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  • Gear Train Toy

    Originally posted by Rick Kr View Post
    Here is the URL for the pattern.
    Scrollsawn Gears Woodworking Plan from WOOD Magazine
    https://www.woodstore.net/Scrollsawn...gr-00942a.html


    Click image for larger version Name: Gear Toy Gears on Board 11-29-18 480.jpg Views: 1 Size: 97.1 KB ID: 861094
    Originally posted by Rolf View Post
    Now that is something I would play with! What a neat project.
    Link to the thread that lead to this one (I'm having trouble inserting this URL properly).
    https://forum.scrollsawer.com/forum/...r-toy-patterns

    I spent an entire day working on making the gears for this toy a couple days ago. I'll post a series of photos to show the progress. I initially was going to make this for my granddaughter's 5th birthday this Monday (two days away now), but decided that was too much and got her something else and will complete the gear project for a Christmas present.

    I had previously cut out round blanks from 1/2" MDF for the gears and 1/4" Baltic birch plywood for the gear bases. I stacked them two, three or five tall, depending on material thickness and the number of gears I was making and applied blue tape and the patterns on the top blank. They needed to be drilled and pinned together for sawing and sanding.

    The usual way to drill these would be by carefully centerpunching the crosshairs at the center of each hole location and then carefully drilling at each centerpunch. If I were doing it that way, I'd likely use the sharp point of a forstner bit to help with locating the hole and might just put in a starter/locating hole with that bit, followed by a regular drill. No sense in dulling the forstner bit any more than necessar.

    But, I have a vertical mill with DRO, which allows me to very accurately locate the holes and drill them. I first lined up the crosshairs using a laser centerfinder, shifting the clamped together stack around until the laser fell on the center point of each of the three peg holes. Then I'd go to the center hole and zero out the DROs. Center hole was drill at this point.
    Drilling Center Holes 11-30-18 600.JPG

    Because the peg holes are on 1" centers, each 1/2" off of the centerline, I could run the table until the DRO read 0.500" on both the X and Y axes and centerdrill each peg hole successively, followed by a drill, similarly run out to the exact dimension. This method has the potential to result in near perfect registration of all the peg holes, better than manually locating each hole.
    image_73975.jpg

    For the pinning, and due to my method for sanding the gear blank ODs, I drilled the centerhole slightly oversized from 3/16" so it would rotate relatively freely on an 3/16" steel shaft. The peg holes were drilled for a snug finger pressure fit for 3/16" hardwood dowels, slightly oversize from 3/16". The stacked and pinned blanks.
    (Can't upload this photo, keeps hanging up and there is no indication of what error occurred.)

    I had stacked the blanks in anticipation of scroll sawing the gear teeth. I ended up cutting them out on my bandsaw, so stacking them higher could have worked, except that the internal cutouts of the two larger gears still had to be scroll saw cut.

    Rick
    Last edited by Rick Kr; 12-01-2018, 02:15 PM.
    "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

  • #2
    The photo that I couldn't load from the post above, showing the stacked and pinned blanks.
    Stacked and Pinned Blanks 11-30-18 600.JPG
    "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

    Comment


    • #3
      I cut the gear blank and gear base rough ODs on the bandsaw. Shown is the Carter Band Saw Stabilizer I use for blades under 1/4" which allows effective scroll-like cutting, especially with the 1/8", 14tpi blade. It is a single, top guide, no bottom guides, which lets the blade twist a bit. Forward tension on the blade is created by pushing the single bearing guide forward, keeping the blade securing in the groove in the bearing when backing out of cuts. Makes if feasible to scroll cut tall pieces and stacks in surprisingly tight curves/turns.

      No tight turns with these blanks, in either the OD or cutting out the teeth. Here I am using a 3/16" wide, 6tpi blade to cut the ODs.




      Rick
      "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

      Comment


      • #4
        Then came cutting the gear teeth. For this, I used a 1/8" wide, 14tpi blade, again in the Carter Stabilizer guide. The curves on the gears did not require use of the 1/8" blade, but making the turns inside to the bottom did.


        After the tooth profiles were cut, I cleaned up the gullets using the bandsaw blade. I held the tooth bottom in close to the blade and moved it laterally using the front surface of the blade sort of like extremely fine sandpaper to clean out the roughness left by the turns at the bottom. Worked surprisingly well and allowed me to get nice square corners. Before is the gullet on the left, after on the right.


        Rick
        "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

        Comment


        • #5
          The bandsaw cut gear teeth.
          Bandsaw Cut Gear Teeth 11-30-18 640.JPG
          "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

          Comment


          • #6
            I made a jig for my 4x36" belt sander table for sanding the gear and gear bases to finish size. To minimize the amount of sanding, I did the OD sanding after cutting out the teeth. No point in sanding wood that won't remain.

            The jig consisted of a base which had the key on the bottom for the table slot. This key was pivoted on one end and slotted on the right end to allow adjusting its distance from the belt, the use of which will be discussed below.
            Gear Diameter Sanding Jig 2 11-29-18 600.JPG

            The jig had a top slider piece that had pivot holes for each size of gear and the base. It also pivoted on the left side, on the same point as the base. It had a pivoting slot on the right, but it was never locked down. This pivot allowed the slider to move inward and outward so the roughed gears could be sanded progressively smaller, with the slider moving in until it reached the end of the slot, which acted as a stop on the sanding action. The point of that "stop" was set by locking the base distance from the belt.
            Gear Diameter Sanding Jig 1 11-29-18 600.JPG
            It appears only two photos can be loaded into a single post, so this will be continued in another.

            Rick
            "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

            Comment


            • #7
              Pivot holes were placed such that each gear would "stop" sanding at the correct finish diameter (visible in the second photo of the previous post). The gear base is 2" OD. The gears started at 3.375" OD and increased by two inches for the medium (5.375") and large (7.375") gears. This jig made for very fast and accurate sanding of the ODs of each sized gear/base without any setup changes. After initial jig construction and setup, much faster and accurate than free-hand sanding to the lines.
              Gear Diameter Sanding Jig 3 11-29-18 600.JPG

              Sanding ODs 2 11-30-18 640.JPG

              Gear tooth profiles were sanded on a 1x30" belt sander. The smaller size sander was required due to the narrow width of the platten, for getting in there to the bottoms of the tooth side profiles. The bottoms had already been cleaned up adequately using the bandsaw as described in an earlier post, but I did go in with sanding blades on the scroll saw to sand down the few spots missed by the bandsaw.

              Rick
              "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

              Comment


              • #8
                The finished, sanded gears/bases.
                Finished Gear Teeth 11-30-18 640.JPG
                "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                Comment


                • #9
                  Next came drilling the holes for the cuttouts, prior to scroll sawing. I centerpunched each hole center location and used forstner bits.
                  Cutout Drilled Blanks 11-30-18 640.jpg

                  And the finished scroll cut and spindle sanded cutouts. After scrolling the cutouts, I used a spindle sander, but the 1/2" spindle sleeve was closer to 5/8", so the smaller corners in the large gears became enlarged.
                  Scroll Cut and Spindle Sanded Cutouts 11-30-18 640.JPG

                  And with this, I am out of material for now. Still to come for the gears and bases is drilling out the respective peg and center pivot holes, but that may have to wait a bit. Granddaughter arrived this morning and these will need to be put away until it is clear to work on them again.

                  Rick
                  Last edited by Rick Kr; 12-01-2018, 02:46 PM.
                  "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                  Comment


                  • #10
                    Thanks for the step by step.
                    I do wish I had a Bridgeport with a DRO or even 2.5 axis CNC. No room. How well does the Carter roller work with the 1/8 blade?
                    I still think about building a small CNC router for very precise holes etc.
                    Rolf
                    RBI G4 Hawk, Delta SS350, Nova 1624 DVR XP
                    Philosophy "I don't know that I can't, therefore I can"
                    Proud Member of the Long Island Woodworkers Club
                    And the Long Island Scrollsaw Association

                    Comment


                    • #11
                      Originally posted by Rolf View Post
                      Thanks for the step by step. I do wish I had a Bridgeport with a DRO or even 2.5 axis CNC. No room. How well does the Carter roller work with the 1/8 blade? I still think about building a small CNC router for very precise holes etc.
                      Rolf,

                      DROs are an incredible improvement in all sorts of tasks on the mill and lathe. I no longer pay any attention to the dials on the axes that have the DRO. Incredible relief from tedium. I have a two-axis DRO on my Monarch 10EE metal lathe. The mill I have has three axis, X and Y, and the vertical "Z" axis of the knee. It is the smallest knee mill I know of (6x26) and takes up about 1/2 the space of a full sized Bridgeport. I would love to have a BP and I do have the space.

                      The Carter Stabilizer works surprisingly well. Properly tensioned and adjusted, the blade does not pull off the bearing at all, allowing pulling the piece back out the saw kerf. It can make surprisingly tight turns also. "Properly tensioned and adjusted" means good tension on the blade along with pushing the blade forward by the grooved bearing about 1/8-1/4". This puts backwards tension of the blade against the bearing so it will not pull off the bearing when parts are backed out of the kerf.

                      These turns were made with it in 4" tall Douglas fir. The turns are probably 3/8" diameter. It probably can do finer turn, but I haven't tried it.
                      Bandsaw Box 1 07-25-18.jpg

                      Rick
                      "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                      Comment


                      • #12
                        Originally posted by Rick Kr View Post
                        I cut the gear blank and gear base rough ODs on the bandsaw. Shown is the Carter Band Saw Stabilizer I use for blades under 1/4" which allows effective scroll-like cutting, especially with the 1/8", 14tpi blade. It is a single, top guide, no bottom guides, which lets the blade twist a bit. Forward tension on the blade is created by pushing the single bearing guide forward, keeping the blade securing in the groove in the bearing when backing out of cuts. Makes it feasible to scroll cut tall pieces and stacks in surprisingly tight curves/turns.


                        No tight turns with these blanks, in either the OD or cutting out the teeth. Here I am using a 3/16" wide, 6tpi blade to cut the ODs.

                        Rick
                        Just learned there is a timer that prevents one from editing their posts after some unspecified time. Can't edit, so will repost, in effect. I noticed some photos missing from this post, so here they are again...

                        Bandsawing Large Gear OD 3 11-30-18 640.JPG
                        Bandsawing Large Gear OD 2 11-30-18 640.JPG
                        "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                        Comment


                        • #13
                          Originally posted by Rick Kr View Post
                          Then came cutting the gear teeth. For this, I used a 1/8" wide, 14tpi blade, again in the Carter Stabilizer guide. The curves on the gears did not require use of the 1/8" blade, but making the turns inside to the bottom did.


                          After the tooth profiles were cut, I cleaned up the gullets using the bandsaw blade. I held the tooth bottom in close to the blade and moved it laterally using the front surface of the blade sort of like extremely fine sandpaper to clean out the roughness left by the turns at the bottom. Worked surprisingly well and allowed me to get nice square corners. Before is the gullet on the left, after on the right.


                          Rick
                          Similar deal, reposting photos.

                          Bandsawing Gear Teeth 1 11-30-18 640.JPG

                          Bandsaw Cleaning Tooth Gulets 11-30-18 640.JPG

                          "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                          Comment


                          • #14
                            Plans for the gear train called for using commercial "axle pegs" used for attaching wooden wheels to wooden toys for attaching the Gears to the Gear Bases, but I didn't like the diameter (too small - 7/32" [0.218"]) of the nominal 1/4" axle pegs and didn't like the uncertainty of how far in the pegs would go when gluing the Gears in place on the Gear Bases. So I machined some "precision" axle pegs.
                            Turning Axle Pegs 1 12-10-18 580.JPG
                            Turning Axle Pegs 2 12-10-18 640.JPG

                            I made them with specific diameters for the axle portion (0.270") and for the portion that gets glued into the Gear Base (0.246").
                            Completed Axle Pegs 12-10-18 640.JPG

                            The shoulder is a positive stop for how far in the peg will go, setting a close spacing for the Gear from the Base. Makes for cleaner and less wobbly rotation.

                            Rick
                            "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                            Comment


                            • #15
                              The gears are made from MDF and the gear bases from baltic birch plywood. I am finishing them with Tung Oil. I don't care for how the gears are darkened and am considering remaking them from plywood. I'll do that only after the whole project is completed in time for Christmas so there is no danger of not finishing at least something. Here is the first coat. What I don't like about how dark the gears are is they have lost the contrast against the darker peg board background.
                              Finishing Gears with Tung Oil 12-13-18 640.JPG

                              Rick
                              "If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes a bit cheaper."

                              Comment

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