Edge Finder & Centre Finder

Over on 'Homemade Tools' is a piece on using a pen microscope in the machine shop;

**LINK**

I've had a look on a well known auction site and there seem to be some very cheap ones.

Does anyone know if the software is likely to be compatible with Windows 10 and how could it be mounted on a mill?

Brian

There are also lots of edge finders for sale on ebay

Supereyes digital pen microscope has listings that say it works with Windows 10.

Martin C

Hello Paul, yes, I know there are edge finders on Ebay and I already have a Starrett wiggler and an electronic one but the item described on 'Homemade Tools' is in a different league altogether and is more like a shadowgraph.

Thanks Martin for the digital pen info, I'll look into that.

Brian

Just avoid buying any webcam or derivative that requires a driver to be installed

UVC = USB Video Class is a well-established standard that should work with any popular modern operating system.

MichaelG.

Many thanks for the explanation Michael, we learn something new every day, especially on this forum.

Brian

I went through this process on my little CNC mill, mounting a CCD microscope on the side of the column and using the CentreCam software. Obviously the 'scope centreline is offset from the spindle axis when you do this. In order to evaluate the offsets I used the following process.

• Used a spotting / centre drill to make a very small dimple on the surface of a bit of stock
• Zeroed the axes
• Moved the table until I got the surface of the stock in focus and the centre of the dimple on the cross hairs.
• The values of the axes, with reversed sign, give you the offsets of the spindle from the microscope.

However I have never found the method very useful because it's a faff and manual, much better to have a probe linked to the controller and find the edge or centre automatically.

You can see some pics in my "Microscope" album.

Edited By John Haine on 21/11/2020 10:02:39

Many thanks for your input John, I did wonder about the offset between the camera and the machine spindle and wondered if a WiFi camera could be the answer, held in an ER collet on the machine.

Brian

I tried CentreCam and a webcam camera as well. Tried to make a suitable spindle mount and found it so hard to set it on the centreline of the spindle

You can set it on the centre line at one height then find it is not right at another height so try again to centre it, repeat this process a few times and give up.

Effort involved compared to potential return was too high so gave up on it.

Martin C

Interesting, thank you Brian. I don't think I'd use one as a centreing device but do like the idea of having a shadow graph type facility in the workshop.

Thanks Henry, I described it as a centre and edge finder because I couldn't think of another description that others would identify with.

Brian