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Sitrex Nut Torque

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DownHomeDraft
Join Date: Apr 2005
Posts: 13 Western Central Maine
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2005-05-16          111107


At what foot pounds of torque do I torque the blade retaining nut for a SM180 Finish Mower.
It is a metal lock nut for an 18MM spline, and a 27MM
socket fits on the nut.
My Sitrex dealer doesn't know, and said Sitrex does not supply an Owner/Operator Manual. The dealer just tightens them as much as they can, and I had to cut off all three nuts to get my blades off.
I checked some torque charts and a rough estimate seems to be 60 to 130# for low grade bolt, 201# for Grade 8.8, 283# for Grade 10.9 and 247# for Grade 12.9.
I am assuming I have a low grade spline/nut. The dealer doesn't know, and I'm convident the dealer torqued them more than 130 foot pounds.




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Sitrex Nut Torque

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Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster  View my Photos  Pics

2005-05-16          111115


Not knowing if a bevel washer is used I'd say go with at least 60 if not closer to 80. Often they are attached by air wrenches or battery powered wrenches in the shops. ....


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Sitrex Nut Torque

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DownHomeDraft
Join Date: Apr 2005
Posts: 13 Western Central Maine
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2005-05-16          111133


There are no washers involved.
The parts book does not show washers.
One thing that bothers me is the nuts are metal lock nuts
and while tightening them to 70 foot pounds it seemed some holding torque was lost to the resistance of the lock nut. I greased the treads on the end of the spline to reduce as much friction as possible, but there was still a noticable amount of drag due to the lock nut.
Because of the lock nut, I know the blade won't come off due to under torqueing, but I'm not sure if the nut offers enough resistance to keep the blade from braking loose from normal cutting operations. I quess I'll find out, if it ever stops raining and I can start mowing.
Thanks Art ....


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