spinner bar ratio

[Danjr1]

Re: spinner bar ratio

had a quote of £72 for a 5kg hardox bar which is pretty decent. is hardox 400 a good grade?

[maddox10]

Re: spinner bar ratio

Ok, thanks. Who's SSAB?

3 seconds on Google

[maddox10]

Re: spinner bar ratio

had a quote of £72 for a 5kg hardox bar which is pretty decent. is hardox 400 a good grade?

72/5= £15 per kilo. If the size is exactly what you want, good deal.
If not, then you can ask yourself, what will I need to work this stuff?

And there ain't no bad grade of hardox. Its good or better.

[Danjr1]

Re: spinner bar ratio

it would be what i want. would just need the axle hole drilled and the pulleys attached. also some bearings in there. I've taken the density of hardox as approx. 7.86g per cu.cm. that correct?

[maddox10]

Re: spinner bar ratio

That weight is correct.

Now, how are you going to drill holes accuratly enough for bearings in something that is about as hard as a cheap drill from an avarage DIY?

[Danjr1]

Re: spinner bar ratio

Outsource the machining work.

[jonny]

Re: spinner bar ratio

you'll never be able to drill a hole large enough to fit bearings into. a 20mm bore bearing will be roughly about 40mm diameter (or atleast the one i'm looking at is). drilling a 5mm hole through 5mm hardox 400 is a pita even with plenty of coolant and a good pillar drill. if you have access to a medium-heavy duty cnc milling machine with decent tooling you could mill a 40mm hole. if you have access to waterjetting facilities you could waterjet the hole.

where are you buying this hardox? jl steel, mtl steel and steelpro all have cutting/machining facilities. you'd probably be best seeing if they can do the work. alternatively kenny should be able to mill the hole out for you. i knew a really good waterjetting company in kent but i'm afraid i've forgotten there name

[jonny]

Re: spinner bar ratio

here's a link to the company in kent i was talking about: http://www.mlfabcuts.co.uk/

[Danjr1]

Re: spinner bar ratio

They ain't far from me. Was thinking of a 12 to 14mm Steel axle for it to spin on with bearings pressed into the bar

[jonny]

Re: spinner bar ratio

i'd go for 20mm myself as the shaft has to take alot of force and you should be getting a crazy amount of ke from a 5kg 40cm bar, 12mm or 14mm could bend after a big hit and break your weapon system

[maddox10]

Re: spinner bar ratio

20mm axle. Prefable very good steel, like chromalloy, or even Titanium.

[Danjr1]

Re: spinner bar ratio

What's the opinion on slipper clutches in spinners?

[maddox10]

Re: spinner bar ratio

What's the opinion on slipper clutches in spinners?

A neccesity. Now to source one strong enough to do the job in the size and weight we want to devote to it.

[Danjr1]

Re: spinner bar ratio

Hmmmm well in it's most simple form, a piece of rubber can be bonded to the pulley which runs against the bar, allowing it to slip when it hits something. The bolt which is the axle can then be loosened/tightened for correct pressure

[maddox10]

Re: spinner bar ratio

Burning rubber indeed.

I hope you calculate in the spares and ease of maintenance.