| Home | Site Map | Plans | Crafts | Freebies | Challenges | Pictures | Energy | Astronomy | Contact | Order |

CNC Piranha
copyright 2015

Shop Built Add-Ons for the CNC Piranha

Work in Progress

The CNC Piranha is a small, low cost CNC milling machine for the home woodworker. This construction note covers a number of shop-built add-ons to make this machine easier to use.

The add-ons featured are:

  1. Front Table Extension -- This addition to the table improves the clamping in the front area to insure that the work pieces is properly held down front and back.
  2. Wooden clamps (built) -- These are less risky than metal clamps in that not much happens if one is hit by the mill.
  3. A foam box to control sound and dust (prototype build) -- This foam box lets you do show-and-tells by controlling both noise and dust.
  4. Plywood Router Body Clamp (being built) -- This plywood piece lets you clamp other brands of routers into your CNC machine.
  5. Back Table Extension -- This addition to the table improves clamping particularly when using long pieces of stock.
  6. Centering Board -- This simple alignment tool helps you insure that the bit always starts in the same place.

_______________________________


Emblem for Big Moon Dig

The Big Moon Dig

As odd as this may seem, we bought this little CNC machine to make 3D wooden blocks of sites for settlements on the Moon. If you are interested in human space exploration then please check out our big lunar project, The Big Moon Dig.

You will find a detailed process for the use of the CNC Piranha on our Web Site at: The Big Moon Dig / Lunar Surfaces. The detailed procedure is also available as a Adobe .pdf document a: "LRO Data to CNC Machine"

Return to the Moon with us now to prepare the ground for a real lunar settlement through study, simulations, team building, and exploration. We can do this.

You might find our new approach easier to understand if you read our science fiction short story: "The Big Moon Dig".

  • Pictures of our other Projects

    Pictures of many of our other Woodware projects can be seen in our Picture Gallery.


  • _______________________________


    1. Ordering the Sketches

      This design includes five detailed sheets that are critical to you successfully building this add-on. Here is where to get all the ordering information. Look for "Other Woodworking Projects / CNC Piranha Add-ons", or you can write "CNC" in the text box at the bottom. All the available Piranha add-ons and support files will be sent free on one request.

      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. Tools

      These add-ons are designed so that they could be build by an amateur woodworker of moderate skill with a modest home shop. Construction requires the use of a radial-arm or table saw, and common hand tools.

      The major construction challenges relate to:

      1. Aligning with the slots with the existing table
      2. Laying out the CNC cables
    3. A safety equipment
    4. Safety

      A CNC machine generates quite a bit of noise and dust. You should always use safety glasses with side shields, ear protectors, and a simple dust mask.

      The foam box, detailed below, helps control dust and noise.

    5. Electrical

      A CNC machine needs to have its own outlet strip sperate from the router with electrical noise suppression. Routers generate electrical noise.

      The router needs an sperate extension with an external power switch particularly if the noise box is used.

    6. Finish

      I did not finish any of these add-ons but you can.


    7. _______________________________


      Sketch of Front Table Extension for CNC Piranha
    8. Front Table Extension

      This addition to the table improves the clamping in the front area to insure that the work pieces is properly head down front and back.

      1. Discussion of Sketches, Front Table Extension

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

        1. Front Table Extension, CNC Piranha (graphic above)

          This Sheet shows the completed front table extension and provides the overall diminutions.

          Note that the tracks for the T-bolts continue from the existing table through the extension. These are cut from an aluminum extrusion, Universal T-Track. The extension attaches to the front of the CNC machine with two bolts. Holes for these bolts already exist.

        2. Front Table Extension, Sheet 02 -- Cut Plan

          This Sheet shows the individual parts of the table extension.

          The drawing shows only five sections of T-Track as that is as many as you can cut from one 24" piece.

          The table extension is full width of 15 inches which is wider than the original table, but which will not interfere with the y -axis mechanism .

        3. Front Table Extension, Sheet 03 -- Alternative Layout

          This Sheet shows the table extension with an alternative layout for the T-Track. Here two pieces run side to side.

          Be sure to notch the edge of the extension board enough to let T-Bolts to be slipped into the tracks with the extension in place. Also the screw blocks have to line up with the predrilled screw holes in the T-Track. Here the screw blocks are also notched into the front board to reinforce a weak joint.

      2. Materials, Front Table Extension

        These add-ons are made from hardwood, scrap plywood, and speciality hardware.

        1. Clear Wood:
          • Sheet 02 ---- .9 board feet

          Example 1 bft @ 7.50 /bft Oak ------- Subtotal: $7.00

        2. Hardware:
          • Universal T-Track ----------- 24" ----------- $14.00 (Rockler 22104)
          • T-Bolt, 5/16" 1-1/2" --------- 2 ------------ $ 2.00
          • Five-Star Knob --------------- 2 ------------ $ 3.00
          • Flat washer, 1/4" ------------ 2 ------------ $ 0.20
          • Screw, flat head ^3 - 3/4" ----14 ----------- $ 3.00

          Hardware subtotal $23.00

        3. Omissions and Contingencies (~12%)(Tax, sand paper, etc.) $ 5.00
        4. Estimate Total Cost $34.00

        This is only an estimate (made in the spring of 2015). The price may vary in your area. Getting a good price on the hardware is critical to keeping the price down.

      3. Image of Front Table Extension for CNC Piranha
      4. Fabrication Notes, Front Table Extension

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

        1. Options

          Look over the add-on drawing as decide what you are going to do:

          1. Extension Width -- The extension is shown extra wide at 15 inches.
          2. T-Track -- You may use other brands of T-Track or route a "T" grove directly into the wood. The T-Track can run side to side.
        2. Top

          The top is 4.5 inches wide and has groves to accept the T-Track extrusion. Only 5 tracks are shown because that is how many you can cut from one 24" piece of stock. These must align with the existing groves in the top.

          The top extension also has short notches in the locations of the top groves that are not extended. This allows T-Bolts to be easily slipped into them.

        3. Front

          The extension front is a simple piece of hardwood. It has two - 5/16" holes for T-Bolts in locations factory-made in the CNC front. These holes need to be carefully aligned.

        4. T_Track

          Cut the 24" piece of t-Track stock into 5 - 4.5" pieces. File off all tool marks. Drill them from the bottom for a #6 screw body and then countersink the holes from the top.

          The two screw blocks are shown so that 3/4" screws can be used to hold down the T-Tracks.

        5. Assembly

          Glue and screw the wooden parts together. Check the alignment. Install the T-Track pieces.


    9. _______________________________


      Sketch of wooden clamps for CNC Piranha
    10. Wooden Clamps

      These are less risky than metal clamps in that not much happens if one is hit by the mill.

      1. Discussion of Sketches, Wooden Clamps

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

        1. Wooden clamps, CNC Piranha (graphic above)

          This Sheet shows the completed wooden clamp and provides the overall diminutions.

          Note that the grain of the interior plies runs the long dimension of the clamp and you should have a variety of wooden blocks on hand to suit different blank material thicknesses.

      2. Materials, Wooden Clamps

        These clamps are made from scrap materials.

      3. Photo of wooden clamps for CNC Piranha
      4. Fabrication Notes, Wooden Clamps

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

        1. Options

          Look over the add-on drawing as decide what you are going to do:

          1. Height of blocks -- Cut several blocks of each thickness of material you use on your CNC.
        2. Top

          The top is a strip of 1/2 inch plywood with one corner trimmed off and a sloppy 5/16 inch hole in it.

          Note that the stronger interior grain run the length of the clamp. I make up about eight of these strips at a time.

        3. Blocks

          Cut several blocks with each thickness of material you plan to use.

          Be careful not to let the spare blocks get under the CNC machine and block its movements.

        4. T-Bolt

          The wooden parts are held to the table with the standard T-Bold, flat washer, and knob.

          Be careful that no part of the clamp is more than 3.0 inches above the table.

        5. Assembly

          You can glue the blocks to the strips or simply let the clamp hold them.


    11. _______________________________


      Sketch of dust box for CNC Piranha
    12. Dust Box

      This foam box helps you do show-and-tells by controlling both noise and dust. I include sperate sketches for .5" and .75" foam board. Use which ever is available locally.

      1. Discussion of Sketches, Dust box CNC Piranha

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

        1. Dust Box, CNC Piranha (graphic above)

          This Sheet shows front and side of the completed Dust Box and provides the overall diminutions. The space needed for the CNC Piranha is shown as a red box inside and includes space for the Table Extension and the cables.

          Note that there is a plastic window in the front, two cutouts for cables in the back, and a handle made of duck take.

        2. Cut Plan, Sheet 02 -- Cut Plan

          This Sheet shows how to cut up the sheet of 1/2 inch foam.

          Note the two rough cut lines that you can easily do in the store with a utility knife so you can more easily get the material home.

      2. Materials, Dust Box

        This add-on is made from a sheet of foam and a plastic window. It is held together with hot glue and duck tape.

        1. Materials:
          • .5" foam sheet, 4' x 8' ---- 1 ----- $10.00
          • Plastic sheet, 24" x 18" --- 1 ---- $12.00
        2. Hardware:
          • Duct Tape --------------- 1 ------------ $ 6.00
          • Hot Glue Sticks --------- 6 ------------ $ 5.00
          • Hardware subtotal $33.00

          • Omissions and Contingencies (~12%)(Tax, sand paper, etc.) $ 5.00
          • Estimate Total Cost $38.00

        This is only an estimate (made in the spring of 2015). The price may vary in your area.

      3. Photo of dust box prototype for CNC Piranha
      4. Fabrication Notes, Dust Box

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

        1. Options

          Look over the add-on drawing and decide what you are going to do:

          1. Cable notches -- There is a major concern that the cables can get trapped between the moving parts of the CNC and block its movement. This problem is particular important inside a box as you cannot see what is going on very well. Run your machine back and forth several times and plan where you want the cables to come out of the box. Having the notches on the bottom edge makes it easy to lift off the box.
        2. Foam Cut

          Cut the foam squares out with a utility knife and large square, or cut them on a tale saw.

        3. Glue Up Box

          Start with the top laying upside down. Note how the edges overlap. Glue on one side and the back with a hot glue gun. Be careful with the hot tip of the glue gun; it is bad for both foam and hands. Hold these part in place with temporary duct tape until the glue cools.

          Add the second side and then the back.

        4. Add on Window

          Check that the window plastic fits the front. Add the two foam strips to make a supporting lip at the bottom.

          Secure the window with hot glue and duck tape.

        5. Add stiffener strips

          Cut strips of foam from the scrap pieces and glue them in inside to reinforce the five foam-to-foam edges.

          Glue foam strips diagonally across the large internal foam areas to strengthen the box and reduce sound transmission by drum head.

        6. More Duck Tape

          Remove any temporary duck tap and dust off the outside of the box. Run a neat strip of duck tape along each edge and along the bottom.

          Make a duck tape handle or two for the top of the box.

        7. Cable Notches

          Cut the cable notches in the back. The x-z cable and the router power cable may have to move in and out a little and the carriage moves in the y-axis. Don't make the holes any bigger than you have to or they will leak dust.

        8. Flashlight

          It is hard to see inside the box so it helps to keep a flashlight handy.


    13. _______________________________


      Plywood Router Body Clamp for CNC Piranha
    14. Plywood Router Body Clamp

      This plywood piece lets you clamp other brands of routers into your CNC machine.

      1. Design Concern

        The heavy black plastic router body clamp provided with the CNC Piranha is well built but raises a number of design concerns:

        1. It fits only a limited number of routers.
        2. The four mounting holes do not align well after the router is clamped so they distort the clamping pressure.
        3. The bolts do not have flat washers.

        These problems can be addressed by using the CNC machine itself to make a new custom router body clamp.

      2. Proposed solution

        The sketch above shows our proposed solution. Note that in this pattern:

        1. The center hole is a custom size for a specific router.
        2. The four mounting holes are drilled oversized. These bolts can not act as locating pins!
        3. All the bolts do have flat washers.
        4. The material is a double thickness (1 inch, 25.4 mm) of quality hardwood plywood which the a home woodworker can obtain and work.
      3. Files

        When you request the sketches you will also get five software programs:

        1. CNCRtMtM.skp -- SketchUp Version 15 drawing
        2. CNCRtMtM.v3d -- Cut3D file
        3. CNCRMMR.tap -- Rough Cutpath file
        4. CNCRMMF.tap -- Finish Cutpath file
        5. CNCRMMC.tap -- Cut Out Cutpath file

        All of these are for a Makita RT0701C router (***M.) with a body of 2.53" (64 mm) diameter. The SketchUp file can be edited to suit the diameter of your router.

        Unfortunately, this editing however takes access to a SketchUp Version 15 or later ($500.00) with the export .stl module (free). This combination does let you draw up anything you please for routing on your CNC.

        Please e-mail me if you need some other common size, TomRiley@WoodwareDesigns.com

      4. Materials

        This router mounts requires:

        1. 2 -- 6" square (150 mm) squares of 0.5" (12-16 mm) high-quality hardwood plywood
        2. 1 -- 2" - 1/4" bolt
        3. 10 -- 1/4" flat washers
        4. The four corner bolts provided with the CNC work well but require a star diver.

      5. Router mount being machined
      6. CNC Routing

        Two copies of this routing will be needed, top and bottom. Most of the steps in our detailed routing procedure apply.

        Note that in Step 4, the box labeled "Create an extra path 90 degrees to the first" is checked. This greatly improves the roundness of the central hole.

        Put a piece of thin sacrificial plywood under the material. Center the blank in the workspace.

        The strongest internal plys should run in the y-axis. This usually means the thin surface plys will be in the x-axis. Clamp the blank well around the edges.

        The center circle comes loose about 1/2 way through the finish pass. It is best to pause the machine and router. Remove the loss disk. Restart the router and machine.

      7. Construction

        After routing clean up the edges of the two wooden pieces.

        Note the two sides with slots through the clamp tab. These are the inner surfaces. Apply a thin, even coat of good wood glue to both interior surfaces.

        Clamp the two pieces together using the four bolts and flat washers. Match the two internal circles as exactly as you can. Do not over tighten the bolts and let the glue set over night.

        Remove the bolts and smooth all edges.

        Drill out the clamp bolt hole to be a loose fit for the body of your bolt using the rectangular hole as a guide. Put a piece of waste wood under the plywood for all drilling.

        Make a saw clef through the clap tab only as shown in the drawing. This is most safely done with a hand tool, a wide clefted had say.

      8. Check Fit

        Check fit the new router mount on your router body. Sand the inside of the curve as needed.

        Chase a drill through all five holes to be sure they are a loose fit on your bolts.

        Grind or file two of the 1/4" flat washers into a "D" so that they do not rest high on the clamp tab to body curve. Install the clamp bolt with these flat washers. The original bolt is not quite long enough.

        Check how well the router mount clamps to your router body. Point the router cable to your left and slightly forward. The bottom of the router mount should be about 1.5" (38 mm) from the outside of the nut that locks the router bit. Check that the mount has a good grip on the router body.

      9. Mount on CNC

        Trial fit the router mount, with the router, on the CNC machine. Start with the two back bolts. All the corner bolts must point up so that they will not interfere with the clamps. Install all four bolts before tightening any of them. Use eight flat washers. If the bolts do not go in fairly easily, chase out the two front bolt holes to be slightly larger.

        In the future, always loosen the two front bolts before adjusting the clamp bolt. This prevents the concentrations of stress that can brake the mount.

        Draw a line around the top of the mount on the router body with a Shapie. Also mark the saw clef.

        Make a test run of your assembled CNC machine using cheap stock with our detailed alignment procedure. Check that the router has not moved.


      _______________________________


      CNC real table extension
    15. Back Table Extension

      The Back Table Extension is similar to the Front Table Extension except that it is narrower and has on one T-track. It is use to improve clamping when particularly when long stock is used to mill a series of slices.

      It is build very like the Front Extension and the two pieces of T-track left over from that job are used here. The vertical board does have to have a cutout for the motor and drilled pockets for the heads of four bolts.

      The big difference is that there are not mounting holes in the back. This means that you have to use the pattern provided to drill two 5/16" holes. Be sure to cut out the space for the motor and bolt heads from the pattern so it will sit flat.


    16. _______________________________


      CNC centering board
    17. Centering Board

      The Centering Board helps you insure that the bit is in exactly the right position at the start of each software run.

      The Centering Board is used by placing it on top of the work and pressing it against the side and front of the table. The bit can then be moved to the exact center of the work area.

      The Centering Board consist of three pieces, (1) a think plywood top, (2) a side board, and (3) an end board. I used softwood for the side and end boards so that I could nail and glue them.

      The side and end boards are wide enough to allow the Centering Board to be used with stock material already clamped in up to 2 inches thick.

      The dimension in the drawing are include the space for the Front Extension Table. If you do not have this table you will have to adjust the dimensions.


    18. _______________________________


    Conclusion

    Thanks again for using a Woodware Designs 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 add-ons, we would be happy to put it on our web page. We need pictures of add-on with real people standing beside them.

    Don't forget to order the sketches.

    Return to Woodware Designs

    Visit The Big Moon Dig

    Woodware Designs, Woodware@woodwaredesigns.com
    | Home | Site Map | Plans | Crafts | Freebies | Challenges | Pictures | Energy | Astronomy | Contact | Order |