Modern mass manufactured furniture employs a range of fixings to ensure that it can be produced efficiently, flat packed, and assembled quickly and easily. There are a wide variety of fixings available as standard, however these can be subject to country availability, unit system (metric/imperial), and minimum order quantities.
This is a problem for open making, any fixings used may not be available to other makers. The solution to this, design out the fixings. Furniture originated without fixings so this is nothing new, joints are fit tightly and glued so they are set in place, problem solved. However, introduce the requirement for disassembly and you need to remove the glue. What you are left with is fixingless, glueless joints, essentially, tolerance joints.
Tolerance joints rely on the components being made so accurately that they fit together snuggly allowing no movement. Of course in the real world there is variation in cutting accuracy and material thickness making it very difficult to maintain a snug joint and requiring designs and cutting files to be made for the exact material thickness you are using. However once all these factors are considered it is possible to create brilliant furniture with fixingless, glueless furniture.
Most designs on the Opendesk platform are designed on the principle of not requiring fixings or glue. Generally, there are 4 types of tolerance fits used to ensure a solid assembly:
- Mallet-Tight (-0.60mm pinch) The idea is to cut the hole/join smaller than the overall thickness of the material. This way makes for a tighter, more secure hold as the wood is slightly crushed/compressed into place.
- Press-Fit (0.00) With a press fit there should be a small amount of friction that holds the parts together in a flush slot that has zero play. The benefit of this join is no tools are needed for assembly, normally just a press in by hand.
- Push-Fit (+0.20) A push fit is similar to a press. It makes a product easy to assemble as there is a larger amount of space in the join to play with. It is normally associated with locking mechanisms.
- Slide-Fit (+0.50) These are commonly slot fit joins. Parts that need to go through one another, or parts that need to move freely. An example of this is a cable management tray/lid.
As the joints are highly dependent on tolerance it is very important that you work to the thickness of plywood that you have at the time of manufacturing as adjustments may be needed on some of the parts. Generally we recommend being within a 0.1mm consistent measurement across a sheet to make sure the product can go together in the correct way as smooth as possible.