Controlling the cut Hydraulic feed control

Controlling the cut:

Hydraulic feed control

The weight of the saw arm typically provides all of the force needed to move the saw blade through the workpiece. In fact, if the full weight of the arm is allowed to make the cut, rapid blade wear and poor cutting accuracy will result. Therefore, a hydraulic feed control is provided which gives the operator control over the speed and efficiency of cutting.

The hydraulic feed control is a single-acting hydraulic cylinder attached between the saw base and saw arm. The hydraulic control cylinder has two flow controls. The control needle valve -- used by the operator to control the rate of cutting -- is on top of the cylinder. A quick shut-off valve is located in a hydraulic line on the outside of the cylinder.

The control cylinder is single-actingbecause it can be used to resist motion in the downward direction, only. The control cylinder offers no resistance to upward movement.

The amount of downward force can be controlled by using the needle valve on top of the cylinder. When the needle valve is closed the cylinder is "locked." With the needle valve open slightly, the cylinder permits slow, or light downward force. As the needle valve is opened further, increasing weight of the saw arm presses on the blade and workpiece.

The needle valve is opened, during any cut, until the operator determines that the saw is operating efficiently. This is usually evaluated by observing chip formation. See the section on Blade Selection, for more information on evaluating cutting efficiency.

The quarter-turn quick shut off valve in the external line of the control cylinder can be turned to lock the cylinder at any time. For instance, it can be used to lock the blade above the work piece to allow you to measure the length of cut on the workpiece. Or, it can be used for making repeated cuts after the needle valve has been set for best cutting efficiency. (This is described in the next section.)

To close the hydraulic control circuit and lock the cylinder, turn the quick shut off valve handle so it is at right angles to the hydraulic line or hydraulic cylinder.

To open the hydraulic control circuit and return feed control to the needle valve, turn the quick shut off handle so it is parallel with the hydraulic line or hydraulic cylinder.

Figure 6: Using the stock stop

Using the stock stop for repeated cuts

If you are cutting multiple pieces of stock, all to the same specified length, use the stock stop.

1.Lower the saw arm to its horizontal position.

2.Loosen the stock stop set screws as necessary to slide the stop upward and more-or-less into position.

(There are two set screws which are use to lock the stop stock in position. One is on the saw table and is typically used to adjust the distance between the stop and the blade. The other set screw is on the stop, itself, and is typically used to adjust the height of the stop above the table. However, you can use any combination of set screws you find convenient to adjust the stop to the distance and height which works for the stock you are cutting.)

3.Using a ruler or scale, measure the distance between the blade and stock stop.

4.When the correct cut-off distance is obtained, be sure the stock stop is at a position which allows the cutoff piece to fall away from the blade as the cut is completed. Then, tighten the stock stop set screws securely.

5.Raise the saw arm.

6.Place a workpiece in the saw vise and slide the workpiece so it contacts the stock stop.

7.Open the hydraulic control cylinder quick shut off valve and move the saw blade to just above the workpiece - then close the needle valve so the arm is locked in position.

8.Measure the distance between the end of the workpiece and the blade to verify that you have set the stock stop at the correct distance. (See Figure 6.)

9.When you are satisfied that your cut-off distance is correct, you may begin cutting by turning on the saw and opening the needle valve until the blade is cutting efficiently.

To continue making multiple cuts take the following steps:

1.Do not change the setting on the needle valve.

2.Raise the saw arm so it clears the stock being cut and lock the hydraulic control cylinder using the quick shut off valve.

3.Release the vise slightly using the handle wheel -- move the stock up to the stock stop -- tighten the vise again.

4.Turn on the saw and open the quick shut off valve. Because you established an efficient cutting rate on the previous cuts using the needle valve, there is no reason to change its setting. The quick shut off, alone, can be used to begin and complete the cut.