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Ebony tonearm board for my SP-10

speedysteve

Wammer
Wammer
Dec 25, 2007
3,259
39
0
The New Forest
AKA
Stig Forsberg
I finally got around to ordering some ebony big enough to make the polygon shape 8" x 4" needed for the tonearm board.

The gunmetal one that Mr Coco cut out on my chopsaw (with suitable metal blade) a good while before I bought the deck from him, has done good service. It was drilled / cut for a SME series 5 12" at that time.

I drilled another hole for my Fidelity Research FR64s (a fair bit nearer the spindle:)). If these two drillings had a negative effect or changed the sound - who knows...

Anyway a piece of the right sort of ebony 8" long is not so easy to come by. I tracked a suitable piece down in Portugal - intended for a stringed instrument fret board it was 500mm long. Nice piece of wood, dried rough planed and ready to cut / smooth.

A bit of chopping with the table saw, hole cutting and mounting hole drilling and a quick sanding / smoothing / polish and I was listening in know time. I also took the opportunity to make some brass threaded cylinders as blind nuts. I epoxied these to the slate underside.

It was a pain accessing / holding M4 nuts in place as the armboard bolts were located.

Here's a couple of shots of making the blind nuts

Drilling out (used my centre drills first;))



Tapping the M4 threads



So easy this with a variable speed lathe - from 10rpm up under perfect control. Reverse switch and back the tap out.

4 made up ready to go



Then on to the arm board.

Here it is mounted up.





The board is 12mm thick. I thought about laminating another thickness underneath that would then sit in the recess of the slate further but thought things might get too damped?!

Listening it, there are subtle changes. Rhythm and drive in bass and mid range seems better.

Funny how TT things interact, stylus & cart / arm / armboard / plinth / drive unit & platter.

 

paulf-2007

Wammer
Wammer
Jun 18, 2008
4,422
79
93
souf east for work
HiFi Trade?
  1. No
Nice Steve, where do you source your brass material, post from eBay is ridiculous. Looking for a piece 100mm long x 40mm dia for a tone arm pivot/counterweight.

 

awkwardbydesign

Perfect, apparently.
Wammer
Mar 5, 2012
10,117
1,788
173
HiFi Trade?
  1. No
Scrapyards are sometimes useful, but hit and miss and it takes time and effort.

 

paulf-2007

Wammer
Wammer
Jun 18, 2008
4,422
79
93
souf east for work
HiFi Trade?
  1. No
Scrapyards are sometimes useful, but hit and miss and it takes time and effort.
yes my local scrapyard has given me some phosphor bronze in the past but rarely has anything of a decent size as the engineering works probably hang on to it. Heavy metals have heavy post charges. Will have to go on the scrounge at an engineering place where I know someone I knew at school, I had better get my cash out ready so he knows I'm not after freebies
 

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