Export thread

1999 Husqvarna built/ Sears Craftsman with a 46" deck. I can't remember the model number but can get it. It's out in my storage building and it's pouring down rain at the moment.

A few years ago I came too close to something and broke the weld on the left hand deck hanger. I welded it back and it held for about 5 or 6 more years until the other day I came too close to my storage building and cracked the weld once again!

Since I welded next to and on top of the old welds, I can't really tell exactly where the original location where this bracket needs to go back on. I did try to hold it on and mark it but couldn't really tell much.

I took the bracket into work and got out a massive 6" grinder and trimmed all the old welds off the bracket. I still need to grind the old welds off the deck and fill in the large crack.

When holding the bracket up the deck, it doesn't seem to jive. I tried not to grind into the bracket itself. Just the welds.

This time I decided instead of welding it on like the factory did, I found some metal off the rack at work and made some aluminum L-brackets and drilled some 5/16" holes through them. The idea is to place one bracket on one side of the steel hanger bracket and one on the other and line the holes up and run a bolt through both the hanger bracket and these L brackets. And bolt these L brackets to the deck.

The theory is five 5/16" bolts should be stronger than a weld. And if I do hit something hard again, my theory is the aluminum brackets may break before the bracket does. Allot easier to just make new brackets and bolt them on.

So here is my request.

Does anybody have one of these mowers or a 46" deck like mine laying around (early 2000s) they can measure the distance from one hanger bracket to another at both ends?

Any chance Husqvarna has not made a design change in their decks and I can just go up to Lowes with my tape measure and measure the distance from one hanger bracket to another?

The other option is to bolt the deck on, attach the other hanger to the hanger bracket, shim up the deck on the broken side and see where the hanger bracket sits on the deck and mark it. Then pull the deck back off and drill the holes. Kind of a pain but if I had measurements that would save me some time.

Seems like there is enough play in the hanger brackets I can make some adjustments if necessary if I don't get it mounted exactly where it was. Like using a longer bolt, flat washers, etc. Since the deck is not "ridged' and just floats around if you know what I mean.

I think the main thing is the deck is level. I was afraid if the deck ends up being cock-eyed, it could through the belt off.

But kind of doubt it.

Aluminium has the lowest fatigue strength of just about any engineering metal
So your strengthening plates will not last long
If that weld cracked then you are either not getting enough penetration or have way too much vibrations from the deck, or both.
I find that gas welding makes a much better deck repair than electric welding as the extra heat stress relieves the weld and the adjacent steel.
We use swing back blades down here so I have a never ending supply of high tensile patch plates but what your deck hanger needs is some better left right bracing so a buttress of some king that does not foul on the deck lift is in order.
pay very careful attention to your blade balance.

bertsmobile1 said:

Aluminium has the lowest fatigue strength of just about any engineering metal
So your strengthening plates will not last long
If that weld cracked then you are either not getting enough penetration or have way too much vibrations from the deck, or both.
I find that gas welding makes a much better deck repair than electric welding as the extra heat stress relieves the weld and the adjacent steel.
We use swing back blades down here so I have a never ending supply of high tensile patch plates but what your deck hanger needs is some better left right bracing so a buttress of some king that does not foul on the deck lift is in order.
pay very careful attention to your blade balance.

Click to expand...

I never got a notification that I got any replies.

I bought this mower in 2009 The factory weld broke around 2015. My weld broke the other day. It's always the bracket on that side that breaks because I hit something. I was going around my storage building and came too close to it.

I ended up using those aluminum brackets I made. I only made a few laps to see how well it mowed and it seemed to do OK.

If these brackets do break, I'll make some out of steel. A friend said he had a 46" deck at his garage. I went over there and it was a different design. I managed to line the bracket up based on the remaining weld and made a template out of cardboard based on the cable bracket and think I got it lined up to where it was.

I also welded up any cracks and that gaping hole from where the weld broke and pulled a chunk out of the deck. I did not weld the bracket back on. It took longer to grind all these welds off than it did to drill holes for these brackets. I think I spent a total of three hours repairing this bracket today.

Probably the same deal as OZ but in the US, years ago people use to weld trailer hitches onto trucks. We went out west in 1977 with our camper and somewhere (middle of Kansas) the weld cracked on the hitch. Luckily the hitch did not break completely off. We were lucky and found a welding shop to weld it back. He did not tell my mother this happened. Otherwise she would have freaked out. Since then the US government has banned welding hitches onto the frames of trucks. They must bolted the frame. Since a bolt is stronger than a weld. So that was my logic.

I forgot to take a photo before putting the deck on. Dad stopped just by to tell me he heard a lot of grinding and hammering going on and wanted to see what I was up to. So I got distracted.

But here are two pics with the deck mounted on the mower.

Battery on laptop went dead before I could upload the pics:

Good luck.
The fatigue strength of most aluminium alloys is around 250,000,000 cycles.
If you assume a single rotation of the blades is 1 cycle & they are turning at engine speed 3,600 rpm or there abouts , you can do the maths but it should work out around 1000 hrs.
Another good thing about torch welding ( & TIG for that matter ) is you can rework the old weld, no need to grind it off.
When I reweld a hanger I put a strengthening plate ( old blade ) under the deck and use a bigger tip to weld all 3 together , flip the deck, do some smithing on the plate then a circumferential on the plate.

Not had one fall off again to date.
However when electric welding decks I get an unacceptable short life failure rate.

And yes hitches must be bolted on here as well.
The bolt in shear is actually weaker than a GOOD WELD in shear but that rules out about 40% of mine.
the other problem is a lot of trailer chassis are made from heat treated sections and welding can substantially weaken them.You probably have noticed a lot of truck chassis with "NO WELDING" warnings, usually right above where the hangers for the mudflaps are welded on.

I hear what your saying. This probably won't be the last time I have to pull this deck off. The mower itself has been good. The only problem I've had with it is related the deck due to my yard being rough as hell. I take better care of my mowers than most people do their cars. I think you commented on how clean the underside of my deck was in another post. I even goto the trouble of blowing the deck and entire mower off with my leaf blower before blowing my driveway off.

I realize the reason the factory decided to weld the hanger brackets onto the deck was it was quick and dirty on the assembly line.

The main reason I used the aluminum was because it was the correct size I needed. Most of what we have at work is angle iron and was going to require more cutting on the bandsaw and this was what was convenient at the time.

I mowed yesterday for about four hours and the brackets are still holding. I think as long as I avoid hitting stuff, they should hold up. If not I'll make some out of steel. I have to keep my eye out for scrap metal at work.

I know what my main problem is. I've got allot of tree roots on my property and I try to avoid hitting them with my deck but sometimes it's hard to. I think what broke these welds to begin with was not metal fatigue or a bad weld but those plastic anti-scalp wheels hitting small tree roots and putting pressure on the hanger bracket. I've actually had to weld both the front wheel brackets onto the deck from hitting tree roots.

The welder I have is electric. It's not a high dollar unit. Flux coated wire.

Hitting things bends, twists & warps.
If a weld is overloaded by a shock load the area around it is deformed so if you simply redid the welds the hanger hole would not line up with the frame.
If a weld breaks cleanly so it looks like you could just glue it back together and the deck would fit perfectly, that is fatigue.
Fatigue is caused by sub critical vibrations.
On a mower that is either from the engine or from the belts & blades
Because the deck is loose mounted to the frame the engine vibrations are usually not a problem.
So you are left with the blades.
Because the blades are a single bar they produce a vibration on every rotation, even if they are perfectly balanced, left - right & front - back.
A cross shaped blade would produce less vibrations.
If you are into helicopters it is the same principle as the number of blades on the rotors, the more blades the smoother the lift.

Then there is things like the tension arm.
If you put your hand on it ( VERY CAREFULLY ) when the blades are spinning you will feel it vibrating.
Add to that the pulleys are not perfectly balanced either static or dynamically .
And finally there is the belt itself.
Belts are not made in a ring like a tube then cut to width, they are made from a continious length of rubber cut & joined.
Thus there is a spot, the join, that has different stiffness to the rest of the belt.
This will also set up vibrations.

If you talk to machinist, particularly lathe operators they will tell you about chatter marks that are made when taking fine cuts caused by the join in the belt.
This is why on multi belted pulleys you never align the joins.

Then there is the weld itself.
With an electric weld you suddenly apply a drastic amount of energy to the joint, so the steel goes from room temp 20c to 2000c in a few millimeters.
This has a drastic effect on the microstructure and it becomes even worse on stuff that is made during winter where the deck pressings can come in from an outside sub 0c yard then be welded.
Without post weld heat treatment every electric weld is a very high stress zone and being highly stressed make it very prone to fatigue as the crack relieves the internal stresses created by the weld.
Way back in high school chemistry they tried to tech you that every thing on the planet will attempt to go to its lowest energy level , which is why metals corrode and why stressed joints crack.

And finally what most people forget, a weld is a casting and castings are stiff where as the deck pressing is wrought steel which is flexiable, so at the weld face you have a flexiable part and an inflexiable pat subject to vibrations fllexing them.

SO fear not about munching & crunching through your grass.
You are not to blame unless you are using blunt blades that are not balanced.