Acrylic platter

[diviy]

Today i managed to acquire a nice large sheet of 10mm thick I was only after a 13x13 square for a fried to make a acrylic platter for his rega deck ,He has access to a cnc cutting station so as I have loads spare I been wondering if I double it up he said he could machine a acrylic Technics platter for me .
so I am wondering has anyone ever made one I am just wondering the pros and cons ?

Thoughts please

[Qwin]

The biggest difficulty with your idea, is how you incorporate the bearing and magnet.
The Technics platter has a tapered centre hole which is a precise fit on the tapered spindle in the bearing.
The magnet has only 0.5mm clearance against the motor coils, so has to be fixed and aligned precisely on the underside of the platter.
The rotation sensor, used to monitor/adjust the speed also has to be mounted to the platter.

I adapted a Pro-Ject RPM 9.1 platter/bearing to fit into my custom deck, if you check out my project, you will see the issues involved.
https://www.jkwynn.co.uk/Tech3_HTML/Tech3_Thumbs.html

[diviy]

Thanks ken I am in the lucky position of having a friend that has access to a 500k cnc machine so I am going to look for a second hand platter with the magnet and send it to my friend and let hime have a play around the worst that can happen is it fails it would have only cost me a second hand platter and postage .
Nothing ventured nothing gained .

[Qwin]

Maybe cut the centre from the alloy platter, housing the spindle tapper, magnet and sensor location bosses.
Then machine a recess and hole in the acrylic to locate it on the top surface?
You would probably need to do this to maintain the correct height of the platter top. Mounting on the underside would increase the height by the thickness of the acrylic used, probably beyond VTA adjustment limits.

[karma67]

like a linn lp12 .

[BB Wan]

Maybe cut the centre from the alloy platter, housing the spindle tapper, magnet and sensor location bosses.
Then machine a recess and hole in the acrylic to locate it on the top surface?
You would probably need to do this to maintain the correct height of the platter top. Mounting on the underside would increase the height by the thickness of the acrylic used, probably beyond VTA adjustment limits.

I did this, worked out quite well for me. Just used a jigsaw to cut out the middle of the Technics platter (I used an SL1700 platter as it's the same taper dimensions and they're cheaper than an SL12xx platter), then mounted it on a drill which was fixed into a vice to create a makeshift lathe and then ground it down and sanded it off to give a nice smooth finish.
I'd spent a fair amount of time thinking around the problem before I came to this, but it was (is) lockdown so not easy to get any bespoke parts made like the brass 'collar' you had made Ken.
Here's a few pictures of the finished item:
IMG_20200611_135843034 by BB Wan, on Flickr

IMG_20200611_131844189_HDR by BB Wan, on Flickr

I then mounted my 38mm acrylic platter on top and bolted the Technics platter centre into the acrylic. Worked a treat.

Keep meaning to do a thread of the full project...maybe I should actually just do it.