Another Carbonfiber tonearm

Armtube is a 20mm diameter continous carbonfiber tube with solid carbonfiber inserts at headshell location, verical bearing stub and counterweight end.
Inside the hollow section there is compressed, force fitted balsa core to reduce resonances.

Horizantal movement is by miniture presicion ball bearings and vertical movement is by double needle and cub joint.
The needles are old 78rpm steel disposable needles and cubs are inox setscres with custom cup shaping.

I have chosen the bearing subchasssis as brass. Hoping to form a higher inertia anchoring transmitted mechanical waves.

The needle tip and veritcal bearing axis are co linear.

The counterweight has a long adjustment range to accomodate wide cartridge weights and tracking forces.

Anti scating is achieved by counteracting magnets and a magnet linearly moving on arm lifter support bar.
Veritcal tracking can also be adjusted on the fly by a screw.
Arm lifter is a classic design implemented from brass and teflon for this arm.
All the machining is done on a umimat 1, forcing to its limits.
Carbon fiber is cut and shaped from comercial carbonfiber rods. This is a beyond imagination messy and probably unhealthy task. I can understand why most comercial arms have metal sections for cartridge mounting.

The arm mount is fixed by 3 screw bottom disc but I regret not to make it a screwed disc as an alternative fixing method.

The wring is twisted litz form catridge to armborad and twisted pair screened cable to minixlr connectors. The carbon fiber has some conductivity and this is used for shielding throughout the arm.

The arm is my unique (as much as it could be) design performed on autocad SW.

I am 30+ year MsEE with strong meachnical skills but not a professional armtube designer, so I am hoping to recieve comments for improving the second run.
 

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That's pretty impressive. Have you had it on a turntable and tried it out yet?
I was planning to build an open frame turntable to use this arm but not started it yet.
I am trying to fit it on an old AR esl-1 with great difficulty. Which I will succeed soon.
I will use Denon DL301R, which I had prviously tried on my grace 707 arm, not a ggod march for 301.
I will comment on the sound soon
 
Took a bit of staring to get my head around the vertical bearing. Nice. Only bit that might worry me is the dressing of the tonearm wiring as the loop will compress across the record which 'might' affect something.


Two thumbs way up though.
Thanks,
You are right I can feel that the loop is aiding the anti scating.
Some people just use the lead force for antiscating.
I will change the wiring with a bigger loop and may be less effecting force.
I had previously used a different cabling architecture but because of very high capacitance I had to change it. That used single litz with selected wires from the bundle.
Now I have to use a cotton seperation between the ltz to reduce capacitance. (40pf for 90cm run)
 
I was planning to build an open frame turntable to use this arm but not started it yet.
I am trying to fit it on an old AR esl-1 with great difficulty. Which I will succeed soon.
I will use Denon DL301R, which I had prviously tried on my grace 707 arm, not a ggod march for 301.
I will comment on the sound soon

That's pretty impressive. Have you had it on a turntable and tried it out yet?

I have recently istalled it on my AR ESL-1 (modified with dc motor and electronic speed control). I had do remove the armlifter to achieve correct geometry.

Compared it with Denon DL103R previously mounted on grace 704 (with headshell modification).
The sound field felt more stable and defined. The mid were definitely more forward (carbonfiber resonance 2-5khz range?) and detailed.
Overall arm felt stable and comfortable to use with no electrical issues(hum noise even while touching the arm)

I can say I am happy with the result and have currage to go on with differnt designs.