Schroder-like Tonearm Variant 2

As in my first example, these arms are NOT Schroder-clones.  Clones are described as being exact copies of the original - I'm not sure that I could clone the real thing. My arms use the same principle of magnetic suspension, but have significant differences from the published specs, pictures, and patents of the real Schroder arms. 

In the first place they are simpler to build.  I finally settled on using Neodymium ring magnets for my projects.  This means that I do not have to drill holes through the magnets  - they already have 1/8 inch holes in them.  This is claimed to be a 4 hour task in the Schroder FAQ.  I just have to drill though the arm (and place the magnets concentrically around this hole).  As well, the bottom magnet is held in a steel magnet cup, which is connected to the base mount using a brass screw. 

Secondly, because I primarily use woodworking tools in  my shop, almost all of the tonearm bits and pieces are wood or lucite for easy machining, and any metal parts are stock hardware store variety off-the-shelf pieces.

Thirdly, I use glue in the preparation of my tonearm blanks.  I glue up the arm tube blanks so that the wiring channel or channels are essentially formed into the arm in the rough state, and then the tonearms are turned on the lathe, exactly centred on this pre-created channel. This is based on  my experience producing pens and pencils on the lathe, where the hole is drilled first and the turning is concentric to it. This avoids the difficulties in drilling a long thin hole down the centre of the arm wand after it is turned.  The Schroder FAQ warns about sonic consequences in using glue anywhere in the system, but I confess to not being able to hear a signature in my arms that would be due to this.  However, I do not claim to have "golden ears", and I have limited experience with tonearms and no direct comparisons so cannot say it does not exist.

Finally, everything I have done is designed to work around the low platter height of the Lenco turntables, and having a fixed axis point for the suspension, i.e. the little downward pointing alignment stub, which allows the arm to be fixed in such a way that you can have on-the-fly VTA adjustment.

After successfully building the 10 inch magnetically suspended tonearm, I looked at the possibility of learning from my first experience and building a second version, this time a 12 inch arm, with lower mass.

The starting point is an arm-tube blank made of cocobolo with ebony inlay strips forming the wiring channel.  This blank was threaded to couple with a smaller joining nut (this time 1/2 inch rather than 5/8 inch).  This starting point is a much lighter and smaller piece of metal, and the resulting tonearm will have much lower mass.  The completed arm-wand is show below.

More to come as I work out the details of mounting the longer arm.