Precision matthews PM-1127VF-LB

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Overview

Technical Specifications
Usage Features
Maintenance Features

The PM-1228VF-LB is a heavy-duty engine lathe designed for metalworking, offering a range of features for precision turning, threading, and facing operations. It is powered by a 110 Vac, 2 HP brushless DC motor, providing variable spindle speeds from 50 to 2000 rpm across two ranges (50-1000 rpm and 100-2000 rpm). The lathe has a large 1-1/2 inch bore spindle, which is unusually short, making it ideal for through-spindle work. The spindle uses a D1-4 camlock mount for chucks and faceplates. The machine offers a generous 28 inches between centers and a 12-inch swing over the bed.

Technical Specifications:

Power: 110 Vac, 60 Hz, 1Ø, 20A circuit, 2 HP (1500 W) brushless DC motor.
Spindle: Variable speed (50-2000 rpm), 1-1/2 inch bore, D1-4 Camlock mount, MT5 internal taper.
Work Envelope: 28 in. max between centers, 12 in. diameter swing over bed, 7 in. diameter swing over cross slide.
Travel: Saddle travel along bed 24 in., Cross-slide travel 6 in., Compound (top slide) travel 3-1/4 in.
Thread Cutting: Leadscrew 8 TPI, 3/4 in. diameter. Offers 27 inch threads (5 to 72 TPI) and 14 metric threads (0.5 mm to 4 mm pitch).
Feed Rates: Turning operations from 0.0016 to 0.0115 in./spindle rev; Facing operations from 0.0008 to 0.0061 in./spindle rev.
Dimensions (approximate overall, incl. stand): Width 59 in. x Height 49 in. x Depth 28 in.
Weight: 490 lb net (excluding stand), 600 lb net (with stand).

Usage Features:

The PM-1228VF-LB is equipped with a multi-speed gearbox for full-range screw cutting, including TPI and mm pitch. It features bidirectional power feed for both the saddle and cross-slide. The motor controls are intuitive, with a power switch (1 for ON, 0 for OFF, 2 for 110 Vac outlet on back panel), an E-Stop button, and buttons for spindle direction (FORWARD/REVERSE). A 4-digit LCD displays continuous spindle speed in rpm. The speed control is a potentiometer, set fully counter-clockwise for minimum speed.

The lathe incorporates safety features, such as requiring the end cover to be closed for the machine to run, and the E-Stop button instantly disconnecting power. The spindle direction can be changed from forward to reverse without pausing or powering down, as the motor controller electronically brakes the spindle to zero before spooling up in the opposite direction.

Chucks and faceplates are installed using D1-4 Camlock studs. Proper installation involves supporting the chuck's weight, aligning cam markers, and tightening the cams. The cross-slide and compound both have 10 TPI leadscrews with 100-division graduated collars, allowing for precise movements of 0.001" per division. The compound can be rotated 360 degrees and secured at angular positions indicated by a ±60 degree graduated scale.

For thread cutting, the machine uses a saddle-feed gearbox and external change gears. The leadscrew is quickly reversible for left-hand threading. The threading dial is used for TPI threads, with specific rules for re-engagement based on the TPI value (even, odd, or not divisible by 2). For metric threads, the split-nut must remain engaged throughout the entire process, and the gearbox is driven slower by a translating gear pair.

The lathe can be equipped with a Quick Change Tool Post (QCTP) as an alternative to the standard 4-way turret. The QCTP offers rigidity, reliable repeat positioning, and individual height adjustment for toolholders, saving time during tool changes.

Maintenance Features:

Regular maintenance is crucial for the PM-1228VF-LB. This includes checking oil levels in the gearbox before use. The manual emphasizes the importance of proper lubrication for rotating and sliding parts to prevent premature wear. Recommended lubricants include ISO 68 oil for the gearbox, ball oilers, machine ways, and leadscrews, and NLGI No. 2 general purpose grease for external change gears.

The gearbox oil should be drained and refilled every 12 months. Ball oilers should be checked and oiled frequently. Gib screws for the cross-slide and compound require adjustment to achieve a balance between rigidity and smooth slide motion, aiming for minimal backlash. Spindle bearings are factory-adjusted but can be re-tightened if end play becomes evident, with a procedure to ensure proper pre-load and temperature after adjustment.

Installation of Digital Readout (DRO) scales is also covered, with suggestions for mounting the scales and reading heads on both the longitudinal and cross-slide axes. This involves careful planning, precise shop work, and ensuring proper alignment to achieve accurate measurements. The manual provides detailed steps for setting up the DRO display, including parameter settings for cross-slide and longitudinal axes.