I need to make some new pins to adapt a couple buckets to a werk-brau hydraulic coupler. With these pins not actually working in a bushing will any decent steel work like cold roll.
Cold rolled will be considerably weaker than real pin material, and if you do any pounding with the buckets it will break pretty fast.
The pins will still be WORKING in those bushings, just not rotating. I'd still keep them greased with a moly grease, it will just last longer between greasings. If you don't want to order some 4140 or 1030 or similar, then find some junk hydraulic cylinder rods in the right diameter.
The coupler has a slot on one end and sliding lock on the other. I haven't got the machine yet but it only has a three foot and five foot bucket with it. I use one and two foot buckets most of the time. I have a one foot from the cat backhoe I sold like new and have a good used two foot cat bucket found. I don't know what the difference in pin size is yet, I've build shims to use different size buckets on different machines. I've got a company near me that rebuilds cylinders, that would be a good place to look thanks for that info.
1050 is common for pins.
Got it home, looks like two inch pins. I've got a almost new 12 inch bucket left from 436 cat backhoe that has a two inch main pin. Just have to make a back pin. Looks like a lot of bigger backhoes used two inch pins which helps alot.
Just go to steel supply store with your measurements and they will fix you up Make all my own pins
Just happen to have about 12 foot of 2 inch cold role I brought home from a job years ago. I've already got both buckets roughed in just need time to do a bunch of welding. I think I'm going to make a bobtach bracket with a quick attach on it for my jackhammer and auger.
Cold rolled wouldn't be the best.
You are probably right but it's what I have. These pins don't have bushings on them they simply set in a slot with a hydraulic clamp pushing on the back pin. There is nothing moving on them. That is my main reason for thinking cold role is good enough. I have a gap of maybe a quarter inch on each side of the coupler so shear shouldn't be a concern.
Cold rolled Will break if you want to actually use the machine for digging in anything other than sand, mud, very soft soil, etc...
One thing to remember the pins you put into the bucket when using a coupler are always softer than the standard bucket pins so they wear instead of the coupler.
My other mid size excavator has the POS tag coupler. The ears that lock on three inch pipe are mild steel and wear terrible. I would think if a half inch thick by one inch doesn't break from the stress of a jackhammer and prying bucket a two inch thick pin will stand up. Time will tell. The werk brau coupler has a cast pieces on all the coupler and show hardly any wear. I would rather the pins wear, not hard to make new pins every few years and at my age that's not very many changes.
I use cylinder rod for my bucket pins. I have 8 attachments and Case thinks pins are worth $200 a piece. I go to a local hydraulic shop and get odd lengths of 1-3/4 usually long enough for 2 for $25-40. Grind through the chrome on both sides before you drill the retainer hole. They work great and won't rust or get gummy with mud.
cold roll steel can be purchased in 1018, 1045 and 4140, and the 4140 alloy is perfect for pins and bushings, but the bushings made from it would need to be flame hardened before using... but the pins should NOT be hardened, as its better to wear the pins out than the bushings, because the pins are easier and cheaper to make and replace when they wear...
Both Werkbrau and JRB insist on mild steel pins in buckets to be used with "pin grabber " quick attach brackets. Factory hard pins are used only to retain coupler to the stick. If you can't make a ding in it with a gasket hammer, it's too hard for the bucket.
So is 4140 QT SRA a suitable material? If i have to weld a tab on the end, will the pin become brittle?
no... very weldable, and wont cause any brittleness.. preheat the end of pin just enough that its slightly hot to the touch, and then weld the tab on...