This short and easy 'ible will show you how to make a tripod spreader. All that's really needed is a saw, but having a drill makes the process much easier. If you have no idea what a tripod spreader is, no worries, see the next step.
Step 1: What Is a Tripod Spreader?
Well a tripod spreader is used to press up against tripod legs to lock the tripod legs in place and stabilize the tripod. For astronomy observing, the use of a good spreader helps stabilize the set-up. The original cast tripod spreader only had a single 2" hole. I usually use four 2" eyepieces during an observing session, so I had to do something. Why I have a scroll saw at home, so I might as well make one.
Why might you need one?
Maybe your telescope doesn't have or you lost tripod spreader. It sure does make a difference in stability.
Perhaps the one you have doesn't have eyepiece holes or maybe not enough.
Well for whatever reason, this is a simple and cheap project.
Step 2: Wood?
I chose to use some spare popular wood I had at home, but after making it I wish I chose something more dark and ornate like walnut or maple. The most important part is to choose wood that is at least 0.5" thick. Anything thinner is at the risk of cracking or warping when you tighten the lock knob on the spreader. If you choose to make a spreader that doesn't need to exert force on a tripod, then something thinner would work fine. You could also use other materials like plastic, acrylic, aluminum, you name it.
Step 3: Design: Part 1
It really helps having an original tripod spreader here, but if not it's no big deal. I'll walk you through every step.
The first step is a figure out how big you want your spreader. Do you plan on using many eyepieces or just a few? Is your tripod wide or skinny? Will it be in the way of your feet when observing? My criteria was it should be able to fit in a 12x12" case I use for my mount and hold as many eyepiece as possible.
Step 4: Design: Part 2
After figuring out how large you want your spreader to be, find/choose the material you want to use. Make sure it's large enough.
What shape do you want your spreader to be? Mainly there are two shaped used due to their structural rigidity: a circle or a triangle.
I chose to go with a circle since it will allow me to fit more eyepieces in there.
Triangles can fit fewer eyepiece, but they would be more streamlined. By curving the edges inwards a little, you'd be able to fold up the tripod with the spreader still on there.
I made 3 rough designs in Paint (you can already see that I'm not much of a graphical designer). In the picture above the red dots represent the tripod legs. On the left is how the spreader will look when locked into the tripod. On the right shows how the spreader is stowed away. The 1st one requires the tripod spreader to be removed (this is the design I chose). The last two allow the tripod to fold up with the spreader still on it. The important thing for all 3 designs is to make 3 small notches (see comment in 2nd picture of the next step) in the shape in which the tripod feet can lock into so that the spreader doesn't rotate.
Step 5: Design: Part 3
The final part is the eyepiece layout. I found out that the best thing to do is to cut out a bunch of circles in the 1.25" and 2" format (unless you don't use 2" eyepieces) and lay them out on the spreader to see what works best for you. Make sure to leave a good amount of space between each eyepiece hole so that eyepiece with particularly large bodies don't bump into each other. If you'd like leave some empty space on there on the spreader. You can always drill/cut more holes later.
After figuring out the layout of eyepieces, draw the holes. Let me say this right now: DO NOT make the holes exactly 1.25" and 2" wide. Add an extra 1/16 to 1/8 of an inch to the diameter. (I chose to make the hole 1/4" bigger so that way I can fit in eyepiece without removing their end caps) This makes inserting and removing eyepieces smooth. I used a drawing compass to draw the holes, but you can use an eyepiece barrel or anything round.
Step 6: Cut and Drill
How you want to do this part is up to you: scroll saw, laser, CNC, etc. It depends on your material I guess. I didn't have the right size hole saw drill bit for the eyepiece holes, so I improvised and ended up just cutting out the holes with a scroll saw. The circles ended up a little rough, so I sanded down all rough ridges.
Put the spreader on the tripod and check if it lays flat using a carpenter's level or eyeballing it. Recut the notches deeper as necessary.
Step 7: Final Touches
Sand/smooth all the rough edges because you don't want your eyepiece barrels getting all scratched up. If you have access to a router, I highly recommend rounding all the edges. (I ordered a router bit and it didn't arrive yet. Once it does I'll smooth the edges + add finish then post an updated picture) I also recommend adding a finish to protect the wood and the bring out it's detail. If you use a finish that gasses, leave it out for a few days. You really don't want the gas to ruin the eyepiece optics.
Step 8: Enjoy
You've just increased the stability of your tripod and made a convenient eyepiece holder.
Add glow-in-the dark strips or, better yet, red LED lights to the tray to make finding the right eyepiece easier.
Add a lip to the edge as a safety precaution.
If I inspired you to make you own tripod spreader, please consider voting for me in the Space contest.
Now what are you waiting for? Go outside start observing through your scope!