Who makes their own wheels?
 

In an effort to collaborate with my teaching comrades, I think a wheel project would be good. It is a great way to connect with a physics teacher with Newtons Laws of motion and overcoming the moment of inertia.

If any one has done this please offer advice.

We can use our Velox CNC to mill them out of aluminum and finish on a Lathe. We can also 3d print using PLA, ABS, and Polycarbonate.

Re: Who makes their own wheels?
 

We used 2.5" 3D printed idler wheels on our track system this year. They held up better than expected and were very light weight. Our test wheels didn't have bearings and the later ones used 4 skate bearings to help support the hub. Without the stacked bearings the wheels would waller out quickly. We also used some large 6" 3D printed idlers on the prototype. They used two flange bearings and held up fine.

We replaced the large printed idlers with turned aluminum. I'd recommend turning your blanks and then machining the features. I blanked the idlers at work and then had the students mill the bearing pockets. The lathe at the school is pretty tired. I uploaded the video of the process. The students had to mill the soft jaws before milling the wheel.
https://www.youtube.com/watch?v=8Y0hI6mcwCg

We also modified some COTS idlers, these videos may give your some idea of the secondary operations.
https://www.youtube.com/watch?v=WkNYmihLryo
https://www.youtube.com/watch?v=EDhaW5d9uDk

If we need to ever make a lot of wheels we'd likely mill out a pattern and cast the blanks several at a time from scrap. Material cost on large wheels can add up quickly as round bar is typically a few bucks a pound. I think the large idlers were about 7 lbs each in material. We made four.

A method that I'd like to try would be to mold some from castable plastic resin in a silicone mold. Any teams casting them in plastic?

Re: Who makes their own wheels?
 

We made custom hubs for 10" Harbor Freight pneumatic wheels this year from stacked laser-cut plywood plates. Worked great and were much lighter than the original hubs. I can find a picture/ render if there's interest.

Also experimented with making CNC-routed wood wheels before the season.

Re: Who makes their own wheels?
 

The version 2 of the wheel is downright cool. What a great basic cnc project. I would think machining them from something like birch plywood would prove very sturdy.

If some draft was designed in (or profiled with a tapered end mill) the wooden wheel could then be used as a pattern for casting in resin or even aluminum.

Re: Who makes their own wheels?
 

I agree the wood wheels are downright cool.

Re: Who makes their own wheels?
 

In the years we have done West Coast drive with traction wheels we have used custom wheels. We have our sponsor machine them for us but we could make them ourselves if we so desired.

One thing you should look into is milling cutters where the shank is smaller than the cutting flutes, look up T-slot cutters. This might let you make it all in one go on your router if you are clever, it's how our sponsor machines them.

The most important feature you should look at how to machine is the cross slot for installing the tread on the wheel.

Re: Who makes their own wheels?
 

Great information RoboChair, I had not thought of T-Slots for this purpose.

Re: Who makes their own wheels?
 

Re: Who makes their own wheels?
 

We used to make custom wheels, but there are so many good options now I don't see why 99.9% of teams should. We likely won't ever again.


I was just thinking that's such a great quote.... Then clicked on the link and laughed.

Re: Who makes their own wheels?
 

So 2056 doesn't teach students or collaborate with other teachers in the offseason? I agree that making custom wheels during the build season is not an ideal expenditure of time.

However, I thought my job was to educate students. Which I do year round. If my students know how to design and make a wheel, they will understand how to select the best wheel for our application.

I guess we could go the route of copying what the best teams do, but I prefer my students to understand why we do things.

Re: Who makes their own wheels?
 

You can argue that the best of both worlds is to have your students design and make something that doesn't directly have more COTS options and is more analogous to the type of things they would design in season.

Also, it probabaly wasn't intentional but your tone seems to really dismiss system level design. Effective use of COTS parts is real engineering and exists in all industries. It's really an arbitrary line anyway, in terms of a robot scoring points is a wheel really all that different from a bolt? A connector? Etc...?

Re: Who makes their own wheels?
 

Re: Who makes their own wheels?
 

Since there are so many good COTS options for drivetrain wheels, another suggestion might be looking into making custom wheels out of a softer rubber to use as intake or shooter wheels.

I know 125 cast their own urethane wheels for their 2012 shooter, there should be some pics up on CD of that process.

Re: Who makes their own wheels?
 

https://www.chiefdelphi.com/forums/s...4&postcount=14
https://www.chiefdelphi.com/forums/s...75&postcount=8

Re: Who makes their own wheels?
 

I like the idea of making shooter wheels. Currently on the COTS market there isn't much to be said for wheels with a large moment of inertia but remain grippy. Sure, there are the McMaster options, but those tend to be rather expensive.
Maybe something made of aluminum with holes to put steel rods into? This would also let you try balancing the wheel.

Re: Who makes their own wheels?
 

While we're on the discussion (and since I have one hanging on my wall)-

195 made a custom shooter wheel for 2013.

The wheel was ~12" in diameter, weighed 4.5lbs and was direct driven by a CIM.

It started as a 14"x14" block of aluminum that was Wire EDM'd to have a spoke profile.

The block was then placed on a CNC mill and the 'wheel' was milled out using a .5" end mill. This left the 14"x14" block with a 13" hole cut out of it.

The rim of the wheel was then sandblasted to allow for the urethane to hold while at speed.

The outside of the block was used as the mold for the urethane cast. The wheel was replaced back inside the block and a .5" dowel pin was used to make sure the wheel was centered in the block. 60A durometer urethane was poured into the mold and was let to sit.

The overall process was a lot of work, but it worked well as a flywheel.

Mountain Dew can for scale.

Re: Who makes their own wheels?
 

In 2012 Skunkworks made a flywheel using a method similar to what you are proposing. We cut an aluminum hub that was .25" thick and of 6" diameter iirc. We added .25" steel rings with matching OD and 5.75" ID, sandwiching the aluminum hub. The assembly had considerable mass, but the mass was where we wanted it to maximize moment of inertia. We covered the wheel with a section of inner-tube from a motorcycle tire to give it a more desirable surface.

I would consider constructing a custom flywheel a worthwhile endeavor, but in my experience an accurate shooter has much more to do with proper control than superior mechanical design.

Re: Who makes their own wheels?
 

We 3D printed and then cast hubs for urethane tube to use as intake wheels in 2015.https://scontent-yyz1-1.xx.fbcdn.net...048631_o.j pg

Re: Who makes their own wheels?
 

Uploaded a video of another flywheel I build for a physics project with the method I outlined previously. Might help make sense of my garbled description.

https://youtu.be/XKjixa894uU

Re: Who makes their own wheels?
 

I don't think one aspect is more critical than the other. You need both, period. 469's shooter in 2012 was not the best mechanically (double axle, very low MOI, low compression), and as hard as we tried, no amount of code was going to make up for that.

Re: Who makes their own wheels?
 

I'll concede to that in general, perhaps I was being a bit shortsighted. I appreciate your response.

Re: Who makes their own wheels?
 

I didn't mean to dismiss anything. I will argue to my dying breath, that every part (bolt, cotter pin, wheel, rivet, screw, etc) is critical to a successful system. Just like a chain is only as strong as its weakest link, a system is only as good as its worst part. Selecting the best part for an application, only comes through luck or knowing what your doing.

Yes we are building robots right now, but my students have higher aspirations.

Re: Who makes their own wheels?
 

I think what people are objecting to is the idea floated in this thread that buying a wheel is inherently a decision that is against the interest of teaching students. There are educational things about buying subsystems, and most of the skills and principles taught in designing and machining a drive wheel could be taught with designing and machining a manipulator part, for example. To each their own and all that.

Re: Who makes their own wheels?
 

+1 There is no need to reinvent the wheel (insert groan). There are plenty of other parts that do not have such a strong COTS variety that are both educational and productive to make.

Re: Who makes their own wheels?
 

We were having a normal discussion about a simple offseason project, when the trolls show up with "WW2056D" and then we get told that for 99.99% of teams it is a waste of time.

Constructive criticism is one thing, but dang.

I have been on investigations into a number of mishaps, many times we found the reason for a multi-million dollar loss of aircraft and/or life came back to a faulty "trivial" part of the system or the improper installation of a "trivial" part.

Many times the "trivial" part failed because someone substituted an inferior part for the one that was called for. Which is why everyone working on a system has to understand at the very least the specifications for the correct part.

Yes it can be taught many ways, this is one way I selected.

Re: Who makes their own wheels?
 

You guys are also missing my point about collaborating with academic teachers.

Getting normal teachers to step outside of their comfort zones is not easy, getting a physics teacher involved with wheel design isn't that far out of his normal classroom teachings.

Re: Who makes their own wheels?
 

They're looking at the problem from a different paradigm than you are. Many mentors on this forum are trying to find the perfect intersection of teaching students, inspiring the team, and maximizing competitive success. You're clearly more interested in the specific lessons that can be taught about locomotion from wheel design in addition to manufacturing, etc. So while their advice isn't really relevant to you, it's useful for other people to learn why teams that prioritize optimization of resources / competitiveness don't machine wheels in the regular season. You've got plenty of valid reasons to do what you're doing; rock on.


And I don't think people are objecting to that, really, they're objecting to when you asserted that everyone who doesn't make that decision is opting not to teach their students!

Re: Who makes their own wheels?
 

Chris, I was asking clarifying questions to the troll post of

See my post below

I know that 2056 and all of the top teams teach their students the how and why, they have too. You can't pick the right COTS part without understanding how it works.

The implication I took from the troll post was "don't worry about design and copy what 2056 does."

Re: Who makes their own wheels?
 

Well, if I = (1/2)mr^2 for a cylinder, just attach some weights to a banebots wheel. :p

Re: Who makes their own wheels?
 

How is that a troll post? The poster is simply referencing another thread on pretty much the exact same topic.

Re: Who makes their own wheels?
 

At 696, we made custom wheels for years. When we easily bent our 2005 wheels (1st link) on multiple occasions, which really surprised me since the spokes were 1/4" thick. That inspired me to design a better wheel. That instance is what first caused me to learn how to do stress analysis and FEA, and in 2007, I assisted students with the design of a very lightweight (4 oz) 5 inch diameter CNC machined aluminum wheel (2nd link), that was incredibly strong. They had a design already, but with just a couple tweaks and a couple runs through FEA, as a mentor I was able to help them see the potential failure points, make the wheel at least twice as strong, and reduce the weight. This was real engineering, and not that picking parts out of a catalog isn't, but it's a different type of engineering. In 2014, we did some 4" wheels that really had some nice style to them, in addition to being lightweight. We've also done custom wheels in other years, like our 10" dish wheels in 2010, and 3.5" machined wheels in 2013, and custom hubs for mountain board wheels in 2016.

To me, a lot of the real "let's sit down and design and analyze and calculate this" type of engineering by and large has been on the decline in FIRST Robotics, and the "Let's open the catalog and find something that works" or "let's watch what other people do and do that too" is heavily on the rise. I don't want derail this thread this into a COTS vs custom debate, but while we have made our wheels in the past, I don't know if we always would in the future, and I kind of miss it. You see even teams like 254 using Colson wheels

For students, there is really something magical about designing and making your own wheel, and it's a lot of fun. But today, the competition is really more about time. The less time you spend designing and making things you can buy, the more time you can spend on the other things. And in some sense, I kind of hate that. I have a lab full of CNC machines, and we can manufacture anything. We bought VEX ball-shifters for our 2016 robot, and I have a stock of VersaFrame gussets and Versaplanetaries for our 2017 robot. Why? While we can manufacture literally just about anything a FIRST robot would ever need in our lab, we can't manufacture time. By buying COTS parts, we are buying time, and while I do like that, at the same time I don't.

Anyhow, back to the wheels.

In 2009, there was a team 13something (1388?) from an area near San Luis Obispo, CA that had a great 13lb flywheel gyro mechanism that allowed their robot to "lurch" forward when they tilted it, to push their opponents and pull the trailer. It was a great way to get more "thrust" in a game where you couldn't just add more traction, and it worked pretty well actually.

Re: Who makes their own wheels?
 

A link to a post with a link to a stupid video is a troll post.

Re: Who makes their own wheels?
 

How is a post a troll post if it links to a discussion on the same topic, including testimonies from Adam and Tyler, who not only are some of the most Respected mentors I know, but also some of the smartest.

If ANYTHING, it adds to the discussion by bringing relevant info from another thread.

And to be really honest, he linked you to a thread that you COULD have found if you searched.

Seriously?

There is a reason Mike Corsetto says "Steal from the best, invent the rest" in every post asking why 1678 is so good.

No one is trying to tell you to copy 2056. But, from experience and the obvious testimony in this thread, designing a custom wheel IS NOT the best use of time, resources, or knowledge. You'll find much better use of time and I think students would find a better experience designing a different custom mechanism, like maybe an elevator, a more complicated drive train(that uses COTS, most drives SHOULD), or something that is a bit more complicated than something I can make in about 3 clicks in CAD.

Re: Who makes their own wheels?
 

Because it doesn't agree with his point.

Re: Who makes their own wheels?
 

Wow, cell phone cameras have improved dramatically since 2012...

-Brando

Re: Who makes their own wheels?
 

Exactly, we do just that by copying designs other teams have used for custom wheels modifying as needed and making them for our robots. We also have an internal saying that we should only "build what we know" where we only build stuff we have built before and know the fine details of or are sufficiently confident we can pull off. We make that list longer in the off season by doing projects EXACTLY like this. We would have had pretty crappy bots if we hadn't first learned ourselves how to build an elevator off season 2014 and an articulated arm in off season 2015. A drivetrain is the SOUL of your robot, and a badly implemented drivetrain is the single quickest way to to have a shorter competition season.

"I have never built a WCD before and don't feel comfortable switching to this different type of design, so we are building one this off season so we don't make stupid mistakes this coming build season."

We used custom traction wheels in 2013 and 2014 because it mattered. In 2015 there was near zero reason for that level of traction so we ran colson. In 2016 we ran pneumatic and colson because we knew that the custom wheels would not provide the durability needed to survive the game. All those decisions were based off of prior experience, personal or leveraged from the community.

Re: Who makes their own wheels?
 

Ignore the haters and just make your wheels. It's not a huge project in any case, and I'm not sure why people are getting so fired up over it.
A few google searches turned up some relevant threads:
https://www.chiefdelphi.com/forums/s...d.php?t=118873
https://www.chiefdelphi.com/forums/s...d.php?t=115976
https://www.chiefdelphi.com/forums/s...ad.php?t=77309
You might be better served conducting your search there.

As a side note, CD is getting awfully judgey lately. I'm not sure why people have to slam making custom wheels over and over again when they can just not post in the thread.
Maybe it's the offseason.

Re: Who makes their own wheels?
 

FTFY

Re: Who makes their own wheels?
 

Welcome to #summerCD

Re: Who makes their own wheels?
 

No one is fired up over someone making custom wheels in the offseason. What sparked discussion was quotes like these.

Re: Who makes their own wheels?
 

Since I got quoted on here, figured it would be about time to chime in :p

Devin stated a lot of our teams development over the past 4 years. Just as a heads up, the kids are designing a pneumatic catapult on a turret this off-season, pretty much just because we've never done one before. We'll train new kids and add two more mechanisms to our team knowledge base. Its a valuable process that I encourage other teams to try out (we stole the idea from 971 and 973)

"Steal from the best, invent the rest" is something I've been saying for a long time. I probably stole the quote from someone/somewhere, but its been so long I can't remember :p

Would it irk people in this thread to know I will sometimes encourage our students to copy designs even if they don't understand everything about the design they mimic?

Our students are some of the brightest kids I've met. I can say with 100% confidence they are 10x the engineer I was when I was a student in FRC. Their communication and technical skills amaze me every year.

If my students don't understand a few things, I won't lose sleep over it. Inspiration is why I'm here.

Regardless, good on you Clint, please share your results! We have some wheel CAD from 2014 on our site (I think!) if you're interested.

-Mike

BTW, funny story. We tried 3D printing some 4" wheels on our makerbot during the first week of build season 2014. Never again! We had Aluminum custom wheels back from our machine shop sponsor by week 3 that year... :) Live and learn!

Re: Who makes their own wheels?
 

841 has done the custom wheels R&D project, and the students involved at the time got some really solid benefits out of it. We still have the Google Doc that all the research was compiled into, and have used the polyurethane learning for other mechanisms since then.

A couple years down the line now, we've decided the last two seasons that Colsons make more sense on the actual robot, as they offer better durability and more predictable performance than the polyurethane tread we had on the custom wheels.

We've recently upgraded our machining capabilities (our first CNC equipment!!) and I'm thinking it might be a good year to suggest the students take another run at the wheel problem in the offseason. It's a nice simple piece that we can make "as complex as we want to" to try out the new machining abilities.

Re: Who makes their own wheels?
 

The first is a question meant to refute the WW2056D statement, as I know they must R&D in the offseason.

The other is a statement that instead of blindly copying something, I prefer my students to understand why we do things?

How is either inflammatory?

Re: Who makes their own wheels?
 

After looking at the negative comments on my Rep, someone thinks I "dissed" Adam Heard. In no way shape or form was that my intent at all. I have PM'd him my apology for any perceived "diss".

The post that was referenced was not in anyway directed to anyone other that the one quoted in it.

Re: Who makes their own wheels?
 

I enjoy that the least inflammatory post I've made recently has sparked the biggest fire. Never change CD ❤️❤️❤️ xoxo

Re: Who makes their own wheels?
 

What a precious attitude, bless your heart.

Re: Who makes their own wheels?
 

I highly suggest returning to the topic at hand before making yourself look worse.

Re: Who makes their own wheels?
 

I forgot... what are we talking about again?

Re: Who makes their own wheels?
 

I think wheels.

Take a look at teams 2013's shooter wheels. They were really heavy and provided a lot of shooting power.

Re: Who makes their own wheels?
 

At the beginning of the season, my team considered a half-track drivetrain that used a thick rubber-backed timing belt as the tread for the track portion. We printed off an early version of the wheel/pulley out of Ultem 9085 that interfaced with the KOP AndyMark sprockets. Just for testing, we threw it on a CIM and direct drove it to see how it was balanced and how it handled at high speeds, then we put it on a dead axle and hung 100 pounds from the pulley to see how it held. It looked good from those tests, but we soon decided we didn't want to print our wheels, especially since the teeth of the wheel would be taking a lot of shock loading when we went over defenses.

I would echo what several people have already mentioned and voice my own interest in making custom shooter wheels. The urethane casting sounds like a really amazing thing to do, because it seems practical and very educational. Also, for the purposes of involving other teachers, I think you have more opportunities to delve into multiple subjects more easily with some type of shooter wheel than just a drive wheel.

Re: Who makes their own wheels?
 

I'm going to chime in here because I've watched this blow up without any explanation on why we are building wheels other than the intent to teach students the process of manufacturing.

This year we bought some wheels. (I won't say what wheels, they were plastic.) We used them during build season and they failed.

We are building our first WCD this offseason and are trying to keep it as cheap as possible. We found that aluminum wheels are very expensive, so we found that it would be cheaper to just buy aluminum blocks and make them ourselves (about a 50% savings).

Thank you to everyone who gave advice about making wheels. After a very successful year we are trying to venture out and try some new things. We've made the same drivetrain for over 10 years. It has worked well for us, but we see the advantages of WCD. Expect to see more posts from Clint asking questions about certain things, we need the help.

P.S. Part of our inspiration for doing this project was the released materials this offseason. We specifically looked at the CAD of 254 and 1678 on how to make a WCD. :)

Re: Who makes their own wheels?
 

I'm going to assume the wheels you bought weren't pneumatic wheels. Keep in mind that if that is the case and you replace them with aluminum non pneumatic wheels it wouldn't be surprising to see similar failures if used to play the 2016 game, given the impact forces robots see while crossing defenses.

Re: Who makes their own wheels?
 

They were pneumatic. There was a thread about it. I didn't mention the brand/model because I didn't want to bring up the whole discussion again since it was a little controversial.

Re: Who makes their own wheels?
 

In 2013 we ran an 8WD with custom aluminum wheels with blue nitrile wrapped around. The wheels were also hubless and had a tube shaft as part of the wheel. This allowed larger bearings to be run directly on the wheel.

Here's a link to an album with some pictures from it.

Imgur Album

Re: Who makes their own wheels?
 

There are many factors that contribute to wheel hub failure. I wouldn't write off all plastic wheels because you had failures with the AM Pneumatic wheel hubs.

The great thing about a WCD is that it's so easy to swap wheels. You mentioned in the last thread that you drove the pants off the wheels until they failed (which is an absolutely great way to test things). If you have the budget and the time, I'd finish your custom wheel + WCD project and grab a bunch of the various common FRC wheels (Colsons, AM Hi-Grips, VEX Traction, your custom wheels will probably end up being similar enough to AM Performance wheels) and drive the pants off of all of them.

Re: Who makes their own wheels?
 

Did you use loctite?

Re: Who makes their own wheels?
 

We applied the Loctite after the hubs had failed. That was the controversial issue in that thread.

Re: Who makes their own wheels?
 

Those are some baller wheels. What was the run time on those and what machine did you guys use?

Re: Who makes their own wheels?
 

The answer to "what was the run time" was too much. They definitely took some time. Sorry I don't have an exact answer, I want to say we got them week 3 but I'm just about guessing it was so long ago.

We actually outsourced the wheels; with all the other parts we had to machine in house we made the decision to ask a sponsor to help out with getting them made. From what I remember they were made with a CNC, not sure how many axis. Kevin might be able to answer that better here.

Re: Who makes their own wheels?
 

What is this device called, We need one.

http://imgur.com/a/trWYm

Re: Who makes their own wheels?
 

Those are some absolutely beautiful wheels. How did you attach the sprockets to the wheel "shafts"? I'm assuming the two little holes at the end of the wheel "shaft" had something to do with it. Also, why were some of the sprockets hex shaft fit and some round(in pic #2)?

Re: Who makes their own wheels?
 

The sprockets were pinned to the wheel shaft. The wheels with the sprockets that have hex were the ones driven by the gearboxes. This allowed the output shaft of the gearbox to slide right into the sprocket to drive it.

Re: Who makes their own wheels?
 

Here is our latest custom wheel:



Some details:
1) It's about an inch and a half in diameter.
2) It features nine spokes - they're thin but since there are nine of them it should work out.
3) We have a custom bore in the middle to maximize torque transfer without too much shock load on the shaft.
4) There is slightly more material on one end so that the moment of mass is slightly off center, resulting in easier obstacle traversal.
5) It is manufactured through a natural extrusion method our team has worked with the farmers in the local area to develop.
6) It is comprised of a strong organic compound that we believe no team has used before and can give us an advantage on the field.



....or that's a lemon from dinner tonight. I forget which. ;)

Re: Who makes their own wheels?
 

It looks like a Harig Uni-Dex. http://www.harigmfg.com/unidex.html

Or a Harig GRIND-ALL No. 1. http://www.harigmfg.com/grindall1g.html

In grinding these are commonly called whirligigs. Unless your grinding I doubt you can justify the cost of a Harig... even used.

You might try a less expensive spin indexer that can be had for ~$50 bucks.
http://www.grizzly.com/products/5-C-...campaign=zPage

Re: Who makes their own wheels?
 

We made wheels during the 2016 season for our shooter. We needed flywheels and we found some in our many years worth of old stuff and were going to use them but realized that a) the shaft hole and the outside of the wheel weren't concentric (Enough that you could clearly tell when they were spinning in a lathe) and b) that they were custom wheels from an old season (2007... I think...) and so were unusable because of the rule about non-COTS parts manufactured outside the season. So we designed our flywheels and machined them ourselves. That was a sight to see! These were 4" OD wheels with material cut out to the 3/4" (I think...) support for the shaft and into the wheel roughly 1" to the center. The best part... THEY WERE MADE OF STEEL! I need to find a picture of them because the are the greatest thing I have seen come out of our shop without the help of a CNC machine.