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Routing Gears for Gear Toy

5491 Views 26 Replies 8 Participants Last post by  kolias
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I've been working on a gear toy project for my granddaughter, for over a month now. I have a full set of gears cut using a bandsaw, belt sander and scroll saw sanding blades, from medium density fiberboard (MDF) (see photos below). But, even though I have been very careful to sand "to" the lines, the gears don't mesh right. I've even sanded the lines away and they still don't mesh right. (Last photo should be first, showing bandsawing the gear. Second photo shows how the bottom of one tooth was cleaned up and squared off using the bandsaw and the following photos of the completed gears.)

The gears mount on peg board and I found it difficult to figure out how to locate/position the gears at first. I figured out a handy way that I think young kids like my granddaughter can work with (they may be able to do it better than this old f*** anyway) that I may comment on later. The problem I'm having with the gears is that they should mount directly in line in the 1" peg board hole centers (I think). But they are too tight that way. So, by shifting over one hole, I can get the gears to not bind, but then there is more "clearance" than there should be - again, I think. I've set up full gear trains this way, but it is just not satisfying for me. Gear Train in Motion You may notice that few of those gears are mounted with their centerlines "inline".

Plans for the gear toy are out of Wood Magazine and are available for purchase for $7.95.

I want to remake the gears from Baltic birch plywood (BBP), but want to get the gears meshing right before investing anything more in time and materials, etc. To that end, I found a gear program that allows for creating and customizing gears for this sort of thing. Woodworking for engineers
There are also quite a few plans for gear toys/machines available from this site.

I've designed the exact same gears in that program with 1/32" "slop" and they look like they should work. I've imported the gears designed with that 1/32" slop into my CAD program and have worked up "patterns" for printing and mounting up for hand-cutting in the manner described above. I want to cut some trial gears, but it is almost no extra work to cut a stack of three or four, so then I get sucked into remaking multiples, and then into remaking all of them.

That is when CNC comes to mind. I mentioned this in another thread and David (difalkner) PM'd me about that, mentioning a thread he posted about making some gears using CNC.
https://www.routerforums.com/show-n-tell/136765-enigma-cipher-gears.html

I am now interested in learning more. The balance bike project that I posted about would have also benefitted from CNC, rather than the pattern boards that I used. But I was no where near interested enough then.

Rick

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Wow nice work Rick . I have no idea why I find gears so fascinating , but I do .
Impressive looking gear when done in the capable hands of someone with a bandsaw .

For a kid, I think there’s a lot pinch areas with all those gears though lol.

You’ve given me an idea . Done right , a small gear reduction motor turning the gears slowly could potentially make for some really cool wall art. Some plexi and LEDs etc ?
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Wow nice work Rick . I have no idea why I find gears so fascinating , but I do .
Impressive looking gear when done in the capable hands of someone with a bandsaw .

For a kid, I think there’s a lot pinch areas with all those gears though lol.

You’ve given me an idea . Done right , a small gear reduction motor turning the gears slowly could potentially make for some really cool wall art. Some plexi and LEDs etc ?
Thanks.

The bandsaw work was made easier by using the Carter Stabilizer guide, which allows use of blades down to 1/8" for scroll-like work on the bandsaw. WAY easier than using a scrollsaw.

Yeah, the "pinch" thing for kids has risen as an issue. My granddaughter is a newly minted 5yr old and she was only mildly impressed with it and showed no interest in playing with it once it was "given" to her as a gift. Hopefully, that changes as she gets older.

No matter however. When I first started with the gears, she saw stacks of the two smaller ones on my workbench and started playing with them. When I showed her a couple mounted on the peg board she said "Cool. What are you making? A machine?" That was just about enough to make it worthwhile.

I have just the motors for that wall art.

Rick
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Thanks.

The bandsaw work was made easier by using the Carter Stabilizer guide, which allows use of blades down to 1/8" for scroll-like work on the bandsaw. WAY easier than using a scrollsaw.

Yeah, the "pinch" thing for kids has risen as an issue. My granddaughter is a newly minted 5yr old and she was only mildly impressed with it and showed no interest in playing with it once it was "given" to her as a gift. Hopefully, that changes as she gets older.

No matter however. When I first started with the gears, she saw stacks of the two smaller ones on my workbench and started playing with them. When I showed her a couple mounted on the peg board she said "Cool. What are you making? A machine?" That was just about enough to make it worthwhile.

I have just the motors for that wall art.

Rick
I’m really amazed at the labour that went into that project . It’s unfortunate a child can’t comprehend the work and love that went into something like this .
But with any luck that will be around for decades to come , and they’ll be showing how it works and talking about how grandpa made that :)
Generating gears in Fusion 360 is actually pretty easy and you can print the results if you like. Which CAD program are you using, Rick?

David
Generating gears in Fusion 360 is actually pretty easy and you can print the results if you like. Which CAD program are you using, Rick?

David
A no longer supported version of AutoCAD's AutoSketch (ver. 10). It imports and exports common formats and is easy to use. I have TurboCAD 2/3D 18 but have not put the effort into learning it as it seems much less intuitive, but that probably is just a familiarity thing.

I'm not familiar with Fusion 360. Sounds like a 3D program.

What format(s) does your CNC router work from?

Rick
Your patience is amazing. What you might also add is something that turning one gear set moves, such as clock hands or an iris (think old fashioned camera gear) mechanism. I grew up with Erector set kits given to me at Christmas time several years in a row by my grandfather (an architectural engineer). The joy in them was that after playing with them you ended up with (usually) a working toy that also was fun to play with. They also encouraged my imagination to make my own designs with the parts. The lasting box-of-parts toys typically had a destination reward for succeeding to put the parts together in a certain way.

4D
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A no longer supported version of AutoCAD's AutoSketch (ver. 10). It imports and exports common formats and is easy to use. I have TurboCAD 2/3D 18 but have not put the effort into learning it as it seems much less intuitive, but that probably is just a familiarity thing.

I'm not familiar with Fusion 360. Sounds like a 3D program.

What format(s) does your CNC router work from?

Rick
Fusion 360 is an Autodesk product like AutoCAD. The big difference is it's free for hobbyists or small businesses making less than $100k per year. Sadly, I qualify... :grin:

It is a very good CAD and an even better CAM program and if you're already familiar with the other Autodesk products your learning curve is likely short. And yes, it's a 3D program.

I'm using Mach4 to run the CNC and it takes the G-code generated by Fusion 360 just fine. You just have to pick the right post processor (built into Fusion 360) for your CNC.

There's a huge support community for Fusion 360 and tons of how-to videos.

David
Fantastic project!!


I used Mathias's program to make gears, you can export them as DXF and import them right into aspire. My gears were much bigger, your little ones took a heck of a lot of patience!
Fusion 360 is an Autodesk product like AutoCAD. The big difference is it's free for hobbyists or small businesses making less than $100k per year. Sadly, I qualify... :grin:

It is a very good CAD and an even better CAM program and if you're already familiar with the other Autodesk products your learning curve is likely short. And yes, it's a 3D program.

I'm using Mach4 to run the CNC and it takes the G-code generated by Fusion 360 just fine. You just have to pick the right post processor (built into Fusion 360) for your CNC.

There's a huge support community for Fusion 360 and tons of how-to videos.

David
I have downloaded Fusion 360 and have uploaded a couple gear drawings. It will take me a bit to get familiar, I think, as it all seems very strange.

Rick
Fantastic project!!


I used Mathias's program to make gears, you can export them as DXF and import them right into aspire. My gears were much bigger, your little ones took a heck of a lot of patience!
I found his program easy to use and was quite happy with its outputs that I imported into AutoSketch. The real test will be when I make the gears, if they work. I'm feeling lucky.

Perhaps some patience. Didn't seem that way to me. I think using the 1/8" blade on the bandsaw made it so much quicker than on a scroll saw that it was fun. Might not be so much the next time.

Rick
Your patience is amazing. What you might also add is something that turning one gear set moves, such as clock hands or an iris (think old fashioned camera gear) mechanism. I grew up with Erector set kits given to me at Christmas time several years in a row by my grandfather (an architectural engineer). The joy in them was that after playing with them you ended up with (usually) a working toy that also was fun to play with. They also encouraged my imagination to make my own designs with the parts. The lasting box-of-parts toys typically had a destination reward for succeeding to put the parts together in a certain way.

4D
We did not have an erector set when I was a kid. My father did operate a hobby shop as a second job, so I got to build all sorts of models. The ones I enjoyed the most were the balsa airplanes, large and small. He would hold hand-launch glider contests that we would enter and usually win. I have found some of those kits and have them squirreled away in hopes my granddaughter might some day help me build some.

I agree about making the turning gears do something. Lift some marbles that then tumble down something is what I was thinking of.

Rick
I have downloaded Fusion 360 and have uploaded a couple gear drawings. It will take me a bit to get familiar, I think, as it all seems very strange.

Rick
Check your email, Rick. I sent a guide on creating the gears within Fusion 360.

David
Gears are the gateway drug. Then wood gear clocks.

Then there are artists like Derek Hugger
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If marbles are used in the gear set how about making a couple of marble gears? Not sure how well they would work, but instead of meshing teeth make coves in each so that only when a marble drops through it engages mating gears and gravity spins them. Or glue marbles into one gear that ride in coves on the mating gear. Let the marbles serve as the teeth for the gears. Or every other cove in two mating gears has a marble glued into it.

Sorry, but once you said "marbles" I've been possessed by the possibility of marble gears.

4D
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Sorry, but once you said "marbles" I've been possessed by the possibility of marble gears.

4D
Do NOT, I repeat DO NOT search YouTube for "marble machine" unless you have lots of time on your hands...
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If marbles are used in the gear set how about making a couple of marble gears? Not sure how well they would work, but instead of meshing teeth make coves in each so that only when a marble drops through it engages mating gears and gravity spins them. Or glue marbles into one gear that ride in coves on the mating gear. Let the marbles serve as the teeth for the gears. Or every other cove in two mating gears has a marble glued into it.

Sorry, but once you said "marbles" I've been possessed by the possibility of marble gears.

4D
That’s a very unique idea. Something I’d like to see implemented.
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I've been "offline" for a while working on a number of things, learning Fusion 360 and working with David (difalkner) on cutting a set of one of each of my three sizes of gears. It took me quite a while to generate Fusion 360 drawings of the gears such that David could use them to generate the code he needed to run his CNC router, but that is all done, as are the three gears.



I really want to thank David for his generous help with the Fusion 360 3D CAD program. Although I've been creating complex working drawings of multiple parts, drawn in full assembly, with dimensions, all on separate layers, for years, I have always struggled with the 3D programs. I have tried TurboCAD 2D/3D and I tried SketchUp when if first came out and was free. Couldn't get past the initial learning hurdles and gave up. I stuck with it with Fusion 360 and I'm glad I did. It was only truly possible because Fusion 360 had a spur script that generated the gears based on key parameters. I'd have never been able to draw the gears myself at my current level. Still, getting the center and peg holes and the spokes draw in and extruded was challenge enough. Thanks, David. David also put me on to and excellent youtube "lesson" series by Lars Christensen. Excellent stuff, but I'd completed the my work on the gears before really benefiting from it.

Once the Fusion 360 work of creating the drawings was done, I asked David to cut a set of gears for me, through his business, Curly Wood Shop (see his signature block). He did and I now have a beautiful set of three gears, in Baltic birch plywood (BBP), that I will use for one or more of: 1) use as templates/patterns for cutting an all new set of 18 gears (6 of each size), 2) use as patterns for modifying my existing gears, if it is feasible, or 3) bail on making any new gears or modifying old ones and have David cut the remaining 15 for a complete set out of BBP.

To do either 1) or 2) above, I would have to build or buy a pin guide for my router table because the radii in the bottom of the tooth gullets are 1/16", which means a 1/8" dia. cutter and I have yet to find any flush trim bearing guided 1/8" router bits.

I'll get into my attempts at making a pin guide in a subsequent post.

Rick

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Whether I use the Baltic birch plywood (BBP) gears to cut all new gears or use them to modify my existing gears, I need to have a pin guide for cutting the 1/16" radiuses (or radii) at the bottoms of the tooth gullets. The initial pass to cut the major profiles is with a 1/4" cutter which leaves those radii in need of a pass with a 1/8" dia. bit. So far, I've not found any bearing guided flush trim 1/8" router bits. I suspect they aren't made. So, I needed a pin guide

Initially, I just started thinking about how to make one. I had no idea there would be products available for this, but it makes sense. I first tried machining some parts out of brass and attaching them to the clear overhead chip shield that came with my Bosch router table. I machined a sleeve that would mount in the shield to hold the guide pin. I machined a 1/8" dia. guide pin on the end of 1/4" threaded brass rod.




I used an unmachined length, placed downward into the 1/4" collet of the router to align the guide pin assembly.


Then, by replacing that with the 1/8" machined part as the guide pin.


The biggest problem with this was that the shield was not rigid enough. It wasn't supported well against the fence and it just flexed too much. It was sufficient to prove the concept for me. I was still unaware that I could just buy something, but I doubt that would have mattered, as I like making things.

Rick

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I had initially thought of mounting the guide pin to the table insert by using two (the only two) threaded holes, one for the starter pin and the other to mount a clear plastic shield over the starter pin. I took accurate measurements of the hole positions, relative to the router centerline, to get the pin assembly in the ballpark, to be fine tuned by holding an alignment shaft in the router collet. I abandoned this approach for my first attempt where I tried using the clear plastic chip shield, detailed above.


Returning to the idea of mounting the pin guide to the table insert, I machined a 5/16" thick alum. plate with holes for the table mount and for the pin holding assembly. This time, instead of machining something from scratch, and wanting a faux-collet system, I opted to use the compression fittings for 1/8" copper tubing. I drilled and tapped the alum. plate for the 1/8-27 NPT threads on one of the compression fitting. I held the tap square with a spring loaded tapping guide to ensure the threads would be perpendicular to the surface of the plate. I also used that guide while screwing the fitting into the plate, again to try to keep it square.

Here is a photo of the completed guide pin, with the 1/8" guide pin in place, but showing the compression fittings used in the assembly. I have to be careful when tightening the nut so as to not crimp the compression wedge onto the pin shaft. Snugging it lightly with a wrench so far has proved sufficient to hold the pin secure without crimping the wedge. If I were going to use this system much, I would slice the wedge so that it could not crimp.


This shows using a 1/4" shaft in the router collet to align the jig to the router centerline.


Here is the completed compression fitting pin guide in use. The bottoms of the tooth gullets on my existing gears are not as deep as the CNC routed gears. So, here I am using the CNC gear as a pattern to deepen the teeth gullets.


This is Option 2 from above, modifying my existing gears. BTW, I had previously tested the CNC gears and they mesh cleanly and rotate freely. After modifying one each of the three sizes of my existing gears, they also mesh cleanly and rotate freely. This setup works very well and I can see using this for the rest of my existing gears.
https://vimeo.com/313308321
But... that is not the end of the story. Just before embarking on the second iteration with the compression fittings, I did some looking online for router pin guides. I found a lot of pin router machines where the router was above the table and the pin in the surface of the table. Not what I was looking for. I found two above table mounted pin guides for the traditional router table:

One, a fairly simple and much less expensive, the Daisy Pin Router: https://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/daisypin.html

and the second, the Veritas Pin Router Arm: Veritas® Pin Router Arm - Lee Valley Tools

This latter one is far beefier and larger than I expected, when I ordered it. It arrived today and whoa! is it huge. It is intended to mount on the corner of a Veritas router table and it almost does on my Bosch table, but not quite. I'm still working on the best approach but it is looking like building an extension for the rear of my table is the best. I will be building and extension anyway for the Incra LS Positioner System that will be arriving next week.

Rick

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