November 3, 2023

How to look at ordinary lathe screw thread nameplate?

Each factory ordinary lathe has a thread nameplate (usually on the gear box), according to the need to process the thread specifications corresponding to the specifications on the nameplate to adjust the cutting gear. Ordinary lathe thread nameplate - that is, the number on the name plate of the other party, processing ordinary metric and imperial threads.

Steps and methods of turning thread: (Low speed turning triangle thread Vく5 m/min)

1. Requirements for the workpiece before threading:

1) Large diameter of thread: Theoretically large diameter is equal to the nominal diameter, but according to the coordination with the nut it has a lower deviation (-), the upper deviation is 0; Therefore, in processing, according to the three-level accuracy requirements of thread. The outside diameter of the thread is 0.1p smaller than the nominal diameter, and the outside diameter of the thread D= the nominal diameter - 0.1p

2) Tool return slot: before threading, there should be a tool return slot at the end of the thread, so that the turning tool can exit in time.

3) chamfer: before turning the thread, there should be chamfer at the beginning and end of the thread, and the small end diameter of the chamfer く the bottom diameter of the thread;

4) Depth of teeth (cutting depth) : h1=0.6p;

2, adjust the lathe: first turn the handle to connect the lead screw, according to the workpiece pitch or lead to adjust the feed box outside the handle shown position. Adjust to each handle in place;

3, start, write down the dial reading of the knife, exit the turning tool to the right;

4. Close the opening and closing nut, get a helix on the surface of the workpiece, exit the turning tool horizontally, and turn the turning tool back to the right end, stop to check whether the pitch is correct (steel rule);

5, start cutting, using the dial to adjust the cutting depth (gradually reduce the cutting depth). Note that in operation, when the tool will end, it should be ready to withdraw the tool and stop, quickly exit the tool first, and then turn the reverse car back to the tool holder. Cutting depth control, rough turning t=0.15~0.3mm, fine turning tく0.05mm;

6, thread measurement: one-way measurement method and comprehensive measurement method. Experience deficiency

One-way measurement method:

(1) Measurement of the top diameter: the size of the top diameter of the thread is generally allowed to have a large error, the top diameter of the external thread can be measured with vernier calipers or micrometers, and the top diameter of the internal thread can be measured with vernier calipers.

(2) Measurement of pitch: pitch can generally be measured by steel ruler;

(3) Measuring the diameter of the thread: measuring the diameter of the thread with the thread micrometer, measuring the diameter of the thread with the three-pin method. The three-pin method for measuring the middle diameter of thread is a relatively precise measurement method.

Comprehensive measurement method: Comprehensive measurement method is a comprehensive measurement of the dimensions of the thread with a thread gauge.