Power Feed Trip Lever Mechanism

Refer to Figure 25.

The power feed trip lever mechanism will need to be adjusted if worn or whenever any trip lever mechanism components are replaced.

1.Loosen the feed trip adjusting screw lock nut.

2.Loosen the adjusting screw until it is loose in the lever and no longer contacts the bottom of the feed trip plunger.

3.Using the coarse feed handle, move the quill to the bottom of its travel so the quill stop contacts the micrometer nut. Hold the quill on the stop.

4.Pull the feed handle out to engage the power feed system.

5.Turn the feed trip adjusting screw until the power feed disengages.

6.Tighten the feed trip adjusting screw.

7.Release the quill stop so you can engage the power feed mechanism using the power feed trip lever.

8.Using the coarse feed handle, pull the quill stop back into firm contact with the micrometer nut.

Figure 25

Note: The power feed should disengage when the quill stop pushes on the micrometer nut. If it does not disengage, repeat the adjustment steps above.

9.Engage the power feed and move the quill stop to the top of its travel. Make sure that the reverse trip mechanism also disengages the

power feed. If not, readjust the mechanism until positive disengagement occurs when the quill is at the top of its stroke.

10.Check for correct operation using the coarse feed handle. If operating correctly, start the drive motor and engage the power feed mechanism. Verify that the power feed lever correctly engages and disengages when driven by the drive motor.

Table Lead Screw Backlash Adjustment

Refer to Figure 26.

The milling machine table is moved by a lead screw and nut for each machine axis. For proper operation, there must be clearance between the lead screw and the nut, which results in backlash. A second lead screw nut is provided to eliminate most of the backlash. The following procedures provide instructions for obtaining acceptable backlash.

Cross Feed Backlash Adjustment

1.Use the cross feed crank to move the table to the extreme rear of its travel.

2.Remove the pleated way cover.

3.Open the two chip guards enough to expose the cross-feed adjustment nut (the nut that is toward the rear of the nut bracket is not adjustable – only the front nut is adjustable).

4.Loosen the two nut locking screws.

5.Turn the nut slightly to tighten it against the opposing nut.

6.Tighten the two nut locking screws.

7.Using the cross-feed crank, move the table to the middle position.

8.Set up a dial indicator to check cross-feed backlash. Gently move the cross feed crank back and forth while watching the dial indicator. Backlash should be between 0.003 inch and 0.005 inch.

9.If necessary, repeat the steps above to set backlash.

10.Install the pleated way cover.

Longitudinal Backlash Adjustment

Refer to Figure 26.

1.Only one of the longitudinal lead screw nuts can be adjusted. The other nut is fixed. The left hand nut is typically adjustable. This can be determined by looking at the nut from the underside of the table.

2.Loosen the two nut locking screws.

3.Turn the nut slightly to tighten it against the opposing nut.

JTM-4VS specifications

The Jet Tools JTM-4VS is a highly regarded vertical mill that caters to the demands of both professional machinists and serious hobbyists. This versatile piece of machinery combines precision engineering with innovative features, making it a popular choice in workshops and fabrication shops.

One of the standout characteristics of the JTM-4VS is its powerful 1.5 HP motor that operates on either 115V or 230V power supply, providing flexibility depending on the workshop setup. The motor offers variable speed control, from 60 to 4200 RPM, allowing users to adjust speeds according to the material being machined. This capability makes it ideal for a wide range of applications, from heavy milling on steel to delicate work on softer materials like aluminum.

The JTM-4VS is equipped with a robust cast iron column and base, which contribute to its stability and durability. This construction minimizes vibrations during operation, resulting in improved precision and surface finish on machined parts. The table measures 9” x 49”, providing ample workspace for various projects, and is fitted with T-slots for easy clamping of workpieces.

Another notable feature of the JTM-4VS is its easy-to-use digital readout (DRO) system that assists users in making precise adjustments and measurements. The DRO enhances the overall efficiency of the milling process, allowing operators to focus on the task at hand rather than relying solely on manual measurements.

The machine also incorporates a high-grade, hardened and ground bedway that ensures smooth operation and long-lasting performance. This feature not only extends the longevity of the mill but also allows for precise vertical and horizontal movements.

Safety is a primary concern in any workshop, and Jet has addressed this with various safety features integrated into the JTM-4VS. The mill is designed with a protective shield and emergency stop button, ensuring operators can work confidently.

In summary, the Jet Tools JTM-4VS stands out for its combination of robust construction, versatile functionality, and user-friendly technologies. With its powerful motor, variable speed capabilities, and precision features, it is an excellent investment for anyone looking to enhance their machining capabilities in the workshop. Whether it's for industrial applications or intricate projects, the JTM-4VS delivers reliable performance and exceptional results.

Jet Tools JTM-4VS Power Feed Trip Lever Mechanism, Table Lead Screw Backlash Adjustment

Models: JTM-4VS