H&L scarifier teeth

[kevinro]

I have a Rankin mechanical thumb for my JD 48 backhoe. I need replacement teeth for it, and was wondering if I am getting burned by my local dealer on the price. Has anyone else purchased an H&L scarifier replacement, 1 3/4 is the marking on it? How much should I be paying?

The other question I have is does anyone have a better plan for peening the tooth onto the the thumb? There is a dimple in the thumb. When it came from the factory, it looked like they must have some sort of machine to do the peening. I just have a torch and a ball-peen hammer. I have been heating the area that needs to be struck, then wailing on it with the hammer. It works, but seems rather ungraceful and time consuming (and very loud!).

Kevin

 

[EdKing]

I don't know if this would help in your situation or not, but you could get a peening chisel/punch. It has a concave end designed to give you a smooth round peen on rivets.

Ed King

 

[JC4HD]

Kevin, How do you like the thumb and what do you use it for. I'm getting a 4310 with the 48 hoe and I was thinking of getting a thumb put on it.

 

[kevinro]

The thumb is one of the best toys I purchased with the tractor. I use the backhoe more often as an implement for grabbing things than I do digging. By grabbing things, I mean picking up downed trees, moving large rocks around the property, picking up loads of brush, and I also use it as a cultivator in some of the new planting beds around the house. It allows me to scratch and break up the soil with the backhoe rather than by hand. These are in places too close to the house or in too tight of a spot for any other implement.

My other favorite is removing small trees, specifically alder and cottonwoods, from alongside the driveway. I can pluck a 3" tree by grabbing it at the base with the thumb and wiggling it back and forth with the backhoe. It comes up, roots and all, which prevents them from growing back from the same root system.

I have found that the backhoe can lift about a 1500lb rock if I back right up to it. It will lift a 500lb rock at the end of the extension.

I looked at two different models. One used a hydraulic ram to open and close the thumb. The other was a mechanical thumb that you set before you start working, then use the bucket to close things against it. I have the mechanical thumb, Rankin part UAT-100. It was much cheaper ($500 installed by my dealer) than the hydraulic unit ($1800 installed). Every once in a while, it would be nice to have the hydraulic unit, but to be honest the mechanical thumb works just fine.

The unit I have is from Rankin, I believe this is the link:

<A target="_blank" HREF=http://www.rankineqco.com/products/rankin/univadjthumbu17.html>http://www.rankineqco.com/products/rankin/univadjthumbu17.html</A>


Kevin

 

[Rowski]

Keniv

Take a look at this thread shows his new thumb. He has the one like I have. I would like to have the hydraulic option but with having to get on and off the tractor anyways to move it. If I had an excavator or earthforce I would have one.

Don't mean to scary you with the pictures of the broken thumb. Just wanted to let you know. Like I said in the past thumbs to backhoes are like guage wheels to rock rakes.

 

[kevinro]

That picture is not a bad thumb. That is a bad weld job! You can tell since it came off right along the weld. Just looking at the picture, I see poor penetration by the welder. If it had been a good weld job, and cheap construction, you should have seen a tear laterally across the mounting plate, or the pivot point for the thumb would have seperated. (According to the author, he was swinging the boom when this happened).

The 'new' thumb looks like a nice unit. However, it also looks like overkill for the size of backhoe. First, weighing 100 pounds, it is going to diminish the capability of your backhoe by 100lbs or so. It is right out there at the end of the boom. Second, the gauge of steel is definitely impressive, but is too much for the size of the hoe. It isn't clear how well it folds away, or if you have to remove it from the backhoe. Looks like you would have to remove it. The Rakin folds up against the boom. That alone is a very nice feature.

To its credit, I do like the shape of the thumb. It would be nice to have a flat surface to press against sometimes. On the other hand, the curved shape of the Rankin is often times better for me, especially for picking up round things, like rocks, trees, etc.

Like I said before, I routinely pick up very large rocks with my thumb, much bigger than 500lbs. The only issue I have had to date is the scarifier teeth on the thumb being torn off, but that is more an issue of my being overly rough to the thing rather than poor quality. By torn, I mean the steel on the replaceable teeth tears along the backside. The teeth are from H&L, and replace without too much trouble.

I am sure either unit would do you just fine.

 

[Rowski]

Kevin

I don't think the Rakin thumb is a bad thumb. I'll say the weld penetration was not the best on the thumb side of the weld. Granted the weight is an issue but than again it's a compromise between having a thumb and not. I feel that the thumb should be able to take what the hydraulics and digging can dish out. I'm not sure what you mean by being overly rough with you backhoe. The last thing I would want to be worried about when using by backhoe is that I don't put to much "pressure" on something not to break or bend something. I really don't think that swinging the boom with a large load would have made a difference, provided that the weld was good. There have been many times where I could not lift something (with the thumb) at its maximum reach away from the tractor. So I crowd the object as close as possible then lift it. Once in the air I swing it to the side and at the same time extend the crowd cylinder. As the load gets further away the relief valve opens for the boom cylinder and the object get close to the ground. I have used my hoe a total of about 100hrs. About 75 hrs with thumb and field stones. Of that 75hrs a good 30 hrs were at maximum capacity, i.e. running it really hard. To be honest I'm really amazed I did not break bend or destroy something on tractor or hoe.

Here is a picture of the thumb. I you remove the stiff arm at the pin near the bottom of the thumb (by the bucket teeth) and the pin at the top of the mounting plate, the thumb will fold tight against the crowd arm. The <A target="_blank" HREF=http://www.tractorbynet.com/forumfiles/5-51353-P1010001.jpg>picture</A> (of the thumb similar to yours) shows that the thumb when in the rest position the thumb claws stick out. On mine tit doesn't. I did have a picture of the thumb in its rest position but can't find it. I can if you like take a picture of it and post it for you. There is the problem of what to do with the stiff arm once removed, it's too big to keep in the tractor. Does your stiff arm stay on the thumb at all times, both during use and rest positions?

As you mentioned, I fully agree either unit would be fine. I'm not posting these differences between the two to say one is better than the other. I just like to have the information available to other for future reference.

 

[kevinro]

I agree that the thumb needs to handle whatever forces the backhoe can exert on it.

By overly rough, I mean moving around rocks that are too big for the backhoe to lift. I can roll many of them (these are the 2000 lb and bigger sized rocks), partially lift them, and push them around. It is these really big fellows that end up tearing the metal on the scarifier teeth. Usually, its a result of pushing with only the thumb, usually with only one tooth. No problem with the actual thumb.

Yes, the entire assembly for the Rankin thumb stays on the tractor. The stiff arm folds up nicely out of the way. It is pretty slick that way. The thumb is also not much wider than the backhoe arm, so it doesn't seem to interfere much with digging trenches.

Kevin