Lambda Simplified? : This variant of the Lambda top is machined from a single piece of solid brass bar stock. This consumes 4x the amount of brass compared to the two-piece tops, but it also delivers a more perfect spin. Any machinist will tell you that the most accurate part is the one machined to completion without removing it from the machine.
This also means I went from 2 manual machining operations on the two-piece top, to 5 manual operations on the solid top. Does that make the Lambda Solid an even more unpleasant slog of boring, repetitive manual labor? Yep. Is it worth it? Totally.
Finally, the cycle time on the CNC is much higher because I have to remove 3/4" of diameter on the bar stock all along the length of the spindle. It also requires another deep drilling operation to get the spindle hole to 80% depth while on the CNC.
What's up with the hole in the spindle? That is 100% physics right there. Brass is more dense than aluminum; and making a top out of solid brass moved the CG (Center of Gravity) slightly higher when compared to the aluminum top. The CG must be below the Center of Mass of the ring or the top will not want to self stabilize. I tried a number of strategies to lower the CG on the top.
Nothing was working very well and I had the idea to drill out the core of the top "just to see what would happen." Like
the discovery of Champagne, it was a happy accident. I'm a scientist at heart, and that is one perfect, beautiful 0.160 x 1.25" hole because it's EXACTLY what was needed to drop the CG right into the sweet spot for a perfect spinner. I bet you start to see this one on "other" tops out there in top land. It didn't take long for people to catch on to the ruby thing right? I don't mind that (much) but there's still some value in life for being the "original." At least that's what I tell myself.
Through the looking glass: Is awesome a feature? Yeah, awesome is a feature. One additional feature of the Lambda Solid is you can look right through the ruby. This shot is taken looking down the hole in the stem of the top, not looking at the bottom. I've gotten a lot more enjoyment out of watching the ruby sparkle when you hold it up to a light; and I think that's one major thing that was missing from the original two-piece Lambda.
Ruby and stainless tops are carried in inventory. Al2 O3 and SiC tops are assembled to order and will delay shipment by 1-2 days. Now you can choose between instrument ruby, stainless steel, Aluminum Oxide (white), or Silicon Carbide (dark gray). Aluminum Oxide and Silicon Carbide are considered "ceramic" ball bearings.
You will not notice a difference in performance between the contact points, but some people enjoy the difference in appearance, and science behind the materials.
Instrument Ruby is a crystalline form of Aluminum Oxide and called Corundum. Corundum is a naturally occurring mineral, but instrument rubies are synthetic. This material has the distinction of being the very first gem mineral artificially created in a laboratory. A small amount of impurity (Chromium) gives ruby the distinct red color.
Stainless Steel Bearings a good choice if you never want to worry about breaking the contact point. The steel balls used in the Lambda tops are 440C Passivated Stainless Steel. This material is hardened and highly corrosion resistant. 440C is the most common material used in high-quality bearings. It's superior to chrome steel, but not the most exotic steel bearing material.
Aluminum Oxide (Al2O3) balls are classified as a "ceramic" because they are sintered from a powder base. Chemically, this is the exact same material as ruby or sapphire, but it is not a crystalline structure. Al2O3 is most commonly used as an abrasive in the manufacture of sand paper. It is also the coating that grows on aluminum when it is anodized. These ceramic balls are typically used in bearings that see extreme temperatures.
Silicon Carbide (SiC) balls are also "ceramic" and used in even more extreme bearing applications. SiC is heat tolerant up to a staggering 1800*C. It's commonly used in the manufacture of ceramic brake discs, ballistic plates in bullet proof vests, and LEDs. I recommend SiC for the extremely heavy tungsten top because it is the most durable of the three exotic contact point materials.
Durability: Contact points cannot be repaired or replaced. They are permanently press-fit into the spindle to achieve the desired degree of balance and accuracy.
The stainless bearing is the most durable option across the board. Clumsy? Steel. Got kids? Steel. Will you cry if the contact point breaks? Steel.
So why all the fuss about exotic contact points? The difference is the ruby and ceramics are MUCH harder than steel, and will spin more efficiently. It's like the difference between ice skating and snow skiing...both water...both fairly "solid" but which one is more efficient for sliding on?
A ruby is a ruby, and if you abuse it...it can chip. It's like a wine glass; works fine until you drop it. The ceramics can also shatter if subjected to enough force, but are generally tougher than the ruby. Silicon Carbide is the most durable exotic material.