Bucket dentistry: better teeth for b/h & FEL bkts

[dfkrug]

This project has been on my list for a long time. It made it to prime
time when I realized that my backhoe bkt was broken.

I use my b/h for digging up and lifting many rocks, which puts a lot
of stress on the bkt teeth. I have the cast ductile iron (or cast steel)
bolt-on teeth that are seen on most hoes of 7.5 dig depth or less. These
teeth are fairly soft and rather dull. That is OK if your soils are soft and
fairly rock-free, but for me they are less-than-ideal.

The bigger hoes use welded on shanks (aka tooth holders), and replaceable
teeth made of tough plow steel. Just look at the Kubota BH90 vs. the
Kubota BH75. The replaceable teeth are usually either crimped on or pinned
on.

In the past, I could go to my tractor dealer and buy shanks for $15 or so
each, and the teeth for $5-10 each. No longer. In this project I design my
own shanks to fit the teeth commonly sold for box blade rippers. These
shanks are welded to my hoe bkt, and the teeth are tack-welded to the
shanks. I have also designed shanks with the right profile for the Kioti
KL130 FEL bkt.

The first photos show my damaged hoe bkt. Welded on shanks will
substantially increase the strength of the corners of the bkt, where the
front cutting edge meets the side cutting edge.

[dfkrug]

Next I perform the "root canal". I use my plasma cutter to cut out
material along the crack. This will allow me to weld a stronger bead,
and hopefully bend the cutting edge back a bit. The cutting edge that
the old teeth were bolted to is only slightly bent. When performing the
initial weld here, I put a cable come-along between the edge and the
opposite side of the bucket. I also swung my trusty 8-lb sledge hammer
a few times.

[dfkrug]

Now the tooth holders. I first made a template out of wood and fit the
teeth onto the holder mockup. The teeth have a 27-degree pocket. Next
I drew a full scale drawing with my CAD program. I printed the result and
compared to my template. When I was satisfied, I emailed the DXF file to
my favorite CNC steel shop in SoCal. And voila, they came by USPS. These
shanks are cut from 3/4" thick A36 steel plate and cost about $15 each for
the steel, the labor, and shipping.

Next: the installation.

[GuglioLS]

Originally Posted by dfkrug

.....snip.....I emailed the DXF file to
my favorite CNC steel shop in SoCal. And voila, they came by USPS. These
shanks are cut from 3/4" thick A36 steel plate and cost about $15 each for
the steel, the labor, and shipping.

Next: the installation.

Looks like a nice design to replace those worn out teeth, mind laying on the name of your favorite CNC shop? Thats an unbelievable great price you got. Were they cut by plasma, water jet, laser, milled, other?
So, when are we going to see them installed?

Larry

[dfkrug]

First the welding. I used my 220V Miller Thunderbolt buzz box set at about
110A DC, and I used 1/8" 7018 rods. The important part is the shanks now
provide very strong corners to the bucket. I recommend removing the
bkt for welding, unless you are very good at out-of-position welding. I did
all of my welds horizontally, as I am not.

Also pictured is one of the ripper teeth I used...I bought a bunch from
AgriSupply for a bit less than $5 ea, including shipping from back East.
This one has a 0.42" thick cutting edge, which is definitely better than
the 0.32" I have on my box blade.

[dfkrug]

Originally Posted by GuglioLS

Looks like a nice design to replace those worn out teeth, mind laying on the name of your favorite CNC shop? Thats an unbelievable great price you got. Were they cut by plasma, water jet, laser, milled, other?

Thx Larry. (BTW, the teeth I am replacing are not worn out.)

I used Associated Metal Products of El Monte, CA (626) 350-1710, and it
was cut on a plasma table. From the looks of the cuts, it was done under
water....no slag at all. The 3/4" steel did not cut quite as cleanly as the 1/2"
plate they have done for me, but it is quite acceptable. When I cut 1/2"
with my 40A PC, I always get significant slag.

[dfkrug]

OK, now the installation of the teeth onto the shanks. For b/h bkts, I
like the cutting edge on top. I have seen the other way, too. The second
photo shows how I tack welded them on, close to where they are normally
crimped into a dimple in the shank. I decided to do it this way cuz the
crimped teeth are more likely to be a bit loose and I have had some fall off
ripper shanks. Getting crimped teeth off can be more of a struggle than
cutting my 2 welds with a grinder. I don't expect I will wear mine out,
however.

[dfkrug]

I also designed a tooth holder for a Kioti FEL bkt. These shanks will be
welded onto the bucket, rather than onto a tooth bar that gets bolted on.
The reason I am going this route is that a tooth bar is about $325 plus
shipping, and you still have to drill holes for bolts. You also have a bunch
more weight on the bkt and the bolts can be annoying obstructions. The
bkt will use 11 shanks and teeth, for a total cost of about $230. An hr or
2 of welding will be needed, of course. (No welding shown here, as I am
doing this for someone else's FEL.)

The KL130 loader comes with a great bkt: it has a 5/8" cutting edge,
vs the 1/2" you normally see on CUTs. My shank is designed to closely fit
the profile of the cutting edge, and the 1/8" plate of the carcass. Since
the user of this FEL will put most wear on the tops of the teeth, the
teeth will be installed cutting edge up. Many tooth bars have their teeth
with the cutting edges down. I assume that the makers are anticipating
that users will be dragging their bkts on pavement.

AgriSupply sells 2 kinds of 27-degree teeth....I labeled them type 1 and 2
in the photo. Type 1 I used on my hoe bkt. They are made in India and the
welds look fair-minus. The type 2s cost a bit more but have more steel in
the cutting edge. They are made in Italy. The latter seem to be made a
little sloppier: distortions, weld spatter, etc. The welds look a bit better.
One of the shanks in the photo has been radiused with a grinder to make it
fit in the Type 2 tooth better.

[fiddler kelly]

When the teeth get wore down on the back hoe have you ever tried to rebuild the tooth with a welder and grind it then to the sharpness you want.

[dfkrug]

Originally Posted by fiddler kelly

When the teeth get wore down on the back hoe have you ever tried to rebuild the tooth with a welder and grind it then to the sharpness you want.

The OEM teeth on my hoe are composed of a cast steel or cast iron that
is fairly soft. They are very dull when they are new. It would take a lot
of grinding to get any kind of edge on them, and I am sure the edge would
get blunted very quickly. I considered welding some plow steel onto these
teeth, but it is hard to predict how strong that would be, welding onto cast
steel. The same applies to welding beads onto the tips and grinding them
down. Sharper teeth was only one goal of this project.

I just welded more of these shanks onto a 24" bkt, BTW.