Finally, an affordable CD Transport: the Shigaclone story

[DaveM]

I was just looking at the pics of the cd clamp. I had one piece of feedback. Why not make the thread something more substantial like 1/4-20? Once you cut that 2mm hole through the center, there isn't a whole lot of meat left there. There is not disadvantage to a larger coarse thread. More thread depth and therefore much less chance of stripping. Torque holding the disk is not an issue, so I would definitely go with a coarse thread.

Also I see you are doing these out of acrylic. I do like the nice amber look, but acrylic will crack and craze if exposed to alcohol. I would likely go with delrin or lexan. They don't come in the nice translucent colors, but machine better and are more stable to common cleaners. Just my 2 cents, probably worth less than that.



About the switch.... I don't have my player in hand yet. I should be getting mine next week, so I was just thinking without knowing.

[okapi]

Hi DaveM

your input makes sense.

just so you can understand my thinking. 1 ft of acrylic is $8. 1ft of Derlin is $40.

i guess alcohol can be used to clean cd's or laser lens?

i have never machined those other materials but i definitely have acrylic figured out so my inclination at this time is to stick with what i know. can you tell me what makes derlin or lexan easier to work with? do you think it would significantly cut down on the time to make a clamp?

the plan was always to go with a bigger thead, having haphazardly found my way to a smaller one (see my last clamp post) i am going to have the opportunity to compare. i think how well the clamp grips the disk before the causing the motor to spin when tightening will be an important factor. i have a feeling it might be better with more threads per inch but we'll see.

also, like you, i was worried about the the amount of material left after cutting the center hole however, even with 10-32 it seems to be fine.

[nhuwar]

Derlin's a whole lot easier to work with then acrylic.


Just don't try to glue anything to it, chances are it won't work.



Nick

[audio1st]

Nice work okapi, just a note while it is at prototype stage. This probably won't matter but, the CD spins clockwise so would the thread need to be anti-clockwise to prevent it undoing as it spins up? Only asking because I guess it needs to be a lose thread..

[DaveM]

As nhuwar said, Delrin is much easier to work with. It cuts like soft butter. Acrylic tends to crack and this can be seen in surface finish issues as well as strength issues. The big difference would be seen in the end strength of the clamp. Acrylic, Delrin and Lexan are all quite stable in terms of the part holding it's shape once it is cut, but Delrin and Acrylic much are stronger. Have you ever worked with plexiglass. Essentially acrylic sheet. My experience is when you cut it with a table saw, you wait to see where it shatters because it most often does. Cut Lexan with a table saw and perfect cuts every time. Someone at work once saved us some money by changing the material from lexan to acrylic. Cheaper material=>wasted time and junk parts. 1.25" round Delrin rod at McMaster is $7.38/foot in black.

If you would like I can dig up a butt end from the shop and send it to you to play with.


Audio1st. Yes in theory you are right, but the lug nuts on your car suffer the same centripetal forces. If you use a left hand thread, would the clamp not come loose when the disc stops? In the end, it won't make a difference and it certainly doesn't justify the cost of a left hand tap and die.

Nice work by the way.

[JC Fardo]

Originally posted by okapi
Hi DaveM
i guess alcohol can be used to clean cd's or laser lens?

Only isopropylic alcohol is good for use in electronics and laser optics AFAIK, so acrylic puck is not a problem.

[okapi]

thanks for your helpful replies JC and DaveM. i am definitely learning which is the main reason i do most of this DIY stuff.

i've got a couple of follow up questions:

1. do the differences in strength matter for a cd clamp?

2. does the fact that derlin can go brittle matter for a cd clamp?

another strike against derlin is that it is not (as far as i know) transparent. being able to see through the clamp while making the center bore is really helpful as i can see how hard i can push things before the heat gets too high.

having read what i just wrote it seems like lexan is certainly the best choice for the highest quality end product and i will certainly make it an option for others.

3. what cutting lubricant do you suggest for Lexan. (i use kerosene for acrylic)

i requested a quote this morning from the machine shop. let's hope i hear back soon.

audio1st. did you remove your old clamp to test a Play station clamp? i ask because i tried to remove my clamp but was unable to do it with force levels that i felt wouldn't dammage the drive shaft.

[JC Fardo]

Originally posted by okapi
thanks for your helpful replies JC and DaveM. i am definitely learning which is the main reason i do most of this DIY stuff.

i've got a couple of follow up questions:

1. do the differences in strength matter for a cd clamp?

2. does the fact that derlin can go brittle matter for a cd clamp?

3. what cutting lubricant do you suggest for Lexan. (i use kerosene for acrylic)

i

1. No, otherwise use metal.
2. Threads may crack, my guess.
3. Both for acrylic and lexan, water soluble oil at 15% is usual, as per our local suppliers.

BTW I´m learning A LOT too.

[JC Fardo]

And yes and most important regarding question 2. is the snug fitting to 2mm motor shaft. My choice would not be Delrin.

[audio1st]

audio1st. did you remove your old clamp to test a Play station clamp? i ask because i tried to remove my clamp but was unable to do it with force levels that i felt wouldn't dammage the drive shaft.

Hi Okapi, yes I have managed to remove the original from the shaft and it does take some force. I found the best way is to use some form of lever between the base of the clamp and the motor.
You may find it easier to desolder the motor and try to remove the clamp base with the help of a vice?
Maybe you could use external cir-clip pliers somehow?