# ATV Pulled Brush Cutter Build



## gun410 (Jul 31, 2020)

Hello, recently I started on my rough cut mower. It started when I saw a homemade cutter on YouTube. Last week I designed my own mower, and today I picked up a 4’x4’ sheet, 1”x2” channel and rectangle for the build. I got a Briggs Intek engine, an pto mower clutch, a 1 inch 4140 spindle(threaded & key notched) and a 13.75” pulley for the drive system. I designed my drive system similar to the mower below, but for the spindle he used 2 cheap flange bearings. With a mower that cuts small trees it needs to be heavy duty. 

Additionally, he only used the 4 bearing set screws to lock on to the spindle. It seems like even with locktite it would work it’s way out over time. I’m thinking of getting some timken flange bearings and notching the spindle for the set screws to hold better. But there’s still the question of how well could the bearings could hold up to the lateral cutting forces. I could put a bronze pushing in the space between the flanges but I don’t know if it would help much. 

However, I would rather save the $130 on timken flanges and use the trailer hub bellow. I could probably machine a spindle out of 17-4 but my lathe has a some twist so I’m not sure if it would work out.


Trailer hub: https://m.northerntool.com/shop/too...MImNDP_8_46gIVg4bACh1XYwrWEAQYAiABEgI2jfD_BwE

Clay’s Brush Cutter:


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## Nutfarmer (Jul 31, 2020)

In my work on farm equipment the set screw locks on bearings have a high rate of failure. I will only use bearings with the locking ring style. In light duty use the set screw will work,but a mower like your building will see hard use. I would spend the little extra and put in the better bearings. Your time is worth the small amount of extra expence.


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## gun410 (Aug 1, 2020)

Nutfarmer said:


> In my work on farm equipment the set screw locks on bearings have a high rate of failure. I will only use bearings with the locking ring style. In light duty use the set screw will work,but a mower like your building will see hard use. I would spend the little extra and put in the better bearings. Your time is worth the small amount of extra expence.



The timken bearings have set screws too, I’ve never seen a flange bearing with a clamp lock. Are you thinking of a shaft collar lock?


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## Cooter Brown (Aug 1, 2020)

Just spot drill the shaft under the set screw and use a pointed tip set screw, it wont move.......


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## gun410 (Aug 1, 2020)

I’ve been looking at various flange bearings, and I found timken’s V-Series flanges for a good deal on amazon. The V Series has a self locking collar, but it only has 1 set screw. Their design is “claiming” to tighten with use but With only 1 set screw per flange bearings it would seem a bit sketchy. I feel like I might be better off drilling spots for the set screws but these might be a better option.

Has anyone used Timkens V series bearings before? 
https://www.timken.com/products/timken-engineered-bearings/housed-units/v-series/


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## SLK001 (Aug 1, 2020)

What's the reason for the grease zerk?  Is the bearing open on the back?


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## gun410 (Aug 1, 2020)

SLK001 said:


> What's the reason for the grease zerk? Is the bearing open on the back?



The timkens have 2 rubber seals, so I believe their a closed bearing. The grease zerks say they’re for lubricating the unit, but I’ll link them below. They look quality but I don’t know how well the grip will be from the Eccentric locking collars.
https://www.amazon.com/dp/B006MIJFH8/ref=cm_sw_r_cp_api_i_hCxjFbCYRT6WQ


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## Nutfarmer (Aug 1, 2020)

We have had good results using that exact bearing style. The eccentric locking collars lock the shaft way better than set screws. You have to be careful not to over grease the bearings or it will blow out the seals and the bearing will fail in short order. I have had to remove the zerks  on some bearings and replace them with plugs because some operators would grease the bearings until they could see grease coming out of the bearing. Once that happens the seals are gone and the bearing shortly fails.


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## Alcap (Aug 2, 2020)

Have you thought about using spindles from an older garden tractor ?  My Power King used 3/4 or 1" shafts with taper roller bearings to and bottom with grease seals at each end . I'm sure some older tractors might have similar .


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## epanzella (Aug 2, 2020)

I used those flange bearings with eccentric collars on an ATV I built years ago. Not a single problem and my sons beat the hell out of that thing.


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## gun410 (Aug 3, 2020)

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.


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## gun410 (Aug 4, 2020)

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?


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## gun410 (Aug 21, 2020)

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


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## epanzella (Aug 21, 2020)

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


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## gun410 (Aug 21, 2020)

epanzella said:


> 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?


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## epanzella (Aug 21, 2020)

gun410 said:


> 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?
> 
> 
> Sent from my iPhone using Tapatalk


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.


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## extropic (Aug 21, 2020)

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.


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## epanzella (Aug 21, 2020)

extropic said:


> 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.


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## gun410 (Aug 21, 2020)

epanzella said:


> 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?


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## epanzella (Aug 21, 2020)

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.


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## gun410 (Aug 24, 2020)

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?


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## epanzella (Aug 24, 2020)

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


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## tq60 (Aug 24, 2020)

gun410 said:


> 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.
> 
> ...


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.

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## gun410 (Aug 26, 2020)

tq60 said:


> 44 inches in single blade is going to be issue.
> 
> Requires substantial amount of hp to run let alone cut grass.
> 
> ...



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 (Sep 2, 2020)

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


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