Optical drill chuck

I have read a passing mention to something called an optical drill chuck for use in a milling machine on an American amateur telescope making website.

Can anyone explain what these are?. Also, is it possible to buy them in the UK?

David

Sounds like a good idea, David

I've found a brief description of one, here

MichaelG.

Picture here

and related items, here

MichaelG.

Edited By Michael Gilligan on 17/05/2015 07:21:42

This is, I believe, the relevant Patent

MichaelG.

Thanks a lot. Amazingly quick answers! Unless I missed something this does not appear to be available in the UK?

Do patents expire after a certain number of years? Also, if something is patented am I allowed to make it soley for my own use at home?

However, being realistic I have just got a mini-mill which I haven't had time to set up or use yet, I think it will take me around 6 months just to get the hang of making simple things on it.

So making an optical chuck would be a bit overambitious at the moment!

It is a very interesting idea to go on my long list of future projects.!

David

.

Absolutely !!

Attractive as it is in theory; I suspect that there were some durability problems with this design.

... Would love to know if anyone here has actually used one.

MichaelG.

Patent filed in 1946. Even if granted it would have expired by 1966 at the latest. And even if granted and in force you could make one for your own use at home. I wonder if there could be mileage in something similar where the optical viewer is replaced by a laser pointer? Could be simpler to make in the home workshop.

I have made one from a tribrach optical plumb, its fitted to a MT2 spigot and is very useful centering on the 4 jaw chuck. The fine crosshairs make it quite accurate. I will post a pic. later The optical plumb is known as a GOL4 so if you are at an auction and see one thats what you need. Some optical plumbs have a circular graticule.of about 0.3 dia.

Clive

> Also, if something is patented am I allowed to make it soley for my own use at home?

Yes! A patent has to give enough information for someone to be able to copy the idea, but prevents them from using it commercially without paying royalties.

Bought one of these a few years back. Thought it might help centring the D-W. Results were not encouraging - difficult to see through and needed extra lighting to illuminate the workpiece. Like Clive's, it was on a MT2 taper so would have suited the M7 as well. Suspect that it would suit somebody with much better machining skills than me!!

rgds

Bill

You could consider making Stan Bray's very simple optical centre finder in teh 25 years of MEW special.

Neil

I had an optical centering device many years ago. It had very poor optics and required I be a contortionist to get to the eyepiece. You had to rotate the spindle prove the crosshairs were on center. More contortions. I gave it away.

I liked Clives suggestion about adapting an optical plummet from an old tribrach. He and I may be the only ones with an old tribrach to cannibalize. Unfortunately I am older now dislike contortions even more so I may not pursue his idea.

Some time ago I found a link to software called CentreCam on this forum. It allows creation movable crosshairs on an image. I was considering purchase of a cheap USB microscope and mounting it to a spindle. Using CentreCam I could view the crosshairs on my laptop and adjust them so they traced the same point when the spindle ws rotated 180 deg. It is a future project. Has anyone already tried this?

For picking up a punch mark or scribed line I like to use a wiggler fitted with a sharp point. It seems to be close enough when working with scribed layouts.

G'day John. The CentreCam article was published in MEW about ten years ago.

I constructed one using a cheap webcam ($45) and once calibrated it's a handy piece of kit, easy to get accuracy of 0.001".

Unfortunately, was never able to contact the author to register my copy.

Here a few photos that I took during construction

* Danny M *

Danny,

Thank you very much for the post. You have proved that m\the concept is worth exploring. Some of the newer cameras in cylindrical housings and internal illumination look like they would be quite easy to adapt. I hope we don't start a run on the digital cameras that will drive the price up.

Where I served my time we had an optical chuck and has been described it could be a right pain to get your eye to the eye piece, especially if it was across a couple of feet of template, good illumination was needed as has been stated. The advantage was that once aligned you just needed to drill your hole, no faffing about swapping tools in the spindle. These days I just use a sticky pin ( plasticene and a needle)

I have ordered a 10x USB microscope from the Bay. It looks to be about the size of a pencil. Cost was about $18.50. The cylindrical shape make it easy to mount. I will try to work out a mount where the back end will be inside the spindle so I will not loose too much room under the spindle. I can tolerate up to 3/4" diameter shank. The camera was ordered Jan 1 and has not shipped yet. It may take a while before I start. I will report my progress and the results.

This is my version of the Centre Cam made a few years ago. Wouldn't be without it!

Delrin cone housing perspex ring diffuser, home made PCB with surface mount LEDs underneath. Another PCB mounts the USB socket and a pot for setting the LED brightness. Mounted on a 2MT arbor.

LEDs are quite bright but AGC in webcam software copes most of the time.

Set up for edge finding/location.

Screen showing 0.050 holes drilled at .050 centres on test piece.

What a beautiful job!