New moving ground glass mechanism

Frank Ladner · August 3rd, 2005, 02:52 PM

Didn't want to start a new thread for this, so here goes:

Anyone know how to put a small hole in a piece of glass without breaking it?
I got a piece of 3.5" circular glass from a $1 picture frame and I want to try making a glass version of the spinning CD adapter.
The hole should be no bigger than the shaft of a CD motor.

I don't have any precision equipment here. (No diamond drill bits, etc...) I do have a template printed from Photoshop that I will lay the glass over to find out the exact center point. I understand this is a slow process, but I am willing to do it. I want to do this before I grind it because I'd hate to break it after spending all that time on it.

Any ideas?

Thanks!

Daves Spi · August 4th, 2005, 01:06 AM

[QUOTE=Frank Ladner]Anyone know how to put a small hole in a piece of glass without breaking it?QUOTE]
I already did this couple of months before. And I have four glasses with hole to attach on harddrive motor (silmilar to CD holder). I can send it, but its 800 grit. Maybe its to much for you. Im from Europe, so if someone wants, I can send it.

Dan: hey Dan... ignoring me ?

Frank Ladner · August 4th, 2005, 06:36 AM

Quote:

I can send it, but its 800 grit.

Daves: Are you talking about sending a pre-made ground glass? I appreciate the offer, if so. I'm actually going to grind with a larger grit in an effort to get a more even image w/ no hotspot. Since it will be spinning, the grain won't be a problem.

Can you tell me a little more about how you did it? Thanks, Daves!

Daves Spi · August 5th, 2005, 01:11 AM

Quote:

Originally Posted by Frank Ladner

Can you tell me a little more about how you did it? Thanks, Daves!

I did not. I order it to be done for me. They made me 4 pieces, but I do not use them anymore. Since its useless for me, I can send it to you. But I do no know if its enough big for you. I think it have 8cm in diameter, 2cm center hole. Or so. Thickness is 2 or 3mm. Its ready to use, you do not need anything to do with, until you do not want to make grain finer. Now its sanded by 800.

Frank Ladner · August 5th, 2005, 06:31 AM

Hrm..... 8 cm is about 3.15 inches. The one I have now is 3 & 1/2 inches, and that's cutting it close...so I think the 3.15 would be too small to work with the motor and condensors I have. I'd hate for you to go through the trouble and it be too small. I appreciate the offer to send it!

I was thinking about it and maybe I won't have to drill. I could possibly mount something to the glass surface to attach to the shaft. I started thinking of using something flexible so that when the glass spins, it would automatically spin straight (with no z - motion). However, I wonder how well this would work when the camera moves quickly.

Daves Spi · August 22nd, 2005, 12:18 PM

So... Dan, whats up... Tell us !

Frank Ladner · August 22nd, 2005, 12:59 PM

Hey guys!

For those of you looking for an adapter housing, here's one possible solution:

I got my hands on an old hard drive and removed the internal mechanisms (read/write arm, magnets, platters, etc...) until all that remained was the aluminum box with the metal cover.

At the moment, I'm working on a 3.5 inch spinning glass CD and this fits perfectly into the housing...even giving a little room for wobble (because a glass CD spinning quickly and hitting the inside of the housing just might break :-) )

All I have to do is put the holes through both sides.

These drive housings are durable and not all that heavy once the inner workings are removed. I think it's a good solution for an adapter housing.

Once I get the thing finished (including holes, wiring, lens mount, etc...) I'll try and post some pictures.

I took a couple of pictures of the drive housing as-is. They are located here:

http://70.147.193.182/mwtest/

(The images are named harddrive_for_housing_[ 01 & 02 ].jpg )

Andrew Burke · August 22nd, 2005, 01:13 PM

I like the idea with the harddrive. It sounds way better than using plastic. Keep us on the up and up!

Bill Porter · August 22nd, 2005, 06:38 PM

A hard drive spins WAY faster than a CD player. CD players spin at around 500-750 rpm depending on whether the read head is closer to the center or to the outside. Hard drives of course spin 5400 or 7200 rpm.

That means the speed at the outer edge of a 5.25" circular piece of plastic (blank CD, ground glass, etc), with a CD motor is about 8 to 11 miles per hour (circumference times rotations per minute = distance travelled). With a 5400 rpm drive, it jumps to around 84 mph! That is a HUGE increase, especially in terms of dynamic imbalance as well as simple stability. With a 10x speed increase, centrifugal force is increased 100x. That means any instability, even if it is "invisible" at CD motor rpms, will be really apparent at hard drive rpm's.

I would not want to be at a tangent to a piece of plastic or glass spinning that fast. I guess if you have it inside a metal housing it would be one thing but even so, I wouldn't want shards bouncing into my camcorder or my 35mm lens.

Just my two cents' worth, from a guy who has been around a fabrication shop and machine shop environment for years. Wouldn't want to see anybody's soft parts, or lenses, get hurt.

Frank Ladner · August 23rd, 2005, 06:47 AM

Hey Bill!

Thank you for the input - and I agree with what you say. However, I won't be using the motor from the hard drive - just the case/housing. I'm still using a regular motor from a portable CD player. I'll rig this with a variable resistor (potentiometer) to adjust speed. (ie. to be able to increase speed in lower light to reduce grain)

Dan Diaconu · September 8th, 2005, 03:32 PM

Just in case you may have missed the post about Universal Focus Gear for SLR lenses, I do offer them from my site (under construction)

The MPIC will be available before the end of the year offering a few options in terms of different quality parts (filters, screens, motors and adjustable amplitude of motion). You could buy the entry level and upgrade later to higher quality parts. I am still working on pricing it, but I want to make it as affordable as possible. I will list it on the same page:
http://dandiaconu.com/available_products.htm
as soon as I have prices for all parts so you can order it. Thank you all for your sustained interest in this project.

Dan Diaconu · September 26th, 2005, 02:00 AM

I am taking orders now for MPIC and a few other items.

Michael Maier · September 26th, 2005, 02:12 AM

I couldn't find it on your available products page.

Dan Diaconu · September 26th, 2005, 09:41 AM

You're right. Sorry.....
Very long hous.... looks like it was not uploaded. I'll do it by this evening. Thank you.

Aaron McMath · September 29th, 2005, 09:14 PM

How much are you planning to charge for them after the promotional period?

It looks amazing, especially in terms of size and efficiency, but I would want to see independent tests and reviews before putting down that kind of cash.

August 4th, 2005, 01:06 AM	#467
Daves Spi Regular Crew Join Date: Feb 2005 Location: Czech republic, Prague Posts: 159	[QUOTE=Frank Ladner]Anyone know how to put a small hole in a piece of glass without breaking it?QUOTE] I already did this couple of months before. And I have four glasses with hole to attach on harddrive motor (silmilar to CD holder). I can send it, but its 800 grit. Maybe its to much for you. Im from Europe, so if someone wants, I can send it. Dan: hey Dan... ignoring me ? __________________ Daves At the beginning there was an idea, then the ambition came and the idea became to be a dream... The Satisfied Dream => http://film.datriware.com

August 22nd, 2005, 12:18 PM	#471
Daves Spi Regular Crew Join Date: Feb 2005 Location: Czech republic, Prague Posts: 159	So... Dan, whats up... Tell us ! __________________ Daves At the beginning there was an idea, then the ambition came and the idea became to be a dream... The Satisfied Dream => http://film.datriware.com

September 29th, 2005, 09:14 PM	#480
Aaron McMath New Boot Join Date: Sep 2005 Posts: 15	How much? How much are you planning to charge for them after the promotional period? It looks amazing, especially in terms of size and efficiency, but I would want to see independent tests and reviews before putting down that kind of cash.

August 3rd, 2005, 02:52 PM	#466
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Didn't want to start a new thread for this, so here goes: Anyone know how to put a small hole in a piece of glass without breaking it? I got a piece of 3.5" circular glass from a $1 picture frame and I want to try making a glass version of the spinning CD adapter. The hole should be no bigger than the shaft of a CD motor. I don't have any precision equipment here. (No diamond drill bits, etc...) I do have a template printed from Photoshop that I will lay the glass over to find out the exact center point. I understand this is a slow process, but I am willing to do it. I want to do this before I grind it because I'd hate to break it after spending all that time on it. Any ideas? Thanks!

August 5th, 2005, 06:31 AM	#470
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Hrm..... 8 cm is about 3.15 inches. The one I have now is 3 & 1/2 inches, and that's cutting it close...so I think the 3.15 would be too small to work with the motor and condensors I have. I'd hate for you to go through the trouble and it be too small. I appreciate the offer to send it! I was thinking about it and maybe I won't have to drill. I could possibly mount something to the glass surface to attach to the shaft. I started thinking of using something flexible so that when the glass spins, it would automatically spin straight (with no z - motion). However, I wonder how well this would work when the camera moves quickly.

August 22nd, 2005, 12:59 PM	#472
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Hey guys! For those of you looking for an adapter housing, here's one possible solution: I got my hands on an old hard drive and removed the internal mechanisms (read/write arm, magnets, platters, etc...) until all that remained was the aluminum box with the metal cover. At the moment, I'm working on a 3.5 inch spinning glass CD and this fits perfectly into the housing...even giving a little room for wobble (because a glass CD spinning quickly and hitting the inside of the housing just might break :-) ) All I have to do is put the holes through both sides. These drive housings are durable and not all that heavy once the inner workings are removed. I think it's a good solution for an adapter housing. Once I get the thing finished (including holes, wiring, lens mount, etc...) I'll try and post some pictures. I took a couple of pictures of the drive housing as-is. They are located here: http://70.147.193.182/mwtest/ (The images are named harddrive_for_housing_[ 01 & 02 ].jpg )

August 22nd, 2005, 01:13 PM	#473
Andrew Burke New Boot Join Date: Jul 2005 Location: Portland, OR./ San Francisco, CA. Posts: 10	I like the idea with the harddrive. It sounds way better than using plastic. Keep us on the up and up!

August 22nd, 2005, 06:38 PM	#474
Bill Porter Major Player Join Date: Mar 2005 Location: Ventura, California, USA Posts: 751	A hard drive spins WAY faster than a CD player. CD players spin at around 500-750 rpm depending on whether the read head is closer to the center or to the outside. Hard drives of course spin 5400 or 7200 rpm. That means the speed at the outer edge of a 5.25" circular piece of plastic (blank CD, ground glass, etc), with a CD motor is about 8 to 11 miles per hour (circumference times rotations per minute = distance travelled). With a 5400 rpm drive, it jumps to around 84 mph! That is a HUGE increase, especially in terms of dynamic imbalance as well as simple stability. With a 10x speed increase, centrifugal force is increased 100x. That means any instability, even if it is "invisible" at CD motor rpms, will be really apparent at hard drive rpm's. I would not want to be at a tangent to a piece of plastic or glass spinning that fast. I guess if you have it inside a metal housing it would be one thing but even so, I wouldn't want shards bouncing into my camcorder or my 35mm lens. Just my two cents' worth, from a guy who has been around a fabrication shop and machine shop environment for years. Wouldn't want to see anybody's soft parts, or lenses, get hurt.

August 23rd, 2005, 06:47 AM	#475
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	Hey Bill! Thank you for the input - and I agree with what you say. However, I won't be using the motor from the hard drive - just the case/housing. I'm still using a regular motor from a portable CD player. I'll rig this with a variable resistor (potentiometer) to adjust speed. (ie. to be able to increase speed in lower light to reduce grain)

September 8th, 2005, 03:32 PM	#476
Dan Diaconu Major Player Join Date: Dec 2004 Location: Vancouver, Canada Posts: 804	Just in case you may have missed the post about Universal Focus Gear for SLR lenses, I do offer them from my site (under construction) The MPIC will be available before the end of the year offering a few options in terms of different quality parts (filters, screens, motors and adjustable amplitude of motion). You could buy the entry level and upgrade later to higher quality parts. I am still working on pricing it, but I want to make it as affordable as possible. I will list it on the same page: http://dandiaconu.com/available_products.htm as soon as I have prices for all parts so you can order it. Thank you all for your sustained interest in this project.

September 26th, 2005, 02:00 AM	#477
Dan Diaconu Major Player Join Date: Dec 2004 Location: Vancouver, Canada Posts: 804	I am taking orders now for MPIC and a few other items.

September 26th, 2005, 02:12 AM	#478
Michael Maier Trustee Join Date: Apr 2005 Posts: 1,269	I couldn't find it on your available products page.

September 26th, 2005, 09:41 AM	#479
Dan Diaconu Major Player Join Date: Dec 2004 Location: Vancouver, Canada Posts: 804	You're right. Sorry..... Very long hous.... looks like it was not uploaded. I'll do it by this evening. Thank you.