Hey,
I'm working on a design for a Battlebot for their 2005 competition in
Orlando Florida. I am working on a design that I feel will fair
extremely well against any others. Currently, I am looking at a
material to use for the weapon. My design calls for a flat bar, about
36-40" long x 3" wide x .5" thick.

What would be the best material to use? Keep in mind that this will be
a spinner, spinning at 3000rpm, putting a fair amount of kinetic energy
into the other bot.

Hardened S7 Toolsteel fare well against bending or breaking?

Could the peice be bent at a 45 degree angle a few inches from the
ends? Without them breaking off, or bending the whole thing.

Does anyone know of any shops that will sponsor a weapon of those
dimensions, with a huge strength and hardness?

Oh, and this bot isn't a pipe dream. ;-) We've got over $7000 invested
into it. But we still need more money! If anyone wants to donate,
Paypal
Please let me know!
AJ Quick
http://www.HHSRobotics.com/

Check out your local tractor supply store (TSC or whatever is in your
area). They will have replacement blades for bush-hogs used on tractor
equipment. Many of the larger HP designs are pinned about half way out.
The center section or even the end sections may be just what you want.
These are tough and have holes already machined in them.

I think when George is referring to being "pinned" I think that he means
that the blade has a pivot between the center and the end, a three piece
blade. In a mower, that reduces the likelyhood of doing damage to the
mower if the blade hits something solid. That sounds advantageous in
terms of not wreaking havoc on your own bot when it hits something. If
you do not do that, you had better have a clutch or some other way to
allow slip between the motor and the blade.

Good luck and have fun!
Richard


george wrote:
Check out your local tractor supply store (TSC or whatever is in your
area). They will have replacement blades for bush-hogs used on tractor
equipment. Many of the larger HP designs are pinned about half way out.
The center section or even the end sections may be just what you want.
These are tough and have holes already machined in them.

"george" wrote in message
ups.com...
Check out your local tractor supply store (TSC or whatever is in your
area). They will have replacement blades for bush-hogs used on tractor
equipment. Many of the larger HP designs are pinned about half way out.
The center section or even the end sections may be just what you want.
These are tough and have holes already machined in them.

36 inch mower blades are readily available, of course. And the OP could
"double up" to get the thickness required. Battlebot people probably have
safety specs for this. Also, I think there are legal limits for RPM for each
blade length, at least for OEMs. I think a 22 inch blade has a 3100 RPM
limit. 26 inch blade is 2600 RPM

AJ

Have you actually tested that spinning yard long 1/2 inch thick 3 inch
wide balde?? What happens to your robot when it encounters another,
equally heavy, robot ot obstruction?? ?Got any videos to post?

Jerry



"AJ Quick" wrote in message
ups.com...
Hey,
I'm working on a design for a Battlebot for their 2005 competition in
Orlando Florida. I am working on a design that I feel will fair
extremely well against any others. Currently, I am looking at a
material to use for the weapon. My design calls for a flat bar, about
36-40" long x 3" wide x .5" thick.

What would be the best material to use? Keep in mind that this will be
a spinner, spinning at 3000rpm, putting a fair amount of kinetic energy
into the other bot.

Hardened S7 Toolsteel fare well against bending or breaking?

Could the peice be bent at a 45 degree angle a few inches from the
ends? Without them breaking off, or bending the whole thing.

Does anyone know of any shops that will sponsor a weapon of those
dimensions, with a huge strength and hardness?

Oh, and this bot isn't a pipe dream. ;-) We've got over $7000 invested
into it. But we still need more money! If anyone wants to donate,
Paypal
Please let me know!
AJ Quick
http://www.HHSRobotics.com/

In article . com, AJ
Quick wrote:

Hey,
I'm working on a design for a Battlebot for their 2005 competition in
Orlando Florida. I am working on a design that I feel will fair
extremely well against any others. Currently, I am looking at a
material to use for the weapon. My design calls for a flat bar, about
36-40" long x 3" wide x .5" thick.

What would be the best material to use? Keep in mind that this will be
a spinner, spinning at 3000rpm, putting a fair amount of kinetic energy
into the other bot.

Hardened S7 Toolsteel fare well against bending or breaking?

Could the peice be bent at a 45 degree angle a few inches from the
ends? Without them breaking off, or bending the whole thing.

Does anyone know of any shops that will sponsor a weapon of those
dimensions, with a huge strength and hardness?

Oh, and this bot isn't a pipe dream. ;-) We've got over $7000 invested
into it. But we still need more money! If anyone wants to donate,
Paypal
Please let me know!
AJ Quick
http://www.HHSRobotics.com/


AL64V Titanium with S-7 toolsteel heads

"
A leaf spring from a car or truck will probably suffice. Hope you have
a good lawyer on retainer when the **** hits the fan.
"

No it probably wouldn't. The **** would not hit a fan, it would hit a
1" thick wall made of lexan.

"
Have you actually tested that spinning yard long 1/2 inch thick 3 inch
wide balde?? What happens to your robot when it encounters another,
equally heavy, robot ot obstruction?? ?Got any videos to post?
"

Sorry Jerry, no video.. as my first post was trying to get a material
to make the blade out of.

"
Bigger and faster spinners already exist, heh. As for lawyers we've had
our fill! Why d'you suppose Battlebots went off the air? Lawyers,
that's why.. Yecchh!
"

I doubt it though, in our weight class and level of competition.. yeah
it went away because of some bad lawsuits. None related to injuries,
but to who had the rights to the show.

"
AL64V Titanium with S-7 toolsteel heads
"

I'll look into that. I highly doubt we have the funds, as we've already
thrown about $7k into it currently.

Thank you for the link and info "Old Nick".

I'm still kinda looking for a good answer to my original question,
however. To all those concerned with kinetic energy and safety.. don't
worry about it. The spinner has a way to slip.. also, it is powered by
2 5hp electric motors.. with lots of batteries. Its not going to fly
off and kill someone.. if I use a leaf spring from a car.. yeah then it
probably will.

On 20 Dec 2004 22:00:53 -0800, "AJ Quick" vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

I'm still kinda looking for a good answer to my original question,
however.

Which question was that then?..the one about sponsorship, I guess.

You appear to have rejected all the attempts to answer the bit about
what steel to use. You want a steel that resists bending, yet can be
bent at 45deg. Sionce all of the attempts at replies have failed you,
you must know better. So use hardened S7 and see what happens.

Um.. excuse me?

The majority of the replies were about a way to make the spinner slip,
asking for videos, or suggesting something that would not even be
capable.

The 45 degree angle was a question.. would something say tool steel be
able to be bent downward then hardened.. then withstand a side impact
without bending to the side on that downward 45 angle?

If you can find me a supplier to get this "AL64V" or rather "6AL-4V" as
it is known. Or the "quench and tempered steel" as you mentioned than
let me know.


The spinner spins at about 250 miles per hour, and would exert about 13
Kilo Joules of energy.

AJ

I guess I have to apologize about asking for videos. I had assumed that
you'd have tried something since you have spent $7,000.00 on this project
already. I just didnt think you could have gotten this far without having
tried something.
You must know that an automotive spring can be heated and bent. The
question about the durabilty of that spring could be answered pretty easily
with some real life tests. I was curious about what you'd broken so far.
Now that you've aparently become dissatisfied with the replies you get, I
begin to wonder how real this project is. For instance, where does the 250
MPH come from?? I'd have thought a 3 ft long blade rotating at 3,000 RPM
would have a tip speed of about 320 MPH. Maybe I'm wrong.

How about sending us a picture of what you have so far. Assuming this is
a real project, I'd bet you can get some excellant information from guys on
this news group. Your description so far of what you want has been less
than well defined.

Jerry


"AJ Quick" wrote in message
oups.com...
Um.. excuse me?

The majority of the replies were about a way to make the spinner slip,
asking for videos, or suggesting something that would not even be
capable.

The 45 degree angle was a question.. would something say tool steel be
able to be bent downward then hardened.. then withstand a side impact
without bending to the side on that downward 45 angle?

If you can find me a supplier to get this "AL64V" or rather "6AL-4V" as
it is known. Or the "quench and tempered steel" as you mentioned than
let me know.


The spinner spins at about 250 miles per hour, and would exert about 13
Kilo Joules of energy.

On 19 Dec 2004 18:25:28 -0800, "AJ Quick" vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

I will "digest" what has been said here, and add one idea.

The one idea: quench and tempered steel. You will need to get this cut
from sheet, probably. Best with laser. This stuff makes spring steel
look like cookie dough! G. Its yield strength is enormous. The 350
Bn hard stuff has a "0.2% proof stress" (which I have been told is
equivalent to Yield) of around 1100-1200 MPa. 500 is even higher.

Definition Proof Stress: The stress that will cause a specified
small, permanent extension of a tensile test piece. Commonly the
stress to produce 0.2% extension is quoted in N/mm2 for steel. This
value approximates to the yield stress in materials not exhibiting a
definite yield point.

They are just machinable, and are weldable, with lots of care. they
can be bent. They must not be heated beyond very set levels, because
they are already fully treated.

Then George mentioned pivoting. The force on _your_ bot (pun intended)
will be enormous if another bot stops that bar, even if you slice into
it a few inches. The drive shaft and gearing will need to be some
serious stuff, or you need a good clutch. Try a rotating pan, with
pivoting blades a la slashers and rotary mowers. The boits I have seen
with rotary cutters had multiple teeth to have a similar effect.

Ernie mentioned hardened tips on strong bar. I again suggest the
350-500 hardness grades of QnT alloys. Tips should then be chosen for
hardness and extreme impact. From my (limited and often theoretical)
experience, this places the stuff you need into about the 600 650 Bn
range at max, or it starts to shatter too easily above
that.........ah! I see on
http://www.matchrockets.com/teamstupid/materials.html

that they recommend S7 treated to 55 Rc. Roughly the same. Perhaps I
was a little high, and getting toward brittle.

Hey,
I'm working on a design for a Battlebot for their 2005 competition in
Orlando Florida. I am working on a design that I feel will fair
extremely well against any others. Currently, I am looking at a
material to use for the weapon. My design calls for a flat bar, about
36-40" long x 3" wide x .5" thick.

What would be the best material to use? Keep in mind that this will be
a spinner, spinning at 3000rpm, putting a fair amount of kinetic energy
into the other bot.

Hardened S7 Toolsteel fare well against bending or breaking?

Could the peice be bent at a 45 degree angle a few inches from the
ends? Without them breaking off, or bending the whole thing.

Does anyone know of any shops that will sponsor a weapon of those
dimensions, with a huge strength and hardness?

Oh, and this bot isn't a pipe dream. ;-) We've got over $7000 invested
into it. But we still need more money! If anyone wants to donate,
Paypal
Please let me know!
AJ Quick
http://www.HHSRobotics.com/

On 19 Dec 2004 18:25:28 -0800, "AJ Quick" vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Aiiii amd a Dalek. I will now ignore you.

Ignorrre! Ignorrre! Ignorrre!

Hey,
I'm working on a design for a Battlebot for their 2005 competition in
Orlando Florida. I am working on a design that I feel will fair
extremely well against any others. Currently, I am looking at a
material to use for the weapon. My design calls for a flat bar, about
36-40" long x 3" wide x .5" thick.

What would be the best material to use? Keep in mind that this will be
a spinner, spinning at 3000rpm, putting a fair amount of kinetic energy
into the other bot.

Hardened S7 Toolsteel fare well against bending or breaking?

Could the peice be bent at a 45 degree angle a few inches from the
ends? Without them breaking off, or bending the whole thing.

Does anyone know of any shops that will sponsor a weapon of those
dimensions, with a huge strength and hardness?

Oh, and this bot isn't a pipe dream. ;-) We've got over $7000 invested
into it. But we still need more money! If anyone wants to donate,
Paypal
Please let me know!
AJ Quick
http://www.HHSRobotics.com/