Update : Finally got blade bolt out on Super Z HD

JLH52

LawnSite Member
Went to my neighbor, who has about every tool that money can buy, he can also fix anything from a lawnmower to an 18 Wheeler. We took a KD 2500 3 ft. 3/4 in. Torque wrench. I blocked the blade with a short piece of wood, while he didn’t seem to apply much pressure at all and the bolt broke free. I don’t understand how the 600 lb. torque wrench could do more than my 1/2 extension with a 4 foot piece of pipe slide over extension from leverage. I cold not budge them bolt pulling with all my strength.

After freeing the bolt it was still tight removing It with 1/2 ratchet. Threaded part of bolt is 1.25 inches. Carefully examining the bolt it it highly visible that the threaded portion from head of bolt to center, is smaller in diameter than the last half of threaded portion, which is obviously larger in diameter.

There is also a crack around bolt exactly half way between head and end of bolt. Stretch picture of bolt below and you can see crack between 4th and 5th thread.

I don't have a clue how a portion of bolt could change diameter while installed in spindle. Thankful to get it out, will replace with new bolt. Thanks for all your replies and advice from previous thread.

Below is picture of Torque wrench and bolt.
06B8B324-0C0B-4F1F-B503-35C9F9422C88.jpeg



685BBA6C-CE9B-48B6-8D01-609E686B1EB3.jpeg
 

Ridin' Green

LawnSite Fanatic
Location
Michigan
Went to my neighbor, who has about every tool that money can buy, he can also fix anything from a lawnmower to an 18 Wheeler. We took a KD 2500 3 ft. 3/4 in. Torque wrench. I blocked the blade with a short piece of wood, while he didn’t seem to apply much pressure at all and the bolt broke free. I don’t understand how the 600 lb. torque wrench could do more than my 1/2 extension with a 4 foot piece of pipe slide over extension from leverage. I cold not budge them bolt pulling with all my strength.

After freeing the bolt it was still tight removing It with 1/2 ratchet. Threaded part of bolt is 1.25 inches. Carefully examining the bolt it it highly visible that the threaded portion from head of bolt to center, is smaller in diameter than the last half of threaded portion, which is obviously larger in diameter.

There is also a crack around bolt exactly half way between head and end of bolt. Stretch picture of bolt below and you can see crack between 4th and 5th thread.

I don't have a clue how a portion of bolt could change diameter while installed in spindle. Thankful to get it out, will replace with new bolt. Thanks for all your replies and advice from previous thread.

Below is picture of Torque wrench and bolt. View attachment 405296


View attachment 405295
Glad you got it out. As far as the bolt changing diameter.....that's an easy one. It was stuck good. You used a LOT of force to back it out which was actually starting to twist the bolt in two. The threads didn't change their spacing due to them being held in place/spacing by the threads in the spindle housing. If it had not come out on this try, it very well could have snapped off inside the spindle housing. You got lucky there.
 

douglee25

LawnSite Senior Member
Location
TX
Yeah that bolt had yielded. You're lucky you got it out. That would have been fun drilling that out!
 
OP
J

JLH52

LawnSite Member
https://home.howstuffworks.com/impact-wrench.htm

Those bolts are probably tapered for some reason
These bolts are not tapered. The bolt I removed was stretched that's why the it got smaller diameter along first 5 threads from bolt head. If you notice where the crack is between thread 4 and 5 that's where the diameter changes. I compared the stretched bolt to other blade bolts and it is visibly longer, at least 1/32 of an inch.

The OEM bolts were .625-11 x 1.25 HX G5, I replaced all 3 bolts with grade 8 which has a minimum tensile strength of 150,000 psi.
 

MowDaddy

LawnSite Fanatic
Location
Grand Rapids, MN
Glad you got it out.
A question and an observation.
Q. Was there a spacer/washer between blade and bolt head ?
O. Or more like my way of doing blade changes.
When I install blades blades I turn down impact wrench to #3 setting, that way I know when I turn impact to #5 it will remove bolt.
PS. Did you hit any solid objects?
Like stump, large stick or roots?
That sudden impact can tighten bolt even tighter than when installed.
 
OP
J

JLH52

LawnSite Member
Glad you got it out.
A question and an observation.
Q. Was there a spacer/washer between blade and bolt head ?
O. Or more like my way of doing blade changes.
When I install blades blades I turn down impact wrench to #3 setting, that way I know when I turn impact to #5 it will remove bolt.
PS. Did you hit any solid objects?
Like stump, large stick or roots?
That sudden impact can tighten bolt even tighter than when installed.
In this order, the bolt goes through a washer, blade bolt shield, blade and then screws into spindle. See pic below, items 17-20. I may have grazed the top of one pine root, bit not a major impact like something solid or a deep cut into a root, I'm very meticulous taking extreme caution around obstacle. I know where every pine root is on the 10 acres I cut. Even as cautious as I am occasionally I graze the very top of one. It makes me cringe to know I even graze a root. View attachment 405620

D27BE600-82B6-44D6-A8BE-C4D714FCDCA5.png
 

puppypaws

LawnSite Fanatic
Went to my neighbor, who has about every tool that money can buy, he can also fix anything from a lawnmower to an 18 Wheeler. We took a KD 2500 3 ft. 3/4 in. Torque wrench. I blocked the blade with a short piece of wood, while he didn’t seem to apply much pressure at all and the bolt broke free. I don’t understand how the 600 lb. torque wrench could do more than my 1/2 extension with a 4 foot piece of pipe slide over extension from leverage. I cold not budge them bolt pulling with all my strength.

After freeing the bolt it was still tight removing It with 1/2 ratchet. Threaded part of bolt is 1.25 inches. Carefully examining the bolt it it highly visible that the threaded portion from head of bolt to center, is smaller in diameter than the last half of threaded portion, which is obviously larger in diameter.

There is also a crack around bolt exactly half way between head and end of bolt. Stretch picture of bolt below and you can see crack between 4th and 5th thread.

I don't have a clue how a portion of bolt could change diameter while installed in spindle. Thankful to get it out, will replace with new bolt. Thanks for all your replies and advice from previous thread.

Below is picture of Torque wrench and bolt. View attachment 405296


View attachment 405295
You were extremely lucky the bolt did not twist in half, it was to point of breaking with possibly no more than an additional 5 lbs. of torque. You can see the crack between the threads where it was stretched to the breaking point. Always use anti-seize on any threaded object that needs to be removed on occasion, you won't regret the effort.
 

HEMTT

LawnSite Senior Member
Location
Snohomish, WA
I have the same mower I hit a 15 lb thick wall piece of steel that some idiot left in my grass and turned it into a pretzel. :wall My wife and daughter were 250' away and the noise made them cringe. I ALWAYS torque my blade bolts to the prescribed 118 lb.ft., that one blade took a 5 foot bar to break loose, the rest standard 24" breaker bar. I observed no bolt stretch and the threads were fine, screwed back in by finger thank goodness.
 
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