Cutting inch threads – Smithy GN1300 User Manual

Page 82

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Step 5: Loosen the hex head bolt. This allows the assembly to drop down.

Step 6: Position the installed B/C gear unit to mesh with the D gear.

Step 6: Rotate the gear assembly until the B gear meshes with the A gear.

Lock the assembly in place by tightening the hex head bolt.

The hex head bolt also tensions the speed reduction pulley support arm. Be

sure the belts are in the appropriate position before tightening the hex head

bolt.

Cutting Inch Threads

Step 1: Select the desired thread pitch that you wish to cut from the chart

located on the headstock of the Granite 1300 series lathe-mill-drill.

Step 2: Engage selector levers (1-7) and selector lever (I-III). Remember, you

can use the jog knob located on the right side of the gear box to help align the

gears if the levers are difficult to engage.

Step 3: Check the gear set-up inside the pulley box to confirm the gearing is

set-up correctly to cut your desired thread pitch. If the gears are not correct,

change gears using the previous procedure.

N O T E:

The default factory setting is for cutting inch, SAE, threads.

Step 4: Confirm that your belts inside the pulley box are properly set-up to

reach the recommended spindle speed for cutting your work piece material with

your specific cutter.

Step 5: Set your compound angle toolpost to 29-1/2º and install the E8

carbide bit that came with your machine.

Step 6: Inside the pulley box at the left lower side of the gear cluster is the

inch/metric lever, which must be pushed away from you for inch threading.

Step 7: Turn your machine on and adjust variable speed to the recommended

speed.

Step 8: Once you have made all of your tooling and machine settings, you are

ready to begin the first pass. Set the dials on the compound angle toolpost and

cross-slide table to zero. Move the compound angle toolpost into the desired

position and feed the cutter into your workpiece using the small CATP feed

handle. Watch the threading dial rotate until one of the numbers is just about

to the reference mark. At this point apply firm constant downward pressure on

the half-nut engagement lever until you feel the lever drop into position and the

carriage begins to move. (More information to follow on the threading dial.)

10: Threading

10-4

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