Excavator hydraulic thumb build

[asheddie]

Hi all,
I've recently bought a Kubota 5.5ton excavator. I enquired about purchasing a hydraulic thumb for it but at just under $3500 I thought I could build one myself.
It seems the shop made versions are all Bisalloy. I'm waiting on a price for some 20mm plate. The excavator already has plumbing on the arm so that should make life easier! I'll still need a ram and hoses though. Any advice as to where is best to purchase plate and hydraulics in SA? I presume Bisalloy can be welded with a MIG? Does it require pre heating at all?
It's only a small excavator so I don't think I'll have to worry about over engineering it too much?
Any advice is very welcome.
I'm going overseas for a couple of weeks but plan on making it as soon as I get back.
Thanks,

Ash.

[KBs PensNmore]

Hi Ash,
Looking forward to seeing the WIP on this. :2tsup:Our friend google found this link to welding Bisalloy,
www.bisalloy.com.au/contents/welding-of-BISPLATE®
Quite a bit of info available,
Kryn

[.RC.]

Ring up Bisalloy for welding instructions. I have found them extremely helpful in the past. Also know what grade of Bisalloy you are using. As they make many many grades.

[Steamwhisperer]

Hi Ash
Quite a while back I made one of those and did an autocad drawing for it.
It's yours if you would like to have a look at it. The drawing is in a DWG. file that I can put into dropbox should you wish.
The thumb worked very well and as far as I know, it still is.

Phil

[snapatap]

if you have CAD draw up the bits you need in and get ferrocut to profile cut the plate for you, that's how we do most of our stuff at work. Be warned BIS is pretty expensive. how much use is the thumb going to get? You could make it out of mild steel if it won t see lots of use. Bis needs to be preheated before welding, i will look the temp up when i am back at work. welds fine with a mig. Baker hydraulics are pretty good for cylinders, but i'm not sure if they deal direct with the public. BL Shipway are agents for them and they are really helpful. Most of the cheaper cylinders have very thin hardchrome on them, they work ok but will suffer corrosion quicker so make sure you leave the cylinder retracted when not in use.

[Michael G]

Work uses a company called Ezyfit (up Salisbury way) for hydraulic cylinders. Torque hydraulics or Stauff for control gear etc and usually Pirtek (some times Enzed) for hoses.
For the Bis plate, a steel supplier (for example Green Steel in Hindmarsh) should be able to order that in for you but you may be better going to someone like Brister's who have computerised cutting equipment (waterjet, plasma etc). They may have a part sheet sitting around and can supply the components cut to shape.

Michael

[jatt]

Should be an interesting build to watch.

Unfort for me it would be quite an exercise to do the same on my old clunker.