Overview of Massless
Massless is a core function of shredders, without massless or the correct application of massless your shredder will not work. The most common case of this is new players not locking their blade motor so if you're new please read 1.2 Staging blade motors.
Staging
Staging Constraints
Massless does not spread to other assemblies (pieces of your build seperated by constraints), so you have to temporarily weld them together with certain blocks. This is especially necessary when using Hyper M2s because your motor twos will not spread massless with below 100 torque. Even with non hyper motors, it is sometimes needed.Springs are the most commonly used staging block, it leaves no welds behind as long as you dont weld the top or bottom to the build. The only issue is getting stuck within the build and having to be flung out.
Disconnectors also work for staging, but leave behind a non collide part on the build.
Tnt is considered deprecated because of a bug that breaks tnt when placed on a shredder, making it unable to stage. (For ghosting rockets you must add a motor and place the tnt ontop.)
Staging Blade Motors
Blades also require welding, or massless will not apply. This can simply be fixed by locking all blade motors. This used to be done with staging blocks but this is not necessary. Also, your blade motor will still have mass, so do not have it too far out or your shredder will wobble.
Preventing Massless Gyros
Gyros will break when massless is applied to them directly, because their strength is based off of their mass. To fix this you must place a locked and toggle motor below the gyros, and weld both ends of your massless module's motor two together with staging blocks.
After you spawn in, unlock the motor, unweld the motor two, lock the motor.
Massless Modules
Balljoint Massless
This module is an advancement of the three block massless, it has the ability to make anchored assemblies massless.
Massless modules work through making a motor two rotate the entire build, which applies massless to the entire thing.
To prevent massless desync, you must add an assembly that is not welded to the shredder. This can be easily done by adding a motor two with 100+ torque, less than 100 will make the m2 totally massless.
Three Block Massless (deprecated)
It was figured out that a massless module could just be reduced down to three blocks, using an anchor to make it the rootpart and then a motor two to rotate the build and apply massless.
Ancient Massless Module (deprecated)
The first massless module, probably designed this way from a misunderstanding of how it worked.