In today's tutorial we'll be going through some steps and things to consider when mounting a R5 dome from Sith Planet.
The first batch of these domes required alot of router work on the lower ring. I worked with them to develop a lower ring that needed less work to mount to the Rockler bearing that nearly all of us use in our Astromech droids.
1. First of all you'll need a dremel, a router bit, not a drill bit, and this accessory attachment. This allows you to go around in circles and slowing remove the resin material a bit at a time. Be for warned this is going to make one hell of a mess so put on some work clothes and be ready to get dirty.
There are different types of router bits. Notice the bottom of this bit is flat. Use a flat ended bit, not a pointed bit for this type of work.
Remember we are routing the inside material out not the outside. So you'll want your router bit to go slowly around. When you begin just do this in small 1 or 2 inch sections and go slow, you can easily cut thru the entire dome ring if you're not careful. The idea is to slow move that knob and remove a small layer at a time going around in a circle. When I do my friends dome we'll probably shoot gopro video showing the process.
Before you begin remember to do a 'sanity check'. Move your bit to the outside and make sure its not sticking down so far that you'll go thru your lower dome ring. Just do baby steps and you'll be okay. Remember to wear safety googles and don't get hurt.
I removed material until I got the wall thickness to the measurement you see above.
2. Lets talk about the dome plate. I made my own custom dome plate that sits on top of the Rockler bearing. I ordered from onlinemetals.com Aluminum Sheet 6061 O Bare 0.063" - 24" x 24"
You don't have to use aluminum you can use plastic or plexiglass. What I did was tape 4 holes and insert 10-24 bolts with the heads cut off. They are about 2 inches long. The 4 bolts are seen above in the photo sticking out of the top plate. The top plate is fasten to the Rockler ring by 6 bolts coming up from the Rockler that are also 10-24. The top plate is taped by myself and then I cut off the bolts so they are flush with the ring.
Here is an image of this ring flipped over to see the bottom. Note the bolts are not sticking thru the ring. The reason for is is remember you'll probably have a pit man motor system that spins the inner rings and those bolts can't stick down in be in the way.
Here is a close up, you can see this bolt is very close and all of them go right up side next to the wall of the Rockler ring.
So with the 4 bolts, put on some nuts that will help stabilize them as they are just barely holding on to the think top plate. You don't want that top plate too thick, 1/4 would have plenty of aluminum for these to tap into but that won't make this too thick and likely won't fit inside the lower dome ring. You'll have to remove even more resin with your dremel. After you get this system to work you can later use locktite or some glue to keep these in place after you have this dialed in the way you like it.
Another look at the top plate this is now ready to fasten to the dome.
Doing a test fit my Rockler ring sits in pretty flush where you want to have this. Since I had the thin top plate in. I needed to go remove a bit more resin from the bottom. I did this by doing about 5 passes with the dremel. After some practice you'll probably get pretty good at this and learn an new skill if you never done this before you'll find this not hard, just messy.
Another tool I found very handy for this job is a mouse sander. I usually don't buy Black and Decker but this little tools has served me well. I use 100 grit and it goes around the lower ring area and chews up the resin and makes it smooth. You may or may not need this tool but its helpful for all kinds of droid building.
3. Do a test fit, make sure you have this where your ring will spin around and center this the best you can. You might need tooth picks or small shims to help you center if. If you get this wrong your dome might rotate a bit wobbly, if it does just go back to step 6 and do it over.
4. Now duct tape the ring to the dome so it don't move while you'll begin the process of gluing on some parts soon.
5. Go to Ace Hardware and buy 4 of these nylons spacers they are going to be used to slide over the 10-24 bolts on the top plate. These are 1/2 OD, .257 ID and cost .40 cents each. You'll want to counter sink 1 side of them. The reason for this is to make a funnel that is a helper guide this makes it easy for the 4 bolts on the top plate to find the inside of these nylon spacers.
Here is a look at the dome, its upside down sitting on a 5 gallon bucket. You can see the 10-24 bolt sticking down. Notice this bolt is not tight against the wall of the dome. You don't want it tight, nor to you want it too far away from the dome wall. You want it just right because the nylon spacers will be glued to the dome wall. You should test fit the nylon spacers inside before you glue them on.
6. Whip up a small batch of JB Weld. Smear some JB weld on 1 side that you'll carefully stick to the side wall of your R5 dome. Remember to keep the countersunk side up that will help your bolt find its way inside of this spacer.
7. Have some thin strips of duct tape handy, then carefully slide the nylon spacer into place with the JB weld material hitting the inner dome wall. The nylon will start to slide down so hold it in place with the duct tape strips. Expect some JB weld to slide down as seen. REMEMBER. DO NOT JB Well the nylon spacer to the bolt. If you do that's okay as you can probably just use a vice grips and remove this and do it over again. But stuff happens.
Here is another photo of the process. At this point it's time to take a break. Stop and put this project aside for 24 hours to let the JB weld cure.
After 24 hours remove the duct tape take off your Rockler ring and it should look like this. You know have 4 spacers glued inside your inner dome so they can slide over the 4 bolts on the top plate of your Rockler. You're almost done! You'll have a dome that mounts to your droid without drilling thru anything.
Optional, since the JB weld is so thin I whipped up a small batch of bondo and used my finger to put some on both sides of the nylon spacers to bond them better to the inside of the R5 dome. Won't hurt any to make this stronger.
Things to consider. We are looking at a close up photo of my dome drive that is a Pittman motor mounted to my body. The custom top plate is seen just MM above it. What I found out when I made this is the top plate is so low it was hitting against the shaft of the Pitman.
Solution? I unmounted the Pittman and put the shaft against my 6 inch disc sander and grinded down the shaft to what you see in the photo. I even grinded down the 4 allen bolts too. Look at close the clearance is? The dome plate just barely with a hairs distance clears the top of the Pittman. You'll probably also have to do this if you use a Pittman system or any other system.
Done!
My dome is a bit low. I can raise it up by simply adding more nuts to the 4 bolts on the top plate. After I've taken this on and off about 10 times. I'll probably use loctite on the 4 bolts when I get them just at the proper place I want them. This same top plate and 4 bolts also mount my Sith Planet R4 dome using pretty much the same system.
If you have questions feel free to email me at redmech928@gmail.com
