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Milling – alignment – methods – “bent” spigot

Where two spigot are not coaxial but are at an angle to each other then different methods are needed to check that their axes lie in the same plane.

In some cases one of the spigot may well be a workpiece.

In practice there are two key parameters

if their diameters are the same or not

if they are at right angles or something else

Case 1 – same diameter and at right angles

This can easily be checked by using a square

Case 2 – different diameter and at right angles

Devices for doing this are all based on having two v-shaped grooves at right angles.

first – Rawlinson’s device

A similar device is made by Starrett

 

Case 3 – same diameter at any other angle

This can be aligned using an angle plate. This does assume that the angles of the vertical planes that pass through each of them are parallel.

fig “bent” bushes using an angle plate

 

Case 4 – different diameter  at any other angle

This is the same as case 3. The difference is that there will be a gap between the smaller part and the angle plate. this can be “eliminated” by fiiting two bushes on the narrower part to make it the same effective diameter as the wider part.