DIY Golf Club Unipivot Tonearm

[cabsvrt]

Here are some photos of my unipivot tonearm made from a carbon fiber (boron graphite) golf club shaft. It's still in process, I don't have the clips (making those) and the Nextgen RCA jacks.

[Jim Leach]

Intereting design!

I was thinking of using a broken driver shaft for the arm as well.

The problem is that I thought they would be too heavy for my 14.2" arm design...

Probably going to go with straight carbon tubing.

Nicely executed design!

[cabsvrt]

Thanks, Jim. I had purchased eight different carbon composite golf clubs from Goodwill ($3 each - less than half the price of one 4 foot piece from McMaster-Carr) that I chopped apart and then picked the lightest/deadest piece for this project. The length is 16" (approx.) and it required 180gr counterweight. The last straight 10" tonearm I built needed a 145gr counterweight so I feel that this wasn't much of an increase compared to the length. It is also filled with foam and I could have saved weight by using something other than brass for the headshell.

[IZHAKKATZ]

Hey cabsvrt,

Looks beautifull !
Whay is the pivot made out of? the cup? and how did you attach the cup to the shaft?

[Jim Leach]

OH! The headshell is brass?? I am planing to use a piece of plain woven carbon sheet bonded (epoxied) to the end of the arm tube. If I might suggest: Aluminum is light and generally dead, particularly in the lower grades (5000 and under). the (common) 6061 is strong, and can be 'ringy'. Magnesium would be better still, but it is hard to get and no shop wants to machine it...

In my case, I need a 15 degree offset, so I will mill the end of the tube top portion at 15 degrees and bond the flat (~rectangular maybe integrate the lift as well) piece on (after milling mount slots). Just trying to determine how exactly I want the stylus with regard to the centerline of the arm tube and/or arm pivot. I am using a cross axle (similar to Rega arm) and can raise or lower the pivot relative to the arm tube etc. Making it all from scratch gives me freedom; the problem is I am not an expert, so it takes a long time to figure out where I want stuff to be!

[cabsvrt]

Originally Posted by IZHAKKATZ

What is the pivot made out of? the cup? and how did you attach the cup to the shaft?

Izhakkatz-

The pivot is steel (end of an upside down plumb bob) ground and polished to a fine point (with a milled-in cup ring so silicone won't creep down the side.), The vee bearing is bronze and balances just past CG, and that is force fit and glued with plastic steel.

[cabsvrt]

@Jim- I would love to have machining equipment at my disposal but alas; I don't. Aluminum or magnesium would have been my first choice. I wanted a stronger mount that I could make at my jeweler's bench, because with my other arms I've made I've just cut a flat spot in the tubing to screw the headshell to. My wood arms had a similar mounting scheme. The brass mount in this case is pretty light. It is damped by the deadening paint and the cartridge is mounted to a Dymond wood and titanium headshell. I was looking for a more finished appearance on this arm, hence using brass that's silver soldered and hand tooled.

[Jim Leach]

Well, it looks fantastic!

How does it sound? Did you get those clips on yet?

[cabsvrt]

Thanks, Jim! I did put the clips on, just waiting on the RCA jacks... building the interface boxes now. But I still need the TT finished too, I may set the base up unfinished and worry about it later after I test it all.

[Jim Leach]

Sounds good! Best of luck with it!

I am still collecting parts for my project...

Hammering out the details on my power supply too...

I have a piece of straight carbon tube on the way (it was cheap) so we'll see if that has enough stiffness at length.

Have to order the motor today!