All About T-slots

A Few Words on Nuts and Bolts


Thing-O-Matic uses metric hardware for all of its fasteners. Metric bolts are described by the outside diameter of their threads. For instance, an "M3" bolt has a 3mm diameter shaft. Likewise, an M8 bolt has an 8mm diameter shaft. M3 nuts are nuts that fit onto M3 bolts.

The Thing-O-Matic uses bolts of varying lengths. They're specified as the length of the bolt, excluding the head. For example, a 16mm bolt is 16mm from the tip of the screw to the underside of the head. Sometimes you'll see a bolt described as M3x16. That means an M3 bolt with a length of 16mm, excluding its head.

Nearly all of the nuts and bolts you'll use will be M3x16 — the Thing-O-Matic comes with 200 M3x16 nuts and bolts. You'll end up with quite a few left over.

Using T-slots

Most parts of the Thing-O-Matic fit together using tabs and slots. They are secured in place using a "T-slot". These are "T"-shaped slots that appear between tabs. The short arm of the "T" holds an M3 nut perpendicular to a bolt. The bolt passes through a hole in the piece with the slots in it and screws into the nut, holding the parts together.


To Join Two Parts with a T-slot

First put the pieces together by sliding the tabs into the slots. If you have trouble getting the tabs into the slots, sand down the tabs slightly with sandpaper.


Insert the Nut into the T-slot

Assembly using T-slots can sometimes be tricky, especially if the nut is in a difficult-to-reach place. You can make the assembly much easier if you use tape to hold the T-slot nut in place. For every T-slot use a bit of tape on each side of the slot to hold the nut in place until you tighten the bolt. If the fit is too tight and you can't get the nut in place, turn it 60° and try again, or sand the slot lightly.

  1. Place small tape strips over all of the T-slots on one side of a piece
  2. Flip the piece over and insert a nut into each of the slots
  3. Tape over all of the nuts, but be careful not to tape over any other holes, etc.

Bolt the Plates Together

Pass the bolt through the hole and thread it into the nut. Tighten the bolt with the hex key until it the joint is firm. Don't overtighten the bolt! The wood is soft, and if you tighten the bolt too much, the nut will start to chew through the wood.

Once you've finished bolting together your T-slot joint, it should look like the accompanying illustrations.


Bolt Maintenance

Thing-O-Matics vibrate, and vibration can loosen bolts over time. Check the nuts and bolts occasionally and tighten them down if they're loose. Most bolts, like those in the outer frame, may never need tightening; others, like those that hold the build platform down, may need to be checked every few months or so.

Next Step: Prepare wood pieces

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