Machining A Yo-Yo With Speed Holes

A while ago, [Gord] received a notice from his daughter’s school looking for silent auction donations for a fundraiser. It’s pretty much a bake sale, only [Gord] gets to build something. He has a pretty nice machine shop, and eventually settled on building a pair of beautiful vacillating vertical pendulums. They’re yo-yos, in case you were wondering what that meant.

Each half is cut out of a 2.5″, with both sides of each half faced off and tapped. From there, eighteen speed holes shave off 22 grams of weight. The sides of the yo-yo are shaved down to a thickness of half an inch, a 14° bevel is put on each face, the edges are chamfered at 30°, and everything is polished up.

Sending a bare metal yo-yo to a raffle is apparently a little uncouth, so [Gord] anodized each half of the yo-yos in a bath of sulfuric acid, then applied dye to the surface. With everything assembled, a fancy glass and metal case was constructed and a certificate of authenticity printed out. It’s a brilliant final touch to a great project, we just wish we knew how the yo-yo performed.

Thanks [Chris] for sending this in.

55 thoughts on “Machining A Yo-Yo With Speed Holes

  1. “Sending a bare metal yo-yo to a raffle is apparently a little uncouth, so [Gord] anodized each half of the yo-yos in a bath of sulfuric acid”: Sulfuric acid makes everything more couth.

    1. “Sulfuric acid makes everything more couth”?; perhaps I’m missing an attempt at humor. The comment makes Bob appears as as politician or a trial attorney or least someone practicing to be either. Using an incomplete quote as the basis to make a statement. ;)

  2. Very meticulous. Except that (for me) he ruined it by flaring the holes. The silver lining would have looked sharp if he hadn’t nicked the anodized finished in the process. It was well on its way to being an amazingly beautiful piece of engineering until that step…

          1. Flemish is a variant of Dutch, spoken in the northern half of Belgium (Flanders). In written form, there is little difference to Dutch.
            So to answer your question: it’s a variant of a variant of German.

          2. Flemish is Dutch , it’s not a separated language , the term is used to indicate the fact that there is a significant difference between “Flemish” and “Dutch Dutch (= as spoken in the Netherlands) ” in pronunciation and vocabulary.
            Dutch/Flemish is , like German, a descendant of older languages. the “split” between the “Dutch/Flemish” and “German” language tree was around 500 AD.

      1. One measurement system that makes so much sense that almost every single country in the world uses it, except for America, Myanmar and Liberia. Wish I could use measurements like 2.17/32″

    1. … It’s about precision. If he used a 6mm diameter bit, and plunged .300″ Why would you want to see the imprecise conversion of one when you can see both to their precise dimensions?

      If anything this only is proof that we need to adopt one standard instead of having two, not that this site or whomever should or should not mix units.

        1. Anyone who has actually worked in a machine shop instead of just posting about them on the internet would recognize that he specifies the tool as 6mm because he used a 6mm tool, and plunged .300 because his mill reads out in thousandths of an inch. If a given tool that you’re planning to use is set up in a certain dimensioning standard, converting all of your measurements to a different one just for uniformity is actually more confusing.

          Like, there’s a reason we have symbols like mm and ” and so on. If you just blindly read the number and make a guess about what units it’s in, you’re not a very good machinist.

    1. and “Each half is cut out of a 2.5″,”
      a 2.5″ what? 2.5″ air? 2.5″ baby?
      What shall I ever do! This post is so confusing!

      It’s still technically a “Blog” and as such I’d expect a little bit of “flare” to show that Brian is a human and not some newsfeed aggregator.

      1. I noticed these right away when this was first posted, decided not to be the first to point it out, Brian PLEASE read before you post, there is no excuse for this level of sloppy writing and your posts are particularly prone to them, sorry I can’t help but notice them – a few days ago you wrote on instead of won and still haven’t corrected it “What’s not to like”? sloppy writing!

  3. imo he shouldn’t have done this part:
    “I like to add a silver lining around each hole using a chamfer bit on a hand drill.”
    if you look carefully, it unevenly scratches the dyed surface. looks a bit sloppy.
    looked much cooler before that final effect imho

    1. Especially in that cross section it appears to be best suited for looping tricks, which you don’t want metal for at the speed they can get up to. But most other styles of play yo-yoers do prefer metal over plastic for the consistent weight distribution.

      Yes it can get dangerous, I’ve seen a few pictures of people with chunks of skin ripped off their face online from yoyo mishaps.

    2. They’re fantastic. I have a Yomega Metallic Missile in black. It’s fast and allows an amazing amount of control. Sleeps like no other yoyo I’ve owned. It has great bearings as well. The most amusing part of that yo-yo (to me) is the rubber o-rings that are inset on the edges of the yo-yo halves. Yes, your palms get very sore after retrieving the yo-yo repeatedly at speed, and those o-rings help cushion the blow. And yes, strings wear and fray, that’s why you keep extras and learn to look for signs of wear before it goes flying into someone’s forehead. I’ve almost broken a few windows and monitors because mistakes made or strings snapping.

  4. I never ever could get a yoyo to return. It’d either just drop and spin on the end of the string, jerk back up wildly, or hit the bottom then turn sideways and spin around.

  5. Very nice work overall, but unfortunately the current state of those chamfered holes really kills it for me… would some careful high-grit wet sanding clean that up?

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