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Spinning Tops
- Thread starter rwm
- Start date
- Joined
- Apr 21, 2015
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- 894
- Joined
- Dec 7, 2015
- Messages
- 519
5 to 7 min difference? Likely your spin technique. 7 to 15 min difference? Precision machining and design. Ensuring the tip/ball is perfectly on center. Reducing air resistance. Putting the mass at the outer rim and reducing the mass down the top's center line. Tops that stand up just about immediately when released and spin dead smooth/stable- it's a result of the machinist's skill. There's a couple "famous" top makers that are well known for their smooth, long spinning tops (Dan Tochterman, "dt smooth") and then other top makers more well known for their crazy complex designs, but not long spin times (Rich Stadler, Billetspin).
- Joined
- Mar 25, 2013
- Messages
- 5,139
Not sure about the lead and its effect. I probably only have 3% so I could have added more. It machines betters than Silicon Bronze. I'm gonna use some of this in my next top.
Wildo-After your comments above perhaps I need to abandon the reamer idea and go for a micro boring bar with go nogo gauges?
R
Wildo-After your comments above perhaps I need to abandon the reamer idea and go for a micro boring bar with go nogo gauges?
R
- Joined
- Apr 21, 2015
- Messages
- 894
To elaborate further, it's largely the relationship between the center of gravity and the center of mass. Center of gravity should be lower, which is what causes the best to stabilize "instantly". This is why the hollow stems are popular and effective. The further you get the mass out from the center the greater the moment of inertia (by definition), so it requires more effort to spin it up but it then better resists changes to its angular momentum and axis of rotation. Then it's up to the precision and materials to minimize wasted energy through vibration, friction, and air resistance. The best materials and machining won't get you there without a good design, and a good design will only get you part way there if using inferior materials and imprecise machining.
- Joined
- Dec 7, 2015
- Messages
- 519
All that I know is that some time ago, I read a post on the FB group that many of the most renowned makers were boring their ball recesses. That said, plenty of them seem to be just find with drilling or reaming (probably more so the latter). For me, I wanted the fun challenge of boring, and really- if I can get it right, then my top would be better for it. I'm sure you're just fine with the reamer. Hell- my very first top was simply drilled and I still got over 10 mins on the spin. Really, dealing with the contact point is likely more for getting the top very stable/smooth when spinning more so than spin times, to be honest. 10 mins is super cool (and I'm proud of that) but the top doesn't spin DEAD SMOOTH. Getting that contact point exactly on center is going to help with the stability and reduce/eliminate hula hooping and fluttering.
