Backhoe Ripper tooth design - need your advice

[IslandTractor]

Looks good. Two comments. One is that you don't show any bevel on the cutting edge. I presume that is something you will do. The teeth will be more effective as a serrated blade than just flat faced. Second is that the backplate, which is critical for removing spoils, just looks a little smaller than mine. I have posted photos of my ripper you can compare to. I'll try to remember to measure mine next time I am at the tractor. With my ripper and backplate, I can remove roughly the equivalent of two hand shovelfuls of dirt at a time. Very useful for trenching or even digging out a big stump.

I'd also suggest that you consider getting a main bucket pin that is maybe 2" longer than standard and then taper the first 1.75" or so as that will help you line up the mount with the dipper.

 

[bluehog]

Looks good. Two comments. One is that you don't show any bevel on the cutting edge. I presume that is something you will do. The teeth will be more effective as a serrated blade than just flat faced. Second is that the backplate, which is critical for removing spoils, just looks a little smaller than mine. I have posted photos of my ripper you can compare to. I'll try to remember to measure mine next time I am at the tractor. With my ripper and backplate, I can remove roughly the equivalent of two hand shovelfuls of dirt at a time. Very useful for trenching or even digging out a big stump.

I'd also suggest that you consider getting a main bucket pin that is maybe 2" longer than standard and then taper the first 1.75" or so as that will help you line up the mount with the dipper.

I've seen your pics, and I must admit I was trying to copy it's features. I will look at making the back plate longer to help remove more dirt. I did not put the additional center brace/support that is shown in your pics. It looked like it would cause dirt to get clogged within the back area. Did you have any issues with that? Do you think additional support is necessary in the central section of the shank?

As for the teeth - I will put a cutting/knife edge in this area. I just couldn't figure out how to do this with the 3D modeling software (SketchUp V7.1). Every time I tried it I ended up losing surfaces and it made the teeth surfaces "see thru". This is the first thing I modeled with it... a was a bit of a challenge for me.

You had mentioned in your original thread that you had put a large chunk of tool steel round on the back of the shank... did that work out as you had hoped?

My only concern about using longer pins is that the additional tapered part of the pin extending out beyond ripper pin bore would interfere with the digging. I was trying to stay as narrow as possible and with the 9" width the bucket pins would be protected by a little bit. For installing I was going to try the 2 half length tapered pins from each side approach and see how that works out. I'll also have a couple of long tapered knock thru pins as well. Nice to work in a full access machine shop... also having an understanding boss helps a lot too!

 

[IslandTractor]

I've seen your pics, and I must admit I was trying to copy it's features. I will look at making the back plate longer to help remove more dirt. I did not put the additional center brace/support that is shown in your pics. It looked like it would cause dirt to get clogged within the back area. Did you have any issues with that? Do you think additional support is necessary in the central section of the shank?

As for the teeth - I will put a cutting/knife edge in this area. I just couldn't figure out how to do this with the 3D modeling software (SketchUp V7.1). Every time I tried it I ended up losing surfaces and it made the teeth surfaces "see thru". This is the first thing I modeled with it... a was a bit of a challenge for me.

You had mentioned in your original thread that you had put a large chunk of tool steel round on the back of the shank... did that work out as you had hoped?

My only concern about using longer pins is that the additional tapered part of the pin extending out beyond ripper pin bore would interfere with the digging. I was trying to stay as narrow as possible and with the 9" width the bucket pins would be protected by a little bit. For installing I was going to try the 2 half length tapered pins from each side approach and see how that works out. I'll also have a couple of long tapered knock thru pins as well. Nice to work in a full access machine shop... also having an understanding boss helps a lot too!

Understood. The center support gussets don't seem to interfere or clog but my soil is very sandy. Not sure that would be the case in moist clay. I would imagine the ripper blade is stiff enough without them but I do like the idea of the lateral bracing. Perhaps smaller braces would be a compromise. I honestly have no idea if they are necessary.

The chunk of drilling rod I welded to the back works fine. The challenge in using it is to train the operator to be as facile with his "backhand" ripper motion (push and dump motion) with down pressure as with the more standard pull and curl control. Just takes learning to smoothly control that motion which doesn't get as much practice so is harder to do with a fluid motion. It does rip a chunk of wood out when done properly but I have no idea if it is more or less efficient than serrated teeth.

If you use two short tapered starter pins, just make sure to leave flat tips on both so one can easily push the other out.

Good luck with the fabrication.

 

[zanfirico]

This thread is great, I would love into find the time to fab a ripper. Please keep us posted about how you progress! Nice modeling as well; seeing your diagrams really help to understand all the choices that are being talked about.

 

[IslandTractor]

One more thought occurs to me on looking at the proposed design. In my experience ripping roots, the challenge is to get the ripper under the root and not allow the root to ride up the blade as I curl. If a big root rides up then it is simply dislodged rather than cut. Looking at your replaceable tooth, it occurs to me that putting a downward facing barb just above the tooth on the front of the blade would keep the root from sliding up the ripper. Although you have serrated teeth higher up, I think the primary ripping action using hydraulic power would be best accomplished nearer the tip as the distance a snagged root is pulled would be greater. Anything, like a barb, that would keep a root from sliding up during the curl movement would tend to help rip the root.

 

[Arc weld]

In theory you could design the the ultimate root ripper/saw but in reality it still might not work the way you want. If there was some kind of ripper that would cut roots, it would be on the market. I guess something like a vibratory plow does but that's when the roots are packed in the ground, not like when you're digging out a stump. The only way to effectively cut all roots is to have a hyd. shear type attachment like is used on some feller/bunchers. Even when using an ax sometimes roots are almost like rubber and just don't want to cut no matter how sharp the ax is. I think a sharpened edge on the shank would cut some roots but a serrated edge, unless it was very thin and sharpened like a knife wouldn't do much more than just the sharpened edge. If you had a thumb on the hoe to use in conjunction with your sharpened edge could work to cut stubborn roots.

I've dug out some some pretty big stumps just using a 30" backhoe bucket. I think just a plain ripper would be a lot easier and not make as big of a mess. I've also seen really narrow buckets with 2 teeth on them for digging out stumps. Going from a standard bucket to a single tooth gives you a lot of concentrated force on that single tooth.

 

[IslandTractor]

In theory you could design the the ultimate root ripper/saw but in reality it still might not work the way you want. If there was some kind of ripper that would cut roots, it would be on the market. I guess something like a vibratory plow does but that's when the roots are packed in the ground, not like when you're digging out a stump. The only way to effectively cut all roots is to have a hyd. shear type attachment like is used on some feller/bunchers. Even when using an ax sometimes roots are almost like rubber and just don't want to cut no matter how sharp the ax is. I think a sharpened edge on the shank would cut some roots but a serrated edge, unless it was very thin and sharpened like a knife wouldn't do much more than just the sharpened edge. If you had a thumb on the hoe to use in conjunction with your sharpened edge could work to cut stubborn roots.

I've dug out some some pretty big stumps just using a 30" backhoe bucket. I think just a plain ripper would be a lot easier and not make as big of a mess. I've also seen really narrow buckets with 2 teeth on them for digging out stumps. Going from a standard bucket to a single tooth gives you a lot of concentrated force on that single tooth.

I agree with your observations. A plain Jane ripper is far better than a bucket for dealing with roots simply due to the concentration of force. The challenge is to keep the root in one spot so that force cuts rather than moves the root.

 

[DocDryden]

You should take a look at Billstmaxx on youtube. Not sure how long ago it was but he was building a Ripper tooth attachement for his jd 110 tlb. You can go to youtube and do a search for " billstmaxx Ripper tooth ''

 

[bluehog]

Understood. The center support gussets don't seem to interfere or clog but my soil is very sandy. Not sure that would be the case in moist clay. I would imagine the ripper blade is stiff enough without them but I do like the idea of the lateral bracing. Perhaps smaller braces would be a compromise. I honestly have no idea if they are necessary.

I was thinking the same thing with slightly narrower gussets for support. See the attached images below on what I came up with. I extended the back paddle another 1.5" and widened its attachment to the shank to extend 2" on each side of the shank (more scooping volume). I shortened the front paddle 2" and widened it at the shank 2" on each side as well. Shortening this allowed me to add another beveled tooth. (I still can not figure out how to add the bevels to these teeth in this software).

The chunk of drilling rod I welded to the back works fine. The challenge in using it is to train the operator to be as facile with his "backhand" ripper motion (push and dump motion) with down pressure as with the more standard pull and curl control. Just takes learning to smoothly control that motion which doesn't get as much practice so is harder to do with a fluid motion. It does rip a chunk of wood out when done properly but I have no idea if it is more or less efficient than serrated teeth.

If you use two short tapered starter pins, just make sure to leave flat tips on both so one can easily push the other out.

Good luck with the fabrication.

I certainly am a novice at the operation of the backhoe. These things are quite powerful and can certainly do some damage when the wrong lever direction is engaged.

If you use two short tapered starter pins, just make sure to leave flat tips on both so one can easily push the other out.

Good luck with the fabrication.

I will make it appoint to have good size flat tips (625"-.750") so they will have good contact with each other when driving them out the other end.

I appreciate yours and everyone's help on the design & suggestions.

 

[IslandTractor]

Your latest design looks pretty close to mine. Didn't get a chance to measure mine this weekend though.

I'd say even half inch flat tips would be fine to allow the pins to be pushed out. Just don't want pointy tips that might override and jamb.