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#1
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Re: Pre-season purchases
You could start with things that you are nearly guaranteed to need:
Bumper materials (noodles, fabric, plywood, fasteners) CIM motors Wire Fasteners Jaguar and/or Victor motor controllers Controllers (gamepads / joysticks / custom controls of your team's choice) If your team has particular building materials that you know how to use well (or want to learn), you could have some of that on hand: Sheet aluminum, T-slot extrusion, wood, PVC pipe, AndyMark C Channel, angle aluminum, box aluminum, polycarbonate, etc. If your team has a type of drive that you like (or want to learn), you can buy parts for that and build one in the offseason. Then you can use any items next year if desired if they are still unmodified COTS parts. Includes wheels, sprockets, spacers, bearings, gearboxes, etc. Strategically investing in tools is smart. Getting safety glasses that aren't all scratched up is pretty nice. What you'd want to buy preseason depends on a bunch of things. If you have an offseason project in mind, that would tend to drive what you buy. If resources are very limited, one would probably want to get things that are a safe bet to be useful on next year's robot. If you want to have greater flexibility when you find out the game, you'd want to get tools and raw materials that can be used for a variety of tasks. If you want to get off the ground quickly next year, you might want to choose a style of 6WD (or some other drive), build one in the offseason, and have the components ready to go for the start of 2012. |
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#2
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Re: Pre-season purchases
Best advice for stocking up on supplies would be to look at what you used this past year and go off of that. Good thing there's a Bill of Materials to get a good idea
As for raw stock items from a mechanical side of things, I'd suggest standard stock items, such as 80/20 aluminum, aluminum box, C, and L channel, Lexan, PVC pipe and PVC Lumber (my team has found it to be a very useful material), bolts/nuts, and standard axle sizes. These are the things you should order now and look for good prices and not worry about shipping, you're almost guaranteed to find a use for this stuff. Even if you don't, it's better to have something you don't need than need something you don't have! One piece of advice for a team still kinda green Standardize the materials you use! My team uses 1/4-20 bolts and 7/16ths nuts for practically everything that needs a bolt/nut, this saves a ton of time and effort looking for the right drill bit/wrench. Hope this helps, and good luck in your 2nd season! Last edited by Tom I : 04-10-2011 at 20:03. Reason: to make one part clearer |
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#3
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Re: Pre-season purchases
When considering items to purchase during the preseason, it is my suggestion to go as general and generic as is possible. There is nothing worse (and I say this from experience) than making 1-2 McMaster Carr orders a night.
I suggest that you purchase all hardware that you might from McMaster before the start of season. This would include (but is not limited to) complete sets of all bolts, nuts, nylocks, and washers that your team uses during season. When doing so, set standardizations for bolt sizes that you use. It would also be wise to purchase bumper hardware. If you choose to do so, add a bunch of T-nuts and corresponding hardware in addition to pool noodles and the necessary fabrics. You may choose to install a shelving unit to store the purchased hardware. We did this and I consider it one of the best decisions we made as a team. As others are saying, it would probably be a good idea to stock up on extra aluminum with which to build the robot or prototype. In terms of prototyping, you could probably save at least two days during the design process if you acquired a bunch of extra plywood and lumber. This is a good investment that will hardly cost you anything significant. Good Luck! |
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#4
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Re: Pre-season purchases
Check your batteries as well. If you don't have at least 3 chargers and 4 batteries, I'd stock up. How's your pneumatics supplies looking? For our team, last year we basically hit our pneumatic limit simply because we ran out of solenoids. There's also the usual zip-ties, duct tape, WD-40, and Loc-tite to have handy. Some extra wires/connectors would be helpful too
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#5
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Re: Pre-season purchases
#25 chain is a pretty safe bet. I wouldn't get much of anything else pre-season unless it was tools.
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#6
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Re: Pre-season purchases
We're buying zip ties, pool noodles, basic electronics parts, stock metal, and rotary tool accessories. (There's also some vector drive parts on the way, but not many people need that.
)Definitely buy more of what you use up (duct tape, zip ties, bolts etc.) and some more batteries. Also think about getting the new little cRIO. |
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#7
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Re: Pre-season purchases
Quote:
Quote:
We're on the 3rd or 4th different battery in my tenure as a mentor so I would never reccomend a team with limited resources buy them until the season starts. I agree with folks saying stock up on tools, fasteners, and raw material. Those are items you can use no matter what. Anything like controllers, other than the FRC specific cRIO that we know is coming, is at risk of not being in the rules if FIRST decides on a whim to eliminate it. I can think of many kit items and rules that were thought unchangeable over the years that we were proven wrong on. |
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#8
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Re: Pre-season purchases
Carol,
Now is an excellent time to buy into tools. If you have the basics, then I would add the following... Flush cutting wire cutter Chain Break At least one multimeter. (Some nice ones are still available for less than $50) A set of both English and Metric Allen wrenches. A nice machinist's square A good hacksaw with several blades A couple of files, or a set including different lengths and cuts A couple of drill sets Pop Rivet tool, rivets (different lengths and material) and several of the correct size drills for installation and removal. If you are thinking of using Anderson Power Product electrical terminals, then crimping tool for such connections. (Search Anderson here on CD for recent discussions of tools and terminals. MCM Electronics (www.mcmelectronics.com) has nice zip cord wire. Get a 500 ft. roll of #18, #14 or #12, and #10. You will have it for years to come and it make wiring easier as the red and black wire are bonded together. Ty-wraps of varying sizes and lengths. Heatshrink for wire insulation in various sizes. |
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#9
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Re: Pre-season purchases
A good purchase would be a roll away tool box that is labled where the tools should go. Training the students to pick up and put back the tools after use is high up on our training list.
Having a nice transport cart for the robot is a good off season project. Organize your wiring tools you use to make pwm cables, molex crimpers, heavy gage wire strippers. Battery load tester Rivnut gun, pneumatic pop rivet guns, small arbor press for bearings. Roy |
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#10
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Re: Pre-season purchases
Quote:
One of my favorite things to stock up on in the weeks leading up to build season are prototyping materials. Wood, PVC, Small Wheels, etc, that can be thrown together into a quick prototype on Saturday or Sunday are always nice. |
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#11
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Re: Pre-season purchases
If you really want to squeeze a dollar and maximize your purchase I'd recommend that you do the following exercise, which happens to be something we did over the summer.
1) Using an excel spreadsheet we created a table of everything in the KOP plus everything we had bought the past few years. 2) then we did an inventory of all of our raw parts, with cost. great exercise, you can learn how much money is laying around. 3) then we made another spreadsheet of our master wish list. this includes tools, parts, machine, trailer, shirts, everything. It is a huge list. 4) Then you do nothing. 5) Sit on this information ready to pull the trigger on purchases, but only after you KNOW you will need it, not THINK that you need it. After all, the only thing you can assume about next year is a cRio and a Microsoft Kinect. Just in the past few months we have saved a ton of money by doing nothing because we ultimately determined other solutions or that we didn't really need it right now. Planning is more important than spending right now !! . |
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#12
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Re: Pre-season purchases
Engineers can be bought....
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#13
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Re: Pre-season purchases
"I can't be bought but I can be rented..."
Quote from my Physics 101 instructor. ca.1970 |
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#14
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Re: Pre-season purchases
Why is #25 safe ? Not very many people use it. The KOP is #35. So far we have never bought that in 8 years. Then again we have never had a winning robot either !
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#15
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Re: Pre-season purchases
I've heard mixed on 25 vs 35. Pros to 35 is that it very standard on high torque applications such as arms and drivebases and since it is larger, it is easier to work on which comes in handy if you blow a chain the finals. 25 is smaller and lighter but it is a pain to work with in a timely manner with how small the master links are. Great for small applications such as rollers, set and forget.
I have heard of a few teams using a combo in their drivebases to save weight. Use 35 chain to drive the the middle set of wheels in a 6wd and have 25 spanning to the front and back. So even if you blow a 25 chain you can still drive your main dropped center wheel. To save such a small amount of weight I'd rather just drill a few holes but if your aim is to use as little weight as possible from the start of the design it isn't a bad idea. For me, 35 as much as possible. Less spare parts to plan ahead for and I know when properly tensioned it will be consistent and an easy fix if something goes south. Pre-season purchase? Kinects! ![]() |
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