ATV Pulled Brush Cutter Build

[gun410]

I played around with the spindle a little more and ended up getting it a little better with .002” runout. That should be plenty good for this machine.

The next steps are to build the blade assembly, but I gotta figure out how to mount it to the spindle. For the blades I’m going to have a 2.5” wide 3/8” thick bar that the 2.5” wide 1/4” blades will bolt to the ends so they can swing if they hit a stump or rock. I’m planning to weld a 1” id tube/collar to the center 3/8” piece that the 1” spindle will slip on to.

I have to cut the spindle down to size and drill a bolt hole to secure it on the spindle. My first idea it to drill and tap the bottom end of the spindle with a 1/2” bolt going through a hole drilled centered on the center 3/8 bar. The other idea is to put a 3/8” bolt horizontally through the 1” id collar and the spindle, but it would be difficult to drill a hole perfectly centered and at the exact right height on both round pieces with my cheap drill press.

Bolting the blade assembly through the bottom of the spindle would be easiest but with a right hand threaded bolt would it get loose over time and start to back out?

 

[epanzella]

Make sure the blade mount assembly you build is balanced and symmetrical. That's a lot more important than a few thou runout.

 

[tq60]

Back with an update, frame is complete but unfortunately the top plate warped a small bit. I’m working on getting the spindle to run true. Because the top deck warped I had to make custom plates to get the flange bearings to sit flat. I welded the top piece onto the deck and bolted the bottom flange on.

I know that you want everything to be 100% true and concentric with spindles. And considering that this will spin 1700 rpms with a 44” blade It’ll have to be run true and balanced or the vibrations will destroy the bearings.

After mounting the timken bearings and tweaking with their set screws I was able to get the runout down to 3-4 thousands. I’ve spent a few days trying to get this spindle to run true and even with making the flat plates to sit under the bearings I can’t get it perfect. Would I be fine will the runout I have or do I need to figure out a way to get it to run perfect?
Thanks

44 inches in single blade is going to be issue.

Requires substantial amount of hp to run let alone cut grass.

The single bearing likely no good.

A trailer wheel hub as the block and spindle for shaft would be super strong and easy to service.

The vertical housing will be tricky to insure good air flow and not clog.

Good luck.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[gun410]

44 inches in single blade is going to be issue.

Requires substantial amount of hp to run let alone cut grass.

The single bearing likely no good.

A trailer wheel hub as the block and spindle for shaft would be super strong and easy to service.

The vertical housing will be tricky to insure good air flow and not clog.

Good luck.

Sent from my SAMSUNG-SM-G930A using Tapatalk

I should’ve explained it better, the overall cut width will be 44” and it’ll have 2 free swing blades on each end.

If my lathe was level I would’ve used a trailer hub but because I can’t machine a spindle I just used a 4140 1” keyed spindle with 2 timken flanges bearings. I think this should be a fairly strong spindle setup. If for whatever reason the bearings go out in a few years I can swap them for a trailer hub bearing.

The one thing I’m still struggling with is figuring out how to mount the blade assembly to the spindle. I’ll post a picture of a mock-up of how it’ll go together but im not sure if I should put a bolt vertical from the bottom and thread the if of the spindle or if I should put a bolt horizontally through the blade assembly’s tube/sleeve.

The sleeve will be cut 2” long and will be welded to the exact center of the center blade bar. The center bar will have 2 bolts at the end to attach the swinging blades to. Which way would secure the blade assembly to the spindle the best? Thanks

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[Braeden P]

My uncle made one out of an old mower deck it is so loud because he slapped on an engine that has no muffler.