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[DPRG] Re: Big Sumo Ring

Subject: [DPRG] Re: Big Sumo Ring
From: Earl Bollinger earlwbollinger at attbi.com
Date: Sun Dec 15 19:11:00 CST 2002

Thanks for the info Eric, that's most interesting.
You guys are so good at making metal thingies. I know I bought some thingies
>from them and they are good.
All we need then is a estimate on how much it would cost us, for you to make
the metal ring.
We can then get the DPRG membership to vote on it at the next meeting.

Oops, I guess we need to think about the wood frame some. Maybe a simple 2x4
frame setup would be
all that's needed. I don't see a reason to have the entire base as more or
less solid wood.
Of course I'd have to hit up a few Home Depots and Lowes to find several
straight 2x4's.Would countersinking a few screw/bolt holes be OK?
Or should we simply RTV the thing down to a frame?
A roll or two of masking tape, and a few cans of flat black and white
Rustoleum paint isn't a problem.

Looks like we might have to start thinking about what time of the year to
plan for a sumo competition. I would assume we'd want to have it at the
Science place.
Maybe including the Mini-Sumo (micro sumo?) events at that time might be fun
too. Just in case we
don't get a lot of 22cm x 22cm entries.
I see a RC novice class, RC advanced, Autonomous Novice and Autonomous
Maybe a Lego/Kynex class as well. Depends on the interest and entries.
Advanced would likely be the magnet, vaccumn, and custom sticky tire guys.
I would think that if you win 1st in novice you'd move up to the advanced
class at the next competition. That way others have a chance at winning too.

-----Original Message-----
>From: dprglist-admin at dprg.org [mailto:dprglist-admin at dprg.org]On Behalf
Of Eric Yundt
Sent: Sunday, December 15, 2002 1:35 PM
To: Dallas Personal Robotics Group
Subject: [DPRG] Re: Big Sumo Ring


Earl Bollinger wrote:
> But we'd have to get a 5 foot sumo-ring built for this.
> This would be for the 22cm non-dangerous robots.  The latest
> Japanese rules seem to want us to use a 1/4"-3/8" mild steel
> plate as the sumo ring base plate. So this is the limiting
> factor, by the time you add the wood frame to the steel plate,
> we've got a lot of weight to have to man-handle to and from
> the contest site. If I remember we calculated it as weighng
> around 170 pounds+.  Heck a good wood sumo-ring still weighs
> like 70+ pounds.  Yeah you could roll it on edge, but you have
> to be able to pick it up to get it on the edge. Plus set it
> back down when you get it into the contest site.

A simple cart could be made to carry it similar to those little
carts used to move wall-board or plywood -- perhaps a local home
center would donate one of their beat-up lumber carts.  With
enough handles (or rope attach hoops, etc.) there usually should
be enough volunteers around to manhandle such a beast.

> I guess if the Seattle or Parts people can get the materials,
> we ought to see if we can get a metal plate made for us at the
> same time. Making a 5 foot circle steel plate isn't all that
> easy, without someone already set up to make one. I don't know
> of anyone off hand with a 5 foot capable rotary table CNC
> machine myself.
> Eric Yundt, can you guys make a 5 foot diameter 1/4 to 3/8"
> mild steel plate for a sumo ring?  I suppose we could use a
> high power magnet to hold the plate down in the center, or we
> could have a small hole in the center that we can fill in with
> epoxy.  The big question is how much it would cost?  And would
> DPRG want to pay for it.

We are in the process (early stages) of CNC'ing a plasma torch
with (probably) a large enough table to handle it,  but in the
meantime I think we could pretty accurately cut a 5' diameter
circle out of steel plate by either using a cutting torch circle
jig (sort of like rotating a pencil on a string around a center
pin) or by putting a large rotary table out on the end of our
big mill's XY table -- this would require additional support.
A circle carefully cut with a cutting torch could be cleaned up
very nicely with a hand grinder.  We _might_ be able to find a
big enough piece of steel at Garland Steel for 20-25 cents/lb.

Build it and they will come?  Or build them and we'll make sure
they have a place to play?


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