Building the marble machine enclosure
body { font-family: sans-serif; font-size: 100%;}
img { margin-right: 12px; margin-top:0px; margin-bottom:4px; }
Building the marble machine enclosure
The enclosure is made of 16 mm thick boards. Lumber from the store is usually
at 3/4" or 18 mm, but it usually isn't planed that well. If you have a
thickness planer, plane it down a little to get a nice surface. If you don't have
a thickness planer, add 4 mm to the outside dimensions of the enclosure so that
the inside dimensions of the box will still be the same.
The pump protrudes into the board on the back of the machine a little. It's easiest
to just mark the outline of the pump to figure out how much needs to be cut away.
The cutout on the back of the case needs to be deep enough so that the back of the
elevator holder can fit flush against the back of the enclosure.
Rout out the cavity freehand with a router. The outline isn't precision critical,
so hand-held will do.
An even deeper cutout is needed for the pump's slider, which slides forwards
and back. This cutout has to go all the way through the board.
For my machine, I hogged out the material with a Forstner bit
and then used a chisel to clean it out to square.
Join the corners with rabbet joints, then glue the four sides together. Make sure
they go together square. I used a clamping square (blue) to ensure my box was square
as the glue dried.
While the glue is drying, you can make the bottom cover for the box. Bevel the sides
with a 30 degree angle. I'm using a table saw sled as a support for this operation.
You really should use a table saw sled for this sort of cut. If you don't have one,
make one - they aren't hard to make.
Checking the fit of the bottom. The bottom cover is a few millimeters smaller than the box
itself to hide it from view. The recessed bottom and the beveled edges also make it easier
to pick up the machine from a flat surface.
Gluing the bottom in place. It's clamped all around, ensuring for a good bond. Because
the glue is as strong as the wood, it's actually stronger to glue a bottom on flat
than it is to rabbet it into the sides, because the rabbet would weaken the sides.
With the marble pump and riser support in place, measure how far down from the edge
to the shoulders of the elevator base bracket inside the box.
Note that I have two shims on top of the riser support - I tweaked
the design a little bit as I was building it. These two shims were
how much I raised the shoulders of the elevator support by. I glued these shims in place
afterwards. I updated the CAD drawings so that you won't need to add shims.
Place splines into the corner of the box to be at that exact same height as
the shoulders of the elevator support. The
splines help reinforce the box while at the same time providing a ledge for the base
plates to sit on in the box.
Use a wide cutter in your table saw (both outside cutters of a dado blade, half of a
box joint cutter, or just two regular saw blades stacked), and set the fence
so that the distance between the fence and the nearest edge of the blade is equal to the
distance measured in the previous step.
Make a block to help support the enclosure at a 45 degree angle on your table saw sled.
You really do need a table saw sled for the next step. It's not safe to try this without
a table saw sled, so if you haven't got a table saw sled, build one now.
Set the sawblade to protrude 5 cm above the table saw sled. Then, with the box pressed
against the fence, make a cut in each corner of the box. Cut forward only, then lift
the box - do not slide the box back over the blade. Aside from being unsafe, passing
the box back over the blade might widen the slots you cut.
Next cut a strip of wood, 5 cm wide, to a width that will fit snugly into the four
slots in the corner of your box.
Use a thin strip of wood to spread some glue on the insides of the slot.
Also, apply some glue to the triangular splines before inserting.
Have a rubber mallet handy on inserting the spline. The glue on a tightly fitting spline
can set quickly, so if it doesn't go all the way in when you push it in, you may
have to drive it in with a mallet.
Next trim the splines nearly flush. Any type of saw will do. I used my bandsaw.
After that, use a sharp chisel to cut the splines completely flush with the outside of the box.
Glue on some blocks to help stabilize the riser support. These should fit exactly
against the bottom of the riser support. I clamped the riser support against
the inside of the box to use it as a guide for positioning these blocks as I glued them in.
Next it's time to add the crank assembly.
Measure how far from the back and from the top your marble pump crankshaft
ends up, and transfer that measurement to the inside and outside of the left
side of the box.
Glue a 5 mm thick square of hardwood about 4 x 4 cm to the outside of the box.
Glue another piece of hardwood, about 4 x 4 x 2 cm to the same position on the inside
of your box.
Drill a 3/8" (or 10 mm) hole for the crank shaft. This hole needs to be fairly precise,
so it's best not to try to drill the hole freehand. The box was too large to fit
in my benchtop drill press, but by turning the head of the drill press to the side, I was able to
put the box beside my drill press and get enough clearance to drill this hole.
I also clamped a piece of wood against the inside of the block on the inside
of the box to minimize tearout where the drill exits the block.
Dimensioned drawings for the enclosure
Next: Building the base plates, feeder ramp, and hand crank
Wyszukiwarka
Podobne podstrony:
HP BladeSystem c Class enclosuresRFTECH enclosure v2002enclosing floatsCabinets Bathtub EnclosureEnclosuresDance, Shield Modelling of sound ®elds in enclosed spaces with absorbent room surfaceswięcej podobnych podstron