Material list suggestion

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Posted by Philip.

Student on team #45, TechnoKats, from Kokomo High School and Delphi .

Posted on 10/18/2000 11:21 AM MST



After doing some math when trying to figure up some gear ratios, I found that chain is of the essence when designing the robot this year. If four of the extra large sprockets were used, almost all of the chain would be used to just wrap around the sprockets. Leaving very little chain to use for gearing down or for other applications on the robot. Is it possible the amount of chain that can be used could be upgraded by a few feet? If not, does anyone know how to conserve enough chain to get the correct gear ratio?
Phil

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Posted by Raul.   [PICTURE: SAME | NEW | HELP]


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.

Posted on 10/18/2000 11:50 AM MST


In Reply to: Material list suggestion posted by Philip on 10/18/2000 11:21 AM MST:



Joe,

I agree with Philip. Last year we got 20ft of regular and 10ft of track chain. Can we get a little more chain added to the additional HW list?

Since we are not allowed to use gears or make our own sprockets, it is difficult enough to get the right drive ratios.

Actually, can we make our own spockets out of legal additional HW materials?

Raul

: After doing some math when trying to figure up some gear ratios, I found that chain is of the essence when designing the robot this year. If four of the extra large sprockets were used, almost all of the chain would be used to just wrap around the sprockets. Leaving very little chain to use for gearing down or for other applications on the robot. Is it possible the amount of chain that can be used could be upgraded by a few feet? If not, does anyone know how to conserve enough chain to get the correct gear ratio?
: Phil

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 10/18/2000 12:03 PM MST


In Reply to: Re: Material list suggestion posted by Raul on 10/18/2000 11:50 AM MST:




: Actually, can we make our own spockets out of legal additional HW materials?

Yes you can, IF you don't use forbidden methods (e.g. a mill or a lathe) to manufacture it.

As to the bit about not enough chain - relief is on the way. this was an oversite on our part.

Joe J.

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Posted by Raul.   [PICTURE: SAME | NEW | HELP]


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.

Posted on 10/18/2000 4:02 PM MST


In Reply to: yes and no... posted by Joe Johnson on 10/18/2000 12:03 PM MST:



: Yes you can, IF you don't use forbidden methods (e.g. a mill or a lathe) to manufacture it.

I don't mean to push the boundaries of precision machining too much but:

1) Are we allowed to use an indexing head or any other precision fixtures along with a drill press?

2) If not, are we allowed to make a fixture out of legal materials using mills, etc?

Raul

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 10/18/2000 6:15 PM MST


In Reply to: Re: yes and no... posted by Raul on 10/18/2000 4:02 PM MST:



So it has come to this, has it?

The purpose of the no precision machining rule is to try to make it a somewhat level playing field while at the same time making it a 'kids can do it themselves' type of affair.

I don't want to have to get too technical on this one.

As to whether a precision indexing head or other fixture is allowed in conjuction with a drill press... This one is getting pretty close to the line. I would be much happier if I heard that a team used a laser printer to make a template, some tape to stick it to their raw stock and very careful person armed with a center punch and a hammer to transfer the pattern. In the end, I don't know how I would be able to tell the difference in the result.

As to precision machining a custom fixture to use to make your parts (whether made from legal kit material or not), this seems a bit beyond the line to me.

In any case, are you REALLY SURE you need to go to such trouble?

I hope this helps.

Joe J.

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Posted by Raul.   [PICTURE: SAME | NEW | HELP]


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.

Posted on 10/19/2000 6:18 AM MST


In Reply to: Don't let's get too crazy here... posted by Joe Johnson on 10/18/2000 6:15 PM MST:



Sorry, I did not mean to test your patience.
I doubt we will need to do what I asked. Your kit provides enough for us to work with.

But, better to make the boundaries clear to all rather than let each team make their own assumptions.

Another example of this is:
Last year we were allowed to use pop-rivets as a fastener. Rather, than make that assumption, I ask again if it is legal.

Raul

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 10/19/2000 7:23 AM MST


In Reply to: Re: Don't let's get too crazy here... posted by Raul on 10/19/2000 6:18 AM MST:



Thanks Raul.

As to pop rivets, great fastener, I'll allow it.

Joe J.

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Posted by Mike Aubry.

Engineer on team #47, Chiefs, from Pontiac Central and Delphi .

Posted on 10/18/2000 7:19 PM MST


In Reply to: Re: yes and no... posted by Raul on 10/18/2000 4:02 PM MST:



I agree with Joe, let's not go over board on the special machining. The intent was to try to put together a kit and rules that just about anyone with limited tools could still create something that could compete. If we are missing stuff that would assist in reaching that goal, please suggest what it is that could help (everyone) We will fix the chain limitation very soon, so what else do you want added to the materials list? I suggest you ask as soon as possible, as the material list revisions will be closed soon, again to keep the playing field as even as possible.

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 10/18/2000 11:59 AM MST


In Reply to: Material list suggestion posted by Philip on 10/18/2000 11:21 AM MST:



Attention all,

We have my mistake and/or poor planning left off some things we had intended to include or should have included on the Additional Hardware List.

We will publish an officially updated list soon, but before we do, we would like your input.

Please review the following changes comment as you feel necessary.

Joe J.

Adding to the Additional Hardware List:

-Schedule 40 PVC Pipe up to 2 1/4 inch (Nominal Dimension)
-#35 Steel Roller Chain
-#35 Standard Connecting Links
-Steel Springs (torsion, compression or extension) -- 'Off the shelf' & avalilable from typical hardware stores

For reference, any spring from McMaster-Carr on pages 3186 thru 3201 (Cat. #106) inclusive meets the definition of an acceptable off the shelf spring -- in fact you may purchase them from McMaster if you like. You can view the pages online by following the link below to McMaster.com and entering the page number you desire into the field in the upper left corner. Good luck. JJ

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Posted by Samuel Lindhorst.

Engineer on team #240, Mach Vee, from Jefferson High School and Visteon.

Posted on 10/19/2000 7:00 AM MST


In Reply to: Possible changes... posted by Joe Johnson on 10/18/2000 11:59 AM MST:



Hinges.

If we have rubber sheet, it seems that flat rubber belting of the same maximum thickness might be allowed, too.

Sam

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 10/19/2000 7:30 AM MST


In Reply to: Re: Possible changes... posted by Samuel Lindhorst on 10/19/2000 7:00 AM MST:



To my mind, a rubber sheet is sort of, well... ...a flat rubber membrane. A rubber belt brings to mind a composite material with fiber or steel reinforcements sandwiched somewhere in the middle there.

Flat rubber seems okay.

Flat rubber with reinforcements in the middle seem to be not okay.

So Sayeth I.

Joe J.