DOOMBOT

RELEASE INFORMATION

Release date 3 NOVEMBER 2020

Sold direcT AND VIA YOYOEXPERT, SPINGEAR

Retail 469.99 USD

53 MADE (43 A-GRADES, 10 BATTLE-GRADES)

INNER RING BIMETAL DESIGN, RAW TITANIUM BODY WITH BRASS RINGS

Diameter 58mm, Width 44mm, Gap 4.4mm

Weight 64.3G

M4 x 6mm axle

CONCAVE C bearing

STANDARD 19MM RESPONSE

ROAD TO THE DOOMBOT

We are finally approaching the end of 2020, a year tarnished by COVID-19 and the passing of my beloved father after a courageous ten-year battle with nasopharyngeal carcinoma.

In August 2018, just over two years ago, I started RSO as a means to expand my yo-yo collection. It has never crossed my mind that RSO would grow into the brand it is today. Over the years, friendships were forged with incredible individuals - most notably Sonny Patrick (Anti-Yo), Frank and Dominik (ILoveYoYo), and Dr. Tom Kuhn and Brad Countryman (Tom Kuhn). Not forgetting the bonds that were built with RSO supporters (you!) who have backed the brand consistently. Words cannot describe my gratitude and appreciation to all of you who have kept RSO going.

Through trial and error, I have learned so much about yo-yo manufacturing over the years. Fun fact: each RSO yo-yo has an average of two prototypes. The YWETi with Side Effects and the Silver Bullet with the adjustable gap and weight rings have been the most challenging projects thus far.

The DOOMBOT was conceived less than two years ago and announced via an Instagram Stories post on the now-defunct @yoyophotographs page. I was surprised that it generated considerable hype. At that point, the artwork had already been completed (I tend to work on the yo-yo and artwork concurrently for most of my projects). The first prototype was a colossal failure. A painful seven prototypes and four machinists later, I eventually succeeded with a version of the DOOMBOT that I felt was worthy of an RSO release.

THE YO-YO

The DOOMBOT is inspired by the Yoyorecreation Draupnir. For those who have had the privilege to throw a Draupnir, you would appreciate that it is a yo-yo primarily suited for fast combos and play styles of professionals like Iori Yamaki and Akitoshi Tokubuchi. Likewise, the DOOMBOT is tailored for such players. I want to avoid using the word "competition yo-yo" to describe the DOOMBOT since there are so many other competition-winning play styles.

The DOOMBOT has a V-shaped catch zone as it provides an aerodynamic advantage, helping the yo-yo cut through the air. The V-shape also allows for a generous and more forgiving catch zone. Note that step on the catch zone is more centrally located on the DOOMBOT compared to the Draupnir. In fact, I would describe the overall shape as a cross between the Draupnir, Sleipnir, and Onslaught.

Most of us are familiar with the typical bimetal yo-yo marketing spiel about their more peripheral weight distribution, higher moment of inertia, and longer spin times. All these hold true for the DOOMBOT, but there is much more. The bimetal brass ring design on the DOOMBOT does not merely give it a performance advantage. I was always intrigued by the brass ring's aesthetic on the Turning Point Leviathan 4B. It is an engineering marvel. Don't be fooled by the flat appearance of the ring! It has significant weight due to its wide dimension, coupled with the very high density of brass (even higher than that of stainless steel).

From a manufacturing standpoint, brass is a very difficult material to work with. Brass is a very soft metal (compared to stainless steel or titanium), increasing its risk of warping during the machining and press fitting process. A few years ago, at a Turning Point yo-yo meet in Singapore, Kentaro Kimura shared with me that it was extremely challenging to reliably press fit the brass ring into the Leviathan 4B’s body - a reason why it took Turning Point half a decade to do a re-release despite its demand. I experienced this issue first hand with the DOOMBOT.

The Japanese influence extends to the artwork. With the Gundam inspiration, the DOOMBOT had to feel substantial in the hand, albeit not to the extent of the C3 x CLYW H5 Chief. The DOOMBOT has a width of 58mm, 1mm larger than the Draupnir. To my knowledge, the DOOMBOT is the largest diameter titanium bimetal yo-yo ever released. Unfortunately, the large diameter proved to pose a considerable challenge during the machining process.

THE SEVEN PROTOTYPES

The first prototype of the DOOMBOT was a 58 mm diameter behemoth with a body thickness of 0.4 mm at its thinnest portion. The first machinist I approached, who was the same machinist who made the D bearing SPACESHIP prototype, was skeptical about the yo-yo's machinability. A foolish me decided to proceed with the prototype. A total of 10 prototypes were made, with a majority of them tainted with ugly machine lines and pulse vibe.

Not wanting to change the design, I approached a second machinist. I sent him an almost identical CAD with a subtle undercut at the catch zone's step removed (I felt it made the yo-yo play uncomfortably). This machinist also advised me not to proceed but I did not heed his advice. Thousands of dollars were spent on another 10 prototypes, of which 8 of them turned out to be no more useful than your office paperweights.

The first two prototypes taught me an expensive lesson. The large diameter and paper-thin body, combined with the angular V-shape of the catch zone, significantly increased the risk of the material warping during the machining process. These factors resulted in the vibe. It would not be financially feasible to put the CAD into production, as up to 80% of the run would be B-grades.

After the two failed prototypes, I questioned myself: what was the thinnest I could machine a 58 mm titanium bimetal yo-yo? Bear in mind that the Luftverk Fulvia BTM, a 56 mm diameter yo-yo (2 mm smaller than the DOOMBOT), had similar problems with a 0.5-0.7 mm body. In fact, the titanium bodies for outer ring titanium bimetals like the Fulvia BTM are smaller than their true diameter (since the ring makes up the outer diameter) making them less prone to warping during the machining process. Inner ring bimetals like the DOOMBOT are thus expected to be more challenging to machine. I increased the body's thickness to 0.6-0.7 mm for the third prototype and approached another machinist. Unfortunately, the third prototype was again a failure.

A fourth machinist advised me to downsize the yo-yo diameter for the fourth prototype to 56 mm, keeping the 0.6-0.7 mm body thickness unchanged. This increased the yo-yo’s machinability. This was the smallest prototype of the lot. The fourth prototype passed the vibe test, but I felt it was too small and didn't fit my vision for the DOOMBOT.

I upsized the fifth prototype to the original 58mm diameter and thickened the yo-yo body to 0.8-0.9 mm and... I eventually succeeded! We are really splitting hairs here, making increments of tenths of a millimeter. But what is yo-yo design without a challenge? I had to thin the brass rings down slightly, with consequent reduction of a few grams of rim weight. This was a blessing in disguise as it helped to significantly reduce the yo-yo’s kick-back, a common criticism of the Draupnir. The result is a yo-yo that plays like a high precision samurai sword.

I had to prototype one final time because I did not like the design of the rings on the fifth prototype. Just for fun, I made an additional stainless steel outer ring version to experiment how it plays. I ultimately stuck to the more challenging inner ring design for the production version due to its superior play characteristics and aesthetics. The final prototype was still hard to machine and for the production run, approximately a fifth of the run of 53 were B-grades.

I want to share with you my quality control process. A-grades have slight but insignificant vibe on grinds at the catch zone, but are generally smooth at the rim and on the string. B-grades (also termed Battle-grades) have additional vibe at the rim and on the string, and have more vibe at the catch zone.

It was a grueling journey, but I am glad that I persevered. It was worth it, and I can’t wait to hear what you guys think of the DOOMBOT.

WHAT’S IN THE PACKAGE

CNC machined RED DELRIN CAPSULE

Certificate of authenticitY IN THE FORM OF A GUNPLA

DOOMBOT HEAD ENAMEL PIN

VELVET POUCH WITH LOGO

A PAIR OF 19MM MAROON TYPE 40 LANDING PADS AND A RED STRING IN A CRYSTAL CANISTER

For the most complex RSO project yet, I designed a canister which was CNC machined out of red medical-grade delrin. I previously did this with the SPACESHIP, but the DOOMBOT canister was more costly to make due to its larger diameter and its color.

ART BY FREAKYFIR

The samurai Gundam inspired art was done by Firdaus (@freakyfir) from Studio Moonchild. A pioneer of the graffiti scene and one of the top graffiti artists in Singapore, he is a specialist in drawing robots.

THE TRANSFORMING YO-YO