JET Tools 608003 User Manual - Page 20

1. Repeat "Tension Roller Alignment" except raise the sanding drum only 1/4 turn of the height adjustment handle. 2. If both tension rollers are causing snipe then tighten all four hex nuts (A, Figure 29) at this position. 3. If only outfeed tension roller causes snipe, only tighten rear (outfeed) hex nuts on each end of drum at this position, then raise sanding drum another 3/4 turn of the handle. 4. Press infeed tension roller down to rest on conveyor bed and tighten front (infeed) hex nuts at this position. This process sets the tension roller assembly at an angle providing less tension pressure on the outfeed roller. Operation Before using your drum sander, review the previous pages in this manual on initial set-up and adjustment. In this section, you will learn how to operate the machine. Basic Operating Procedure 1. Set depth of cut. 2. Start drum. 3. Start conveyor and select feed rate. 4. Start dust collection system. 5. Feed stock through machine. Setting Depth of Cut Adjusting the drum sander for the proper contact between the abrasive and the stock determines the mechanical depth of cut. 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, 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: 1. Abrasive type and grit size. 2. Width of the piece being processed. 3. Hardness of the piece. 4. Feed rate of the conveyor belt. NOTE: The use of a carrier or backer board (not provided), is recommended for cuts 1/16" or less. This is a flat board, usually of wood or MDF, slightly larger than the workpiece and of even thickness, placed beneath the workpiece as it is fed through the sander. The workpiece may be attached to the carrier with rubber cement, carpenter's tape or some other easily removable adhesive. However, some operators use a rubber or textured surface on the carrier to help stabilize the workpiece by simple friction. Establishing Proper Drum Height 1. To establish drum height, position the stock to be sanded under the drum. Do NOT start drum. 2. Lower the drum to the stock thickness, making sure drum can be rotated by hand while contacting stock. Do not start drum while in contact with stock! 3. Without changing drum height, turn on conveyor and run the stock out from under the drum. Start sanding drum and sand stock at that same position. 4. With the drum operating, feed stock under the drum from the infeed side and against the rotation of the drum. Always maintain control of the stock to avoid kick-back and/or slippage. NOTE: If motor heats up during operation, depth of cut may be too great for size of grit and/or feed rate may be too fast. Selecting SandSmart™ Feed Rates A faster feed rate allows faster sanding but fewer revolutions of the drum per inch of sanding. A slower feed rate provides more revolutions of the drum per inch of sanding to allow a greater depth of cut and smooth sanding. Begin experimenting with the feed rate set at about 40% to 50% of maximum. The best feed rate will depend on a number of factors, including type of stock, grit and depth of cut used, and whether the stock is fed directly in line with the conveyor bed or at an angle. If the drum motor is lugging down, if the conveyor belt is slipping, or if you observe a ripple effect on the stock, slow down the feed rate. If the finish is smooth and the machine is not overworking, you can experiment using a faster feed rate. 20