Using an easy out / bolt extractor

[NormL]

The one thing I should note here guys is that these bolts are held in with Caulk. They are not rusted in and there is little resistance once I get a grip on the bolt.

Here is a pix of the blade setup. Because this is a lighter weight cutter, balance is a key issue so welding needs a delicate touch,

You didn't find a lost roll of page wire fencing that way did you? :laughing:

 

[dieselmechanic]

You might try grade five bolts grade eight are great for clamping force but break easer with a side shock load also a salesman from fastnall told me the specs changed a few years back the new grade five has same rateing as the old grade eight and the new grade eight is higher now

 

[slowzuki]

The grades didn't change as far as I know, none of my tables have been updated, he likely just didn't have any gr 8 in stock.

A grade 8 bolt used as a shear bolt will take too much force to shear and could break equipment designed for a grade 5 bolt. In this application where you need to hold the blade on, no way should a grade 5 be substituted.

An even higher grade such as metric 12.9 class might be used, they tend to be strong and retain some ductility.

I would look for some thing with a smoother head, maybe with a recessed allen head such as disc mowers use which suffer the same wear.

 

[North Country]

I never heard a thing about the grade changing. That's the whole point of standards - they don't change. Is the inch also shorter now? :laughing:

Maybe - maybe - he meant Fastenal's grade 5 as now as strong as grade 8, but that would also be wrong - shear bolts wouldn't shear.

If that salesman told me the sun was setting in the west, I'd go look for myself.

 

[Soundguy]

Now the obvious question: Why do the bolts keep breaking? 6 bouts a year with any kind of extractor would prompt me to find a solution such as a larger bolt. Maybe at least a preventative changing of the bolts before they break.

hmm.. sounds like a place for a gr10 bolt then?

soundguy

 

[sandman2234]

The one thing I should note here guys is that these bolts are held in with Caulk. They are not rusted in and there is little resistance once I get a grip on the bolt.

Here is a pix of the blade setup. Because this is a lighter weight cutter, balance is a key issue so welding needs a delicate touch,

As far as the PT bolts, and blades problems, being there is easier to determine a fix than from the armchair, but it does seem that a protector around the head of the bolt might be one way to fix it, but that does bring up the problem of raising the head by the thickness of whatever you use to bolt it down. However, going around the thickness of the blade might be a way to keep it low(er) than sticking a washer with sides that ramp up over the bolt head to keep deflections going away from the bolt head. I assume that the bolts are shoulder bolts, and step down at the entrance point to the stumpjumper.
David from jax

 

[SPYDERLK]

Due to a design flaw I replace abou 6 5/8 bolts a year on my mower. These bolts hold the mower blades on.
Carl

Going higher Grade ... 10? -- Can you rethread and go up a size on these bolts?
larry

 

[AlanB]

I am thinking along the lines of what Slozuki suggests. My first thought is a large dome headed Allen type bolt. I would take a pic and go to my local bolt supplier and ask if they have any suggestions but I dang sure would be doing something different. If nothing else another entire stump jumper cover with bolt pockets. Put them in at 90 degrees from your existing blade bolts and fit it tight against the heads of the other bolts. Weld a short piece of pipe in for your retaining bolt holes and weld a washer to the bottom. Use the same bolts as for your blades if there is clearance above the existing stump jumper so you don't have multiple sets of hardware to keep up with.

Good luck.

 

[North Country]

Going higher Grade ... 10? -- Can you rethread and go up a size on these bolts?
larry

If the bolts are breaking and you replace them with something stronger, something else might break. As much of a PITA as it is, bolts are the cheapest part of the system.

 

[RickB]

Is that your 'design flaw' hanging from the center spindle in the photo?