I wonder if consistancy in the ground glass face will be an issue. I know flicker can be a problem with these types of adapters.

Thanks Jonathan,
I know that was an issue on the plastic cd version, but the glass version will be ground with aluminium oxide creating a very uniform surface. Im confident there will be no flickering, but the proof is in the pudding.

Wayne.

Good luck with it!

Jonathan-

Thanks Jonathan,

As im still waiting on my glass cutting tools, I thought I would test out my method on a plastic disk to see if i could get it to spin central. It works perfectly well. I added a last step and touched the edge of the disk with sand paper while it was spinning to really make sure it was all central.

I have rubber washers/grommets on the screws to prevent the screws from cracking the glass (well, when it is glass).

Here are some pics:

http://homepage.ntlworld.com/wayne.k.../DSCI0086a.jpg

http://homepage.ntlworld.com/wayne.k.../DSCI0087a.jpg

Can wait to start experimenting with glass.

Wayne.

Recieved my diamond drill bits this morning. Will do some practise drilling first then proceed with the next step. Ill post some images later.

Wayne.

OK,
Turns out the drill bits i got form ebay were a heep of s**t. Made from soft metal so the drill war down before getting very far. Only drilled 1 test hole.

I have ordered a better quality drill bit from a DIY store, so will continue then.

Wayne.

Wayne,

Just a tip or two, but, did you cool and lubricate the bit at all? The best way to do this is to use a steady flow of machining coolant or at least water. Second best way is to use a soft washer (rubber or something) around the hole, to hold the coolant/water in.

Also with glass you have to use very light pressure and go very slowly. Even a good bit will act like the ones you tried, if you use too much pressure or operate them without cooling/lubricant.

One more thought I had forgotten til now, which is, when the drill bit breaks through the other side it will may break or at least crack the glass. For brittle materials with a grain structure like glass, you will want to drill a hole halfway through, from each side.

I read about using lubricant for cutting glass but that was for cutting lines, so didnt relate that to drilling holes, simple really. The drill bits were crap though, i read other ebay member complaining about it (after i bought it, trust me).

The new drill bit i ordered is of a different design, shaped like a spear. Its also made of extremely hard tungsten carbide spear tips, so with this bit, plus cooling with water using your rubber washer method. Thanks for the tip.

I was using the method of going half way from either side, thanks for the tips though.

Hopefully next attempt will be more successful, I WILL have a spinning glass solution, plastic is NOT an option;) hehe

Thanks,
Wayne.

Ok,
I have changed my method slighty, not using a perminant marker or circular glass cutter now, but instead replacing the marker with a straight diamond glass cutter. With the glass cutter mounted solidly to a drill press, the the glass and motor mounted solidly under the cutter, the cutter can be lowered onto the glass (instead of the perminant marker), then the fan motor and glass can be rotated.

The cutter will score the glass in the exact position creating a perfectly centred circle. 8 more scores can then be make spaced evenly around the circle, running from the circle to the edge of the glass. Its then just a matter of breaking the 8 peices of glass around the edges of the circle away.

The glass edge can then be cleaned using 120 sandpaper or a sanding block.

This Method means that the glass can be mounted to the fan motor once and not have to be taken off again, preventing any chance of the glass shifting. Obviouslyt the glass should be ground with Aluminium Oxide before being mounted to the motor.

Thanks,
Wayne.

Will the motor shaft be strong enough to support the glass while you press down on its edge with the drill press? I hope it works for you.
From my experience, it seems that cuts work best with a single pass, so I'm assuming you'll be spinning the glass by hand?
Anyway, as for getting the glass disk out, you can use the spiral cut method.
Starting at the edge of the circle, draw the glass cutter across the glass in a slight arc until your within a couple of mm from the edge. Repeat every 30 mm or so around the edge of the disk. Each piece will then simply break off.
With practice, this can leave a very nice edge, and means you only have to use the drill press method once.

G

Glen,
Sorry i forgot to mention, I will be using a model R/C car/airplane wheel under the other side of the glass to support. This plastic whell has a rubber/foam tire, so will not scatch the glass. Thanks for pointing that out.

Yes, Ill be turning the motor by hand this time, by only 1 revolution so the cutter makes makes the score but does not go over it again. The wheel underneith will rotate as the glass does, providing support.

Concerning your method of breaking the glass out, I was doing the same, but with straight lines not an arc, does the arc shape make it easier to break the glass?

Thanks for your input Glen.

Wayne.

I haven't tried the straight line method. I think the point of the spiral is that all cuts from the circle come out at a tangent to it, so that the cracking glass travels more or less along the arc of the intended disk. I've had 3/4 of the glass fall away with one twist using this method, but I have no experience whether it's better or worse than using straight lines.
Airplane wheel for support, eh? Sounds great!

G

Glen,
Thanks again for the tip, i'll try that on my next practise.

Yeah the model plane/car wheel works perfect. Its mounted on a bolt so it can not move relative to the glass/fan, but can spinn freely. The cutter comes down onto the glass, the wheel on the other side takes the pressure. As the glass is turned by hand on the fan motor, the wheel also turns via friction. Constant pressure is kept on the cutter until 1 revolution is made, ending up with a perfectly placed score line.

Thanks,
Wayne.

Genius! It does take a good bit of pressure to get a clean score, but using a rotating wheel as a bed under the glass-cutter sounds like the solution.

Glen,
Just tried your 'spiral method'. It seemed to work better, the glass would break in a much more pradictable way, always on the score line, which was not always the case using straight lines. Thanks again for this tip.

Although im now sitting here with blood running down my finger. Its like my 10th cut. Only small nicks, but i think the glass is trying to give me an early warning about something. I think some very strong safety measures and eye protection will be in order when i first spin the glass on the motor.

Wayne.