Brush Cutter Backstops

[Central_PA_Chris]

Well, I snapped my first bolt on my brush cutter! It's a rite of passage I'm glad to have passed. It stayed under the mower deck, no flying, no impaling, no bleeding. Snapped a backstop bolt off simultaneously (I think/assume)

I dug through the old posts on brush mower attachments here and Bobrip posted about putting some rubber bumpers made of horse matting on his backstop bolts. I just wanted to see if Bob (or anyone else who has done a simliar mod) had any comments/long term report on that improvement.

I will say, the 425 was amazing at clearing large mutiflora and other brush. I was making clearings/paths to/around downed trees that I want to cut up as fire wood and it really did the trick. I now know why y'all say it's the only tractor that will go where a atv will go.

Thanks,
Chris

 

[woodlandfarms]

I have gone through huge rounds with my mower... I did horse mat, tried to do tire, did hockey pucks (moderate success).

Currently I am at hardened grade 8 bolts with a stack of washers attached. The washers are bent up a bit, but the Grade 8s seem to be holding. Not looking forward to me being wrong on this one.

One thing, I have 3 rotors under my deck. The one that is powered directly by the hydraulic motor and two that are belt driven. The belt driven have the stoppers on them, but on the main drive I have no stoppers at all. Just put in hex caps in the holes. I found that the direct drive rotor was unlikely to have the blade sticking to the stump jumper like the other two.

I have some pix, somewhere...

 

[SnowRidge]

Get longer stop bolts and put a nut on them before threading them in. That will take care of a lot of the problems. The blades will no longer pass over the bolts and jam.

Starting the cutter with the throttle at idle helps a lot, if you aren't already doing that.

 

[BobRip]

Well, I snapped my first bolt on my brush cutter! It's a rite of passage I'm glad to have passed. It stayed under the mower deck, no flying, no impaling, no bleeding. Snapped a backstop bolt off simultaneously (I think/assume)

I dug through the old posts on brush mower attachments here and Bobrip posted about putting some rubber bumpers made of horse matting on his backstop bolts. I just wanted to see if Bob (or anyone else who has done a simliar mod) had any comments/long term report on that improvement.

Thanks,
Chris

The rubber horse mat did not last long. I think the grade 8 bolts with a stack of cheap washers is the best that I have tried so far. They get bent after awhile and break, but hold up for quite a while.

There must be something that would crush and recover, maybe a spring would work. Just thought of that. Weld the middle of two springs to the bolt head, forming an X with the bolt head at the cross of the X , so that the end of at least one spring ( or maybe two) would be hit by the blade. This would give a longer deceleration distance and time and soak up the energy with less damage to the blade and the spring assembly. Sounds real good. Somebody try that and let us know. What was I doing tomorrow, maybe this.

 

[Central_PA_Chris]

I was hoping the rubber solution would mean less blade bending. I noticed that my blades have a bit of curve to them and was thinking that at least part of that is probably the slamming against the stops when bouncing off a stump/rock.

I have been incorporating start at idle into my habits, but I'm not 100% yet, especially when stomping brush down and restarting the blades repeatedly when clearing, though there seems to be little slam then as the brush is taking the starting force.

 

[cqaigy2]

I did the hard bolt w/stack o washers too. That lasted much longer then anything else ive tried.

 

[SnowRidge]

For those of you who aren't familiar with them, the 3PH cutters that are used with CUTs don't have these problems because they don't have stops. Their blades are mounted on a wide pan called a stump jumper and are height staggered so that they can pass over each others bolt ends. They don't need stops.

Hundreds of manufacturers large and small use this tried, true, and reliable system, but not Power Trac, who has to mount the blades on a cheesy brake drum in order to save a couple of dollars.

Edit: By height staggered, I mean they are mildly Z shaped. See the pic, which happens to be a high lift blade, too.

 

[woodlandfarms]

I also made my own new blades. Not sure I did the right thing in my design, but basically went to 1/2" hardened stock, had the edge cut up, and then bent the trailing edge up a bit to get lift. My originals were heavily bowed and the front edges looked like the back edges, they were so easily dented.

I will say mowing late summer things are a LOT dustier than they used to be. Not sure if my cuts are any better (once I get the brush cut down and sprayed, I put in orchard grass) so now I am cutting a lot of grass...

 

[BobRip]

For those of you who aren't familiar with them, the 3PH cutters that are used with CUTs don't have these problems because they don't have stops. Their blades are mounted on a wide pan called a stump jumper and are height staggered so that they can pass over each others bolt ends. They don't need stops.

Hundreds of manufacturers large and small use this tried, true, and reliable system, but not Power Trac, who has to mount the blades on a cheesy brake drum in order to save a couple of dollars.

Snow, could we modify the drum to match the standard brush cutter?

 

[SnowRidge]

Snow, could we modify the drum to match the standard brush cutter?

I think it would have to be replaced. It would be a lot of work with some engineering required.

If there is someone out there with access to a 48" 3PH cutter, could you measure the width of the stump jumper and post the results?