Top Tips?

[Adam Blanton]

So I've got a friendly challenge going with my brother to see who can make a top that spins the longest.

My brother recently got a job with a 3d Printing company which is how this challenge came about. He will be drawing up his top and printing it, while I'll be making a wooden top on the lathe.

I was curious if anyone here had any design tips for a long spinning top? I've only made one piece tops so far, but was considering a 2 piece top using some of the densest wood I've got.

Some limitations to the design, it can only be 4 inches in diameter at the widest and a holding device with a string can be used to propel the top.

[Mike Cruz]

Adam, I don't have a lot of experience with tops, but one of my turning buddies turns them at shows for the kids. What we've noticed is that the mass of the large flat part really does need to be significantly larger than the handle part. He turned one where the shaft was fairly thick, and it was a bear to spin. Thinner shafted ones seem to spin much easier. And I would imagine what keeps the top spinning is the inertia of mass of the wide diametered bottom part. Yeah, obvious, I know, but since no one else answered, I thought I'd start you off with a Captain Obvious answer...

[Richard Coers]

Make the body from Corian. Not easy to find a wood that dense. 4" diameter is huge! It will really take a tug on the string to drive that and get high rpms. I'd make it around 2" dia. Less balance trouble. A 4" piece of wood will likely have a fair amount of wobble as the density of the wood will be different. I'd say you will have the advantage unless he prints at a very high resolution. With the x-y axes travel, a dead round piece off a 3d printer is not easy.

[Adam Blanton]

Nice! I didn't think of using Corian, that's a good suggestion and it should be pretty evenly balanced.

Also thank you for the tips Mike, captain obvious or not still helpful information.

[Paul Williams]

Don't know if this is outside of the rules for your contest, but we make long spinning tops by gluing a marble into the hole of a CD. The marble is a good low friction bearing surface. Another method is to use a fixed point and a small ball bearing to decrease friction. Either idea could be used on a body you turn. I would keep it fairly light so you can easily get it spinning. Also keep the weight out near the rim as much as possible, remember the old gyroscope toys. You might also look at the top sold by PSI. Either use their kit, or adapt their method of holding the string and the post.

[Harvey M. Taylor]

Ok you top tip guys, the rule is====no picture didnt happen, B esides, I am looking for designs too. Max

[Philip Wilson]

Hi Adam,

Here's one of the tops I make - the handle and a brass pin at the bottom help give it a long spin!

https://mail.google.com/mail/?ui=2&ik=46235ef783&view=att&th=141c729268de9967&attid=0.1&disp=thd&zw

Phil

[Scott Hackler]

If you have to use wood, saturate the tip that the top will spin on, with CA glue to make it super hard. Of course Corian will work for the hardness, but might be a little too heavy.... not sure.

[Thom Sturgill]

Jim Underwood posted some in this thread (http://www.sawmillcreek.org/showthread.php?207733-Pull-String-Tops-an-old-Christmas-present&highlight=Tops)
I made a couple using ebony as the points. I would say to use a dense even grained wood for the body - both mass and balance are important.

[Ryan Mooney]

No real experience with tops but I've made a bunch of drop spindles which have similar "spin time" issues/physics.

Putting more weight out near the rim increases run time as Mike mentioned. However it also increases instability so there is some balance there. Moving the weight closer to the shaft increases speed but reduces runtime (seems counterintutive but there it is).

[Reed Gray]

I heard of some engineers who had a top spinning contest. The winner was one who used a CD with a metal pin, and hooked it up to a router for spin. Sounds dangerous. For smaller hand spinning tops, the best I could get with a 1 inch diameter top was about a minute (rosewood, lignum, hard maple). I made some out of maple baseball blanks, and using both hands to spin it, was able to get 3 minutes plus. Fine for adults, but little kids have a bit of trouble with them. Adding the wind up string and a box to hold it, times went to 5 minutes or so. The CA glue on the tip helps. I believe there are plastic and metal tips that you can buy, but your tailstock needs to be dead on when you drill the hole for the point. Another note, the harder tips can drill holes into what ever surface they are on.

robo hippy

[Russell Eaton]

It also needs to come to a sharp point. If you round it off it will tend to run off. Also if you need a stable wood, I made some out of spectra-ply that were very well ballanced. The kid I intended to get it is still waiting on his dad to give it up. +1 on corian. The home stores will give samples sometimes.

[Jim Underwood]

Thin handles, low center of gravity, and a large balanced mass. The tip needs to be absolutely centered as well. I've turned tops handle first and they don't spin nearly as well as those turned tip first.

[Jim Underwood]

Also, turn several and pick the very best one.

[Kyle Iwamoto]

Spun by hand or the old old tops that were tossed with a string? The old tops need a nail for the tip and that's about it. When I was small, those would spin for several minutes no problem. Several decades ago......

Hand spun, I've used the "waste" from my ukulele sound holes. These are from a 2-3/4" hole saw. Got the center hole already. I turn a bamboo chopstick down for the "stick". As mentioned, you want a small diameter stick, since you can get more RPM's. You can turn that bamboo real thin and still have lots of strength. Low center of gravity, but the disc has to be high enough for some wobble while spinning down. If you have some waste 1/4" ply, that would do well, as it's pretty uniform and balanced. Thicker wood is harder to get spinning. So would a large 4" disc.... If you got a big hole saw set, you could try several diameters. Good luck!