Thumb Thumb mounting position

[dboacres]

I purchased a 21" thumb for my Woods 7500BH. I plan to weld it in place so I better do it right the first time. I will be picking up large rocks, as big as the backhoe can handle. Does any one have advise as to how far back on the boom arm I should place the thumb from the bucket when the bucket is at 90 degrees? Bucket is 19" from pin to tip of teeth. Right now I plan on 12" from bucket to thumb when both are at 90 degrees. Any experienced advise?

 

[AKfish]

When I mounted a fixed thumb on my JD 8A hoe, I set the thumb to work at 2 different angles - 45 degrees and 90 degrees. The 3rd position was flat against the dipper for storage or whenever the work was just digging.

Long and short - lot's of welding clamps and vise grips - to hold and reposition and mark the dipper prior to melting ANY wire!

Set it - fire up the hoe and see how it fits and would work.

Also machined pins from solid stainless for the mounting pins. They won't rust and corrode so easily and will make it much easier repositioning the thumb when necessary.

AKfish

 

[dboacres]

I clamped the thumb on at different positions and tried picking up a 5 gallon plastic bucket. The 12' gap between bucket and thumb at 90 degrees seemed to work best. I got the thumb off Ebay. It has 90 degree, 30 foreward and 30 back plus storage position.