Spike evolution (featherweight)

[typhoon_driver]

that's like asking what the price of a new car is without specifying what car or what you need from it. It also depends what tooling you have available to you? If you have access to a lathe or a mill then you will be able to do most if not all of the construction yourself. Otherwise you will need to outsource it. Kenny is usually the go to guy for machining parts.

I have built spinner setups for less than 100 quid in the past but it all depends on what you're after.

[Danjr1]

20cm long by 15cm diameter drum or an axle with 4 or so blades at 15cm diameters. Found a half decent motor (eBay 180644333591). Am thinking of using a belt and pulley system so that it can slip when it hits something?

[Anttazz]

That is a brushless motor so might not be what you're looking for

[Danjr1]

Thought brushless was the way to go for a spinner motor?

[RogueTwoRobots]

Just to elaborate on what Gary said, my first proper drum was outsourced and cost £150. That was with all the material provided and with free machining so if you were to pay for machining and didn't supply the material it would cost a lot more. By comparison, my most recent drum cost perhaps £10, but that was achievable mostly due to the goodwill of others supplying pieces, workshop time and machine work. So the cost of making a drum spinning element is really like the age-old question of how long is a piece of string?

As for ratios, again it depends on what motor you use, what your desired output speed is and so on but for reference, Drumroll II running on a Speed 900 motor at 19.2V has a ratio of 2.2: 1 (a 44-tooth pulley on the drum and 20-tooth pulley on the motor).
When I used a brushless motor for a while, it was a ratio of 5:1 as the brushless had a higher rpm and needed a bit more torque when starting up. So it's all just a case of tailoring it to suit your individual needs or preferences.

EDIT: Brushless motors certainly make spinners a more lethal proposition but they are not the be-all-and-end-all of spinning methods. Brushed motors are a perfectly suitable alternative; for the past three years at the UK FW champs, a spinner has finished 3rd, and all those spinners used Speed 900s as weapon motors so they can do the job. It's more difficult to get a brushless spinner setup running reliably; Dave Moulds (360) went through several motors, controllers and money to get his disc running well. In the end though, the more important factors are the properties of your spinner itself (such as mass distribution, moment of inertia and, to a degree, cutter bite)

[Danjr1]

Just to elaborate on what Gary said, my first proper drum was outsourced and cost £150. That was with all the material provided and with free machining so if you were to pay for machining and didn't supply the material it would cost a lot more. By comparison, my most recent drum cost perhaps £10, but that was achievable mostly due to the goodwill of others supplying pieces, workshop time and machine work. So the cost of making a drum spinning element is really like the age-old question of how long is a piece of string?

As for ratios, again it depends on what motor you use, what your desired output speed is and so on but for reference, Drumroll II running on a Speed 900 motor at 19.2V has a ratio of 2.2: 1 (a 44-tooth pulley on the drum and 20-tooth pulley on the motor).
When I used a brushless motor for a while, it was a ratio of 5:1 as the brushless had a higher rpm and needed a bit more torque when starting up. So it's all just a case of tailoring it to suit your individual needs or preferences.

Ok, cool, thank you. How did you manage the kick back when it hits something? Some form of clutch?

[Anttazz]

I wasn't sure if you meant for the spinner or in place of the drill motor you mentioned. Having a quick scan of that one shows that if you run at 19.2v you'll need to change the fan of the ESC. Also i've heard that people say that sometimes the ebay ESC's can overrate their current handling a bit.

[typhoon_driver]

that motor/esc combo is useless. It's an inrunner brushless motor, high rpm (6000 per volt) low torque. Not what you want in a brushless motor setup. You would need large gearing to use that which makes it pointless going light.

Get a speed 900, strap a relay to it, job done. Nice reliable system for your first spinner.

[RogueTwoRobots]

How did you manage the kick back when it hits something? Some form of clutch?

Not really. I use timing belts and pulleys so technically there is potential for slippage in there but I doubt that very rarely happens. If you want to rely on belt slippage as a clutch, V-belts are the best option.

No I just let the poor motor take the abuse. Maybe not as great an idea with brushless motors, but Speed 900s are tough little jobbies that can take just about anything you throw at them, so once it's running and spinning, I very rarely turn the motor off in a battle, unless it is obvious that the drum is being stalled.

[Danjr1]

Ok cool. Two 150mm discs on some form of axle on a speed 900! Thinking that I'll keep the discs as close to each other as possible then a wedge on the back (or front). Du really need a esc or just a switch for a spinner? In theory, full range speed control seems a little pointless?