ANOTHER LOOK AT BAND SAW TUNE-UP

BY: Bill Skinner

May,1999

The typical tuning advice emphasizes alignment of the wheels, and adjusting the blade guides. And rightly so because these elements of the operation of a band saw are critical to the accuracy of the machine. The purpose of this article is to move beyond the basics to offer another perspective.

There are some things that a reasonably clever craftsman can do to make a good band saw even better. Upon setting up his first machine a woodworker may be surprised to learn that some things do not fit, or work as expected right out of the box. As time goes by, and as more tools are purchased, he learns this is a common occurrence which may even add to the enjoyment of setting up the machine.

Here the example is a 14" Jet, model number JWBS14CS. A medium range quality, this machine is a good value at about $550.00. In this case the Jet replaced a 12" Craftsman which had hummed along very well for over 20 years. The extra capacity, and power was a big consideration, plus it also had the same footprint - a large benefit in a small shop.

The first thing noticed was how the sawdust avoided the vacuum port. About 20% made it through the tube, and the rest went everywhere else. The solution involved cutting a new, larger port in the bottom-center of the lower door. A standard 2 1/2" PVC flange fitting screwed to the door allows a slip-fit to a 3" flex-hose which is connected to a 4" collection system. Be aware of the limited clearance between the door and the lower drive wheel. To increase efficiency of the airflow, mount some sheet aluminum around the lower blade guide area where you have removed the factory supplied sawdust tube. Polyurethane glue works well for attaching these baffles where needed. Then, attach self adhesive foam weather-strip around the lower door edges, allowing the door to be opened while getting a fair seal when closed (again, watch the wheel clearance). The vacuum hose should always be in place before starting the saw.

Tension on the blade is achieved with the usual spring mechanism, adjusted by a steel rod with a knob on top. This factory knob is really tiny. For those who release the tension often (me), turning this small knob becomes very unpleasant. A 6" shop built crank designed to clamp around the factory knob solves this problem

It was then discovered that on a rip cut, especially with softwoods, chips will build-up against the table edge just behind the blade. This condition can result in hang up of the work piece. Simply reversing the throat plate in the opening solves this problem. It is necessary to slightly elongate the blade clearance slot in the throat plate with a rat-tail file. A new keeper notch is similarly cut in the edge of the throat plate opposite the position of the factory notch. Another hang up occurred at the blade removal slot even with the slot keeper in place. The backside of the slot was about .001" higher than the front edge. A little filing with a diamond hone brought this down in short order.

Then a matter of environment came into play. As mentioned above space is at a premium so anything protruding unnecessarily is immediately obvious. This Jet has 7/8" tubes attached to the back and front edges of the table on which the fence rides (It should be noted here that this fence system is accurate, and it did work right out of the box). These tubes extend about 5" beyond the right edge of the table to facilitate use of the fence on the right side of the blade. This overhang was easily sacrificed because I never use a factory fence on the right side of the blade, so the tubes were cut back flush with the table's edge. This left the slot keeper plug sticking out all alone and much too long. Chucking the plug into the drill press and sanding down the diameter allowed it to sink into the table enough to leave only 1/2" extending (use care to avoid changing the angle of the taper on the slot keeper plug).

Next, the fence locking knob was in the way. It is the long handle type knob used to lock the back end of the fence to the back carrier tube. This handle was cut off leaving the captured nut in place. A 3" wheel type knob, 3/4" thick was turned out of scrap wood. The remainder of the long knob with it's nut in place was epoxied into the new knob. This change in configuration carried the edge of the wheel knob beyond the plane of the factory fence. A 1" thick auxiliary fence, double-faced taped to the factory fence, compensates for the new dimension.

Casters were added to the base to raise the height of the table to 48" above the floor, a personal preference, and two 180-degree toggle clamps were affixed to anchor the whole thing to the floor. The wheel alignment, and blade guides mentioned first, above, did not require any further adjustments. Both these systems are well engineered, and have delivered superior results.

Probably the only other improvement yet to be added to this already outstanding machine will be a magnetic switch. Perhaps some rainy day in the next century.