Wigglers?

[DickDastardly]

Hey Fellas,

What's the deal with wigglers? I understand that you can use them for finding an edge as well as centres for holes. Can any one please explain how it is set up/done.

At risk of sounding like a fuddy duddy, when I was an apprentice we were taught to use a sticky pin (which I personally despise) for finding the centre of a drilled hole and a wobbly centre with a dti when setting up on a 4 jaw for drilling! Is the principle the same as a wobbly centre?

Thanks in advance.

DD

[jackrae]

Wiggler is a rotating shaft with a free end (cylinder or ball) of known diameter (generally 0.2"). The driven end has a ball end which is lightly held within a matching pin (actually a ball) chuck. This chuck in turn is held and rotated by the chuck of the lathe, drill, milling machine to be used.

Now the height of the edge of the job is set to be roughly similar to that of the cylinder.

The wiggler is set rotating by the machine. Because of the ball chuck, this shaft will probably have a slight wobble.

As the work edge is moved towards the wobbly cylinder the cylinder will tap the edge and tend to true itself, so reducing the wobble. As you progress, the wobble gets less and less until you reach the point where the work edge is now exactly in line with the machine chuck centre line PLUS 1/2 the diameter of the cylinder.

As the edge is moved further towards the chuck centre line (like 0.0005"), the cylinder now rapidly runs away down the edge and develops a gross wobble.

At this point you know that the edge was exactly in line with the chuck centre (PLUS 1/2 the wiggler cylinder diameter)

Easier to try and see than explain but I hope this helps

Perhaps the more knowledgable technocrats could put a short .wav video file on the board

regards

Jack

[IP]

DD,

If you get the chance to have a look at the George Thomas books, there is a chapter on setting up wigglers [edge finders] which makes all very clear.

Regards,

IP

[DickDastardly]

Thanks very much,

I think I'll have to invest in a set, seems like a good idea.

DD