My team has been playing around with the idea of increasing our moment of inertia on our shooter. I have no idea where we would get a counterweight like that without making our own. Does anyone know of any trustworthy vendors selling 4" brass, steel, etc flywheels?
Edit: Additional information regarding how you machined your own flywheels- specifically brass or steel flywheels or some other heavy material would also be greatly appreciated.
Ideally using steel or brass rather than aluminum to increase the moment of inertia even more. Haven’t really put a huge amount of thought into machining our own, and we don’t have experience machining those materials. Could always try though.
What about the SDS flywheels is insufficient for your purposes? If it’s cost, turning your own is pretty much gonna be the only way it’s gonna be cheaper.
Could just start with at thicker block of aluminum. Ours started as a 4" x 6" block and just rounded it.
In 2010 my main team machined a 12" diameter steel one in that a sponsor then balanced for us.
You might try looking for a local company that specializes in flywheels for machinery.
Our local company, Schenck, specializes in balancing spinning machinery.
We used two of these from McMaster. https://www.mcmaster.com/2305t94” cast iron with most of the mass in the rim. It wasn’t that difficult to balance them after broaching them to 1/2 hex. We took a pair of hex bearings, pried the seals out of them and cleaned the grease out so they’d spin freely. A shop-built plywood frame held the assembly. We spun the wheel, let it come to stop and removed mass at the bottom with a cordless drill and 1/4” drill. We kept at it until it didn’t stop anywhere in particular. It works well.
Hi, this is a great idea but like my team( and i imagine other teams), Not all teams have a lathe, having a 3rd party source would greatly help teams expand their horizons
We simply used some gears, but they fit our mechanism ok. If you do this, you need to make sure the gears don’t touch anything - a spinning gear can cut through stuff quickly, would totally annihilate a power cell.
Copperforge almost put something out this year, but I don’t know if they’re still planning on doing it. I believe they were relying on machining labs available at WPI though, so they may be unable to do it right now.
Perhaps see a local automotive workshop? They should be able to balance any flywheel you machine or even have a small engine flywheel that is going to scrap.
I should point out that while free-machining brass does indeed turn quite nicely, the “chips” (really dust) are a pain on a manual lathe. While the normal grades of aluminum produce comparatively tidy spiral chips, the aftermath of turning my bronze flywheel segments (and brass flywheels in 2017 as well) looked like Liberace had a party on top of the lathe.
TL;DR Brass/bronze machine quite nicely, but the cleanup will make you regret it.
ehh… a paper towel taped over the ways, a paintbrush to dislodge the tiny chips in the corners of the machine and a vacuum should make short work of the cleanup (provided the chips aren’t saturated in coolant/WD40). But yes, it is quite a bit more cleanup vs 6061 chips.
you can always use hotglue (in a recessed area) to balance a flywheel, no need to do subtractive balancing if you aren’t setup for it. That being said, watching someone who knows what they are doing balance a small flywheel is cool (it’s amazing how quick some people can do it).