Front Vent Surrounds Surround

It’s funny, I’ve been working on the new astromech.net website and DroidWiki all week and today used it myself for the first time to look something up.

Sadly I came up blank, but I don’t think it’s the fault of the wiki, but our part naming standards. I don’t think the blue surround that goes around the front vent surrounds has an official name. It’s kinda weird calling it the surrounds surround, but that’s what it is 🙂

My droids skins are removable, and the vents are attached to the inner-frame somewhat permanently. Getting the skins on and off with the blue surround permanently attached to the skins would be tricky, so I decided to kept the blue piece separate and use some magnets to hold it in place. I’m sure I saw the idea on someone else’s website, so I can’t take credit for it.

I carefully marked the optimum spot and glued the magnets on with epoxy

Using some tin snips I put some thin steel and made little tabs that would attached to the skins and allow the magnets to hold on

I attached them to the skins using CA glue

Here you can see the tabs just poking around the vent

And the blue surround in place

It’s not a perfect solution, and I’m a little worried it may pull off to easy. The tabs are also made from pretty thin steel, so the magnets don’t have a lot to attract to. At some point I’ll probably go back and add some thicker steel behind each to help the magnets grip better.

I could trim the surround a little and glue it permanently to the skins, but getting the skins on is hard enough and I’m not sure I want to take too remove that much material and like the tight fit.

Posted by Chris on April 5th, 2008 in Body | 5 Comments

Tags: , , , ,

Rear Door Magnets

Now that WonderCon is over I’m hoping to go back and post details on the final few steps of my build – I’m probably going to post some things out of order, so you may see some things in the photos that I’ve not covered yet.

First up is the the rear panel/back door. I’d deliberated this for a while and tests a few different methods before finally settling on using the rare earth magnets.

I’d bought a bunch of different sizes, with the intent of using them on various spots on the droid.

One of my fears was the smaller magnets wouldn’t hold, and if I’d went with the larger magnets they’d get in the way of my movable electronics panel, or the door would be impossible to remove.

Frank Cerney had posted a few months ago about using 1/2 inch cylindrical magnets (NSN0818) from Magcraft successfully to hold the door on a wooden frame, so I decided to do something similar. Here’s Frank’s original implementation –

Frank Cerney Door Magnets

I don’t have the luxury of being able to drill holes in a wooden frame, so I needed to come up with something to hold the magnets to the skin. On hindsight maybe I should have gone with square or block magnets instead, but I was stuck with what I had on hand.

After a few experiments I ended up cutting some aluminum U channel into 1 inch chunks and bent them to clamp the magnets.

The gap is slightly narrower than the magnet, and I simply tapped the magnet in making sure they matched the opposite one.

I then took my CA glue and excellerant and glued them to the skins

I could have used epoxy, but I really wanted this to setup quick without worrying about clamps, movement etc. It seems to hold okay, but I still may still go back and re-enforce them with some epoxy at some point.

Here’s the skins/frame assembled showing the final location of the magnets

One of the issue of using the magnets to hold the door on from the sides is that the force pulls outward, instead of pulling or holding the door tight toward the frame/skin, like if I’d used screws to hold it in place.

You probably can’t tell from the photo, but this results in the door,which naturally curves a little tighter than frame, to bow out at the top.

To combat this I added a tab which will pull everything together and hopefully add a little more hold and reduce the strain on the magnets.

Again I used CA glue to hold it in place

I topped everything off by added some white tape to the inside line of the skins.

Remember I’d had a problem closing the gap at the bottom of the door once I’d cut it from the skins, so rather than fight with it – I simply masked the problem by covering the raw aluminum which blended the door into the skin. I have to thank my wife for this suggestion.

Due to the electronics panel having to swing out I had to either attach the rear power coupler to the door or make it removable from the frame. I opted for the latter as I didn’t want additional weight on the door.

I simply cut a chunk of metal (not aluminum) and secured it to the back of the power coupler. I then used a large magnet on a bracket on the frame to secure the power coupler and allow me to pull it off when needed

The good news is the door holds on great and I had zero problems with it at WonderCon – it even held on even when I did the R2 death spin 🙂

Posted by Chris on February 27th, 2008 in Body | No Comments

Tags: , ,

Magnetic Shoulder Hubs

I’ve worked on a bunch of things the last few days, the simplest is probably getting my shoulder hubs finally installed.

I borrowed another idea from Victor and used rare earth magnets fix the hubs in place.

I started off by marking and drilling the holes. The magnets I used are 3/8″ x 1/8″ thick from MagCraft. There’s two magnets per hub, and two matching magnets inside the leg.

I’ve been doing a lot of drilling the last few days, and I’ve been extra careful to secure everything before I drill – even when I’m pressed for time or tired of doing it. You can never be too careful.

I then checked the polarity/orientation of the magnets to make sure they’d not repel another magnet. Otherwise I’d be in trouble when they’re presented to the magnets in the legs. Sounds simple but I almost got it wrong at least twice.
I roughed up the back of the magnets and epoxy’d them into place

I took two more magnets and epoxy’d them inside the leg stacked on top of small nuts.

Here’s a short video demonstrating the new magnetized hubs

I’ll try and post some more updates on new things in the next day or so.

Posted by Chris on December 30th, 2007 in Legs | No Comments

Tags: , , , , , ,

Stacks of Magnets

I’d ordered a bunch of super strong ‘earth’ magnets last week and they arrived today. I’m hoping to use them in quite a few spots, hence the tall stacks.

The larger 3/4″ discs will be used to secure the battery boxes to the feet, the rods will be used on the removable back door, and the small 3/8″ discs in various spots, like securing the shoulder hubs to the legs for easy removal, and holding the front blue panel around the vents. I’m also going to experiment with using them to hold panels and doors closed, but they maybe too strong.


Posted by Chris on December 20th, 2007 in General | 3 Comments

Tags: , , , , , ,