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  • Rick Kr
    replied
    The saga continues. I was diverted from working on this for quite a while by an urgent family matter and a request from my daughter to make her a "twined rag rug" weaving loom" for her birthday, one week ahead of said birthday, which was yesterday. The loom was completed enough to assemble it with partial hardware.
    Rag Rug Loom 12-21-18 640.JPG

    There is a lot of finishing work yet to be done. I used my new planer extensively in preparing the wood, which delighted me. I'd never really used a planer much before. Also, because I planed the wood, all the corners were very square and sharp and need rounding. I also want to radius the edges of the board for the gear toy, but did not have a decent router or router table. I solved that, with a Bosch router and table, which arrived yesterday and I assembled and started using last night. I don't have a table saw and do not have room for the one I want, so I have to use other methods for certain types of cutting, etc.

    As of last night, I am back on the gear train toy for my granddaughter's Christmas present, with only three days to go. For the gear train toy peg board, I am building a torsion box backing so it will be rigid, using 3/4" square molding for the internal members and 1/4" Baltic birch plywood backing. I will use the new router/table extensively for trimming the torsion box assembly and radiusing the corners. I tested using it in jointer mode last night and then used it today to size the Baltic birch plywood backing, The router/table will be used with ball bearing guided router bids for trimming the sides of the sandwiched torsion box and for the radiusing.

    I used some of the axle pegs I turned for aligning the internal members so they did not overlap any of the peg board holes. 1/4" dowel would have worked, but the axle peg "hubs" are larger than 1/4" and did a better job of centering the ribs.
    Aligning Members 12-22-18 640.jpg

    Completed peg board front with torsion box members. I used small wire brads to nail the members to the peg board as well as glue.
    Completed Torsion Box Members 12-22-18 640.JPG

    I wanted to mount the backing without using nails, just with glue, and wanted to add considerable weight during gluing so I "set" the backing position using some of the wire brads, driven into the internal members at the corners to keep the backing from shifting once glued and the weight added.
    Positioning Nails 12-22-18 640.JPG

    Then 3/4" plywood to distribute the weight.
    Three Quarters Plywood 12-22-18 640.JPG

    And finally the "weights", four 50lb. bags of chicken feed (my daughter has a lot of chickens).
    Two 100 LBS Chicken Feed 12-22-18 640.JPG

    I am anxious to see how it all turns out, but have to wait until tomorrow morning to ensure the glue sets up well.

    Rick
    Last edited by Rick Kr; 12-23-2018, 01:47 AM.

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  • Rick Kr
    replied
    Originally posted by Rolf View Post
    The machine shop was my secondary responsibility my main job was running and maintaining a semiconductor processing lab. We designed and processed special silicon detectors for High energy physics and photon science research. I got to play with CAD and all sorts of neat equipment, like wire bonders that put down wire that is 25 um in dia. or .001 inch. I did the original design and prototype fabrication of this device. others in our group developed the readout electronics etc.
    https://www.bnl.gov/newsroom/news.php?a=212196 I spent many hours at a microscope.
    Very cool, Rolf. That seems like a bit of a high powered job. I use CAD as a design tool/step on nearly all of my "making" projects, both in wood and metal. Love using it and there is a whole creative design aspect to it, that, to me, is vital to successful projects. I have not heard of Brookhaven NL before. I now understand why your machine shop had such high end machines. I worked for Argonne Nat'l Lab in near Chicago (where the atomic bomb was partially developed in the '40s) in the mid-80s, but my job location was actually Portland, OR, as we were doing Environmental Impact Statements for cumulative impact assessments of multiple small-hydro projects in the Pacific Northwest.

    As shown in the photos and videos above, my gears are already made, but they are not meshing properly, too tight. I have been using CAD to redesign them and supporting pieces but time is running out and I don't know if I'll get to re-making the gears before Christmas. If I do, I'll make them from Baltic birch plywood this time. I've taken on another project, that of making a "twined rag rug" loom for my daughter. That is a lot to do in just a week remaining.

    For the redesign of the gears, I'm using a gear generator program from WoodGears (http://woodgears.ca/). I've purchased a number of their wood gear projects as well as their gear generator program. Just hope I make the time to make some of them, as I think they could be more fun for my granddaughter that the Gear Train Toy.

    Rick

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  • Rolf
    replied
    The machine shop was my secondary responsibility my main job was running and maintaining a semiconductor processing lab. We designed and processed special silicon detectors for High energy physics and photon science research. I got to play with CAD and all sorts of neat equipment, like wire bonders that put down wire that is 25 um in dia. or .001 inch. I did the original design and prototype fabrication of this device. others in our group developed the readout electronics etc.
    https://www.bnl.gov/newsroom/news.php?a=212196 I spent many hours at a microscope.

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  • Rick Kr
    replied
    Originally posted by Rolf View Post
    This is one really cool project I would love to play with it myself.

    One of my many hats while I was still working was managing an experimental machine shop. My favorite machine was a new Hardinge lathe that I purchased when I took over the shop. We already had a couple of the Monarch lathes old but still incredibly precise. We retrofit all of the machines with DRO. I have a very small OLD Logan in my basement. I may add Wixey DRO to at least the cross feed. I inherited it from my Dad. He was a old world German tool maker.

    For non machinists DRO is digital read out.
    Thanks, Rolf. You were a lucky fellow with that job. I have never operated a Hardinge. They are a suburb machine. Lore among machinists I know have the Hardinge and the Monarch 10EE as the two ultimate home shop machinist lathes. I feel exceedingly lucky and happy to have the Monarch. As pictured, it as DRO on two axes, crossfeed and carriage feed. I've had a DRO on my mills for over 15 years, but this is the first lathe with one, had it for about two years. Love it. I have not looked a the dials on the mill since and am now not looking at the dials on the lathe either, except what thread cutting and using the top slide.

    The gear toy is turning out to be much more challenging that I anticipated. Mostly due to the difficulty of finding peg hole placements to get the gears to mesh. Quite an unnecessary difficulty, but I've not come up with a better alternative yet. I'm wondering if something there the center hole is used for locating and a second peg for locking. Something like that would require redesigning that feels beyond me at this point.

    Rick

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  • wjbclocks1
    replied
    I agree the Hardinge lathe was one that I lke also.

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  • Rolf
    replied
    This is one really cool project I would love to play with it myself.

    One of my many hats while I was still working was managing an experimental machine shop. My favorite machine was a new Hardinge lathe that I purchased when I took over the shop. We already had a couple of the Monarch lathes old but still incredibly precise. We retrofit all of the machines with DRO. I have a very small OLD Logan in my basement. I may add Wixey DRO to at least the cross feed. I inherited it from my Dad. He was a old world German tool maker.

    For non machinists DRO is digital read out.
    Last edited by Rolf; 12-15-2018, 09:41 AM.

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  • Rick Kr
    replied
    With just the first coat of Tung Oil on the gears, I just had to try setting them up in a gear train. If nothing else, just to test them to be sure it actually works. Blue tape is the size I plan to make the peg board.
    Gear Train Setup 12-14-18 500.JPG

    It does, but I see some issues with a couple things. One, the pegs I made for attaching the gear bases to the peg board may be too short and not holding the bases in securely enough. Also, the pegs on the gear bases are hidden and the bases rotate freely, so it is very difficult to locate the bases over the peg board holes and get the gears lined up to engage properly. And the gear base pegs are lined up on the diagonal of the peg board holes, not the horizontal or vertical 1" spacing of the peg holes, so, positioning the gear bases is not at all intuitive. All of these will be unnecessary challenges for a 5-yr old. I can fix the peg lengths easily. The latter two issues will be much more difficult.

    Here are a couple videos of the gear train in motion. Initially, just putting the gears up on the board and seeing how well they engage and rotate. They do, but there is some tightness and hanging up at times. Makes me wonder if the teeth didn't need to be sanded down further. I sanded nearly all of the lines away, maybe they needed to be sanded completely away. Maybe if I remake all the gears from plywood.
    https://vimeo.com/306520517

    And here, I actually tried sequencing the gears to get some reduction. It worked, resulting final reduction is 26:1. It needs more of the largest gears and could used some spacer so small gears don't have to be used.
    https://vimeo.com/306520540

    Rick
    Last edited by Rick Kr; 12-15-2018, 02:08 AM.

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  • Rick Kr
    replied
    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

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  • Rick Kr
    replied
    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

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  • Rick Kr
    replied
    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

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  • Rick Kr
    replied
    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

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  • Rick Kr
    replied
    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

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  • Rolf
    replied
    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.

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  • Rick Kr
    replied
    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, 03:46 PM.

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  • Rick Kr
    replied
    The finished, sanded gears/bases.
    Finished Gear Teeth 11-30-18 640.JPG

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