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spinning weapon advice
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Glen
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spinning weapon advice

just run into a bit of a crossroads with cobras disc attachment.

what im thinking of is either welding the disc straight onto the shaft OR sandwhicing the disc between two split shaft collars like hazard.

im thinking having the split collars may serve me better as i can take the assembly apart and change to a bar or whatever is should need. im just unsure whether the shaft collars would loosen up and make the disc slide down the shaft.

any advice appreciated.
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Post Sun Jul 11, 2004 6:23 pm 
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mytqik



Joined: 26 Jun 2004
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Try a taper lock hub. They are available for a large range of shaft sizes. There are esentially an inner & outer hub, the mathing surfaces of the hubs at a taper. The tighter you pull the the two hubs together the further up the taper the hubs go & the tighter they lock onto the shaft & the disc.

I have used them for mounting conveyor pulleys onto shafts with great success. They can transmit huge amounts of torque but can easily be undone. If I find a picture online I will post the link.

Post Sun Jul 11, 2004 6:28 pm 
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Glen
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sounds like a trantorque. ive heard they are pretty expensive too.

i was also thinking of having the shaft lathed out so the base of the shaft would rest on the bearing and stop it slipping through it and having a hub lathed onto it as well. this would eliminate the need for clamp collars and all the rest.
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Post Sun Jul 11, 2004 6:52 pm 
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mytqik



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What about threading the shaft & put two nuts on each side of the disc? Use the second set of nuts to "lock" the first set onto the disc. Much cheaper option.

Post Sun Jul 11, 2004 6:57 pm 
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Glen
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i could use threaded rod, but most of the threaded rod is that weak zinc steel stuff isnt it?

id like to try the shaft with hub etc option first though so ill see what can be done in regards to that domain.
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Post Sun Jul 11, 2004 7:01 pm 
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Valen
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how often are you going to bend the shaft?
given that the disk and shaft are the strongest parts of the bot, your going to break something else first I think.

The fewer bits you have that can break the better.
my suggestion is so weld to the shaft, bolt the pully on, then top and bottom of the shaft secure the bearing to the shaft with a bolt. (this serves to keep your top and bottom frames tied togther at the peak of the A.

Post Mon Jul 12, 2004 2:51 pm 
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Nick
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The trantouque idea is a winner - I love 'em! The only downside is the price, at least $60 for the size you would need.

Perhaps its way off track, but can youmove the pulley to be next to the disk? ATM, it sounds like you have

-B-D-B-P-

Where B=bearing etc. If you could move the bearings apart and butt the disk & pulley beside each other, then the pulley could also be the hub. ie:

-B-D-P-B-

Just run some bolts thru the disk & into the hub. The other upside of this is that all the power is transmitted directly from the pulley to the disk and you don't need a keyed shaft to stop slippage (which would be a real problem with the dual shaft collars).

One other thing to remember is to keep the axle as short as possible between the bearings to help prevent bending.
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Post Mon Jul 12, 2004 4:06 pm 
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Glen
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yep thats the one nick. its going to be B-D-P-B.

i think i like just having the shaft welded to the disc, served you guys well on plan b and itll save on weight (its going to be tight).


quote:
secure the bearing to the shaft with a bolt. (this serves to keep your top and bottom frames tied togther at the peak of the A.


not sure what you mean there, can you eleborate? do you mean stick a bolt through the shaft so it stops the shaft sliding through the bearing?
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Post Mon Jul 12, 2004 5:27 pm 
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Nick
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I think he means to thread the ends of the axle at each end and put a bolt on the outside to keep the axle from moving. Good n strong, but if you are using those pre-made bearing blocks like RCM sells, they have 2 grub screws to hold the axle. If that what you are using, save the weight of the nuts and extra axle length. BTW what size axle were you thinking of using? I have some 3/4" keyed steel that might be long enough.
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Post Mon Jul 12, 2004 5:47 pm 
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Glen
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nope not using the cast iron pillow blocks at $18US each its a little more than i care to spend, otherwise im using those little clamping bearing holders you originally had for basilisk along with the 16mm sealed bearings.

ah and i get the bolt think now, got ya Wink
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Post Mon Jul 12, 2004 6:02 pm 
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Nick
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Those bearings still have the locking grub screws and they are less brittle than the cast iron blocks too - good choice.
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Post Mon Jul 12, 2004 6:14 pm 
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Knightrous
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Only real advice about spinners that I can offer is that:

* You build within your ability and don't try to take on something more then you can manage, this results in waste of time and dangerous weapons.

*Anyone can spin a lump of steel on a motor, but the hard part is making it reliable and keeping it running. Andrew has done an awesome job on Annihilation, not once did the weapon stop from break down at the 6-7 battles it was in during the Sydney event, the problems we endured were the link coming out twice and our IBC's going to sleep.
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Post Mon Jul 12, 2004 7:13 pm 
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DumHed
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see if you can find a dead lawn mower in a council cleanup or something.

They generally have a large flat blade disc, which bolts onto a tapered fitting, and the matching tapered shaft.

It'd be pretty easy to either machine up a shaft that fits the mower fitting, or cut the end off the crank shaft and drill it to fit your own.
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Post Mon Jul 12, 2004 10:38 pm 
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timmeh
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What si the deal with tran torque hubs?
Dose it have any GIVE or SLIPPAGE so theres less stress on your motor and gears if you are using bevel gears?
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Post Sun Oct 03, 2004 6:51 pm 
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Nick
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As the only local user of Trantorques in bots, I can say they are not meant to slip, just the opposite! They are great for joining nearly anything to a shaft but you won't get any clutch action out of them.
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Last edited by Nick on Sun Oct 03, 2004 11:38 pm; edited 1 time in total

Post Sun Oct 03, 2004 10:06 pm 
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