How To Design A Puzzle Box : The Basics ( Tutorial )

what's up I'm Jonathan and I'm walking
to maker tales where I'm sharing my maker journey to help you go further
in yours so don't forget subscribe and hit that little Bell icon to never miss
an opportunity to keep making in this video we're going to be working off the
knowledge from the first video which is how to design a laser cut finger joint
box accurately in this video I'll be showing you how to make a mechanical lid
lock this mini mechanism will be using for individual sliding lock pins which
we will develop in future videos to be able to move all four pins with one
rotational movement plus we're going to be keeping to the no glue theme for now
this is going to be a great video for the very basics and fundamentals of
puzzle box design and if you haven't seen the first finger joint box video I
strongly suggest that you watch that them first as I am NOT going to go over
how to find the perfect joint parameters in this video the link to that video is
down the description once again I'll be using Rhino 3d but feel free to use your
own preferred vector editing program just remember to stay laser accurate
before we go any further I would like to explain what I like to call layered
design and sandwich mechanisms honestly I don't know if there are any actual
words for these concepts to me the concept of layered design is the idea of
slicing a 3d design into layers of assembly for example the lid of the
first box already had a form of layered design we had two pieces which we joined
together to make one solid slightly more complicated part a sandwich mechanism
plays off the same idea except there are usually four or more layers involved
along with moving and usually mechanically interacting parts
sandwiched in between the top and bottom layers to make the next coming steps a
little easier to understand here is a visual explaining the layer names that I
use starting from the top down we begin with the user interface layer which I
also call the UI layer this is the very outer layer of the sandwich mechanism
this is usually the layer that has all the switches knobs buttons cogs and
sliders under the UI layer you get the top layer this layer along with the
bottom layer are solely there to keep the mechanism
together in between the top and bottom layer you have the mechanism layer or in
more complicated designs the mechanism layers now that we know the general
understanding of a sandwich mechanism let's get on to the first design here is
where we left off our finger joint box design our initial box with a simple lid
to take this lid to the next level let's start with just the internal and
external dimensions of the box now with these dimensional constraints let's
reapply that 0.5 millimeter offset to the internal part of the lid plus I'll
give the corners a small Filat this will let us have a little bit more wiggle
room especially while working with wood as zero-tolerance designing is usually
not a good idea with natural materials from here I'm going to be adding a few
construction lines this will make it easier to find the center point and
other points of interest these construction lines will be removed later
on and are only there to aid the designing process all these lines will
be in red from now on as this is a relatively simple design I'm going to
jump straight into the internal mechanism generally speaking I usually
work from the UI and top layer downwards when creating more complicated designs
so getting straight to it in essence we have one sliding lock pin mechanism
which is repeated four times to work smart and not hard we are going to just
design one of these lock pins and then copy the other three in place using my
construction lines I'll place a 15 millimeter wide lock pin from the center
to the outer limits which will become the top layer outline later on from here
we need to keep in mind the movement we are wanting to achieve with this lock
pin I want this pin to move a minimum of three millimeters back to be able to
unlock the box as a rule of thumb I usually add an extra 0.5 to one
millimeter of movement if I'm able to do so adding this extra little bit means
the pin will now move back four millimeters it's pretty obvious in this
design that the pins will not get in the way of each other
but it's still good practice to check this to do this I'll add a 15 millimeter
construction line box to the left of the lock pin from here we can see that the
full range of motion is not going to get in the way of any other pin to interact
with the lock pin we need a way to interact with the UI layer to add a
simple sliding button to the UI layer we need to keep in mind that we are working
in a sandwich mechanism this means we need to go through the top layer to
reach the UI layer to do this we will add a hole through the top layer this
hole will let us add a pin joint from the sliding button to the sliding lock
pin let's start this connection from the mechanism layer adding a hole to the
lock pin for the pin joint going up a layer we are now on the top layer I'll
make this layer green to make it easier to distinguish while adding the hole to
the top layer we need to keep in mind the range of movement of the connecting
pin joint this means that we need to make the hole four millimeters longer in
one direction to let the pin joint shaft move freely
lastly going up one more layer we reach the UI layer i've colored this layer
magenta personally i would like to hide the hole in the top layer for this
design meaning that I'll make my button 18 millimeters by 18 millimeters I'll
also give the button a small Filat on the corners and finish it off by adding
a pin joint hole hiding the construction lines this is what we're currently
ending up with to finish off the design we need to add all the moving parts into
the mechanism layer to do this I'll bring the construction lines back and
use the center point to help place three copies of the full mechanism rotating at
90 degrees as I go along we're almost there only three more steps
to the end staying on the MEC layer now that everything is in place we need to
add the standoffs standoffs are the part of the mechanism layer that do not move
and are there purely to keep the top and bottom layers off the moving parts in
essence there are the empty spaces in the MEC layer to make these standoffs
I'll look for the areas in mec layer that needs support this will
usually be the whole outer perimeter and any large voids these standoffs are then
held in place by pin joints and hold the entire sandwich mechanism together keep
in mind the movement of the mechanism to make sure not to accidentally impede it
with a standoff while making these standoffs and adding all these pin
joints to all the other layers let's also check each layer to make sure it
has everything it needs most notably is the outer perimeter of the bottom and
top layers fundamentally that's the tricky part done all that's really left
to do with the sandwich mechanism now is to add all the kerf compensation a
couple of fillets to make sure nothing catches on itself and then what I like
to do is add a small 0.25 margin to any moving parts to make sure that there
isn't any additional friction on any of them moving connections with that done you should have something
that ends up looking a little like this on to the last step you may have noticed
that currently the lid would not fit on the current finger box design this has
been intentional to keep the layers in the sandwich mechanism to a minimum
what's left to do now is a small edit to the box faces plus a small edit to the
top layer of the sandwich mechanism let's start with the top layer the
outcome of these small edits is to create an interlocking lid to do this we
need to remove as much of the overlapping lid rim but keep just enough
that will still hold the lid in place to slide the lock pins into place to do
this I'll be removing all the rim apart from 11 millimeter finger that
will slot into the rim of the box now onto the box faces we need to add a
small slot to let this finger slot into Plus we'll be adding a small hole to let
the lock pins slide into I know the hole for the lock pins is nine point five
millimeters away from the edge of the top layer and three millimeters down due
to the thickness of my material I'll also be adding a zero point five
millimeter offset to this hole to give it a little bit of wiggle room a few
finishing touches such as Phillips to the slots and that's the design done now
it's a simple case of separating the layers of the design nesting it and
cutting it out once cut I hit it with a little bit of
sandpaper on all the moving and exposed parts from here is a case of simply
assembling it make sure you take care with the orientation of the parts while
putting them together as these parts can be put on backwards or inside-out a
rubber mallet come in handy to persuade the pins to go in but make sure they go
in straight because if you don't there is a high chance of splitting the wood
when they go through to the other side a small thing I would like to mention is
that all these designs have no glue this does not mean that a small amount of
glue won't help especially when it comes to the degradation of joints after a
long amount of time due to changes in humidity and wear and tear but
personally in my experience using these finger joints I have not had a single
problem with any of my puzzle boxes that I've developed over four years ago you've made it now you've just
understood the basic fundamentals of puzzle box design that's right
technically speaking you could see this as a very simple four-step puzzle box
next up we're going to be working off the fundamentals of that design to move
all four pins with one quick little rotation in fact from there the sky's
the limit we're even going to cover a 15 step puzzle box and so much more so
thanks for watching keep making and let the quest continue

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