Q & A: Fix a Misaligned Blade-Guide Post
Every time I change the
height of the blade-guide
post on my bandsaw, I have to
readjust the thrust bearings and
the guide blocks. Is there any way
to fix this?
The problem is that your blade-guide post is not traveling parallel
with your blade. As you raise and lower the post, its position
relative to the blade can change from front to back and from side to side.
This requires readjustment of the thrust bearing and the guide blocks
with each setting.
The condition can be remedied on a cast-iron saw by shimming the
joint where the upper arm connects to the base or riser block. Brass
shims are easy to use and come in a variety of thicknesses (see
Source, below). The process takes a little trial and error, but once
you’ve got the arm shimmed right, your saw is set for life.
1. Use a square to see whether the table is dead-square to the
side of your blade. Loosen the table trunnions to correct.
2. Put the square up to the back of the blade to see
whether it is square to the table. To correct it, adjust
the tracking to center the blade on the wheel.
3. Remove the guard and blade-guide
assembly from the blade-guide post.
Lower the post all the way and check
for square. Note the direction the
upper arm must tilt to become
square to the table.
4. Release the blade tension and
loosen the bolt that connects the
upper arm to the base.
5. Shim the joint to correct the outof-
square guide post. You’ll have to
estimate the size shim needed to align
the guide post.
6. Retighten the arm bolt and tension
7. Check the guide post again.
Repeat the procedure using different
shim combinations until the post is
dead-square front to back and side to
Note: Product availability and prices are subject to change.
Lee Valley and Veritas, leevalley.com, 800-871-8158; Brass shim stock, sampler
pack (one 2-in. x 6-in. strip of 0.001 in., 0.0015 in.,
0.002 in., 0.003 in., 0.005 in. and 0.01 in.),
This story originally appeared in American Woodworker July 2006, issue #122.
July 2006, issue #122
Purchase this back issue.