Geriatric Punks

Step 4 – Machine outside diameter Machine bush outside diameter using an external turning tool.
If required, machine flange outside diameter.

Face the end of the bush to length.

Step 5 – Part to length Part bush to length using parting tool.
Ensure that bush does not fall when parted.

Machining in NC lathes Bushes can also be machined on numerically controlled lathes.
Take care to ensure that the clamping pressure does not distort the Vesconite.

Face the end furthest from the chuck Machine the inside diameter Machine the outside diameter Cut to length at the chuck end Machining standard bushes for production runs When machining many Vesconite bushes on center lathes, the following procedure saves time and minimises waste.

Step 1 - Cut to length Cut bush to final length using a cut-off circular saw. Take care to ensure that the cut is square.

If a fine length tolerance is required, allow extra material for facing both ends of the bush later.

Step 2 - Machine outside diameter Machine two mandrels with outside diameters the size of the inside diameter of the Vesconite bushing.

Machine one for the chuck and another for the tail stock.

Mandrels can be made of Vesconite, steel or other readily available rigid material.

Support the bush between these two mandrels by applying a light pressure, and machine outside diameter using external turning tool.

Step 3 - Machining the inside diameter Machine a "pot" with suitable available material (eg Vesconite, steel, etc). The inside diameter should be size to size to the outside diameter of the bush already machined.

Make the length of the pot about 10-25 mm (½" to 1") shorter than the length of the bush. The wall thickness of the pot must be sufficient to support the bush.

Drill a hole in the end of the pot so that the bush may be removed after machining by pushing a rod through this hole.

Machine a disc to be placed loosely inside the pot for removal of the part after machining.

Push the bush lightly into the pot.

Machine the bush inside diameter using a boring bar. Ensure that there is not a large buildup of shavings inside the bush being machined.

Grooves or other internal details may be added at this stage.

Machining bearings with grooves Groove design Machining spiral and round grooves This is done on the NC or manual lathe by normal operating procedures.

If the groove continues right through the bearing, it will usually be required to face the bearing after cutting the grooves.

Machining straight grooves Secure the bearing in the chuck or pot and lock the chuck.

Attach a broaching tool to the tool post.

Set up the tool and machine a groove taking no more than 2 mm with a cut.

Index the chuck to the next point and repeat the process.

Machining large bearings. Diameters >200 mm (8")

Due to the size of these bearings, extra care needs to be taken to ensure that there are no unnecessary stresses placed on the material. These bearing are referred to as XL bearings.

Vesconite XL bearings are easily machined on standard lathes if proper support is provided to prevent deformation and cracking.

Remember that Vesconite should not be clamped like a metal, but should be clamped gently and with care to avoid distortion.

Allow 50 mm (2") extra length for holding and parting the bearing.

Step 1 Set the bearing in the chuck. First face one end of the bearing square. This helps with alignment.

To prevent deformation and cracking, it is important to use an internal support disc machined to size. This disc may be machined from steel, wood, particle board or plywood about 30mm (1¼") thick.

The jaw clamping pressure should not be excessive but only enough to secure the bearing.
Step 2 Switch bearing around, align and face the other end. Once again the internal support is required.

Step 3 Machine the outside diameter of the bearing. Maximum cut depth is 5 mm. Allow bearing to cool before taking final cut. Final cut to be no more than 2 mm deep.

Step 4 Machine the inside diameter without removing the bearing from the chuck, and with the support disc in place.
Ensure that there is not a large buildup of shavings on the tool. Maximum cut depth is 5 mm. Allow bearing to cool before taking final cut. Final cut to be no more than 2 mm deep.

Step 5 Face the bearing to the required length taking care that the bearing does not fall.