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Raising Desk 1

Copyright 2005

Raising Computer Desk

The Raising Desk goes up and down at the touch of a switch. You can use you computer seated, on a stool, or standing. You can move back and forth between these positions with ease whenever you feel the urge.

It is most useful for people with lower back problems who simply can not sit comfortably in a chair for long periods. There are however simplier ways to address this problem. Feel free to drop us an e-mail for farther discussion.

Others simply like the brake in routine the movement gives or the ease it gives in working with a second person, both standing at the terminal.

Other simply like this desk for its whimsy. It oversized scissor beams, axles, and tie rods give it the look of an antique factory and the movement is quite eye catching.

The following information and instructions -- consider them suggestions, not commands -- will help you build the Woodware Raising Desk. Always keep in mind this will be your desk.

This desk is designed so that it can be built by amateur wood workers with a modest shop but it is one of our most challanging designs and should not be taken on as a first project. All the Materials can be bought at your local home improvement store for about $700.

Rockler order link to first page
  1. Ordering the Sketches

    This design includes eleven detailed sketches that are critical to you successfully building this desk. Here is where to get all the ordering information .

    The plans for our major projects are brought to you on the Honor Plan. You may look at as many plans as you like, but when you start to build please pay for the plans you use. These small payments are critical to keeping this Web Site open.

  2. Desk Construction

    You can make this desk by:

    1. Downloading this text.
    2. Ordering the sketches .
    3. Studying the information and locating Materials.
    4. Purchasing Materials.
    5. Cutting, drilling the wooden pieces.
    6. Assembling the wooden mechanical parts.
    7. Assembling the desk.
    8. Installing the electric drive
    9. Testing the movement
    10. Building the printer stand.
    11. Disassembling the desk
    12. Finishing all pieces
    13. Reassembling the desk
    14. Installing the computer.

  3. Discussion of Sketches

    After you download the sketches, these notes will help you understand them.

    1. Raising Computer Desk (above)

      This drawing shows the front side and top views of the Raising Computer Desk and table. The mechanism is shown in both high and low position with the low position drawn with dashed lines. Note that the linear actuator moves forward while the desk is raising.

    2. Raising Computer Desk, Sketch #2, Overall Dimensions

      This sketch shows the overall dimensions of the Raising Computer Desk without the printer stand.

    3. Raising Computer Desk, Sketch #3, Movement Arcs

      Shows the position of the moving components at the low and high positions. This drawing was used to set the length of the tie rod. If a different actuator is used, then the tie rod length may need to be adjusted.

    4. Raising Computer Desk, Sketch #4, Cross Sections

      Shows cross sections trough several parts of the base and scissor lift. These cross sections show the location of the plastic washers and locking screws.

    5. Raising Computer Desk, Sketch #5, Top

      Shows dimension of the top pieces. The top track and joint pieces are also shown.

    6. Raising Computer Desk, Sketch #6, Legs

      Shows the pieces that make up the legs. All Materials are 3/4 inch hardwood. The bottoms of all leg pieces are beveled.

    7. Raising Computer Desk, Sketch #7, Front-to-Back

      Shows the pieces of the base that run front-to-back. All Materials are 3/4 inch hardwood. A small amount of material must be removed from one corner of some of the pieces.

    8. Raising Computer Desk, Sketch #8, Side-to-Side

      Shows the pieces that run from side-to-side. This includes both stringers in the base and the drive axes. The yokes are glued up from two pieces of 3/4 inch hardwood with a 1/4 inch pieces of plywood between. The dowels are 1-1/4 inch diameter and often used for closet rods.

    9. Raising Computer Desk, Sketch #9, Scissor Beams

      Shows the pieces for the scissor beams. The tie rod ends are plated on both sides with 1/4 inch plywood. The filler block is build up to the thickness of the inside scissor beam plus two plastic washers. The plastic washers are cut from polyethylene container lids.

    10. Raising Computer Desk, Sketch #10, Electrical Components

      Shows the electrical components. Three switch options are shown: drum switch, push button, and foot switches. Only one switch options is needed. The cable is a common 50 ft. extension cord with 14 gauge wire.

    11. Raising Computer Table, Sketch #11, Overall Dimensions

      Shows the support table. The width of this table can be anything that you need from 16 to 48 inches.

    12. Raising Computer Table, Sketch #12, Frame and Shelf

      Shows the support table with the top removed. The shelf is the same size as the top.

    13. Raising Computer Table, Sketch #13, Pieces

      Shows the pieces that make up the support table frame. All Materials are 3/4 inch hardwood.

    Rockler order link to first page
  4. Materials

    This desk is made of hardwood lumber throughout. Any tough hardwood could be used; hickory would be particularly nice, but ash, oak, or maple would be good.

    1. Wood

      Wood:

      1. Raising Desk ----- 26 Board Feet ----- $190
      2. Table ------------ 16 Board Feet ----- $110

      Plywood:

      1. 1/4 inch Hardwood -- 24x48 ----------- $ 14
      2. 1/16 inch filler --- 4x24 ------------ $ 10

      Wood Subtotal: $324.00

    2. Wood Electrical Parts:
      1. Linear Actuator ----------------------- $200
        • _____ Grainger Catalog 387 pp 248
        • _____ AC Linear Actuator 4Z845
      2. Switch -------------------------------- $ 28
        • ______ Drum Switch 2X440 pp 42
        • ______ OR
        • ______ Push Button, green, 4B683, pp 498 ---------- $ 6
        • ______ Push Bottom, red, 4B685, pp 498 ------------ $ 6
        • ______ 2-Contact Block, 4B763, pp 500 ------------- $ 18
        • ______ Plastic Enclosure, 2-hole, 4B579, pp 504 --- $ 16
        • ___________________ Push Button Option ----- $ 46
        • ______ OR
        • ______ 2-Foot Switch, 5X361, pp 521 --------------- $ 52
      3. Cable (any hardware store) --------------- $ 12

      Electrical Subtotal: $240.00

    3. Hardware
      1. Flat Head Wood Screws 1-1/4x#8 ----- box 100 ---- $ 4
      2. Steel Strap, .5 x 36 inch ----------- 1 --------- $ 4
      3. Bolts (for actuator) ---------------- 2 --------- $ 5

      Hardware Subtotal: $ 13.00

    4. Finish:
      1. Stain -------------------- 1 Quart ----- $ 9
      2. Polyurethane ------------- 1 Quart ----- $ 14
      3. Enamel Paint, oil based -- 1 Quart ----- $ 14

      Finish Subtotal: $39.00

    5. Omissions and Contingencies (~14%) ( Tax, sand paper, etc.) $84
    6. Estimate Total Cost $700.00

    This is only an estimate ( in the summer of 1996). The price may vary in your area. Getting good prices on the hardwood and actuator are critical to keeping the price down.

  5. Tools

    This desk was designed so that it could be build by an amateur woodworker with a modest home shop. It requires the use of a radial-arm or table saw and common hand Tools. The electrical work is no more complicated that one encounter in normal home repair jobs.

    Rockler order link to first page
  6. Fabrication Notes

    This is not intended to be a detailed step-by-step construction guide but rather a number of points to consider. It is your desk and you can build it to suit your likes.

    1. Making Tops

      The top is made of one by hardwood lumber edge glued with biscuits. It may be easer to make the desk top, table top, and table shelf as one piece and cut them apart after the glue has set. The front edge of the desk top is doubled up and strongly rounded for comfort.

      It is possible to make the tops of tung and groove lumber. You can make the tops from hardwood plywood with a hardwood edge trim. This provides little cost advantage.

      The width of the table top can be set to suit your specific floor space. It should be large enough for your printer, telephone, and any other devices you use. The depth of the table can also be adjusted to suit your needs. The dimensions of the Raising Desk itself are much more difficult to adjust.

      The top track guides the two outside scissor beams and supports the joint for the inside scissor beam. The track is screwed but not glued to the top. Only the front screw is tight. The back screws are loose and in elongated holes. This allows the top to expand and contact slightly without breaking.

      The two joint pieces are spaced out the width of two plastic washers using either cardboard or the very thin plywood sold in crafts shops. The two pieces are tied together with a small piece of plywood.

    2. Making the Base

      The base is made of 3/4 inch hardwood boards held together with screws and glue. The screws should be counter sunk just below the surface and to a uniform depth then left exposed.

      The top of the front-to-back assemblies serve as a track for the center scissor beam. Also some material must be chiseled from the front legs to allow the scissor beams to turn all the way down to the low position.

      The top back side-to-side stringer can be finally attached. The other two should be only temperately screwed in place so that they can be adjusted when the mechanism is tested.

    3. Moving Parts

      The Raising Computer Desk moves (It's alive! It's alive!). Most of the moving parts are wooden and oversized for the weight they carry. Much of this is for show but it does make a mechanism that works reliably without sticking.

      1. Yokes

        The Yokes spread the load from the central power point to the two scissor assemblies. They are ox-yoke shaped so that the point at which the force is applied will be behind the center of the axis. This makes them self-aligning and takes up some of the excess actuator length.

        The yokes are constructed from two pieces of hardwood lumber with a 1/4 inch piece of hardwood plywood glued between. The center portion is also plated with the same plywood. Strongly round off all edges.

        The ends of the yokes must be make into uniform dowels 1.75 inches in diameter. This can be made done with hand Tools. First cut a hole the size needed in a scrap of hardwood or metal. Mark the center of the yoke end and draw a circle the right size. Remove excess material with a hand saw and chisel. The rasp the end round using the hole in the scrap material to find hinge points. Take all the time necessary to do this job carefully and safely.

        The holes are best cut with a hole saw and mandrill in a drill. These are available in a variety of sizes at reasonable cost.

        The mountings for the linear actuator must be fitted to your specific actuator. Your specific one will have to have custom hand-made spacers so that the ends fit firmly against the yokes without much slop.

      2. Dowels

        The long and short dowels are cut from 1.25 diameter stock. This material is of often used for closet rods. This material is usually clear softwood rather than hardwood. All the dowel ends are beveled with a wood rasp.

      3. Scissor Beams

        The mechanism is basically a scissor jack just like the one in most new cars. Spreading the scissors apart raises the desk top evenly.

        The four outside scissor beams have holes for the top yoke and two inside beams have notches.

        All the holes must be sanded smooth with all edges rounded. The holes should be a loose fit on the dowels and yokes as wood can expand with temperature and humidity. Finishing will also shrink the holes and expand the dowels slightly.


  7. Trial Assembly

    First assemble all the parts and check for fit and proper movement. Then partially disassemble the unit for Finishing. Finally you will reassemble the completed desk and lubricate all the moving parts with paraffin wax.

    1. Base

      Assemble the base using screws and glue. The screws should be slightly countersunk so that they will not be touched in sanding. Having all the screws to a uniform depth is important for the appearance. A better-quality Screwmate drill does a good job for this.

      Do not glue the top and bottom side-to-side stringers. You will have to adjust their final positions after you are sure of the limits of movements of other components. Just screw them in place for the trial assembly. Base

    2. Actuator

      Electrically wire the actuator, switch, and cable. Make the cable lengths a little long so that you can later shorten them for final assembly.

      The actuator and switch come with papers showing how they are connected. The switch can handle several types of motors, be sure you have the correct diagram for a bidirectional, single-phase, 115 volt AC motor. If you have questions, you can E-mail us but we will need copies of the papers that came with the actuator and switch (by electronic, FAX, or mail).

      Three switch options are possible and the parts for all three are listed under Materials. The simplest and least expensive is the drum switch. This switch is designed specifically for this type of application. It has a lever you push one way for up and the other for down. The lever is spring loaded in the middle stop position.

      The second type of switch is push-bottoms. Two complete push-bottom switches and a special box are needed. The exact type of switch needed must be matched to your specific actuator.

      The third type of switch is the foot peddle. Two are required, one for up and one for down. They can be mounted together on a piece of plywood. Again the exact switch requirements may vary with your actuator.

      A separate electrical junction box will also be needed for electrical connections. These are available at any hardware store.

      A simple way to obtain the cable is to use a 50 ft. heavy duty exterior extension cord with three #14 wires. These are readily available at all hardware stores and come in orange, black, or blue.

      The green wire is always a safety ground and must be connected to all metal parts. The white wire is the power return and is not switched. You will probably need two runs of cable between the actuator and switch.

      All cables must be clamped where they come out of boxes. These clamps are available at most hardware stores. You may need to add a small electrical box to your actuator as a place for connections.

      When you are confident you have the connections right, test run the actuator. Most wiring errors result in no movement. A few types of errors can blow the house circuit breaker, so be ready for it.

    3. Scissor Beams

      Assemble the two sets of three scissor beams. Use two short dowels, four plastic washers, and the two spacers blocks. Yogurt cup lids make good washers. Dry fit all the parts; do not use lubricate at this time as lubricate will spoil the finish.

      Trial fit the scissor beam assemblies to the front joints on the base. Using two short dowels and plastic washers (no lubrication). Some material will have to be chiseled from the base pieces to get free movement.

    4. Long Dowels

      Install the two long dowels. Operate the scissors by hand and be sure that the inside scissor beams run smoothly up and down their tracks in the base. The locking screw locations are shown in Figure #4, Cross Sections

      .
    5. Yokes

      Install the tie rods lower long dowel. Place the lower yoke in the tie rods and install the end caps with two screws each. Install the upper yoke by removing and replacing some of the locking screws.

    6. Top Tracks

      Dry assemble the top tracks and joints. Check fit them before screwing and gluing. You will need to chisel some material from the tracks inside the joints. The space blocks may need some chiseling also.

      Disassemble and glue the top joint parts. Install the top short dowels, washers, and locking screws.

      Temporarily screw a 1 by 6 board across the two tracks in stead of the top. The top would be in the way right now.

    7. Install Actuator

      Install the actuator and check the movement. Do not keep running the actuator when it reaches its limits. This drive should take about 90 seconds to run between limits.

    8. Top

      Remove the temporary board and install the top -- do not glue --. The front screws should pull down tight but the back screws should be able to move slightly in their holes if the top expands.

      The hand-built, metal tip preventer keeps the top from tipping up if some one sits on the front edge of the desk. It is made from a piece of 1/2 inch steel strap.

      Drill one end for a screw and bend the strap with vice grips. Install the back end of the preventer with the top in the low position. Raise the desk to the top position and mark the preventer for its front bend. Remove the preventer complete bending it and drill a second screw hole. Reinstall it and check the movement.

    9. Locate Stringers

      Locate and glue the two side to side stringers that were only temporally installed. The shaft of the tie rod end should rest against the lower stringer when the desk is in the low position.

      The actuator should just touch the upper stringer when the desk is in the high position. This stringer is curved in the middle to allow it to go as far to the back as possible.

    10. Disassembly

      Disassemble all unglued parts. Sand everything well.

    Rockler order link to first page
  8. Finish

    The Desk can be finished to suit you taste. The original design suggested the look of an old factory. For this look, the wood is stained dark brown and the metal painted back and red.

    1. Wood

      Stain the wood, sand lightly, and finish with polyurethane varnish.

    2. Metal

      Lightly sand all metal parts and wipe them down with paint thinner to remove grease. Mask off all labels. Paint the actuator in the shortest position.

      Prim the metal parts with gray automotive spray primer. Use two colors of oil based enamel on the actuator, we suggest black and orange or red. Consider the color of the wiring in you color scheme. Be sure to prime, mask, and paint the switch box, and all junction boxes.

  9. Completion

    All that is left is to reassemble the desk, and install the computer cables.

    1. Reassembly

      Allow the finish to dry for several day before final assembly. The varnish must be completely dry, at least 48 hours after the last coat.

      Rub all places where wood rubs against wood with paraffin wax. An old candle works well. Also wax all the plastic washers.

      Reassemble the desk from the ground up then check out its movement. Make sure you have all the locking screws in place.

      Move the desk to the low position. See if the inside scissor beams touch the front, lower hinge pieces. You may want to add small rubber bumpers at this point to fill the space and give the desk a more solid feel in the low position.

    2. Actuator Cable

      The actuator power cable should not plug into the computer's spike suppressor but should directly into a wall outlet.

      Locate the switch in a convent but out-of-the-way location up under the top. You may want to shorten the cables so that they look nice but do not bind when the desk moves.

    3. Cabling

      Detailed cabling instructions and plans for a remote power switch are given in our Web page under 'Freebies'. Make up several cable tie mounts and be ready with mounting screws and tie wraps. The remote power switch is optional but is really helps the desk user.

      Install a generous number of cable tie mounts under the table and Raising Desk tops sections where cables will run. Construction of the cable tie mounts is also covered in the switch box documents.

      Move the desk into position, but slightly away from the wall. Place each piece of the computer on the desk, then route the cables. You will probably need extension cables for everything on the Raising Desk. These are available at most computer stores. Neatly wrap the connectors with electrical tape so they do not fall apart when the desk moves.

      Tie wrap all cable securely at the top of the Raising Desk top. If you have cut cable holes in the top, route all cables through them and tie wrap the cables to the underside of the top at the back. If you did not cut the cable holes, then tie wrap the cables the rear edge of the top and be sure that they do not rub against the wall.

      Drape the cables behind both long dowels and the two back stringers. Raise the desk to its highest position, then tie wrap the cables to the back of the upper rear stringer leaving some slack in the cables.

      Dress the cables neatly base and table legs using tie wraps. Do not pull the tie wraps too tightly, the cable should be able to slide back-and-forth a little. Trim off all the tie wrap ends. Black tie wraps look best and last longest.

Rockler order link to first page

Conclusion

Thanks again for using a Woodware Computer Furniture Plans. We very much want to know how you are getting along with your project and would be happy to answer any questions by email.

If you send us a picture of your finished desk, we would be happy to put it on our web page. We need pictures of desk with real people standing beside them.

Don't forget to order the sketches .

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