Robot Parts and Materials - Answer Thread

[GDC Ring Master]

I have just received an email from LEGO stating that their small and medium sprockets are on back order until January. We have our first tournament on Dec. 8th. Are we allowed to purchase the following sprockets from McMaster Carr http://www.mcmaster.com/#roller-chain-sprockets/=k9ewmh to use in their place. We are in desperate need of these of sprockets to complete our robot.

A: Due to the issues with delivery of the small and medium sprockets, FIRST has decided to allow teams to purchase sprockets from alternate suppliers. However the sprockets must be functionally equivalent to the Tetrix sprockets (same number of teeth, and pitch). The sprockets may be made of steel, aluminum, plastic, etc.

[GDC Ring Master]

Going by post 72 and 93 the Drylin W Linear slide is legal, but we just wanted to make sure that the following linear slide and guide system is allowed
http://www.andymark.com/FIRST-Choice-p/fc13-053.htm
Thank you for your time
Team 4922

A: Yes, the Drylin Linear Slide is legal per rule R02.a

[GDC Ring Master]

Are we able to use Reynobond?

Reynobond is an aluminum composite material. It is raw material that consists of 2 sheets of thin aluminum with an extruded thermoplastic core which is 4mm thick. A plywood like material for metal. (http://www.alcoa.com/aap/north_ameri...sp?cat_id=1756)
The team would like to use it in place of plate aluminum.

It can be acquired from their sales reps.
http://www.alcoa.com/aap/north_ameri...y=usa&state=IA
The sales reps can also inform you of local fabricators who may have scrap material.

Thanks
6480 Bots in Black

a: No, Reynobond is a pre-fabricated material made by assembling and bonding mulitple materials into a final structure. It is not allowed per rule R02.b

[GDC Ring Master]

Q1: Are lift supports be allowed using them as linear sliders? such would be found at http://www.autopartsbylou.com/

Q2: Are non-Lego pneumatic pistons allowed as linear slides provided they are not being actuated with compressed air? (used explicitly for the sliding motion, not using compressed air and a solenoid to actuate) http://www.smcpneumatics.ca/en.aspx

Q3: Are rack and pinion assemblies allowed providing they are used only for the sliding motion and not exploiting the rack?

A: Q1: Lift supports are not considered linear sliders and may not be used on the robot.
Q2: Non-Lego pneumatic cylinders are not allowed on the robot, regardless of their intended use.
Q3: Commercially available Non-Lego and non-Tetrix rack and pinions are not allowed regardless of their intended use.

[GDC Ring Master]

The rules specifically allow the use of duct tape and plastic cable ties on the robot. Is there a limitation for this use:

1. Can duct tape be used structurally to attach pieces to each other, as a hinge, etc?
2. Can cable ties be used structurally to attach parts together? To form a plastic ring?

A: 1. Yes, duct tape can be use to attach parts together or to make a hinge
2. Yes, cable ties can be used to attach parts together or to make a hinge.

[GDC Ring Master]

The rules list several fastening devices as legal but do not specifically list washers.

1. We want to use washers when attaching a part to the larger hole in the Tetrix parts with standard bolts and nuts. Is this OK?
2. Are there any limitations on use of washers?

A: Washers are considered a fastener. There are no rules limiting how they may be used.

[GDC Ring Master]

Is 80/20 (see 8020.net) considered a legal raw material or COTS because of the T-slot?

If it is legal, are corner brackets, gusset brackets, and joining plates legal?

A: This question has been answered in Post #5.

[GDC Ring Master]

We have a 3D printer that we had repaired and they replaced the lead screw and nut for it that raised and lowered the tray that the 3D parts were built on. Can we use the lead screw and compatible nut on our robot per rule 4.2.2 <R02> A3 "Lead Screws and Threaded Rod plus Compatible Nuts"

A: There are no rules restricting where a legal part may be acquired.

[GDC Ring Master]

Our team has read through this forum and what classifies a "bearing" and it was talking about how the supplier classified their product. We are looking for some general clarification along with a specific part

Q1: If in the description it describes it being composed of a bearing but is not titled such, is it legal?

Q2: If a product uses a trade name, but is evidently a bearing, is it legal. An example would be a "deck organizer" in sailing, it is comprised of a few bearings but has an application specific name, or a "traveler" it is clearly a linear slide but is not called such.

Q3: The product we are looking at is called a "Micro sheave" by Harken, but is clearly a U-groove ball bearing. Would this product be legal? http://www.mauriprosailing.com/us/1-...es/HAR277.html

Thanks again for clearing up everyone's questions, it clarifies the rules immensely!

A: Q1: Just because an item contains a bearing does not make it a legal part. To make it easy for the Inspectors to determine the legality of a part the rule is that the part must be sold as a "bearing". It is the simplest way to insure consistency across the large number of FTC events.
Q2: This question does not provide enough information to make a ruling. Please provide a link to the product description.
Q3: This part is a pulley that contains a bearing and is not an allowed COTS.

[GDC Ring Master]

I know 3D printing is allowed this year, but to what limits are there for what parts we can create? Are we allowed to 3D print our own gears?

A: The rules do not restrict the type or quantity of parts that a team may fabricate from allowable raw materials, including those made by 3D printing.