what's up I'm Jonathan and welcome 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 making this little box which is a great starter to understand
finger joints and box making with a laser cutter not only that is held
together without any glue and won't come apart after the smallest tap let's go to
make this little box need to understand the basics of laser kerf for those that
don't know what a kerf is it's the material lost in any type of cutting
process I will make an in-depth video in the future about laser kerf if that's
already out is in the description every single material you cut will have a
slightly different laser kerf so first decide on the material you would like to
make this box out of there are many ways to find your laser kerf my preferred
method goes like this I cut a square which on my computer is
exactly 20 millimeters by 20 millimeters once cut I make sure to mark the
orientation of how it was cut I do this because some lasers and materials cut
differently depending on the cutting direction ie the axis that the laser is
moving on from here I use my calipers to measure this freshly cut square I get 19
point 8 5 millimeters and luckily for me it's the same on both the X and of Y so
together the kerf from this number it's 20 millimeters minus nineteen point
eight five which is zero point one five millimeters now we need to divide this
number by two as we are currently measuring the kerf that was taken away
from both sides of the square doing this leaves us with zero point zero seven
five millimeters with this new information we now know we lose zero
point zero of 75 millimeters of material on either side of our laser cut line
from this point it's a little bit of trial and error
now I create three finger joint tests one using a
kerf of point zero of seven millimeters another one of point zero seven five
millimeters and lastly one of point zero eight millimeters to create these test
files you can use your preferred vector creation tool I like using rhino3d I
first create a simple finger layout which each finger is a minimum of ten
millimeters wide as long as the material is thick if you go smaller than ten
millimeters wide per finger you may skew your results due to the material giving
way to the pressure of the adjacent finger once you have this basic shape
you can then add the new curve value into the mix for example I'll be using
my point zero eight millimeters in this one as my other two tests are already
made to add this value the way I go about it is I think of it as expanding
each finger to fit into its joints everybody does curve Corrections
slightly differently some people like to apply it to just one side some people
like to do it to both sides I personally like to do it to both sides I select all
the anchor points that need moving in one direction and move them all at the
same time by my point zero eight millimeters and then I go and do the
same for the other side one thing I like to do before putting this to cut is I
add little kiss cut lines to them to distinguish one from another now that
these first test pieces are made let's get them cut when it comes to the
pressure fit results of this test it's hard to explain what we're looking for
as it's something that will come with experience but if I had to explain it
I'm looking for a good fit not a tight fit the reason for this is that once you
have this kerf correction in the layout of a box structure there are going to be
many more finger joints fighting against your forces along with other forces such
as twist and warp of the wood thus if you pick a joint that is too tight there
is a high probability that you can break your box or chip your wood while
together out of my tests I'm happiest with the point zero eight millimeter one
now that we know this I personally feel that the hardest part of most laser
designs is now done when it comes to box designing there are two ways to go about
things now that you know your kerf you can use an automated solution like make
a box .io personally I like to have full control over my box designs so
let's go make one all you really need now is some dimensions for your box plus
some sort of idea of how you would like it to look I'm going with an internal
dimensions of 90 millimeters tall 70 millimeters wide and 70 millimeters deep
with a very simple pull up lid in essence all finger joint boxes are made
of three parts not including the lid which are two (A) sides and two (B) sides with
a bottom piece interlocking them all together I'm going to show you my
preferred box design style which lets you hold a lot more weight inside of an
unglued box but please keep in mind that there are many different styles out
there to keep things as clear as possible
let's grab the two side pieces a and B let's add the unsized
to each one now before uniting them let's resize the width of each finger
where they need to be resized using our kerf joint value an extra step to keep
the Box corners as flush as possible is to also resize the length of the finger
by the original curve that being point 0 75 millimeters once they're all resized
mirror these fingers over to the other side unite these and that is sides a and
B almost done when it comes to joining the bottom to the sides
I prefer pin joints rather than finger joints to make these pin joints I'm
going to first add two holes to both the sides
I'll be keeping the holes a minimum of 3 millimeters from the bottom edge and
taking note of the exact location of where I place them I will also shrink
these holes by the joint curve value but I will make sure to keep a note of
the original width now on to the bottom piece I will be adding fingers or pins
to fit into these holes making sure that they are exactly placed and expanding
and lengthening them by the kerf values as well once these are united the open
box is designed to finish things off now let's get onto the lid taking a look at
our box from the top view we know that the internal dimensions are 70 by 70
millimeters starting with this 70 by 70 we will offset this by a value of 0.5
millimeters inwards I do this because working with zero tolerance for moving
parts is a little bit too risky sometimes I'll also offset the 70 by 70
curve by 3.075 millimeters this is the material thickness plus the kerf
finally let's add a hole in the middle to lift the lid up from deleting the
original curve we are now left with a lid that would fit on top of the box and
an interlocking piece that would go under this lid you could glue these two
together however to keep this build without glue we are going to need to use
pin joints once again let's add four small holes where these two pieces will
be joined together with once again shrinking the holes with the kerf
values and separating the two lid pieces all that is left now for this design is
some pins these pins will be just over six millimeters long as it's going
through two layers of 3 millimeter wood plus the kerf value on each side of the
pin so in total these pins will be six point one five millimeters long as
for the width my original hole is 10 millimeters plus adding the kerf joint
value to each side gives me a width of ten point one six millimeters lastly I
will give the pins a small 0.5 millimeter filet on the bottom side to
make it easier to insert these pins into the holes in assembly after coping
the design over and the pins and nesting at all let's get it cut out
once cut I give it a light sanding then it comes to assembly it should all
pressure fit together some very precise rubber mallet in can come in handy for
some extra persuasion if needed
and following all of those steps you will come out with their lovely little
box on top of that you've learned how to master a kerf on the one of your
materials and from there the sky's the limit I'll be showing you how to make it
this little box of the foundations of that which is a little twist locking
mechanism of box from there you get as complicated as 15 step puzzle boxes all
this is coming and much more so make sure you subscribe hit that Bell icon
thanks for watching keep making and let the quest continue