Monday, October 14, 2019

Installed Bearings, Motor Test for New Right Drivetrain

Tonight I was able to get a little further in my effort to replace the drivetrain bodies for droid #1 so that I can use bearings instead of flanges to house the axels. Tonight's work was on the new right drivetrain body.

After getting R2 back together late last week, I had to explode things again.

I had paused on installing the bearings into the new drivetrain bodies because I wanted to ensure that the wheel would fit. It does, with just a little room to spare.

Confident now that there'd be room for everything, I placed some wood on the inside of the drivetrain body to avoid deforming it, as I used a mallet to tap on a piece of wood on top of the bearings to fit them into place.

Once I had the first pair in, I tried to fit an axel through, to make sure things lined up properly, and they did.

Then I fitted the wheel in as well. I also added a thin washer to the mix, as there was just a slight amount of play in there.

Next, I transferred the drive wheel gear and the motor mount from the old drive train to the new one.

And finally, the motor, as I prepared to test everything. I also used the old chain and the 1/32" steel shim between the motor and the motor mount. The fit seemed pretty much perfect!

I ran the motor both with the drivetrain upside down and rightside up, and it ran fine. The slight noise is the washer rubbing the inside of the bearing. It sounds worse than it does in person, and I don't think it's anything to be concerned about long-term.

I also took care of a couple nagging issues. Ever since I first installed this motor, one of the holes that receives a mounting bolt had its threads slightly stripped. I decided thoroughly clean the hole with acetone (along with its corresponding bolt) and line the threads with JB Weld.

I also applied JB to the the threads of the bolt, and screwed it into the hole as far as it would go, to let it dry overnight.

Finally, one of the new bearings isn't sitting very tightly, so I cleaned the hole with acetone as well, and applied JB Weld along the circumference of the hole in the drivetrain.

Then I pressed in the bearing, and I'll let it set overnight. Hopefully it's in there to stay now.

Still lots more to do, like the other wheel, the rest of the gears, and drilling the hole for the idler gear. Oh, and the left drivetrain.

Sunday, October 13, 2019

LA Comicon 2019

Today was the only day R2 and I attended LA Comicon, at the Los Angeles Convention Center. The main reason why I didn't go on Friday and Saturday is that for the first time ever, we weren't provided a booth on the show floor. Instead, they located the droid builders in a gaming room far from the show floor, far enough that I could tell it would get no visitors and there was no point in going. Instead, I went today because our R2 Builders panel was scheduled for noon.

Here's the room a little before show opening.

Since we had exhibitor badges, Michael McMaster and Mike and Amy Senna and I decided to do a quick walk-through of the show floor.

I should have yelled down to the people waiting to get in where they could find the droids.

This is the room the droids were in after the show opened. Pretty much the same thing as the before-picture; just us and a few other poor souls manning fan club booths.

David Annetta designed and 3D-printed this little figurine of Chris Romines, and Ed Perello painted it in minute detail, down to an accurate portrayal of Chris' tattoos. They had planned on presenting it to Chris at R2LA, but Chris wasn't able to make it, so Ed gave it to him today.

This was one of two visitors I saw at our booth.

Finally noon rolled around, so we went upstairs to do our panel. It too was lightly attended, because it too was way off the beaten path.

On our way out, I saw this neat Darth Vader TIE fighter for a man's daughter with Down Syndrome. It was very impressive.

And there was this as well (it was actually driving around under remote control and playing music).

Hopefully LA Comicon will have a better booth situation next year, we'll see.

Saturday, October 12, 2019

Started (and Stopped) Installing Bearings

Tonight I planned to install the bearings in the new drivetrain bodies, but as we'll see, I didn't get far.

I fitted some scrap wood into the drivetrain body, because I planned to use a mallet to hammer on another piece of scrap wood on top of the bearing to tap it into place. The wood in the drivetrain body helps to ensure that I don't crush it.

A few minutes of light (and not so light) tapping, and the first bearing is in place.

When I inspected the result, I saw that the bearing protruded a little less than 1/8" into the drivetrain body (the drivetrain body is 3/8" thick).

I decided to stop at this point, because I want to make sure that the wheel will fit into the drivetrain body when all the bearings are installed. Since I have an event coming up tomorrow, I certainly don't want to start pulling wheels off the droid right now, so this will have to wait a little longer.

Sunday, October 06, 2019

Drilled Holes for Motor Mount and Channel on New Right Drivetrain Body

Tonight was pretty much an exact replay of the work I did last night, which can be found here, so I won't go into quite as much detail.

The first step is to remove the motor mount bracket from the old drivetrain body.

Next, I measured and marked centerpoints, to translate the motor mount location to the new drivetrain body.

Once I had determined where to mount the bracket on the new drivetrain body, I clamped it down tight and got to drilling.

With holes for the motor mount bracket done, it was time to work on the center channel piece. I measured, marked, clamped, punched and drilled. Unlike last night's effort, this time I didn't use the bracket as a template when I did the actual drilling, as the punch left a sufficient location on where to drill.

Everything looks nice and centered.

And now the new right drivetrain body has its motor mount and channel holes drilled.

Next I'll work on installing the bearings.

Saturday, October 05, 2019

Drilled Holes for Motor Mount and Channel on New Left Drivetrain Body

It's happening in slow motion, but I'm working on getting the new drivetrain bodies ready for action. Recall that what makes these drivetrain bodies different is that they will have bearings within which the axels will spin, rather than stationary flanges. This will help with the problem of the axel slowly milling material from the flanges, described in this post. The cutting and drilling of the new drivetrain body is described in this post.

Step one is to take apart the left drivetrain, seen here with the new left drivetrain body, which has holes drilled in it for the bearings.

I removed the motor mount, and found something I didn't even recall, a thin 1/32" shim layer underneath the motor mount, that helps align the gear on the motor with the gear on the axel, so the chain will be straight.

Next, I used my handy ruler with a center finder to mark the center of the top edge of the drivetrain.

After that, I placed the motor mount back onto the drivetrain, so that I could make a centerpoint alignment mark on it. I also measured how far from the top of the drivetrain body that the top of the motor mount bracket resided (about 3mm).

I then used the ruler to locate and mark the center of the top edge of the new drivetrain body.

Next I measured how far from the top to locate the motor mount on the new drivetrain body, and align the motor mount to its centerpoint.

All this alignment is to ensure that the motor fits inside the battery box of the droid, and to hopefully be able to recycle the same chain by keeping the distance of the motor and the drive gear the same distance. This second goal is quite touchy, even a millimeter or so difference may lead to the need to either build new chain, or change how the motor needs to be shimmed from the motor mount.

I clamped everything super tight and started drilling the four holes, using the motor mount itself as a template. After each hole was drilled, I dropped bolt into it. I think the clamp was holding everything so tightly, the motor mount wasn't going to wander, but this adds a degree of confidence that all the holes will line up.

Once the holes for the motor mount were drilled, it was time to turn my attention to the top channel piece. It is held onto the old drivetrain body by a couple of short 1/4" diameter bolts and nuts.

I measured and mark center points on the new drivetrain body, to ensure that the channel would be centered on it.

I removed the channel piece from the old drivetrain body and centered it on the new one, and used my trusty punch to indent the point at which to drill the first hole.

As with the motor mount, I tightly clamped down the channel piece to the new drivetrain body, and drilled.

I repeated the process for the other hole, and temporarily fitted the motor mount and channel piece on the new drivetrain body.

Still lots of work to do. First up, replaying the whole process on the right drivetrain, and then I'll need to press-fit the bearings and start checking if the existing chain from the motor to the drive gear will fit (I'm expecting it probably won't). I should be able to use the chain on the other side of the drivetrain body if I don't mess up, since there is an idler gear that takes up slack on the chain, and it can be placed anywhere it's needed. (That will be clearer when I get to that step.)