Here is an accurate way to adjust and align the blade guides of this tool.

    1. Loosen the left-hand guides and make sure they are jammed firmly against their seats in the miter sides, and re-tighten.
    2. Insert the saw and, using a trusted square make sure the saw is at right angles to the left-hand miter sides. Adjust the left-hand sides as necessary, being careful to retighten firmly. Withdraw the saw.
    3. Loosen the right-hand guides and jam them firmly against the right-hand sides, and re-tighten.
    4. Re-insert the saw between the guides. There should be a nice silky resistance-slip feel to the saw as you draw it between the sides. Adjust for a good fit by loosening and adjusting the right-hand sides. Retighten firmly.
    5. Raise the left guides almost high enough to clear your fretboard or fingerboard. Readjust alignment as necessary to get a good slip fit and re-tighten the guides.
    6. Put a shim under the forward and rear left-hand guides. Use a shim whose thickness is equal to the depth of cut you want (about .005" thicker than your fretwire tang).
    7. With the shims in place, raise or lower the left guide until the saw is resting on the surface of your fretboard or fingerboard. This sets your depth of cut.
    8. The right-hand blade guides should now be adjusted. They do not need to be precisely the same height as the left-hand guides (it is better to have only one side gauging the depth, to avoid awkward slight differences).
    9. That's it! If you have small differences in the height of your fretboard or fingerboard stock, you will need to go back to step 6-7 to readjust the depth of cut.
    10. Well, not quite finished! Remember that if there is any relief in the profile of your fretboard or fingerboard, you will need to finish up the depth of cut by hand on each affected slot. That's where the Steward-MacDonald's Depth-of-Cut attachment comes in!
    11. By the way, cut a couple of scraps to serve as in-take and out-take tables for the Fret Slotting Tool. That will help stabilize your operation, especially at the beginning and end of the template. Just make sure they are not higher than the floor of the miter box!
Aligning the Stewart-MacDonald
Fret Slotting Miter
Blade Guides