ATV Pulled Brush Cutter Build

[gun410]

From what I heard from reviews some people had problems with them. I ordered the timkens with the set screws. I’m thinking about drilling them for pointed screws but the good thing is the shaft is threaded. So the pulley will be resting on the bearing’s collar with a 1-14 lock nut above it. I’m thinking with the nut holding the shaft it shouldn’t be able to come out.

I started cutting and forming the steel for the deck. I should have it put together soon.

 

[gun410]

Framing is complete, some could say this is a little overbuilt but it’s better safe than sorry.
Next step is to get all the sides built and welded than it’s onto the engine’s mount.

I’m also trying to decide if I should run a pulse fuel pump or an electric pump. It looks like I would need to drill into the engine for the pulse pump so that’s a downside, but with an electric pump you have to worry about moisture.
Any one with experience have suggestions for running these?

 

[gun410]

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

 

[epanzella]

Just make sure you're not eliminating runout by bending the shaft. I always use the self aligning bearings.

 

[gun410]

Just make sure you're not eliminating runout by bending the shaft. I always use the self aligning bearings.

I haven’t put any pressure on the shaft but I actually am using self aligning bearings. I’m still getting about .003 of runout with my indicator. These are also nicer bearings by timken so they shouldn’t be the problem. Have any idea why I’m getting this runout?

 

[epanzella]

I haven’t put any pressure on the shaft but I actually am using self aligning bearings. I’m still getting about .003 of runout with my indicator. These are also nicer bearings by timken so they shouldn’t be the problem. Have any idea why I’m getting this result?


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If you're getting runout with self aligning bearings it's gotta be the shaft. Three thou isn't bad. The propshafts on my boat engines have about that much runout and the bearings are still fine after 16 years.

 

[extropic]

The setscrews are pushing the shaft to one side of the bearing bore. That pretty much guarantees TIR at least equal to the shaft-to-bearing clearance.

I don't have any experience with larger (than 24") lawnmowers. I assume that there are commercial mowers with 44" blades. Do they also run a shaft as small as 1" diameter? Just a gut feel, but it seems a bit light to me.

 

[epanzella]

The setscrews are pushing the shaft to one side of the bearing bore. That pretty much guarantees TIR at least equal to the shaft-to-bearing clearance.

I don't have any experience with larger (than 24") lawnmowers. I assume that there are commercial mowers with 44" blades. Do they also run a shaft as small as 1" diameter? Just a gut feel, but it seems a bit light to me.

My Swisher is a 44 inch but it has two blades.

 

[gun410]

If you're getting runout with self aligning bearings it's gotta be the shaft. Three thou isn't bad. The propshafts on my boat engines have about that much runout and the bearings are still fine after 16 years.

I doubt the shaft had bent it’s a strong 4140 go keyed kart axle I got from eBay and I check it by rolling it on a granite plate seems true.
Should I be concerned about more runout with the 44” blade or 14” v belt pulley up top?
It doesn’t make sense why it’s not running true.

Nice swisher mower you got if I was looking at them used but for rough cut mowers they use 1 spindle. Have you checked if it’s spindles have any runout?

I tried moving around the collar’s set screws to different spots and tightening them to eliminate runout out but that didn’t change much. Is there a way to eliminate it with set screw bearings or should I work with it? Only concern are the blades vibrating from runout, would the non concentricity and make the blades swing unbalanced?

I’m making my mower similarly to Clay’s on YouTube, is seems he has chinese non self aligning bearings but they do have the set screws too. So do you think would his runout would better better or similar to mine?

 

[epanzella]

I haven't checked the spindles for runout but I would be shocked if they're better than .003 TIR. If you're determined to reduce runout put a .001 shim at the high spot.