# Making thin discs



## Bogstandard (Mar 6, 2008)

I told John T that I would show him how I make thin discs for a small sterling, but this technique can be used for almost any material, and within reason, size.

I am going to be using an old CD case for this demonstration, and cutting discs of 46mm diameter. If using these cases be sure to get them fairly warm first otherwise they are very brittle, and razor sharp tools and drills are the order of the day.

I marked out the size on the material a little oversize (50mm) and where the centre mark was, I drilled the required (2mm) hole.








Next job was to cut them out roughly and cut a couple of scrapper bits with a hole in them.







Mount a bit of bar end in the chuck, and face both sides. Then on one side centre drill for a rotating centre and follow it down with a drill the same size as the holes in your parts to be made. Remove from chuck, and put it with the other bits.







Put another piece of bar end in the chuck, face it and drill thru with the same sized drill. Leave this mounted in the chuck. Take the drill and put it with your bits and replace the drill chuck with a rotating centre.







Got to your bits now and make up a sandwich as shown. Put drill thru metal bit, then a scrapper, followed by the parts to be made then another scrapper. The recess for the centre has to be on the outside as shown.








Feed the point of the drill into the hole in the piece still in lathe chuck, and push the drill in until it is inside the centre drilling. Then bring the rotating centre into its hole and clamp all the bits between it and the bar in the lathe chuck.







Turn on, and using light cuts across the sides (I used 10 thou), gently bring the parts down to the correct diameter, polish the edges at this stage if you want to.







This is what you should end up with.






This method can also be used if you are gentle, to make discs without holes. Use a bit of double sided tape between them on the sandwich and just clamp it together on the lathe as before, but take slightly shallower cuts.

This is a take on my post about making flywheels from plate from many months ago.

John


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## J. Tranter (Mar 6, 2008)

Thank you for posting that I greatly appreciate it.
John T


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