pic: CV Robotics WCD 6wd Drivebase Prototype

Originally Posted by Dunngeon

To be honest, we weren't sure how the cantilevered shafts would affect the 2x1 bearing holes. Last year our shooter utilized 2x1 with bearings mounted directly into the 2x1. Over the season, the pressure caused the holes to ovalize. The forces aren't equivalent, but the construction is. I linked a picture of our shooter mechanism (JVN Cam).

I wasn't aware you could add cams to this type of bearing block

Look at 2791's recent drivetrains. I'm sure Chris Picone can elaborate more on their processes, but they run a C-C WCD variant without blocks and haven't experienced any problems that I'm aware of.

And those cams were invented for that kind of bearing block.

[Thad House]

Originally Posted by Dunngeon

To be honest, we weren't sure how the cantilevered shafts would affect the 2x1 bearing holes. Last year our shooter utilized 2x1 with bearings mounted directly into the 2x1. Over the season, the pressure caused the holes to ovalize. The forces aren't equivalent, but the construction is. I linked a picture of our shooter mechanism (JVN Cam).

I wasn't aware you could add cams to this type of bearing block

Those blocks are designed to be put in slots and moved by cams. That's exactly how our drive worked last year. If you use the blocks, it doesn't hurt to slot them and make them slide.

EDIT. Andrew beat me to it.

[Dunngeon]

Originally Posted by Andrew Lawrence

Look at 2791's recent drivetrains. I'm sure Chris Picone can elaborate more on their processes, but they run a C-C WCD variant without blocks and haven't experienced any problems that I'm aware of.

And those cams were invented for that kind of bearing block.

This is why I love Chief Delphi, I feel stupid for missing that ... Thanks for pointing it out

[Oblarg]

Originally Posted by Dunngeon

This is why I love Chief Delphi, I feel stupid for missing that ... Thanks for pointing it out

I learned that a month ago, and had the exact same feeling.

[T-Dawg]

Are CIMs glossy or am I clinically insane...

[Merfoo]

Originally Posted by T-Dawg

Are CIMs glossy or am I clinically insane...

I'm pretty sure CIMs are not glossy...

[asid61]

Nice drivetrain! Very clean, looks good. A few questions, if you don't mind:
1. What is the weight with what is shown in the picture?
2. What size wheels are those? Are they custom or COTS? Tread?
3. What is the thickness of the 2x1 and the bellypan?
4. How are you planning on tensioning?
5. Are those gearboxes mounted directly to the 2x1 or via standoffs? If it's the latter, change it to the former.

A small recommendation: Make sure the gearboxes shown have the same mounting hole pattern as either the Vex or WCP gearboxes, just in case. Or both even.

Originally Posted by asid61

Nice drivetrain! Very clean, looks good. A few questions, if you don't mind:
1. What is the weight with what is shown in the picture?
2. What size wheels are those? Are they custom or COTS? Tread?
3. What is the thickness of the 2x1 and the bellypan?
4. How are you planning on tensioning?
5. Are those gearboxes mounted directly to the 2x1 or via standoffs? If it's the latter, change it to the former.

A small recommendation: Make sure the gearboxes shown have the same mounting hole pattern as either the Vex or WCP gearboxes, just in case. Or both even.

Read the thread. Half of your questions were answered within it.

[Dunngeon]

Originally Posted by asid61

Nice drivetrain! Very clean, looks good. A few questions, if you don't mind:
1. What is the weight with what is shown in the picture?
2. What size wheels are those? Are they custom or COTS? Tread?
3. What is the thickness of the 2x1 and the bellypan?
4. How are you planning on tensioning?
5. Are those gearboxes mounted directly to the 2x1 or via standoffs? If it's the latter, change it to the former.

A small recommendation: Make sure the gearboxes shown have the same mounting hole pattern as either the Vex or WCP gearboxes, just in case. Or both even.

1. Mass Properties says 40lbs (which is heavy)
2. 4in, custom, they will be 70a Polyurethane
3. 1/8th and 1/8th
4. In thread
5. The front plate mounts directly, it's already setup for Vexpro IIRC

[T-Dawg]

I just updated the mass properties, and it gave me approximately 40lbs. I'll edit this post if I find any mistakes in the settings.

[Aren_Hill]

Originally Posted by Adrian Clark

I cannot stress enough how important it is to test new fabrication methods before the season. In 2013 I tried to cut a bellypan out of .090 5052 Al on a plasmacam machine, a machine I had never used before. When I came to the shop and showed the staff what I was making they told me it wouldn't work, and they were right. As I was cutting out the profile the sheet began to warp, I had to give up shortly after I started because the sheet bent up and hit the torch. This is exactly what I was warned would happen.

I've had to cut a fairly large sign out on a plasmacam machine and ruined a nice piece of material due to this issue, I then tried again but leapfrogged around the piece doing various cutouts far away from others. This technique allowed enough time for the sheet to stay relatively cool and prevent warping, but it did take awhile longer.

Sometimes all it takes is the right technique.

(also CIMs are Gloss black paint, just not as glossy as that render, and the end caps are tumble finish)

-Aren

[Aren Siekmeier]

Originally Posted by Aren_Hill

I've had to cut a fairly large sign out on a plasmacam machine and ruined a nice piece of material due to this issue, I then tried again but leapfrogged around the piece doing various cutouts far away from others. This technique allowed enough time for the sheet to stay relatively cool and prevent warping, but it did take awhile longer.

Sometimes all it takes is the right technique.

(also CIMs are Gloss black paint, just not as glossy as that render, and the end caps are tumble finish)

-Aren

We ran into the same issue with the first rev of our 2013 bellypan and had a much better time after "leapfrogging" on the comp bot version as you described.

[MrBasse]

Originally Posted by compwiztobe

We ran into the same issue with the first rev of our 2013 bellypan and had a much better time after "leapfrogging" on the comp bot version as you described.

The Plasmacam software will cut the holes in the order they were created. So if you take the time in your pre cut operations to lay out your design with cutting in mind you can avoid this problem all together. I have cut many 4x4 sheets of thin steel and aluminum with no warping and my torch running full power at 45 amps. Speed is also important, if you are cutting that thin of a sheet the machine should be zipping along at a maximum speed of 380 IPM according to my book. If you aren't careful, moving that fast can be mildly terrifying.

[JesseK]

I really like this approach to bumpers and mounting. For a pre-season prototype the most significant advantage of it I see is the ability to change wheel size without re-designing things for ground clearance or field obstacles. This should allow for some fast Day 0 answers.

Personally I'd adjust only one thing about the bumper system, and that would be to add a "wall" (like half of a 3"x1.5" C-channel, probably only 1" length) at the very center of the front & rear rails in order to give the upper part of the bumper some support against hard collisions. As it stands, it seems like the bumper would flex a lot if hit in the middle by a team whose bumpers were not at the lowest possible point of the bumper zone.

[Sam_Mills]

Originally Posted by Adrian Clark

I cannot stress enough how important it is to test new fabrication methods before the season. In 2013 I tried to cut a bellypan out of .090 5052 Al on a plasmacam machine, a machine I had never used before. When I came to the shop and showed the staff what I was making they told me it wouldn't work, and they were right. As I was cutting out the profile the sheet began to warp, I had to give up shortly after I started because the sheet bent up and hit the torch. This is exactly what I was warned would happen.

Before you take the time preparing to go to your sponsor and make the test parts I recommend you talk to an operator first. They will know the machine and it's limits and can tell you if your parts can be made on their machine and even give you tips on how to design your parts to be easier to cut. The main things you need to convey to the operator is the materiel, its thickness, and the complexity (run time) of your parts. With that information they should be able to tell you if they can cut them without the sheet warping.

-Adrian

In 2013 we tried to use our plasmacam for the exact same operation and had the exact same issue. Luckily it was in house, so we were only wasting our own time and resources, but we quickly learned a plasma cutter is not a precise machine, even if the software and rigging is.

Warning you now, do not try to do bearing holes or gearboxes with the plasma cutter. You could do a solid 1/16 Al bellypan, if you just use it to make ziptie holes for your electronics. Think of the plasma cutter to be just more precise than a bandsaw, that can also do pockets. If you have access to a manual mill, that should get you most of what you need for a WCD.