How to Replace the Blade Shaft on an MK Diamond Tile Saw
The blade shaft is a major part of your tile saw. The diamond blade attaches to it. It is supported by two bearings that attach it to the head casting. The shaft is driven by the belt and the belt pulley (which is also attached to it). Over time, the shaft can be worn down. The blade can wear the shaft, causing play. The threads for the arbor nut can wear down. A seized bearing can damage the shaft. The keyways can wear, causing play. Any of this damage can lead to deflection and vibration while cutting.
Let's get started.
REMOVING THE BLADE SHAFT
1. Remove the blade.
a. Pivot the guard toward the rear of the saw (away from the blade).
b. Engage the blade-lock to prevent the arbor from rotating.
c. Use a wrench to remove the nut securing the blade to the saw.
d. Remove the outer flange.
e. Remove the blade from the saw.
2. Remove the belt.
a. Unscrew and remove the adjustment knob.
b. Remove the screws securing the belt cover to the saw.
c. Pivot the saw away from post.
d. Remove the belt cover.
e. Manually advance the drive belt (toward the rear of the saw) while applying pressure to the belt (from inside to outside).
f. Remove the belt from the saw.
3. Remove the lower belt pulley.
a. Use a hex wrench to loosen the set-screw on the lower belt pulley.
b. Slide the lower belt pulley off the blade shaft.
c. Remove the key from the keyway on the shaft.
4. Remove the blade shaft.
a. Use a rubber mallet to tap the blade shaft out of the housing.
b. Remove the blade shaft (along with the pulley) from the saw.
5. Remove the inner bearing from the blade shaft.
a. Use a bearing press to remove the collar from the blade shaft.
b. Use a bearing press to remove the bearing from the blade shaft.
INSTALLING THE NEW BLADE SHAFT
6. Install the inner bearing.
a. Slide the shaft bearing over the threaded end of the new blade shaft.
b. Use a bearing press to press the bearing onto the new blade shaft.
c. Slide the collar over the threaded end of the new blade shaft.
d. Use a bearing press to press the collar onto the new blade shaft.
7. Install the blade shaft and bearing.
a. Slide the new blade shaft (and bearing) into the saw housing and through the outer bearing.
b. Tap the end of the blade shaft to seat the inner bearing into the housing. (This may cause the outer bearing to disengage the housing. That's OK. We'll re-seat the outer bearing in the next step.)
8. Re-seat the outer bearing (if necessary).
a. Locate a socket with a diameter that is approximately the same as the INNER RACE of the outer shaft bearing.
b. Align the socket with the inner race of the bearing.
c. Tap the end of the socket with a hammer until the outer bearing is fully seated within the housing.
REASSEMBLING THE UNIT
9. Reinstall the lower pulley.
a. Install the pulley key into the keyway on the blade shaft.
b. Install the pulley onto the blade shaft.
c. Leave the set-screw loose at this point (to allow adjustments to the belt).
10. Reinstall the belt.
a. Loop one end of the belt around the upper pulley.
b. Stretch the belt toward the lower pulley and carefully work the belt onto the edge of the pulley.
c. Manually advance the belt while applying sideways pressure to the belt and lower pulley (until the belt is fully seated on both pulleys).
11. Align the belt.
a. Loosen the set-screw on the upper pulley.
b. Visually inspect (sight-down) the belt from the rear of the saw.
c. The distance from the housing to the inside of the belt should be approximately the same at both the upper and lower pulleys.
d. Adjust the (upper and/or lower) pulleys as necessary to align/straighten the belt. (Adjustments can be made by simply tapping the pulleys inward or outward with a rubber mallet.)
e. Tighten the set-screws on both the upper and lower pulleys.
12. Reinstall the belt cover.
a. Install the belt cover.
b. Secure the belt cover with the bolts.
c. Install and tighten the adjustment knob.
13. Reinstall the blade.
a. Install the blade onto the blade shaft.
b. Install the outer flange.
c. Engage the black lock to prevent the shaft from rotating.
d. Secure the blade with the nut.
e. Lower the blade guard.