Mini Motor Grader build

[sawdustdad]

Another test drive with the new lights and completed paint. I'm working on the blade support and pivot frame. More on that next time.

https://youtu.be/w3UDzXzjSiA

[bugeye]

Looks great. Amazing build. i'm enjoying your progress.

[sawdustdad]

Here's an update. I've completed the blade mount and traction frame. This initial implementation will have a manually adjusted blade angle. I'm working as well on a gear driven blade circle, which I will retrofit at a later date.

I've been fabricating the hydraulic cylinder attachment points. Each point needs to have two degrees of freedom--pivot in two different axes. The third axis for each point is actually the piston rod which can twist inside the cylinder. So each point has, in effect, three degrees of freedom.

The reason for this (and it complicates the build somewhat) is because the traction frame moves up and down and left and right in an arc, so the cylinders and attachment points need to pivot to permit this without binding.

I've ordered the thrust bearings from McMaster, so once they show up and I've finished turning the rotation bushings for the cylinder brackets, I'll post some pictures to show how all this will work.

The last picture has only one blade lift cylinder--of course there will be a pair, plus a third cylinder which controls the blade skew right and left. Some of the attachment points are shown in another picture.

[athomas]

Looks like the real deal !!

[guido]

Totally awesome. I can see there is no dilly dallying in your shop.

[jaynjeep]

Originally Posted by sawdustdad

Here's an update. I've completed the blade mount and traction frame. This initial implementation will have a manually adjusted blade angle. I'm working as well on a gear driven blade circle, which I will retrofit at a later date.

I've been fabricating the hydraulic cylinder attachment points. Each point needs to have two degrees of freedom--pivot in two different axes. The third axis for each point is actually the piston rod which can twist inside the cylinder. So each point has, in effect, three degrees of freedom.

The reason for this (and it complicates the build somewhat) is because the traction frame moves up and down and left and right in an arc, so the cylinders and attachment points need to pivot to permit this without binding.

I've ordered the thrust bearings from McMaster, so once they show up and I've finished turning the rotation bushings for the cylinder brackets, I'll post some pictures to show how all this will work.

The last picture has only one blade lift cylinder--of course there will be a pair, plus a third cylinder which controls the blade skew right and left. Some of the attachment points are shown in another picture.

I've followed your builds for quite a while now.. All I have to say is this one goes far above and beyond.. this thing is freaking awesome.. you sir have some serious skills and motivation!

[sawdustdad]

Been working on the blade hydraulics set up.

The two blade lift cylinders are mounted, supported by a pair of fabricated trunnion bearings at the main frame. These allow the cylinder supports to pivot at the frame while the cylinder collars allow the cylinder to pivot within the support bracket. These two degrees of freedom, along with the fact the cylinder piston rod can rotate within the cylinder gives the necessary 3 axes of rotation.

The rod end brackets at the traction frame rotate on thrust bearings, have pivot pins and, for the third degree of freedom, depend on the piston rod rotation.

The next two pictures show the skew cylinder set in place, not fully installed. The skew cylinder support frame will get welded to the main frame (just clamped here) and the rod end bracket goes through the traction frame near that corner. Again, each attachment point pivots, rotates and relies on the piston rod rotation for the necessary three degrees of freedom.

Since the traction frame is connected at the front through the ball hitch, movement of the blade up/down and left/right results in all the traction frame attachment points moving in arcs. The frame itself moves, relative to the ball hitch, in roll, pitch and yaw. So each attachment point has to move in all three axes to avoid binding.

The skew cylinder end point brackets will take shear loads but only have thrust bearings. The thrust bearings do take some of the shear loads as there is a small moment arm through the attachment point, transferring some of the shear load to the thrust bearings. The shear loads will primarily be taken up by the 3/4 inch threaded shafts. I'm not totally happy with this set up so I need to revisit this, with more robust ball bearings, or, perhaps, bushings welded to or within the traction frame member. Not sure how long they will last the way they are right now.

Next task is to start measuring for the hydraulic lines and getting them made up. I'll post pictures of the valves once I've started to run the hydraulic lines and am happy with the set up.

[IHinIN]

Well done! That thing is going to be awesome. What kind of equipment do you have in your shop? Mill, lathe, etc

[jaynjeep]

Originally Posted by IHinIN

Well done! That thing is going to be awesome. What kind of equipment do you have in your shop? Mill, lathe, etc

Adam, I don't know what kind of equipment he has but I know he has some serious fab skills! All his builds are off the chart impressive for sure!!

[sawdustdad]

Originally Posted by IHinIN

Well done! That thing is going to be awesome. What kind of equipment do you have in your shop? Mill, lathe, etc

I've been a lifelong woodworker (hobbyist). Hence my screen name. After we, our kids and all our relatives ran out of room for furniture, I had to find something else to do. I still do some woodworking, but the metal bug has bitten.

For metal working, I have two vintage lathes, a 9 inch Logan 400 and a 10 inch South Bend, a nice Taiwanese clone Bridgeport knee mill, a Portaband saw, Mig welder, stick welder, plasma cutter, and a 12 inch disk/6 inch belt sander. And the usual drills, grinders, etc.