**CORKSCREW MK2 **
Hi all, friends - here again.

Struggling in vain for a decent solution for the

** MoonTracker** (the vertical RTA #4333) I thought back to my

**corkScrew** RTA # 4174 #4219 (starting from # 3762-70 ....... #4084- 4144 - 4150) and it's

*original sin*, which is precisely the central spring blade of the

*corkscrew joint* itself.

Perhaps someone will recall, even from the videos of tracking #4208, that on LPs with small warps the

** corkScrew** performs effortlessly, however my measurement set showed that, over 1.5 mm warp, i.e. beyond the

* elbow lever effect*, the VTF tended to to vary increasingly. Nothing worrying for a correct listening of well stored discs, but from a theoretical point of view, yes. What is inacceptable for me; and others, i know.

The only alternative for a Radial rail TA with true parallel H and V articulation seems therefore just my previous

**Lil Casey MK 2 - 3** or the new smart moving parallelogram invented by

**Mike56**, now perfected at truly excellent levels, confirmed by incontrovertible measures and signal graphs: but that solution is unfortunately too bulky for present corkScrew structures.

Why not, however, to make a sort 90 ° turn: using the parallelogram the "wrong side",

**"squeezing"** it almost to a flat one seems clearly a desperate fool's solution. However a parallelogram remains a parallelogram at every angle: a rectangle at 90 °, a line at 0 °,

**but always a parallelogram**.

Will it be feasible?

- attachment A simulation

Full of doubts I have made a super quick cardboard mockup, that seemed to work. and made me understand that the horizontal arrangement is a limit condition, better to start from a less uncertain, more stable one.

- attachment B - C simulations

Loads on pentip bearings with angles close to zero may be relevant, so there must be almost no play to maintain parallelism. Fortunately the force is applied from below, but it's behavior must be verified in practice.

There are also problems with miniaturization (levers, pentips seats and tuning screwcups) to use the same previous corkScrew rail and base. Even the distribution of weights would be problematic: for this Mike gave me the clever idea to position one CW moving inside a hole in the first lever. (thanks again, M)

- attachment - drawings

Here are the results for a prototype: small parts require considerable precision and consequent time. Luckily for the cart I had kept the assembly jigs, but the mini parallelogram was really challenging.

- attachment - photo of parts
- attachment - photo of assemblage

The first results seem interesting, and the behavior reliable. My usual set of measures (videos of the crash test - 3mm warp +- 1,5 eccentric; vert + hor friction - VTF variation) will come later. And again no personal listening impressions: i trust mine even less than other's ones

ciao - carlo