ACRA KNEE MILLING MACHINE “BRIDGEPORT COPY” OUR TOP SELLER!
Two Table Sizes : Model LM 42 features a 9 x 42 Table or the LM-50 with a 10 x 50 Table
Available with a 16 speed Step Pulley Head or a Variable Speed Head
Main Features
About the Mill Head, A matched pair of super-precision ABEC-7 angular contact bearings supports the spindle. The quill is CNC-ground to a mirror finish, and then chromed to fit the housing. Together, they insure spindle run out of no more than 0.0004” TIR- the best in the industry.
To dissipate heat in the 3 HP motor driven head, a pair of high output fans is installed. This allows the machine to work demanding jobs for extended periods without damaging the motor, belts and bearings. The motor shaft and Vari Drive pulleys are dynamically balanced, then hard-chromed this allow a vibration free milling even at high speed. Since the Vari-speed drive system is operated by sliding the Vari Drive pulley up and down the motor shaft. The motor shaft is therefore chrome-plated, and has an oil channel that is fed by a grease fitting on the lower end for self-lubricating purpose. This ensures the sliding motion is trouble free at all times. The motor shaft that drives the pulley and the spindle is subject to a lot of lateral stress. A roller bearing is installed for the lower support of the motor shaft
The Step Pulley head features 16 speeds via belt change and two speed motor.
Beside swiveling 90 degree side to side, the head can also swivel up and down by virtue of a knuckle joint design. The new design developed by Sharp uses 6 bolts, 3 each side, that fitted into a circular T-slot milled at the inside of the over arm and secured by nuts from the outside. It secured the head tightly and offered high accuracy in milling operations.
The Base: Certified MEEHANITE castings are used for superior rigidity and better dampening of vibrations. Turcite B is applied to all female sliding surfaces. Table and saddle backlash is controlled by a double-nut design that keeps the feed screw in contact with a pair of bronze nut at all times.
The end of the table and saddle are mounted with thrust bearings that pre-load the feed screw, eliminating end-play for precisely controlled lateral movement.
| MODEL | LM 42 | LM-50 |
| TABLE | ||
| Working surface | 9” x 42″ | 9” x 50″ |
| T-slot number, size | 3, 5/8″ | 3, 5/8″ |
| CAPACITY | ||
| Table travel; x-axis | 30″ | 37” |
| Saddle travel; y-axis | 12″ | 12″ |
| Ram travel | 12″ | 12″ |
| Quill travel (Z-axis) | 5″ | 5″ |
| Knee travel | 16″ | 16″ |
| Spindle to column (min-max) | 6 3/4″ – 18-1/2″ | 6 3/4 – 18-1/2″ |
| Spindle to nose table | 2 1/8” – 18″ | 2 1/8” – 18″ |
| SPINDLE | ||
| Motor | 3 HP | 3 HP |
| Wiring voltage | 220/440v, 3 phase, 60 Hz | 220/440v, 3 phase, 60 Hz |
| Taper | R-8 | R-8 |
| Speed (vari-speed) | 60-4,500 RPM | 60-4,500 RPM |
| STEP Pulley head 16 speeds | 80-5520 RPM | 80-5520 |
| Quill feed (IPR) | 0.0015”, 0.003”, 0.006″ | 0.0015”, 0.003”, 0.006″ |
| Head swivel | 360º | 360º |
| Head tilt; right-to-left (each way) | 45º | 45º |
| Head tilt up-and-down (each way) | 45º | 45º |
| DIMENSIONS AND WEIGHT | ||
| Floor area (w x d) | 7’ x 6.5′ | 7’ x 6.5′ |
| Net weight | 2,400 Lbs. | 2,400 Lbs. |