Hardware Reference
In-Depth Information
Figure 16-9:
Fixing the
pendulum to the
threaded rod
and channel.
The magnets are extremely powerful and can be prone to damage. Never let them ly together,
no matter how tempting it is. This is because they come together with such force that they
will shatter and small pieces will chip off them. This can happen the very irst time they come
together. Another thing is that strong magnets can pick up iron ilings in a workshop. You need to
remove those to get a uniform magnetic ield. I have found the best way is to use
blue tack
- the
sort of putty used for ixing posters to a wall. Use this to mop up a magnet of ilings and then
throw the piece away. Better still - do not let ilings get onto the magnet in the irst place.
Smooth Swinging
he bearings I used were the type MR126 sealed, which are quite low cost and are widely used
in the construction of 3D printers, inline skates and tools. hey have a 6 mm hole for the
threaded rod and are 12 mm in diameter. I drilled each side of the channel with a 12 mm drill
and used a vice to push the bearings into the hole. his produced a nice interference it. At irst
this appeared to work well, but as the threaded rod was tightened up I noticed that there were
sections of the rotation that appeared stif. So in order to exactly align them I iled one hole so
that it was slightly larger, allowing a very small amount of slack all around, and then I tightened
