A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as zeroing, shaving, facing, cutting, tapping, drilling/boring, and turning down with tools that are applied to the workpiece to create an object with symmetry about that axis.
Stock Types
The difference between hex and thunderhex is the roundness of the edge. Hex has sharp pointy edges while thunderhex is more flat and rounded on its edges. We primarily use thunderhex because we use thunderhex bearings. Hex | Thunderhex | We have ½” and ⅜” stock. This means the outside diameter of the part is one of these widths, respectively. On round stock, you can measure this diameter from anywhere, but on hex and thunderhex stock, this diameter can be seen by measuring from opposite flat edges. |
Reading a Part Drawing
This diagram shows each of the dimensions required to read and effectively use a part drawing. Important:
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- Fastest speed: For cutting or shaving
- Slowest speed: For tapping
Basic Operations
Zeroing the Z/Y-Axis and X-Axis
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- The Z-axis on the silver lathe corresponds with the Y axis on the blue lathe.
- When zeroing, you don't want to remove too much material from your part. Even a thousandth of an inch can affect your measurements and potentially require remaking the part.
- Always approach the workpiece slowly and carefully to avoid damaging the tool or workpiece.
- Some machinists prefer to zero the Z-axis first, then the X-axis, but the order can be adjusted based on personal preference or specific job requirements.
X-Axis Zeroing
- Slowly move the cutting tool towards the workpiece in the X-axis (radial direction).
- Approach the surface of the workpiece very carefully.
- Continue advancing the tool until you see very small chips forming.
- This point of contact is your zero reference for the X-axis.
- Set the X-axis digital readout (DRO) to zero at this point, if your lathe has one.
Z/Y-Axis Zeroing
- Move the cutting tool to the end of the workpiece.
- Slowly advance the tool in the Z-axis (along the length of the workpiece).
- Approach the face of the workpiece very carefully.
- Continue advancing until you see very small chips forming.
- This point of contact is your zero reference for the Z-axis.
- Set the Z-axis DRO to zero at this point, if available.
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- Place your part at least 70% in the lathe.
- Turn the speed setting to the lowest. This is essential, as going too fast will likely break or weaken the tap as they are very fragile.
- Turn the black knob left and push the entire chuck mechanism gently towards your part until the tip of the tap is just against your part.
- Slowly turn the wheel (pictured) clockwise until the chuck mechanism starts moving into the part on its own.
- Once you’ve tapped halfway to the tap length, turn the black knob back to the center.
- Turn the black knob to the right to take the tap out of the part (this is the ONLY time the lathe should ever spin away from you).
- Clean the tap and part with air.
- Repeat this process, this time going all the way to your desired length.
- Repeat this once again to ensure clear threads.
Tips and Best Practices
- "Measure twice, cut once" - Always double-check your measurements. You can’t make something longer but you can make it shorter.
- Face only .005-.01 of your part if the face is rough/jagged to ensure your part has a smooth face so that you can more accurately zero or set the part length in the machine
- Shave only 0.01-0.04 inches at a time for better control and finish.
- Use slow, consistent movements for optimal results.
- Use tapping fluid for tapping operations and cutting fluid for other cutting operations.
- When zeroing your part, approach slowly until you see very small chips to avoid removing too much material.
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