Centering the Mill using Video Camera
My expert friend Stuart Tankard suggested that I try a digital video camera to locate work on my milling machine.
I have various gadgets for finding edges and tool heights, and I find that the electronic edge and height finders are the most accurate. But, I have never been satisfied with accurately locating other points in workpieces.
So I purchased this small video camera which is attached to a shaft for attachment to a collet or chuck which is held in the spindle.
The camera on the left is as supplied. It needs to be adjusted so that the camera is pointing exactly to the centre under the spindle. The adjustment is made to the 3 grub screws in the metal disk shown. When the unit is inserted into the collet, the screws are inaccessible unless only a fraction of the shaft engages in the collet. Also, the setting which is eventually determined seems quite precarious and liable to be altered with a slight bump. A very unsatisfactory arrangement.
So Stuart came up with the modification on the right. A CNC’d perspex disk replaces the back of the camera case. The new camera back is attached to a larger, more solid, steel disk. The screws are now accessible when the shaft is fully engaged in the milling machine spindle collet. Altogether, a superior setup.
Lining up cross hairs with the centre of the spindle is still fiddly and time consuming, but with the new, more solid setup, it should need to be done only once. It is done by loosening the cap screws and nudging the camera laterally.
Any slight angulation in the camera lens, or the chip, or the steel backing plate or shaft is compensated by fixing the focal distance. This is accomplished by making a small sleeve to fit between the lens and the camera body. It is the brass bit in the photo.
The following photos show some of the steps in making the modifications.
The camera is a TP-03 Machining Camera, purchased from Homann Designs. It cost $AUD88 plus postage plus GST.
The software to put the fine cross hairs on the screen was downloaded from http://www.kd-dietz.de and it is version 3.02 of “WebcamPlugin” for Mach3.
Check out the following link suggested by reader Hamish. It is a more complete discussion of the process and the technology. It is in the comments section below.
I’ve spent hours on this sort of thing. The problem always comes down to getting the hairs fine enough and then adjusting them. I tried a microscope called “supereyes” about £10 on ebay (3 of them actually). They even have software for putting lines on but it seems to be totally naff. I even tried paying a student to generate lines using software using a raspberry pi.
I hope you have more luck than me.
check out the webcam plugin for Mach3 at
I am using version 3.02
I also tried Supereyes and found it was a waste of money.
The unit described in my post is designed specifically for milling machines, and is OK, but is substantially improved with the modifications described in the post.
I will check where I bought it and let you know in a subsequent reply. It cost about $AUD120
Hello again John
the camera is a TP-03 machining camera, from http://homanndesigns.com/ Designs
It cost $AUD88 plus postage plus tax.
Interesting thread. Have a look at this page:
It shows one way of using a cheap webcam to do the same thing.
Best wishes for Christmas, and congratulations on your expanded family.
thanks for that link. That is a much more detailed and erudite explanation of the same process. He uses the same software (Mach3 and K Dietz crosshairs addon) and the camera looks the same although the casing is different. The US prices are always frustratingly cheaper.
Xmas wishes to you and Jeannie. John