Clive, got some links to save hunting about ?

Clive,

OK thanks now see that it's just a CNC touch probe.

What is not quite clear to me now is how you want to use it given no CNC ?

It could be used manually but it would be an absolute pain, move X and Y using a DRO ? bring Z down and note the reading, move on and repeat. This would give you what is known as a point cloud map but without software or CNC what use is it?

Perhaps I'm reading this all wrong and all you want is an edge finder or similar ?

Nigel,

No they will work as an edge finder, they have three sets of contacts that the probe sits on and it only has to move off one to break contact.

Imagine you are probing a steep cone like a church steeple when it goes down and makes contact the movement will be more X or Y than Z due to the angle. Hope I have explained it clear enough ?

John S.

Hi all,
Here is an idea for a variation on this design. A ball on the end of the probe sits in a conical depression on the end of a rod. It is held in contact with the depression with an insulaing fibre passing through a hole in the rod and attached to a tension spring. The origin idea was that the rod was made of three 120 Deg segments with thin insulators between them. If the ball was not displaced it would make contact with all three segments. If it was diplaced from any direction it would no longer make contact with all three segments. I could not see an easy way to make the rod in three segments so a possible alternative would be to make the rod of insulating material and drill three holes down it spaced at 120 Deg. Three thin metal rods would then be glued into these holes. When the glue had set the end of the rods would be machined so they formed part of a conical depression. The ball could sit in contact with the end of these rods. Here is a sketch of the idea.

I have not yet tried to make one of these to test if the idea will work.

Les.

Here's a cheap one

Martin.

Clive,

I think it's worth reading through this recent thread.

MichaelG.