Rookie Team Help Request - Kit of Parts Chassis

Good Morning,

My rookie team is having an issue with the Kit of Parts chassis. We followed the directions supplied by AndyMark for the “SQUARE” configuration and we are still OVER the maximum length allowed by over 1/4". We have a gap on both ends where the front and rear pieces attach to the drive train sides. I have provided a picture of the issue below and labeled the points of the issue (1),(2).

If we try to perform another cut we have to use the hole at point (3) but if we do that and move the fasteners (4) we will hit the tire and lose the Churro at point (5). Any help is greatly appreciated.

Google Photos

The frame coming out around 28.25" does seem to line up with their measurements in the manual. I guess the real question is how to make it meet the 28" Starting Configuration rule.

33" x 28 " is maximum Starting Configuration (55" Tall)

The Square Configuration according to AM is 27.5" x 28.3"

That could be your issue over 28" by .3" on at least one side so either modify from AM spec or reorder parts …however the other side should be **slightly **less than 28" in square is it?

Edit: If so…Square still should work … as 28.5 < 33 and 27.5< 28 could be the gaps are too much putting it out of spec?

What are the dimensions on both sides that you measure as the pic is not showing?

Basic check will your bot fit in a 33x28x55 cube as that is how they will inspect it as I have seen? If so you are good IMO

Hmmm…it might be a little bit late, but it’s a good idea to figure out all this size stuff before you start cutting metal. It’s hard to put metal back together.

The kit chassis, and the instructions for it, were designed when the maximum robot size rules were different. The instructions were not revised for the current game rules. The three available sizes shown are merely suggestions–you can make the robot whatever size you want, although there are some real constrains such as the sizes of belts that you can buy, which limit how far apart the wheels are from each other, and also the width of the parts, which kind of limits the minimum and maximum widths.

But there is nothing anywhere that says you MUST make the robot the same size as one of the examples in the instructions.

We built the kit chassis to use the “long” length, and the “square” width, so our robot will end up being just under 33" long, and just under 28" wide, although the bolt heads will stick out past the 28", which is allowed. We are considering making it an inch narrower, by cutting the end frame members an inch shorter. This will give us some extra leeway for stuff that might make the robot wider than is allowed–a common problem, over the years, we have noticed is that robots seem to grow as build progresses.

The churros can be placed wherever they will fit, it is not vital that they go where they are shown in the instructions.

But the tip about changing your concept of what is “width” is the easiest thing to do :slight_smile:

This is one thing to keep in mind, there are many holes for the churro to go, the other is if you were to cut that little bit off and move the back plate in, you can notch out the little section where the metal hits the wheel(See red lines in this picture). We did this in 2016 when we switched to 8 in wheels to get over the defenses and that game was much rougher on bots so you shouldn’t have any structural problems unless you cut an opening in the front and back plate and didn’t use the AM frame opening kit or a piece of 1x2 to replace the structural integrity.

one thing about moving the end frame pieces closer to the wheels, is that it gets just about impossible to assemble the frame screws and nuts, because there’s no room to fit fingers in. We notched the ends of the web of the end frame pieces to allow finger/wrench access

And I forgot to take a picture of it.

Hmmm, this Q&A answer might effect that…

143 Does the exclusion of minor protrusions pertain to height?
Does the exclusion of minor protrusions in the starting configuration (R02) in the horizontal directions pertain to the vertical dimensions? For example, would a bolt head protruding above 55" be acceptable?

No, the exception for minor protrusions in R02 applies to the determination of FRAME PERIMETER only and does not apply to any of the dimensions in R03. ROBOTS must meet all STARTING CONFIGURATION size constraints in R03 with no exceptions.

Just to make things a little more clear for the rookie team in question:

All you have to do is to remember to put the robot in the sizing device with the now-28"+ side on the 33" dimension, and you should be good. There’s no particular requirement that you drive in the long dimension.

A couple of other notes while we’re here: This should also put you within the standard advice to build with at least 0.5" of room in each dimension (there’s a lot of bitter experience behind that advice is all I’ll say for now).

Also, I would take careful note of BryanLee’s comment about the Q&A. Bolt heads have to fit in the sizing box too. (See previous paragraph.) You should be OK, but still measure that direction too.

And if you need any other help (like where you need to put bumpers on the robot’s frame) feel free to ask!


We left our robot wider then 28" in the front and back so we can not use your suggestion but it would have worked if we did cut the width down too 28".

I think what you’ll need to do is to decide whether you want to run long (cut the width down) or wide (cut the length down).

As alluded to before, and as you found out, this is not necessarily a “follow the instructions and you’ll be fine” competition. The good news for you guys is that it’s Week 2, and you’re already aware you have an issue. Many an inspector has a horror story of someone not finding out they have an issue until arriving at the event…

Just one thing to add from an inspection standpoint…
Wheel axle bolts insert from the outside of the chassis. The nylock nuts go inside. The head of the bolts is 1/4" or less in keeping with the protrusion language in the robot rules. The nuts are greater than 3/8" and with the threaded portion of the bolt, the protrusion is greater than 1/2". This is a typical mistake for teams using the kitbot chassis.

Something that can always help is if you draw/tape out the box (33x28) and see if your robot can fit in it in either direction, since there is no rule about orientation of your robot, it may help to see if it can still work before you cut any more metal.

Hope this helps, and if you have any questions feel free to ask.

Zach G.
4944-Hi Fives

Read and understand this point! The size enforced at inspection will be the maximum STARTING CONFIGURATION defined by R03. There are NO allowances for fastener heads, or other minor protrusions, beyond this size. If you make your FRAME PERIMETER to the STARTING CONFIGURATION maximum size I almost guarantee you will fail R03, unless your frame has a perfectly smooth exterior.

Sizing rules are enforced at competitions. Failing R03 will be bad and cause much unhappiness and rework.

I think we should rethink if a complaint R02 bot with minor protrusions beyond the max dimension would automatically fail R03. There was a QandA on this very topic.

190 R03 - Do fasteners on the outside of the frame count towards the measurement of the robot?
R03 doesn’t say anything about Fasteners not counting in the Maximum Robot Size. So do fasteners on the outside of the frame count towards the measurement of the robot? Do the fasteners in the Kit of Parts for bumpers count against the size measurements during inspection?
asked a day ago by FRC 7056
Yes, R03 has no exemptions for minor protrusions, the entire ROBOT must fit in the size constraints. With respect to BUMPER fasteners, please see R30-G and the Blue Box below R29 for additional information about determining whether an item is part of a BUMPER or part of the ROBOT (and therefore subject to R03).

IMO this Q190 was specifically about bumper fasteners (considered permanent part of the robot) or could be about anything beyond the frame itself… and yes if they stick out past a complaint R02 then R03 has no exception… That does not automatically mean IMO a robot compliant with R02 and minor protrusions beyond max size will almost always fail R03…before teams rework what they designed, I find it hard to believe one rule allowed robot can at the same time violate another rule on the same item…Starting Configuration when talking about the Frame Perimeter.

Perhaps another Qand A to clarify if unsure?