Nepenthes Display Modules
Construction
The contents of these pages are ordered so that assembly concepts develop as reading progresses. In
addition, the Contents Links enable access to individual sections. If you need a glossary at any
time, Overview and Specification may help.
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The image shows the kind of tools you will need; in addition you will need a screwdriver, drills bits, pencil, etc. You will need a lot of clamps, as you can see in the images that follow in the instructions. The glue shown is not mandatory, it is simply the one I have; use your favourite.
Do make effort to provide yourself with a flat surface of adequate size on which to do the assembly. Protect the surface from glue deposits with waxed paper. Do make effort to get joints square, and the whole assembly flat and true. The modules are made from Baltic Birch grade B-BB - and it warps, gently. If you concentrate on making square joints, etc., the warps will disappear adequately as you proceed with assembly.
Sometimes joints require a little fitting. The plywood does not always cut evenly, it can contain hard spots which cause distortions of one kind and another. Furthermore, the thicker components often show the taper of the laser beam, which is focussed at a particular level within the wood. Fitting involves removing a small amount of material. A good tool for fitting seems to be a bastard file normally used on metal; a wood rasp probably is too course. But, be careful, and file into the nearside of the wood to avoid breaking off small pieces of the downside ply, which will disfigure the joint. File from the other side if necessary so that the downside ply becomes the nearside ply.
Apply glue with a tool, such as a lolly-stick; the tool enables the glue to be spread evenly over the joint surfaces.
When clamping a joint, use a straight piece of material as a pressure pad; this will result in a straight joint, with residual curvature of the plywood minimised. Masking tape applied to the edge of the pressure pad will prevent inadvertant attachment of the pad to the job. There are examples of this approach in the images that follow; and it is a good fall-back technique.
After clamping a joint, remove glue that squeezes out of the joint, particularly in and around the various notches that are used later in assembly to locate other components. It is a lot easier to remove glue before it has cured than after. A dental pick with a spoon end is very effective for this job.
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The image below shows a hard-spot in a piece of 6mm plywood. The laser cut was being made from the bottom of the image upward; thus the white area is the hard-spot; the area toward the bottom of the image shows more soot - burnt wood - than elsewhere. The wood at the hard spot was cut with a knife in order to separate the component from the plywood blank. Cutting the hard spot with the knife also was difficult.
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Crate is a funny word to use; but it came from a visitor, who referred to the assembly pictured below as an eggcrate. A label was needed, and [egg]crate stuck. The important issue is that all except Lid modules are built on a foundation, which is a crate. And so this task is a natural way to begin.
The image shown is of a complex crate for a 24 inch wide module that is 36 inches long. Smaller modules have slightly simpler crates, but the construction of all is very similar. This section of the instructions assumes that the module is simple, either a Base or a Main, either fullwidth or halfwidth. Other configurations are covered in other sections, but they build on the basic information in this section.
One thing to note is that the rib in the image that is pointed toward you does not run down the centre of the crate. The offset, toward the right side of the image, avoids interference when this crate is stacked on top of halfwidth modules. The cutouts in the bottoms of the ribs also are there for the purpose of avoiding interference. Mostly, module components can be assembled in just one way; but there are traps, and not lining up the cross-slots shown in the above image might be one of them.
Prior to glueing, trial dry assembly and planning ahead are highly recommended procedures. However, a warning is that when disassembling castellations (finger joints) that have been assembled dry, it is very easy to break off small pieces of the castellations, which can spoil the module appearance.
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The first things to stick together are the ribs that make the centre of the crate. And the important things are to make the joint square and fully engaged so that both ribs sit completely on the assembly table. If you have the patience, it may be a good idea to let this joint sit overnight to ensure that the glue cures completely.
The identifiers of the components "just growed"; but there is some meaning in them that may be useful. The sides of the modules are labelled SE1, the ends SE2. Side-parallel entities, such as crate ribs, are odd-numbered; end-parallel entities are even-numbered. The outermost ribs are SE3 and SE4 (but SH4 for halfwidth modules); the interior ribs are SE5 and SE6. Read the Material List for your module.
Thus, the first joint is between an SE5 and an SE6 for a Main module, or BA5 and BA6 for a Base module.
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Now you just glue away until the crate is finished. There are different ways to do it, and no-one knows the "best" way. However, make sure that you do not assemble so that further assembly is impossible. The images that follow show different assemblies, ending with a complete crate. One image shows an assembly that cannot be completed because subsequent interior brace additions require both assembly from the top, and from the bottom, at the same time.
Probably it would have been better procedure to use some squares during the next operation; clamping with squares is good practice.
The following images show some potential pitfalls.
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The locating tabs on the ends of the ribs should protrude a little beyond the mating faces of the outermost ribs - unless you are assembling a Base unit crate. These protrusions are used to locate additional components, as well as making clamping difficult! Base units do not have the further additions that need the protrusions. Avoiding these protrusions is shown in the image below. The clamp at an angle is being used to correct a minor out-of-squareness during glueing, probably caused by omitting to use a square and clamps.
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If you are building a Base module your crate is complete; otherwise, spacers SS3 and SS4 are to be installed around the perimeter. These spacers provide the clearance that enables the male plug at the bottom of a module to engage successfully with the female socket at the top of another module. The spacers are not as deep as the crate ribs, which creates the mating clearance; and which you can see very clearly when you examine your module components. Also, once the spacers are fitted, the ribs should no longer protrude, the locating tabs have completed their function.
The image shows use of a straight, relatively stiff, piece of wood, well clamped to ensure both a good joint and a straight edge to the module and its interface plug. When all four spacers are in place the crate is complete.
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The next few sections cover information that applies, in a general sense, to all modules.
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With a Main or Base module the next step is to install the module ends onto the crate. The ends are installed before the sides because the ends are located by the crate, and the sides are located by the ends. The process is easy, as shown in the images. Note the use of straight pressure pads backed with masking tape.
Warning. With a halfwidth module take care to ensure that any latch holes on the ends are located adjacent to the same side. This side then will be the back side of the module. In the image, the bottom latch holes are out of sight, so the only clue to correct assembly is the lock holes that exist because this is a module to be fitted with a Lid. Otherwise this would be a perfect set-up for making a misteak.
With a Base module, the sides now are fitted in a similar way to the ends. A Base then is completed by Installing the Top and the Base-specific assembly described in Base. Other modules require what is next.
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Jumping ahead in the interest of comprehension, the image below shows one of four finished corner pillars of a module. Already fitted by the current procedure is the end, which goes off to the right of the corner in the image below. The crate is at the bottom; nothing else has been fitted in the current assembly procedure. The side is identified by two small holes near its top. All the other pieces are called top straps or vertical straps. Note that the bottoms of the vertical straps are not flush with the crate members; this is correct.
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Now it gets difficult. The question is whether to install the straps, and then install the sides; or to install the sides and then install the straps. Various approaches have been tried and images of most steps have been captured; all of the images provide useful information on the modules' structure and assembly. However, perversely, the current recommended order of assembly is slightly different from what is shown in any of the images. Bear this in mind when referring to the images.
The current recommendation is to install the straps, and then the sides. The main reason for this is to enable concentration on one assembly issue at a time. As a counter-example, the downside of the sides-first approach is the amount of glueing that has to be done in one step, together with the associated clamping and squareness requirements. If you feel competent enough to do more than one step at a time then there is no reason not to do so.
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By inspecting the assembly-so-far, it can be seen that prior to installing the sides it is necessary to install the straps that use the locating slots toward the tops of the ends. Straps are double layered with a thick strap, e.g., TS1, ultimately glued to the side, and a thin strap, e.g., TSA, glued to the thick strap. The top straps form a wood band around the inside of the module. This band supports the module top, is glued to the top, and forms the top of the window framing. The vertical straps form corner columns joining the top straps and the crate, and form the sides of the window framing.
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The first task is to glue together TS1 and TSA to form a strap sub-assembly, but without glueing the straps to the ends. The image shows how this is done using the location slots in the ends. The thin strap is innermost, i.e., closer to the centre of the module, and the location slots in the straps all face toward the bottom of the module. The pressure pad must be straight, and the tops of the straps should be essentially co-linear, i.e., avoiding dips and humps along the top edge. You can label the strap assemblies, front and back, by writing on them in an unobtrusive place; however, this should be unnecessary, since the straps will be interchangeable with careful assembly.
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When the TS1/TSA side strap assemblies are complete the TS2 and TSB straps can be glued to the ends as shown below; the side strap assemblies provide locations for end strap positioning. Avoid smearing glue over the inside of the end by disengaging one end of a side strap to provide maneuvering room. Applying glue to both sides of the thick strap, and none to the thin strap, seems to work cleanly. The side straps are not glued in place.
A little examination of the image above reveals the rest of the structure. The window framing can be seen, although, unusually, it is not used on this particular module, intended to be a toolbox. Also seen are the location slots for the vertical straps that join the top wood band to the crate.
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Next the side strap assemblies are glued in place. This procedure requires a considerable amount of careful setup, but has the advantages of good control over the glueing, alignment, and squaring tasks, and keeping the crate flat on the assembly surface. The result is a true structure. The first image shows one corner of the setup; this is repeated at each corner as shown in the second image. As cautioned earlier, these images are not quite representative of the current assembly procedure: the end top straps are missing.
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Each side now is glued into place; be careful if the front and back sides are different. For example, if the module is halfwidth, but not to be fitted with a Lid, then the side with the cutout that extends almost the whole way along the top, is the back side, i.e., the side that will be across essentially the middle of the plug of the mating module above it. This is the usual case. But, if a Lid is to be fitted, then this is reversed: the side with the cutout is the front side, and the side with the plain top is the back side. Inadvertently swapping the front and back sides is possible, there is no protection other than being vigilant.
Installing each side needs careful planning. The key issues are that all four edges must be clamped; two of those edges have castellations; the sides must be kept square to the ends; and surplus glue must be removed from all joints, including from the window channels.
Various assembly techniques have been tried, and there is no image of the recommended technique. However, the images below cover most things.
It is best to have the module upright with its crate on the assembly surface, and the side overhanging the surface edge for clearance; this is shown in the first image. However, this is an unstable configuration once the clamps, etc., are in place; the module tends to tip over, especially if it is halfwidth. And, thus, it is essential to have the crate heavily weighted or clamped down to the assembly surface. The image is of an early attempt, and the weighting and clamping is inadequate.
The next images show much better clamping, but the module has been laid on its side to prevent tipping, and that, in turn, prevents use of a clamp on the side castellations, weights are used instead.
Once the sides are installed, the main module box is complete except for the corner columns, which are constructed from vertical straps. The image below shows typical empty locations for the vertical straps.
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Straps TS4, TS3, TSD, and TSC now are glued into each corner, in that order (thick-wide-end, thick-narrow-side, thin-wide-end, thin-narrow-side); see the Material List for your module. Dry assemble first, and be careful not to get the strap trapped before it is glued. Clamping can be awkward, but may be very important to ensure that the strap is properly bottomed-out. The images show the use of three pressure pads and two clamps.
- To avoid marring the outside skin of the module when clamping, make sure that you use a smooth pressure pad.
- Be careful not to leave glue residue in the locations for the straps that follow.
- The bottoms of the vertical straps, correctly, are not flush with the crate members when they are installed. The cause is the spacers that surround the crate. This offset can be of great concern if you are not expecting it.
Installing the vertical straps is a somewhat long and tedious task: there are sixteen straps to glue in place. Patience is a virtue.
The outside view.
The inside view.
And this may be adequate for clamping if the component definitely is bottomed-out.
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The module top adds considerably to the strength of the module; a closed top clearly is stronger than an open top. However, installation of either is straightforward. A full width open top uses four OT1 components; a half width open top uses two OT1 and two OT2 components. A closed top uses PT1; a Base uses BA7. The images are self-explanatory.
Clamping is crucial to ensure a good glue bond; and, after assembly, and while the glue is wet, it is worthwhile to tap the edges of the top with a mallet to ensure that the top is properly seated and not hung-up on a side or end. The images show weights being used for clamping purposes, and waxed paper to prevent incorrect glueing. However, it may be that a better method is to use wood strips along the top components, with the module upside-down, so that the wood strips are in contact with the flat assembly surface. Weights can then be put onto the crate, which will be on top, to load the joint. The latter method has not been tried.
Weighting an open top:
Weighting a (closed) Base top:
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This section describes Base-specific assembly. However, if not already completed, initial construction of a Base should proceed according to the descriptions in Modules and Installing the Top.
Once these initial steps are complete, you have a crate, sides, and ends with a top glued directly to the crate. It remains to install mounting pads and a bottom, BA8, which are unique to a Base. The pads are for mounting wheels or other support. Details of such mounting are not covered herein, but are left to the builder. However, it is noted that non-swivelling wheels should be mounted so that the module stack on the Base will travel parallel to the modules' sides, perpendicular to the ends; otherwise, the module stack might be too wide to pass through a standard 30 inch doorway.
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Mounting Pads
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The images below show the mounting pads being installed in the corner pockets of the crate; this is a straightforward glueing operation.
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Bottom
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Glueing the Bottom is identical to glueing the Top, except for a little more glue for the mounting pad surfaces. It should be obvious that once the top, pads, and bottom are glued together, the Base is a study structure.Note that the images show a Base with side and ends made from 3mm plywood, this was a prototype Base. All Base sides and ends now are made from 6mm plywood; any weight advantage of the thinner material being overshadowed by the weight of the wheels. And the thicker material is more suited to rough duty, as might occur close to the ground.
The Base is now complete, except for hardware and wheels.
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The image below is of a complete Base with 8 inch wheels, two swivelling, two not. All production Bases have a complete complement of latches and will support correctly any other module. The Base shown weighs 36 lbs, two-thirds of which is the weight of the wheels. Handles are not fitted to the Base shown, but handles are now standard equipment since they help greatly with maneuvering the Base itself during transport, etc.
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Positioning the hardware is straightforward since pilot holes for the screws are pre-cut. However, there are assembly rules that should be followed. These rules are dictated by the need to ensure adequate screw engagement length for attachment strength, and by the need to ensure alignment of the over-centre latches between modules.
The whole of this section should be read before starting assembly.
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Rules
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- A Bottom Latch ATB is the part with the moving pieces, and it is mounted at the top of the display module with three screws A64. A Top Latch ATT is mounted at the bottom of the module with two screws A64.
- A Handle ATH is mounted with two Handle Bearings ATC and four screws A68.
- A small amount of lubrication is a good idea when driving screws. Normally, one drop of water is adequate; olive or other vegetable oil can be used if it seems desirable. Water will dissipate and evaporate over a relatively short period of time. Otherwise, avoid any quantity of oil that will soak into the wood and damage or mark it.
- In some places, notably in the socket at the top of each module, the screw points protrude and are sharp edges which can catch clothes, fingers, etc. After assembly, a finishing job is to remove these sharp points with a Dremel grinder, or other method. Considerable thought has been given to eliminating this requirement, but the final conclusion is that, since modules are kit-built, the best solution is to require a finishing task of the builder. The issues that arise, and complicate, any modification to hide the screws, include adequate screw engagement length, interference with other modules on assembly, proper latch engagement, and number of special cases.
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Mounting Pads and Anchors
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Spacing pads are used, or not, for latches and handles, as follows.- A Bottom Latch ATB is mounted on pad PV5 if the appropriate module side or end is made from 3mm plywood. The pad can be glued to the module. If the side or end is made from 6mm plywood, then no pad is used.
- A Top Latch ATT is mounted on pad PV4 if the appropriate module side or end is made from 3mm plywood. The pad can be glued to the module. If the side or end is made from 6mm plywood, then no pad is used.
- A Handle Bearing ATC is mounted on three stacked PV1 pads. In addition, if the side or end is made from 3mm plywood, then a PV6 pad is added to the stack. It is recommended that each stack be assembled with glue and clamping prior to mounting the handle assembly and pad stack to the module. If this pre-assembly is not done, the pads can slip and become distorted with "steps" as the mounting screws are tightened. The pad assembly should be glued to the module.
- A Bottom Latch ATB uses a PT9 Anchor, which is glued to the inside of the module socket at the same time as attaching the latch.
- A Handle Bearing ATC uses a PV2 Anchor, which is glued to the inside of the module socket at the same time as attaching the latch.
- A Lid uses an LDL Anchor to replace PT9 and PV2 Anchors. The LDL Anchor looks better than the others, and does not encounter the interference problem that the others must deal with. LDL Anchors do not have pre-cut mounting holes due to different requirements with different module configurations. These anchors should be drilled after assembly with a #44 drill (0.086 inch dia) using the side or end mounting holes as positioning guides.
These images show a Handle installation on 3mm plywood.
These images show an LDL prepared for a Handle installation.
This image shows Latch and Handle installations on 6mm plywood.
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The configuration of the interior of a module depends on how it is to be used, and is beyond the scope of these instructions. However, a platform that is positioned on top of the crate is provided; it is made up of platform halves SPH, anchors PHA, and screws both to hold the platform together, and to attach the platform to the module crate. The platform is detachable from the crate; this enables replacement of the platform, which thus enables multiple or changed use of the module. Also, it is not required to use the provided platform. Other materials, or methods, can be used. Components SPH can be used as size and shape templates.
The installation method for the standard platform, described below, is not especially strong. The justification is that Nepenthes Display Modules are intended to display and transport over relatively smooth terrain. This point is made simply to draw attention to this design reality. A user might want to use more screws, or use other methods, to increase mechanical security, ruggedness, etc.
Platform installation is as follows. The images below show steps in this technique.
- At the marked positions in the platform halves, drill and countersink a clearance hole for a screw AXX in your Material List. The countersink will be on the inside of the module, the non-countersink side will be in contact with the crate.
- Stand the module on its end, or whatever is required to be able to access the top of the platform and the bottom of the crate more or less at the same time.
- Install a platform half, without screws, precisely in place. Spacers are provided for this purpose; but any method is acceptable. The platform halves must allow room for any removable window to seat easily between the platform and the module side and ends. It is important to be confident that the half being installed is positioned precisely; clamping is a good technique.
- Position an anchor, accessing from the bottom of the module, by clamping it to the crate. The screw hole in the platform should be approximately in the centre of the anchor, which will cover the hole. A spacer is a good idea to position each anchor with respect to the perpendicular crate members.
- Drill from inside the module, through the countersunk hole, into the anchor. A #46 (0.081 inch) drill-bit to a depth of 3/8 inch is suitable.
- Optionally, but recommended, glue the platform/anchor interface. Then install an AXX screw, and tighten to draw up the anchor and clamp the glue.
- Without delay, repeat for the other anchor on the platform half.
- Remove the platform half assembly. This is mainly to ensure that the assembly does not glue to the crate, but also enables the glued joint to be clamped externally until cured. Clearly, platform half assembly removal must be done carefully so that the glued joint is not disturbed.
- Repeat for the other platform half.
- Replace the platform halves. Seat each half onto the top of the crate, and put a screw AYY through the appropriate crate rib and into the anchor. The best technique may be to mark the screw position on the anchors with a screw, remove the platform, drill the anchor, replace the assembly, and then drive the screw.
This image shows a countersunk hole and its matching screw.
The platform halves in place. The screw is removed to drill through into the anchor.
The bottom of the crate showing an anchor clamped in place prior to drilling from the other side. The small piece of wood is a positioning spacer.
A platform half, removed, and clamped for glue curing.
The bottom of the crate, showing the platform anchors screwed to the crate.
Inside the module.
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I want you to be happy with your modules. So, if something goes wrong, please do contact me; I may be able to help. Importantly, each job has a unique identification number, and all the computer data used to create your parts are kept, so parts can be re-made.
last-modification-date: 27 Dec 2015