Bush Hog repair question

[rslee]

I have an old 6’ Bush Hog that has a cracked blade bar at the edge of the shaft hole for the gear box. It doesn’t have a stump jumper, and I hit the bar on a stump the last time I mowed. Is this something that can be safely welded to repair, or is that too risky? I know balancing will be an issue, but being right at the center hole should help. Otherwise, the part is $440 on an old cutter, so would be a total loss and would replace the bush hog.

 

[scootr]

Sure sounds like something that could be welded up. Can you post a picture?

 

[rslee]

I’ll try to get under it this evening. I’d sure hate to scrap it. It’s solid otherwise. Just put top and bottom seals on the gearbox, and it runs like a champ. It’s a Bush Hog 266, so old solid built machine.

 

[scootr]

I’ll try to get under it this evening. I’d sure hate to scrap it. It’s solid otherwise. Just put top and bottom seals on the gearbox, and it runs like a champ. It’s a Bush Hog 266, so old solid built machine.

Know what you mean about solid built - I'm working on one of these old BH units right now.

 

[rslee]

Here’s the crack.

 

[manac]

Please junk it. You wouldn’t want to throw a blade.
The stresses on that bar are huge at speed.

 

[beckmurph]

You should be able to replace that cross bar.
Check with a Bush Hog dealer.

 

[John0829]

As simple as that cross bar is go to a machine shop and have a new one made if it is not able to be sourced.

 

[Williy]

I would differently weld it. No cause to spend money on a new
one when what you have is very fixable! If a weld in not very
strong then they wouldn't make welders!

willy

 

[rslee]

No way I’m buying a replacement bar. They are $440 online from multiple suppliers. Not worth it. I think a competent welder could grind that crack open a little and fill it with a good bead. I’m not him. I’ll check around and get some opinions from a couple of shops. Otherwise, I’ll have to sell it for parts and buy another.

 

[hosspuller]

Willy might weld it for you, but I would not. Even at half the price of a new part, the liability isn't worth the squeeze to me.

 

[mikester]

Willy might weld it for you, but I would not. Even at half the price of a new part, the liability isn't worth the squeeze to me.

Looks like Willy already welded it a couple of times.

Maybe the previous owner welding bush hog blades also cleans/cleaned his loaded guns in order to save time and money.

 

[Tinhack]

That right there is death waiting to happen. I'm not a mechanical engineer but I bet there's 5 tons or more force on that bar.

 

[Slowpoke Slim]

I think a pro welder (not me) could weld that just fine.

If it was me, and it was here, I'd take it to a local weld shop called Glen's Welding.

We're talking relatively low rotating rpms here guys. This is not a turbine shaft for a jet engine rotating at 100K+ rpms.

I'd be much more concerned with not having a stump jumper.

 

[diesel85]

I would weld it. Even if it did come off, it will be like a rock getting hit. Also, there should be NO bystanders around when using a bush hog.

If there is that much questionable debris, I would consider a flail mower to keep things contained. Which is a reason why I went with a flail because they are much safer.

 

[hosspuller]

I think a pro welder (not me) could weld that just fine.

If it was me, and it was here, I'd take it to a local weld shop called Glen's Welding.

We're talking relatively low rotating rpms here guys. This is not a turbine shaft for a jet engine rotating at 100K+ rpms.

I'd be much more concerned with not having a stump jumper.

Let's do a little math ... The blade is turning a 6 foot circle. Don't know the gear box ratio.. so lets say 1 to 1 then, the blade is turning at 540 rpm.
What's the tip speed ? 6x3.14x540=10,173.6 feet per minute.
How fast is that? 10,173.6 /5280 = 1.93 miles / minute
My car speedo reads miles/hour so...1.93x60=115.8 miles per hour.
I can then say... the approx 25 pounds of half blade holder plus attached blade is moving around 100 mph when it lets loose.

I won't be standing in it's path. Would you ?

 

[LD1]

I am a welder....but I wouldnt weld that.

I dont care what anyone says....but a weld is never as good as virgin metal. Sure the "weld" may be stronger.....but the heat affected zone of the bar is gonna become a new weak area.

Take it off. If its splined, see if you can match a replacement via other sources. If its a simple keyed hole, or even tapered and keyed....might be easier for a machine shop to replace

 

[ROUSTABOUT]

Please junk it. You wouldn’t want to throw a blade.
The stresses on that bar are huge at speed.

Ive thrown several blades. Every one was laying in the path I was cutting. Weld it up and keep going. Full pen only.

 

[ROUSTABOUT]

Let's do a little math ... The blade is turning a 6 foot circle. Don't know the gear box ratio.. so lets say 1 to 1 then, the blade is turning at 540 rpm.
What's the tip speed ? 6x3.14x540=10,173.6 feet per minute.
How fast is that? 10,173.6 /5280 = 1.93 miles / minute
My car speedo reads miles/hour so...1.93x60=115.8 miles per hour.
I can then say... the approx 25 pounds of half blade holder plus attached blade is moving around 100 mph when it lets loose.

I won't be standing in it's path. Would you ?

2:1 is ratio for bush hog. Cheap off brand cutters are 1.5:1

 

[mrmikey]

I am a welder....but I wouldnt weld that.

Same here, wouldn't tough it with a ten foot pole.
If the non-welded version broke so will the welded version...only faster. Does it have any particular type of fastening method, spline, notch or some other kind of attachment? If it's just the bolt in the center, why can't you make one from a suitable size piece of flatbar?