Powermatic DDS-237, DDS-225 Maintenance, Operations, Basic Operation, Stock Feeding Angle

Maintenance

Note: See also Maintenance Checklist on page 19.

For best results, perform the following proced- ures on a routine basis:

ˆGrease the four leadscrews on the table.

ˆLubricate the bushings at each end of the pressure rollers. Use a dry type lubricant for this, such as graphite or silicone that will not attract dust.

ˆKeep the chain below the table clean and oiled.

ˆClean sawdust from the abrasive strips with a soft brush or cleaning stick.

ˆBlow dust from motors and switches.

ˆCheck screws, nuts, etc. for tightness.

ˆCheck the tension and condition of the belts; dress with paraffin. (Do not get paraffin on the abrasive belts.)

ˆCheck the oil level in the gearbox by removing the oil plug on top, and inserting a depth gauge (not included). Generally, the oil should be about 3-1/2” lower than the top surface of the gearbox. If low, fill as necessary with EP2 oil.

NOTE: If using oil from a new source (i.e. different brand), it is advisable to flush and clean the gearbox before filling to avoid potential incompatibility issues.

ˆEvery 2,500 hours, completely drain and refill gearbox with EP2 oil.

Operations

Basic Operation

The basic operating procedure for the Dual Drum Sander is as follows:

1.Set depth of cut.

2.Start drums.

3.Start conveyor and select feed rate.

4.Start dust collector system.

5.Feed stock through unit.

Determining depth of cut is one of the most important procedures for the sander. It may take some experimentation to determine the proper depth of cut, given the variables of abrasive grit,

type of wood, and feed rate. For best results, use scrap wood to practice sanding and to develop skill and familiarity with the machine before doing finish work.

A good rule of thumb when sanding with grits finer than 80 is to lower the drum so it contacts the workpiece but drum can still be rotated by hand. When using grits coarser than 80 grit, you can lower the drum slightly more. However, a combination of several variables will determine the proper depth of cut to use, including the following:

ˆAbrasive type and grit size.

ˆWidth of the piece being processed.

ˆHardness of the piece.

ˆFeed rate of the conveyor belt.

Stock Feeding Angle

Some pieces, because of their dimensions, will need to be fed into the machine at a 90º angle (perpendicular to the drums). However, even a slight offset angle of the stock will provide for more effective stock removal. The optimum feeding angle is about 60º (Fig. 24). Angling the workpiece for stock removal provides other advantages, such as less loading of certain areas of the drums due to glue lines or mineral streaks in the stock, more even wear of abrasive strips, potentially faster feed rates, and lighter loads on the motor.

Note, however, that to get the best final finish the stock should be fed through the machine so it will be sanded in line with the grain of the wood on the final one or two passes.

Multiple-Piece Sanding Runs

When abrasive planing (or thickness sanding) a run of similar pieces that you want to have the same thickness, it is best to determine the thickness of the thinnest piece and process all pieces to that same thickness in one session. Be aware that the sander will remove cups and crowns in the workpiece; consider this when measuring and processing stock to the same thickness.

When sanding multiple pieces simultaneously, make sure to stagger (step) the pieces across the width of the conveyor belt. This provides better contact with the pressure rollers. Try to only process multiple pieces of similar thickness. If there is a significant thickness difference, the thinner pieces may slip on the conveyor belt if they do not contact the pressure rollers.

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