Intro: Portable Lap Desk & TechShop Tool Kit
Long inspired by the Studley Took Chest (http://en.wikipedia.org/wiki/Henry_O._Studley) I gravitated toward the idea of a tool kit with a wooden briefcase form. Unlike the Studley Tool Chest, which has a specifically designed space for a set of finite tools, I need a flexible storage solution that can evolve along with the tools in the kit. I also wanted something that could be used as a lap desk to sketch and draft on while sitting on the couch or in a public space without tables. The concept I settled on was to create a suitable briefcase styled tool kit that combines old school woodworking craftsmanship with sleek minimalist aesthetics. The end result is a portable lap desk and flexible tool kit that is equal parts function and beauty and of a level of quality that will easily outlast my own lifetime.
Due to the demand for a specific aesthetic and desire for robust high quality materials in this project I ended up custom machining both the front handle and inner lid stay hardware on this project. Since the tools & materials required to create the hardware are so different from those used to create the wood case portion I have split the required tools and materials section into two portions. Required tools and materials for this project are as follows:
Wood Case, Inserts, and Stock Hardware
- Table Saw with 40 tooth general blade and dado stack
- Biscuit Joiner
- Measuring Tape & Calipers (indespensable for getting accurate measurements and tool set ups)
- Rabbeting bit with multiple bearings for various depths
- Multiple Flush Trim bits
- Chisels & Mallot (multiple size options allows for greater efficiency and better end result for various areas being worked)
- Marking Knife
- Clamps (a box clamp or picture framing clamp will come in handy)
- Laser cutter & PC w/ graphics software (used to cut lap desk insert and organization trays; could use a table saw, router, hand saw, or band saw just as efficiently)
- Hand Drill & assorted drill bits (Forstner bits & twist or brad point bits)
- Assorted screw drivers (to attach hardware to case)
- Random Orbit Sander & sandpaper (150, 180, and 220 grit used for this project)
- 1/4 sheet of 1/4" Walnut Plywood - G2S (Good 2 Sides)
- Typically only available to buy in 1/2 sheet or full sheet quantities ($80-120 per full sheet)
- 4/4 Walnut Hardwood ($6-10/BF; appx. 3 BF needed)
- One piece 5" wide x 66" long will suffice as long as you don't make any mistakes
- 1 Pair of #101 Soss Concrealed Hinges in Satin Brass finish ($20/pr)
- Qty. 2 of Woodcraft Medium Catch (brass plated) ($5.25/ea)
- Qty. 1 of Horton Brass half-mortise box lock (PN: LK-6) ($23)
- Wood glue (Elmers or Titebond II)
- Water based wood dye (medium brown)
- 100% Pure Tung Oil
- Paste Wax
Custom Brass Handle & Lid Stay
- Mill w/ associated tooling (parallel set, center finder, center drill, 1/4" end mill, 3/8" end mill, and countersink)
- Lathe w/ associated tooling (basic lathe cutter, parting tool, drill chuck w/ assorted drill bits)
- Assorted taps & dies (1/4-20 tap & die, 6-32 tap, 8-32 tap)
- Metal cutting saw (cutoff saw, metal band saw, hack saw, etc)
- McMaster Carr Alloy 360 Ultra-Machineable Brass
- Appx. 4 inches of 1/8" x 3/4" bar stock (McMaster Carr PN: 8954K403)
- 2 feet of 3/8" x 1/2" bar stock (McMaster Carr PN: 8954K294)
- Appx. 1 foot of 3/4" rod (McMaster Carr PN: 8953K951)
- Appx. 15 inches of 1/4" rod (McMaster Carr PN: 8953K45)
- Appx. 6 inches of 3/8" rod (McMaster Carr PN: 8953K49)
- Qty 1 - Brass Thumb Screw w/ 6-32 thread (McMaster Carr PN: 92421A144)
- Qty 4 - 8-32 x 1/2" brass machine screws with Countersunk Head (Ace Hardware)
- Qty. 4 - #8 x 1/2" brass wood screws with Countersunk Head (Ace Hardware)
- Off the shelf 2 part epoxy
Step 1: Develop Requirements
- Entirety of work surface should be flat with no obstructions that interfere with writing/sketching
- Should be capable of opening 180 degrees to lay completely flat on work surface as well as lock at varying angles to support upright/titled reading position of tablet in multiple sitting postures
- Organizational spaces should be tailored to contents, but not overly customized to be obsoleted by newer versions of contents
- Overall dimensions should be roughly the size of a briefcase
- All contents should stow securely to avoid damage during transport
- Should have a latching feature to avoid inadvertent opening & spilling of contents
- Should have a locking feature to protect contents when not in sight
- Should have a method of supporting hands-free carry
- Ergonomics should support use on a bench top as well as a lap desk for research & project development while being lazy around the house
- All hardware should be flush mounted or recessed so that the cube silhouette is completely unmodified and the case can be set completely flat on any of the six sides
- Tablet or Laptop
- Cell Phone
- Phone Charger
- Head Phones
- Keys & Wallet
- Thumb Drive
- Tape Measure
- Work Gloves
- Ear Plugs
- Xacto Kit
- Utility Knife
- Safety glasses
- Reading glasses/Sunglasses
- TechShop badge
- Pen & Pencil
- Drafting tools
- Tooling consumeables such as router bits, end mills, lathe tooling, countersinks, etc
- Arduino and small electronics kit
- Larger compartment for specialized hand tools such as planes, chisels, and marking gauges
Step 2: Project Design
The overall design of this lapdesk/toolkit is simple. It's nothing more than a wooden box embellished with various pieces of hardware and several wooden inserts for added organization. From past projects I've learned that when working with components that fit inside of other created components it's much better to take measurements as you go rather than designing every last detail on paper and expecting it to fit together flawlessly in the end.
With this in mind I started the design process by generating a quick Visio file to determine overall proportions of the box. Having the overall dimensions of the outer case was enough to determine my material needs and determine the relative sizes of the various hardware components that would be required for the project. By design, the compartment dividers, tray, and lapdesk insert were designed on the fly using the actual dimensions of the case assembly.
Step 3: Machine Custom Hardware
I made the hardware components at TechShop (www.techshop.ws) and can't overstate how cool it is as a woodworker to have the ability to customize hardware for specific projects. The TechShop staff was great at helping me to complete my first ever milling project and I truly wouldn't have been able to do it without them.
The rough build process for all flat pieces including the lid stay base plates and flat handle components is as follows:
- Cut flat stock to approximate size
- Clamp piece in mill & use center finder to locate zero for X & Y axes
- Use stop clamp if available to maintain datum when moving from one component to next
- Use end mill to clean up cut ends and mill to precise length
- Locate feature locations and use center drill to pre-drill all holes
- Mill out component features using mill of appropriate size
- Clamp 3/4" rod in lathe chuck
- Use drill chuck and center drill to mill hole in end of peg
- Use basic lathe cutter to mill the two required diameters of pegs
- Cut peg off at proper distance
- For upper peg: use mill to drill 1/4" hole for rod to slide through; use hand drill to drill hole for #6-32 threaded thumb screw
- For lower peg: use mill to drill hole for 1/4-20 threads which will receive threaded rod
A brushed finish was applied to the brass pieces using non-aggressive wire wheel on a bench grinder. An off the shelf, two part epoxy was used to glue the handle rod and 1/4" insert pins together; next time I'll aim for a press fit, but clearly I'm not a real machinist yet.
Step 4: Create Wooden Case
The first step to creating the wooden case is to prepare the hardwood by jointing the board to obtain a straight edge and then planing the walnut hardwood to the desired thickness. Then cut to width using the table saw. I cut to 4-3/8" wide for a finished case height of 4-1/4" (1/8" material lost to saw blade kerf when cutting box open after glue up). I then set up a dado stack on the table saw for approximately 1/4" overlap of the top and bottom panels into outer frame and just over 1/4" depth to accommodate thickness of plywood. Be sure to go slightly deeper than the panel thickness to ensure the panel is fully inset into outer case. You can remove excess material of outer case using sander prior to finishing, but if the panel sits proud then you can't sand it away because you'll burn though the veneer.
Once both sides of the board have been dadoed to receive the panel, cut the pieces to length at a 45 degree angle using the miter saw. Measure and dry fit the 45 degree cuts on a practice piece prior to cutting the walnut to ensure a good square of the final box. Cut the four sides of the box and pay attention to keep the grain flow continuously wrapping around the box. I then used a biscuit joiner to create grooves for the biscuits that would provide extra joint stability in the corners. As always, make a test cut with the biscuit joiner prior to cutting into the real pieces. Place the biscuits in an area that won't been visible when cutting open the box later on. At this point it's a good idea to mark the top of pieces so that you know where to place biscuits and which side to cut open after it's completely glued up.
Glue up and clamp the four sides of the box. Then the exact measurements of the panel insets can be taken to determine the panel sizes. Cut the plywood panels to size on the table saw and glue into the dadoes on each side of frame. Apply as many clamps as needed to verify the panels are fully inset into the case. Once the glue has set, cut the box open using table saw. Pay attention to the markings applied earlier to ensure the cut is being made on the proper side of the box. I used a dimension of 3" on the bottom portion for my design.
Step 5: Layout & Inset Hardware
This is the toughest and most difficult portion of the build in my opinion as it requires great attention to detail, coordination and practice with a wood chisel, and a lot of patience to do the job the right way.
Since I have a laser cutter available to me at TechShop I chose to create laser cut router templates for the individual hardware pieces as a test. The templates worked well for some pieces of hardware, but were not viable for others due to clearance issues. In all case I used a marking knife to "trace" the hardware onto the wooden case to score the wood fibers and reduce the chance of tear outs while working with the router or chisels later. When it was possible to use the laser cut templates, I used a router with a pattern bit to cut out the general shape of hardware insets, and then finished the corners with the chisels. For the Soss concealed hinges I used a Forstner bit to remove the bulk of the material and then used chisels to clean up the edges and finish the job. For hardware where the templates couldn't fit at all, I used a marking knife and chisels to complete all of the material removal and finish work.
When laying out hardware insets, calipers are an invaluable tool that can be used to determine precise hardware sizes, router bit depth, etc. and then transfer those measurements to other tooling or templates when needed. The key to using chisels, as with all hand tools is to keep them sharp and work slowly. If you feel like you're forcing it then there's a good chance you're getting ready to blow out the side of your project. Don't try to remove all the material at one time. Remove the full depth of material in multiple passes. And again, keep your chisels sharp! Sharp hand tools results in a better looking finished product, more efficient use of your time in the shop, and ultimately a much safer experience since a sharp chisel will cut with much less pressure than a dull one.
Remember to dry fit all hardware. It can be tempting to move on, but don't progress until the fit of all hardware is perfected. Otherwise there's a good chance you'll find yourself revisiting this step in the future after the finish has already been applied.
Step 6: Create Lap Desk, Divider, and Tray Inserts
To create the lap desk insert, dividers, and tray I use calipers and a ruler to lay out inner case dimensions in Illustrator. I drew the lap desk insert based on these inner dimensions minus roughly 1/16" for clearance. I then played around in Illustrator with a few layout options before settling on a divider and tray design that I thought would accommodate lots of different tool configurations. I measured the inside depth of the base to be 2-1/2" and decided to make the bottom dividers 1-1/2" tall. The tray is 1" tall minus 1/4" for the plywood bottom makes 3/4" of usable depth. After laser cutting the pieces I glued up the dividers using tape to "clamp" the pieces in place. I then placed the dividers in the base of the case while drying to ensure a good fit. For the tray, I followed the same process with the addition of having to route the backside to 1/4" depth using a rabbet bit. This rabbet is required to inset the tray bottom into. Chisels were used to clean up the corners where the router couldn't reach.
If a laser cutter were not available to me I would have used a table saw and band saw to create the same finished pieces, and believe it would take roughly the same amount of time in the end.
Step 7: Sanding & Finishing
I sanded the wood using 150, 180, and 220 grit sand paper. Based on the minimal amount of tool marks left by the planer and saws, anything more course than 150 grit would have been overly aggressive and unnecessary. The bulk of the sanding was done with a random orbit sander, and areas with limited accessibility were sanded manually by hand.
When using a random orbit sander only slightly more pressure than the weight of the hand is required. Be careful not to dig into the material by using the sander at an angle. Also, don't be overly aggressive on the plywood or else you may burn through the veneer which is typically less than 1 mm thick. One last tip is to be careful not to round any edges unknowingly or prematurely. Always keep the sander or sandpaper as flat as possible. To maintain clean lines on a sharp (90 degree) edge wait until the last pass of sanding using 220 grit paper by hand to slightly "break" the edges. Even with 220 grit only a tiny amount of pressure is required. Creep up on the finished look because once the material is gone you can't get it back without cutting further into the surface.
For those stubborn gaps that inevitably appear on every project I prefer to use Cyanoacrilate (CA) a.k.a. Super Glue as a filler. Apply thin super glue to the joint that needs filling and then immediately sand over top of it to move wood dust into the joint. This will dry darker than the unfinished wood, but will blend in well once the clear coat has been applied. This method provides a much better color match than messing with wood putties or fillers, and is a lot more efficient than trying to mix sawdust with wood glue.
To decide the clear coat I used a scrap piece of plywood to test different finishes I had on hand. The three finishes I tested were a wipe on polyurethane, a tung oil varnish, and 100% pure tung oil. I tested all finishes both with and without a water-based medium brown dye underneath the clear coat. The theory behind the dye was to deepen the grain a bit, and even out the difference between the lighter and darker areas of the walnut.
Every time I test multiple clear coat options I'm happy I did because the finish I choose is always different from the option I had planned on using. For this project I chose to use the 100% tung oil finish over the medium brown water-based dye. I also applied a coat of paste wax as a final protection on top of the tung oil coating. The tung oil and wax combo is an appropriate finish for this project because it is a matte finish that will wear well over time, and it can easily be refreshed with extra coats when needed in the future.
For the dye, apply in thin layers and slowly creep up on the desired depth of color. Too much dye at one time is likely to result in a color that is darker than you wanted. For the tung oil, the opposite is true. The proper method is to overly saturate the surfaces to allow the wood to soak up all the oil it wants. Pay attention to areas that are drying up and apply more oil as necessary. After the surface has been saturated and rubbed in with a rag, go back over the top with a dry rag to soak up all the excess oil. Application of the final paste wax layer is similar to the tung oil except that less wax is initially required because the wood is already fairly saturated and won't soak up much more material.
Step 8: Attach Hardware & Admire
As a wrap-up, I have a few lessons learned from this project:
- The skeleton keys that came with the half mortise lock were cheap looking and had an antique bronzed finish. I sandblasted them, cut them, and epoxied them into a small piece of 3/8" brass rod to give them a look more consistent with the rest of the project. They look okay, but could be better. I need to search for better looking skeleton keys or make my own from solid brass in the future.
- I didn't meet the original design specification of having a hands-free carry option, but it ultimately was an aesthetics decision. I designed a few options that would accomplish hands free carry, but ultimately thought they would make the outside of the case look too busy. I think I'm okay with not having this, but will continue to consider this over the next few months.
- This case could easily be made in a larger size if desired. Originally I thought that anything over 12" x 18" may be overwhelming, but the case could easily be a few inches larger in each direction and still look great. The material cost and time input would be roughly the same, but the capacity and overall capability of the case would be significantly increased.