Narrow Frame Cub Cadet Mower Stubborn Blade Nut Removal/ Upgrade

(What to do about getting the spindle nuts off to sharpen or replace the mower deck blades)

Created: December 1, 2023

Back to MY Cub Page                     Home                   

Contact Us                   


The Spindle NUT is #31 in the drawing above.

Issues:
1. Nuts won't come off
For instance:
On a recently acquired 123, one spindle nut was soooo stuck that I had to pull the center spindle (with blade attached) out of the deck so I could mount it in a vise to try to get it loose. Nothing worked, so after stripping the points of the nut off. I had to slice the nut with an abrasive wheel and chisel it off the shaft (while taking great care not to hurt the spindle threads).

2. Nuts are rounded off or the Threaded end of the spindle are buggered up by hitting rocks, etc.. if the nut has worn too much.

Discussion:
I have several narrow frame cubs that have the 3 blade deck.
Annually, at the end of the season and, if needed, during the season, I remove the blades to sharpen them. I use an air impact wrench to get them off and on.
I always use the nickel-based "Never Seize" anti seize compound when reattaching the nuts. However, i do run into a couple of problems from time to time.

Over time, the nuts become rounded off on their "bottoms" from hitting rocks, dirt, etc..
Since the mfr decided to use the thinner "jam nut" style of nut, this rounding reduces the amount of material on the "points" of the nut.
The thinner jam nuts are also susceptible to being rounded off from ill-fitting or mis-applied wrenches and impact tools over time.

Cub Cadet Spindle Nuts
Two new, full size nuts on the left and, to the right, five used (original size) jam nuts that are worn by various degrees.

My solution:
Replace the stock nuts (which are about as narrow as " jam nuts") with standard width nuts of the correct thread, coating the spindles with anti seize each time I service the blades, of course.

Benefits:
These new standard width nuts have much wider points, so there is much less chance of stripping the points in the future. And, even if the nuts still do contact the ground and/or rocks etc., they will protect the threaded portion of the spindle shaft.
=================================================================
Notes:
-Note that the spindle thread is 3/4-16, which is considered "fine thread".
And, if possible, I buy grade 5 or grade 8 nuts so they are even tougher.
The standard nuts are about 5/8" high, while the jam nuts just under 7/16" high.

-Jam Nut: A jam nut is a low profile type of nut, typically half as tall as a standard nut.
It is commonly used as a type of locknut, where it is "jammed" up against a standard nut to lock the two in place. It is also used in situations where a standard nut would not fit.