Backhoe Thumb...weld or bolt?

[Dataway]

I'm going to build a backhoe thumb for my Woods BH750 next month and I'm undecided about bolting or welding on the mounts.
Is there any disadvantage to welding on the mounts? ( I have a welding shop) Other than the obvious fact I can't remove them. I'll still be able to remove the thumb itself of course, and I can't imagine I'd ever need the mounts removed for any reason.

Once installed I can't think of a reason to remove the thumb if it's capable of being folded out of the way.

Anything I'm missing?
Thanks,
JohnnyB

 

[FredH]

Bought my thumb off e-bay . Could of done either bolt on or weld on my 757 new holland . Ended up just welding it with my lincoln 135 . I have moved some things that the back hoe could barely lift yet the welds have held and without any damage to the backhoe frame itself .

Added a rattle can of new holland blue over the black original paint and it looks pretty much original new holland .

I guess it would just depend on your preference . I did take a considerable amount of time though in setting it up as to were I would finally position the brackets , as once you weld , although not a done deal , it is harder to rearrange your plans .

Fred H.

 

[countrybumpkin]

Fred pretty much said the same thing as I was going to. If you weld just make sure that's were you want the brackets, a real pain to move later if they are welded. to me the welded brackets have a much cleaner look.

 

[sizzami]

I say weld because if you drill holes over time the mount will probably shuck around and wear out the holes eventually leading to cracks in the arm , I have fixed alot of them .

 

[shaley]

Doesn't Woods make an accessory BH thumb that uses the bucket pins for a mount? Here is the manual for the BH70 Thumb.
showcontent

 

[Dataway]

Thanks for the input guys...it's helping me make up my mind. (to weld Was thinking all those same things...including paint to match.

Shaley...very cool, didn't know Woods made such an add-on. Wonder if it would fit a BH750. Probably costs $500+ if it's still available. Going to check on that.

JohnnyB

 

[Jaylegger]

You may also wish to check out how these guys attach their thumbsBro-Tek Thumb. No potential bad welds or drill holes to weaken the existing structure and easy transparent reversal of the attachment attachment which should maximize maintained resale value of the structure the attachment is being attached to.

 

[Dataway]

I considered a Bro-Tek...but I can make my own thumb for a fraction of the costs. Being a small fab shop I have my own plasma cutter, extensive welding equipment, milling machine, lathe, Hossfeld, brakes etc.
I purchased the metal today, 10' of 4"x 1/2" A36 Flat ($44). I'll be re-enforcing the boom in the area of the anchor with a solid base plate of 1/2" steel, so boom bending should not be an issue.

I was concerned about the fact that it could not be removed (reversed as you say), but after reading comments from thumb owners I couldn't ever see it as being a "plus" NOT to have one installed. I mean it would be kinda like removing air-condition from your car.... could only hurt the value.

Lack of weld quality isn't a real concern for me, I've been doing it for about 30 years

My concerns were mainly... would there ever be a reason to remove it? Would it get in the way of anything? Is it destructive to the machine in any way?

I've curled so many 1500 lb rocks against the boom as tight as I can that I can't imagine having a thumb would be WORSE for the boom that what I typically do without one
JohnnyB

 

[Runner]

I haven't done mine yet, but when I do, I'm going to mount the thumb on a plate with four holes drilled in it, two on each side of the boom. Then, I'll place another plate on the opposite side, sandwiching the boom in between and use some long bolts to hold the two plates together.

I want to be able to remove/reposition it, just in case.

 

[Runner]

...like this one

 

[akpilot]

I considered both options, in the end I chose to weld it on, it didn't weigh as much and it was simpler.

 

[Dataway]

Pilot...have you got your 1" pins running through bushings there?

If so, what did you use for bushings? I'd rather not have to make something up on the lathe...anything off the shelf with a nice enough fit?
Thanks,
JohnnyB

 

[escavader]

Welded mine.Nice lip of steel overhanging the dipper stick on my BOTA SO IT DIDNT HURT A THING.Been on for several hundred hours now with no issues
ALAN

 

[andymil]

Doesn't Woods make an accessory BH thumb that uses the bucket pins for a mount?

I started a thumb for the hoe I made but haven't finished it yet. I was going to use the pin in the dipper for the links to mount the thumb instead of the bucket pivot pin. This puts the thumb about 5" from the bucket. I thought this geometry would work better and the links move a little less than the bucket. I'll just need a longer pin.

I haven't got to the mount for the other end yet. I haven't ruled out a cylinder instead of a fixed thumb.

 

[akpilot]

Dataway
I made 7/8" pins with my new lathe (for the practice) I didn't use any bushing material as they won't be roatating except for when I fold it up, therefore I didn't see much value. I'm going to drill the pins for grease zerks mainly to keep the rust down in the joint, if left on for long periods.

 

[Dataway]

Pilot,
Bushings was probably the wrong word...it looks like you have sleeves covering the pins in areas between the thumb halves.... the sleeves look to be welded to the inside of the thumb halves and the pins slide through them. It appears you have the sleeves limiting the side to side movement on one end of the link rod. I'd like to do a similar setup.
Thanks,
JohnnyB

 

[akpilot]

sorry ....They are made from heavy wall tubing that I bored to the correct size for the pins, here is a pic just prior to welding the main mount.

 

[Dataway]

Thanks pilot...just what I needed to know.
Nice work btw
JohnnyB

 

[Dataway]

One more question for the T.U.s (Thumb Users).

I'm laying out my pivot points etc. How about some input on where you position the thumb most often. 90 degrees to the boom or extended toward the bucket, or less than 90 degrees to the boom (farther from the bucket).

I'm trying to decide how many, if any, adjustment points I need, and how much they should deviated from 90 degrees in either direction.
Thanks,
JohnnyB

 

[dfkrug]

I'm trying to decide how many, if any, adjustment points I need, and how much they should deviated from 90 degrees in either direction.

You might also want to consider using a CAT 1 toplink, which you already
have, or you can buy one for $20. That would give you infinite adjustments,
but it would not allow full retraction to put the thumb in a storage position
against the dipper. I just removed mine when not in use. CAT 1 toplinks
are also available in different lengths.

I have long since gone hydraulic, but I used my mechanical fixed thumb
most often in a position approximately 75-deg from the dipper, towards the
bucket.