.

 

[Lil Foot]

Seems it would be easier to replace worn pins than bushings.

I agree, it would.
For a reason I don't understand, pins are usually hardened, and bushings are softer.
I have found both bronze and plastic bushings being used, but the folks in the industry that I have spoken with say that soft bushings like bronze, brass, or plastic tend to pick up & imbed grit, which then grinds up the pins, wearing them faster than if steel bushings are used.
I could (and might) use 1 1/4 pins/bushings, but some of the holes in the stick or boom are not big enough for larger sizes. (not enough wall thickness)
I might use smaller (1 1/8" ?) pins/ bushings also.
Most of damage I'm trying to correct is because the pins/bushings were neglected so long that the holes the that the bushings go in are oversized/egg-shaped.
Others are still on-size, just requiring a new, on-size pin to be made.
Having 30mm stock to make pins for at least some locations would save a lot of work.

 

[TheOldHokie]

Does anyone know if Kubota uses (or used) 30mm (1.181") diameter rams on any of their cylinders?

I am having a devil of a time finding 30mm stock to make new pins for the mini excavator, and hit upon the idea of using old hydraulic rams from rebuilt cylinders to fabricate new pins. Trouble is, I can't find any old ram stock in 30mm: everyone has SAE sizes.
So before I go talk to my local Kubota dealer, (shudder) I thought I'd ask here.

I know my FEL & BH cylinders are SAE sizes, because they were made in the US.

Anybody out there have any 30mm steel stock, or old 30mm cylinder rams?

Unless you want to buy a mill length (12') of TGP this is about the best you can do. Personally, 1-3/16 TGP in something like 1045 is damn close and you are making new bushings so I would be looking there.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Dan

 

[34by151]

Does anyone know if Kubota uses (or used) 30mm (1.181") diameter rams on any of their cylinders?

I am having a devil of a time finding 30mm stock to make new pins for the mini excavator, and hit upon the idea of using old hydraulic rams from rebuilt cylinders to fabricate new pins. Trouble is, I can't find any old ram stock in 30mm: everyone has SAE sizes.
So before I go talk to my local Kubota dealer, (shudder) I thought I'd ask here.

I know my FEL & BH cylinders are SAE sizes, because they were made in the US.

Anybody out there have any 30mm steel stock, or old 30mm cylinder rams?

Here on OZ I use 30, 25, 25.4 and 19mm bright bar for pins. All are standard items here in oz. For bushings I use 56/28, 45/25 and 36/16 hollow bar. All of the bushings need the centres boring before parting off. I also have a cross drill mounted on the lathe so I can drill the bolt hole before parting.

 

[Yooper]

I see McMaster has 30mm 1144 but ouch$$. Imperial is way less for a size (1.25”) that you can turn down on the lathe. Checked my stock but no 30mm anything

 

[Vigo]

I would actually think that getting 30mm pins that may not be in the exact correct length, would not be that hard as i believe it's still a very common pin size for anything made in a metric country. It should be a common pin size for mini-excavators outside USA.

I recently bought a mini-excavator bucket from northern tool to adapt to my kubota backhoe. It came with 30mm bushings and pins. Ebay if you're in kind of a hurry, alibaba if you're in no kind of hurry! Just buy longer than you need and cut/drill them. It will probably still be cheaper than buying actual bar and cutting your own.

 

[Lil Foot]

I found some generic 30mm pins in England for about $10ea US, but shipping was about $70ea US.
Everything else has been way expensive, wether it was actual pins or just 30mm stock, and shipping wasn't cheap either.
Too hot to work in the shop anyway, 111°F this afternoon, and no AC.

 

[Old_Paint]

For a reason I don't understand, pins are usually hardened, and bushings are softer.

It probably has more to do with shear strength than one would think. Softer steel will shear easier. Bushings aren't going to shear unless something else VERY BAD is happening because they're encased in harder steel and shaped such that shear force is never applied to them. They're normally intended to be sacrificial to prevent wear in the rod ends and mount sockets by acting as a cushing between two harder pieces of steel. Egg shape the bore for a bushing and you'll crush/distort every bushing you ever put in it again. A slight error in the bore with a hardened bushing would be a stress point and cause a hard bushing to shatter. A soft one will just simply form to the defect. A soft bushing is a lot easier to press into a hardened socket as well with less risk of shattering or cracking the bushing. Shrinking the bushing by freezing or expanding the socket with heat helps a lot, though. Hard metal on hard metal is rarely a good idea. The grease should keep them separated, but only if one remembers to grease regularly.

I may be completely wrong, but that's my line of thinking. I bet I could start a good debate between two mechanical engineers, though.