I'm working on editing the shopping list
; a couple notes here.
The inner diameter of skateboard bearings is 5/16" or 8mm. In the current shopping list there are (quantity 25) 1/4" bolts and nuts. I haven't cut the latest artwork yet (still working the bugs out of my CNC) but 5/16" should be the correct bolt size. Am I wrong about this?
As for bolt length, my bolts are all 1.5", and all the same. I never used the matching nuts on my design because the wood held them well enough for my demos.
The only 1/4 20 bolts, if I understand the current version correctly, should be the ones holding the cameras in place.
Here are some explanatory pictures:
1. The bolts that are holding my scanner together.
2. Here is one of these bolts held against the lifter arm, so you can see the depth. You can see also that I never put the nut inside the pocket. For long-term use, I would have to do that.
3. You can see here that I am not using a nut on the reverse side of the topmost lifter arm hinge piece thingy. The bolt does not go through far enough to do so. For long term, hard-use it would be best to buy a 2" bolt for this part and put a nut on it. However, I've had zero problems with this setup.
4. Another comment on bolt depth. There is a washer in between the two pieces of wood and the skate bearing, to space things out.
5. Those washers are from Fastenal. They have the important property that they hug the bolt, but the outer diameter is small enough that they don't scrape on the outside of the skate bearing.
I want to apologize for not having this list together earlier. Moving across the state ruined most of my plans and made a lot of this much harder than it really should have been. I very much appreciate the help with getting this DIY Book Scanner Shopping List