Originally published September 2007

Be Square!

Table and Tool Alignment on the Dual Wheel Trimmer.

Keeping your trimming tools square and calibrated is an important function of trimmer maintenance. It is challenging on the dual wheel trimmer since the two wheels rotate on separate and independent shaft and bearing assemblies. An out-of-square machine will trim opposite sides of the model at different angles, or will not be calibrated at angle indicators when moving from the coarse wheel to the fine wheel. A number of conditions can affect squareness, and we’ll go through them in sequence - from the simplest to most difficult. Before getting started, remove the trimming table and make sure all plaster residue is removed from the sill beneath the trimming table and the bottom of the trimming table itself. You can only do a squaring and alignment on a clean machine!

Warped Wheel. This can happen with really old carborundum wheels, but more often with diamond wheels that have a fiberglass backing. These wheels may absorb water over time and become “cupped”. Remove the wheel and place a straight edge ruler across the diameter on the non-abrasive side of the wheel. Make sure the straight edge contacts each side of the center hole.  If there is more than .5mm of space between the ruler and either edge of the wheel, the wheel needs to repaired or replaced.

Table out of square. Since the fine wheel shaft is not adjustable, the trimming table is initially squared to the fine wheel.  There is a pin at the right hand side of the table that contacts the front trimmer housing. This pin is a press fit and is adjustable by tapping with a hammer or pulling out with a Weingart plier. Some trimmers do not require this pin so don’t be alarmed if it is missing.  Slide the squaring tool into the slot in front of the fine wheel.  Move the tool side to side and check for excessive play. If play is more than .5 mm, the squaring tool and table may need to be replaced. Place a 3” x 5” card between the rubber pad of the tool and the wheel.  Check for flatness against the wheel. If the edge of the card is not laying flush against the wheel, use the pin to adjust orientation.

Motor out of square. If the fine wheel is square to the squaring tool, but the coarse wheel is not, the motor may require re-shimming. On the back of the motor are four through bolts that fix the motor to the trimmer. At the motor/ trimmer interface, there are shims which can be added or removed in order to square the wheel both vertically and horizontal. Call us for detailed instructions on this procedure.