Bobcat skid steer pin bosses/bushes.

[jd6820]

Hi everyone,

I’m aware there are a few guys on here who fabricate on a professional level, I’m after a little advice on steel choice for my next job.

I’m re-bushing a machine we’ve just acquired (453 bobcat) the boom/ loader arm pivot near the cab has worn the bushes that are welded into the chassis. Luckily for me the welds are easily cut and a machined hole is left behind once the bushes are knocked out so alignment should be simple enough. The current bushes are shaped like top hats and locate in the chassis then the outside only is welded. I’m pondering what grade of steel to make them out of? My choice at the moment is between EN8 and EN16t but not sure if I’m in the right ballpark. The originals don’t look to be made of anything super tough. At least that’s what a file reckons. My understanding is EN8 will easy weld without much preheat prep vs EN16 and EN24 which require more effort but have a tougher alloy/carbon composition?

Done a lot with EN8 and never had an issue but the boss are only narrow at 11mm with an OD of 50mm and ID 25.4 (1”) so not a lot of metal supporting the pin.

So I’d appreciate some advice from you guys, just priced EN8 @ £99 for 3m and EN16t @ £199!

Will machine myself and have insert tooling so toughness isn’t much of an issue there. Just the weld process has me questioning material type.

 

[Nick...]

Just buy parts from digbits or eBay.i bought a load of various width 35 MM washers to tighten my machine just before Xmas.they were probably 30% the cost from a well known supplier
nick...

 

[jd6820]

Bit of a specialist item as they aren't like usual digger bosses they'd be a custom job, so I can't see someone having them on the shelf or not charging a fortune to make them.

 

[doobin]

@V8Druid

 

[CPS]

For what your doing Bright mild steel would be ample. En16t won't be ideal for welding

 

[V8Druid]

yeh I'd give it a crack with the EN8 .. easy to create and weld in ........ do the pins move in them or in the arms? ... if they're simply retaining the pins, they'll last as long the originals?...
I assume from the price of the 3M bar you're talking about circa 50/60 mm O.D.? on the bosses? if the pins're mobile in them, do you have enough meat to machine a hardened bush into them?

 

[V8Druid]

any pix @jd6820

 

[Bri963]

No problem welding EN8 of that size. If you’re MIGing, normal ER70 wire, no preheat, if it’s stick, 7018 again no preheat rod.

 

[jd6820]

Thank you for the replies, EN8 it is. I just wanted to make it out of something harder than mild steel as I think that’s what the originals are and they’ve done 3000hrs. The pins are suppose to be held still in the chassis and greaseable bush in the boom that it pivots in. The EN8 I can use for other outgoing jobs whereas EN16t is a little more specialist.



I can’t believe how narrow they are the pins are 1” diameter and hammering against such a narrow bush must oval them quicker than if they’d made them 25mm thick each side then the chassis supported ends on the pin would be less likely to oval the hole when the machine is repeated drive into solid piles of dirt.

I’ll post the end results on here and maybe some photos of the rebuild on the machine. Got hydraulic gear pump to change out and some slop to remove from the levers. Drive motors and pumps seem to work well. So that’s a major expense avoided, the engine is nearly new as it has had a replacement kubota lump fitted in the past. It starts and runs like a new’en. Lots of genuine bobcat parts fitted and was at a garden centre before us and they just got the local dealer to sort any jobs out. Was cosmetically not too bad just old… Well if you call yr 2000 old, 3000hrs seems quite a lot for these small machines. Especially when you see ex hire at 1900hrs looking rough as.

 

[Gunners]

Good machines, had one at college and it was old then! This pic was taken in 06, I got banned shortly after from the skid steer for wheelieing it

 

[V8Druid]

Thank you for the replies, EN8 it is. I just wanted to make it out of something harder than mild steel as I think that’s what the originals are and they’ve done 3000hrs. The pins are suppose to be held still in the chassis and greaseable bush in the boom that it pivots in. The EN8 I can use for other outgoing jobs whereas EN16t is a little more specialist.

View attachment 43597View attachment 43598View attachment 43599

I can’t believe how narrow they are the pins are 1” diameter and hammering against such a narrow bush must oval them quicker than if they’d made them 25mm thick each side then the chassis supported ends on the pin would be less likely to oval the hole when the machine is repeated drive into solid piles of dirt.

I’ll post the end results on here and maybe some photos of the rebuild on the machine. Got hydraulic gear pump to change out and some slop to remove from the levers. Drive motors and pumps seem to work well. So that’s a major expense avoided, the engine is nearly new as it has had a replacement kubota lump fitted in the past. It starts and runs like a new’en. Lots of genuine bobcat parts fitted and was at a garden centre before us and they just got the local dealer to sort any jobs out. Was cosmetically not too bad just old… Well if you call yr 2000 old, 3000hrs seems quite a lot for these small machines. Especially when you see ex hire at 1900hrs looking rough as.

they something like this JD?
see no reason you couldn't make the pins/bushes longer

 

[jd6820]

they something like this JD?
see no reason you couldn't make the pins/bushes longer

Yeah, the only issue is any extra length on the bushes will affect overall machine width as the boom pivots are the widest part of the machine and this one is a 3ft’r designed for small spaces. Plus I’ve bought all the new pins. My brother is keen for me to make the bushes bigger and make a load of new pins too.

 

[Bri963]

Any pics of the 453? I wouldn’t mind one of those or a 463.

 

[jd6820]

Any pics of the 453? I wouldn’t mind one of those or a 463.

Will put some up in due course but I'll admit currently you'd have a job to tell what it is. The parts are sat on about 6 different pallets, boom off in bits, engine out, drivetrain on a pallet, chassis on another pallet, wiring loom removed and cab separate too. Basically a full restoration. It's for mucking out calf pens and scraping out the cows (not dairy so it won't be plastered in muck), so I figured go through it before we get to using it daily then hopefully it wont let us down. All hoses, the few that there are will get replaced and any other issues sorted. Both myself and my brother are mechanically switched on and like to run kit that's tidy and well serviced. Farm is a hobby as we both have other jobs, so the kit we have is overkill and underworked but what the heck you're only here once, so may as well enjoy it and make life easy. Just couldn't bring myself to pay £20 odd thousand for a new S70, so found a used machine cheap and will go through it front to back and should still end up way less than a new one. Slight snag we hit is that the headstock of a 453 is different to a 463 or S70 so it won't pickup a conventional attachment. Ours will as I've bought a new headstock of an S70 which will fit as the arms are identical to a 453, wasn't expensive either to my surprise, s/h headstocks are hard to come by and knackered usually as was the original we had. I wanted attachements to fit a newer machine incase we ever change or hire in attachments.

 

[jd6820]

Good machines, had one at college and it was old then! This pic was taken in 06, I got banned shortly after from the skid steer for wheelieing it

Yeah, they are good machines in tight spaces, think Bobcat has the market and certainly hold their value. Looks well that machine, they aint the most stable platform, least of all the three footers on narrow wheels.

 

[Bri963]

Yeah, they are good machines in tight spaces, think Bobcat has the market and certainly hold their value. Looks well that machine, they aint the most stable platform, least of all the three footers on narrow wheels.

How’s this project progressing?

 

[jd6820]

How’s this project progressing?

Slowly! I have the 50mm EN8 bar stock ready to machine. Just busy with the day job, got a Fastrac gearbox in a lot of bits, an MF5460 with knackered pto bearings that have had their parts distributed round the gearbox and a plethora of more boring jobs including a few conventional balers that need knotter attention and chamber/plunger issues. The bobcat is more my brothers project and is still unrecognisable as it is now in component parts the engine out, chassis stripped of all the driveline, cab removed and boom taken off. The chassis is just a bare bones shell with all the pin bosses removed ready for the machined replacements to be welded in when I get a second to machine them. Done some machining too, but all paying jobs so have to take priority over my own jobs. Well I suppose we serviced our John Deere on Monday in preparation for some muck shifting this weekend, along with repairing tracking pilot oil valve on the hitachi and a quick engine service whilst we were on with it. I'll update the thread as we progress but thank you for asking.

 

[doobin]

Slowly! I have the 50mm EN8 bar stock ready to machine. Just busy with the day job, got a Fastrac gearbox in a lot of bits, an MF5460 with knackered pto bearings that have had their parts distributed round the gearbox and a plethora of more boring jobs including a few conventional balers that need knotter attention and chamber/plunger issues. The bobcat is more my brothers project and is still unrecognisable as it is now in component parts the engine out, chassis stripped of all the driveline, cab removed and boom taken off. The chassis is just a bare bones shell with all the pin bosses removed ready for the machined replacements to be welded in when I get a second to machine them. Done some machining too, but all paying jobs so have to take priority over my own jobs. Well I suppose we serviced our John Deere on Monday in preparation for some muck shifting this weekend, along with repairing tracking pilot oil valve on the hitachi and a quick engine service whilst we were on with it. I'll update the thread as we progress but thank you for asking.

Sounds a lot like me. Flat out like a badger on a bypass, too busy to fart!

 

[doobin]

So was the consensus here EN8 for welding, but wouldn't hurt to go to EN16 if not requiring weld?

 

[jd6820]

So was the consensus here EN8 for welding, but wouldn't hurt to go to EN16 if not requiring weld?

This link is a good guide for engineering steels and their suitability for welding. I've chosen EN8 for the bosses as requires little to no preheat. EN16,24 etc usually need a low hydrogen process and careful preheat along with maintaining a steady slow cooling process. Hard to pack a chassis in sand and control the rate of cooling so I opted for the easier option. Can't see it is gonna be worse than the factory bushes. I'd use EN24t for making bushings/pins for press fit into bores or non weld applications, requiring a good wear resistance.

https://www.mig-welding.co.uk/engineering-steels.htm