Stump Grinder Questions!

[J_J]

Scotty370,

This is what I have , and it is driven by 12 GPM PTO pump/

 

[Scotty370]

OK- Let's see if I can do this! The frame is finished! Just have to start moving to the rear! Next will be the swing arm and gearbox mounting plate. Ordered rams last night. need them for measurements on this design/build! Picts from top left: 3rd SCV ports installed, which will be my hydro-power. Next 3 are the lift plates and Top link bracket alignment. Next two: Are the hinge fabs for the lift/swing cylinders. The rest are self explainatory. You can see my gearbox, and side plate waiting patiently under the bench for it's day in the sun!! . ~"Scotty"

 

[J_J]

Scotty370,

Looking Good.

Did you test your gear box to see if it was turning in the right direction. We have been talking about some of the gear box's in another thread, in ref to reverse tine tillers. What rpm will it be turning at 540 PTO speed? The input to your gearbox is going to be counterclockwise, correct.

 

[Scotty370]

J-J-Rotation is a funny thing to describe! Looking at my PTO from the back, it rotates clockwise. So, if I were backing up (on the seat!) to the attachment, it would indeed turn the gearbox counterclockwise. This would in turn have the lower wheel cutters, casting the chips to the rear! My 540 PTO, gets stepped up by a 1.47 ratio in the GB, so it'll be about 800 RPM's at the cutter wheel axel. With a 22", (call it 23" wheel w/ cutters), the 'tip' speed comes in at about 4814' per min, or 80' per second! The frame, at least, fits on the Tractor!

 

[J_J]

Scotty, Is that the direction you want it to turn?

 

[Scotty370]

I was have different thoughts on the rotation, but in the final analysis, yeah. I think I want that "stuff" flying rearward! Now I'm rethinking my wheel width! Was going to go with 1/2" plate that I had, but now that I'm buying a piece, I'm toying with going thicker. 3/4" to 1", Purely for the 'inertia', that a heavier wheel would bring to the mix. Thoughts anyone? ~S

 

[J_J]

Scotty,

Whatever you have chosen for the teeth, check and see if the bolts are long enough to go through the wheel. You could also flip the gearbox over and it will turn the other way. Two 1/2 in plates could be bolted together for a 1 in wheel. Have you seen those teeth that look like a shallow cup. You can rotate them 4 times for a new cutting surface.

 

[MikesTractor]

Scotty,

I tend to agree with you on the thicker wheel. Like you said, there would be more 'inertia'. The extra spinning weight would would be more resistant to bogging down. My thinking is that this would take some of the shock out of the driveline also. If you had a light wheel spinning, it would be easy to stop, so it would tend to cause more shock on the driveline. But when you get a heavier wheel spinning, it will take more effort to stop. This would be a slower, smoother stop.......make sense?

Or am I way out in left field?

Mike

 

[Scotty370]

J_J- I think I'm going with Greenteeth: Green Manufacturing Greenteeth Shopping

They can be rotated. Looking at Machine kit for Rayco 1625 Super Jr, or RG1631. I've got some time! Just need 18 or twenty friends to send in for the free sample . They also have "Dollar-Day" specials, that maybe would work. Gotta absorb my ram purchase $ out-flow for a couple weeks, then settle on the wheel purchase first! ~Scotty

No, Mike I think your 'Center-Field'! Everything you say makes sense! But since that post, I'm re-re-re thinkin' what a heavier wheel would do to the gearbox bearing 'testing' that they're going to see! ~S

 

[SuperDuty335]

Very cool! I might have to build one when I finish my hydraulic auger.

 

[kruszert]

Scotty,

I am using a 3/4" thick wheel but only because that is what I found in the scrap pile. When I bought the cutting teeth from Greenteeth I told them the wheel thickness and they sold me slightly longer bolts to accommodate the
3/4" wheel.

Reggie

 

[Scotty370]

KZ Reggie- Talk to me about your teeth count and placement! Any pixs available yet? ~Scotty

 

[kruszert]

Scotty,

I am using 6 sets of angled teeth. A set being two holders angled about 35 deg. out. The six sets are equally spaced, 60 deg. apart. In addition I have two sets (again two holders one on each side) of straight teeth. The straight teeth sets are 180 deg. apart between sets of angled teeth.. I was told that I needed the straight teeth if I wanted to grind straight into the stump. Basically I copied the Vermeer stump grinder SG 252 wheel design. It uses a 16" wheel.

Also, since I am using chain drive, I have increased the speed of the wheel. Again I used specs from several stump grinders. Woods TSG 50 has a tip speed of 5428 ft/min, Worksaver SG-26 has 5515 ft/min, model SG-36 uses 7430 ft/min. I have a gearbox with a 1:1.46 ratio with a 17 tooth sprocket going to 11 teeth on the main shaft. If I got it all right I should end up with about 5739 ft/mim. I didn't take into account the added stickout of the teeth on the wheel so I will end up slightly faster -- haven't measured the final O.D. but I would guess I end up slightly over 6000 ft/min.

I spent yesterday and today at a graduation and have filled up every digital card we own - - if I can find a little space on one I will get a picture or two and post Monday.

Reggie

 

[kruszert]

Here are some pictures. Lots of work left to do - - guards, hydraulics, etc.
Won't get much done this month. Hoping for June completion.

Reggie

 

[Scotty370]

Doggone it Reggie! Ya make me feel like the guy that brought the knife to a gunfight!! Absolutely beautiful!!! Design, Fabrication, Welding, Shop.....what more can I say! Keep us all posted! (And fill out your profile, so we can all see that you're a Machinist/Welder!) ~Scotty

 

[kruszert]

Scotty,
Thanks for the comments but I'm more of a home shop type - - - just good enough to get into trouble. Hope this thing works and makes chips!

I saw your other post about PTO deflection - - I have tried to keep it to a minimum but I have also wondered about that. Also, I wonder if the wheel needs to be balanced - - maybe not perfect but a little. I kind of figured that considering what it is going to be doing, pounding into a stump, that it wouldn't matter. I didn't see any signs of balancing on the Vermeer grinder wheel I looked at. The best I could do is a bubble balancer - - - not sure.

Reggie

 

[Dongerosa]

Hey guys...got any pictures of the finished stump grinders?

 

[Scotty370]

Might want to look here:
http://www.tractorbynet.com/forums/build-yourself/147454-stump-grinder-finished.html