Instead of buying a new spindle for your lawn mower, you can fix the old one by replacing the bearing and it will cost you a lot less.
Steps

Step 1. Remove the top cover from the windrower
This will make the process of replacing the blades much easier.

Step 2. Remove the blade and pulley from the worn spindle
You may need to repair both spindles even if only one is showing symptoms of breakage.

Step 3. Remove the worn spindle from the mower body
Be careful when removing bolts. Use a penetrating oil and let it soak in. Don't panic if the bots start breaking. You can punch new holes next to the worn ones.

Step 4. You must now remove the spindle assembly to replace the bearings
Take the spindle and secure it in a vise or similar object.

Step 5. Install the pulley nut a few turns on the spindle shaft

Step 6. As shown in the photo, hit the nut with a sharp blow with a small hammer
This should cause the shaft to fall out of the spindle housing.

Step 7. At this point, you should be able to remove the shaft from the spindle housing
You will be left with a spindle housing with an open top and bottom bearing.

Step 8. Using a screwdriver, remove each bearing

Step 9. Write down the number indicated on the side of the bearing, go to the nearest auto shop and buy a new bearing

Step 10. Clean all parts well

Step 11. Install one of the bearings at the bottom

Step 12. If there is a sleeve that slides over the shaft inside the spindle housing, place it in the housing before pressing on the upper bearing

Step 13. Press on the top bearing

Step 14. Assemble the spindle shaft

Step 15. Using a tube or bushing, press down on the spindle shaft
It will rest against the upper bearing with the inner ring.

Step 16. That's it
Place the repaired spindle back into the housing and you can use the mower for about 5 more years.