Introduction: Table Saw Blade Angle Lock Modification
Any woodworker (both professional or hobbyist) will tell you that it is critical to have accurate angle cuts.
I have an older Craftsman table saw that is built like a tank. It has a cast iron table and very robust motor. However, there are two major problems.
First: I turn the angle adjustment wheel to my desired angle. When I engage the angle lock that comes with the saw, it throws off the blade by 1-2 degrees. So the very act of locking in your desired angle, throws off your angle!!! Crazy!
Second: Whether the factory angle lock is engaged or not, the angle changes while the saw is running due to the inherent vibration of the saw.
After much frustration, I decided that something needed to be done about this. Or else my hobby would be causing me more stress than pleasure.
My solution was to create a way to manually keep the angle adjustment wheel stationary.
I did this by mounting a toothed gear onto the angle adjustment wheel and an arm that falls in between the teeth of the gear. Thereby preventing the wheel from turning during operation and eliminating the need to lock the blade in with the factory installed angle lock.
Step 1: Adjustment Wheel Size and Removal
The first step is to determine the required size of the incremented gear that will be engaged to lock the blade angle in place. Measure the diameter of the angle adjustment wheel. (Photo 1)
Remove the wheel and take off the handle. (Photo 2&3)
Step 2: Create the Incremented Gear
The gear is one of the two major components of the modification. I made mine out of plywood. I cut the circle out using a jig for a table saw (see link) https://www.youtube.com/watch?v=n4f6nkhPbpo It could easily be done by hand with a jig saw, band saw or giant whole saw (Photo 1).
***In retrospect, I probably made the diameter of my gear too large. If I were to do it over, I would target a gear diameter 1" larger then the wheel diameter.***
Divide the gear into equal sections (I choose 32) and cut out the teeth. I made a jig using my cross cut sled (Photo 2) for this, but again, could be done with a jigsaw or band saw. My width was about the size of two saw kerfs. It is important to keep it wide enough to allow for a substantial size piece of wood to fit in-between the teeth. (Photo 3)
Next I took a hole saw to remove a section from the middle of the gear. (Photo 4) This step is completely optional as it has no effect on the function of the mod. ***NOTE: If you do this, be sure to do it AFTER cutting out the teeth. This way you have a way to mount it to your jig tooth cutting jig.
Finally, mark the locations for the mounting holes and a spot for the knob to pass through. (Photo 5)
Step 3: Drilling and Mounting the Gear
After your gear is cut and mount locations identified, the next step is to drill the mounting holes and attach it to the wheel. I did this with zip ties. I choose an arbitrary hole size, but was careful to make sure it was larger than the width of the zip tie. (Photo 1).
I then drilled the mounting holes and a hole for the handle to pass through. (Photos 2&3). Finally I mounted the gear with zip ties. (Photos 4&5).
One thing I would recommend for this step is DO NOT completely tighten each zip tie at first. Lightly tighten them all, then tighten each one, click by click to center the gear on the wheel.
Step 4: Create the Locking Arm
Once the desired angle is selected, the Lock Arm is dropped into its nearest tooth to lock it in place. The lock arm consists of a mounting block, an arm (hardwood), a screw, washer and a magnet. (Photo 1)
To help guide the arm into a tooth, round off one side of the arm. (Photo 2).
Drill a hole in the end opposite the rounded portion to mount the arm. Select a drill bit diameter that is slightly larger than the diameter of the mounting screw. Ensure the screw you choose has a smooth shank where it will be in contact with the arm, you dont want it to have threads inside the arm. Round off the corners of the arm by the hole to remove any obstructions during its rotation (Photo 3&4)
Drill the mounting holes in the mounting block, one for the arm and two to mount the block to the side of the table saw. (Photo 5) Assemble the arm to the block. (Photo 6)
Step 5: Mounting the Locking Arm
With the gear wheel mounted, temporarily tape the locking arm in place. Once you are satisfied, mark off the location to drill pilot holes in the side of the table saw. (Photo 1)
Remove the main gear and drill your pilot holes and mount the lock arm (Photo 2)
Re-Mount the gear wheel and confirm everything is aligned (Photo 3)
Now Determine the magnet contact point by raising the locking arm as far as it will go and mark off a location that contacts iron. (If you do not have a magnetic table, you can easily epoxy a piece of scrap iron or a magnet to the underside of your table saw. (Photo 4)
Remove your locking arm and epoxy a magnet to your marked location. (I cut out a section for the magnet to sit into, that way it was flush with the top of the arm. This step is probably unnecessary. (Photo 5)
Remount your locking arm, ensuring that it isn't too tight or too loose. You want it to move up and down freely, but not have too much slop.
Step 6: Final Inspection
That's it! Do one final inspection to ensure there are no issues.
Simply flip up the arm when you want to adjust the blade angle, turn the wheel, then flip it down to lock it in.
Have fun, and as always, be safe!!