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03-02-2009, 12:59 PM #1
Make spur or helical gears out of wood on a tablesaw.
My uncle tells me that I would have been a good machinist. He taught machine shop classes at a vo-tech school in Malvern, AR years ago. I do woodworking in my workshop and have developed a technique for making spur or helical gears using my tablesaw or scrollsaw. I use AGMA gear formulas to calculate various dimensions using number of teeth, diametral pitch, pressure angle, and helix angle for helical gears. Have a look at my web site to see a few videos I have made of the gears, and there is also a link where you can purchase the technique if you like. www.stevengarrison.com Thanks!
I have attached a picture of my most recently made gears, a pair of 45° left-hand helicals that are used on my shop-made wooden window blinds. These are 5 pitch with a 25° pressure angle.
03-02-2009, 03:51 PM #2
Helical, elliptical gears??
Are you out of your mind?
That was amazing.
Those spiral pieces.. WOW.
Thanks for humiliating me. Very nice.
03-02-2009, 04:14 PM #3
On a table saw?! Awesome work
03-02-2009, 04:17 PM #4
03-02-2009, 05:05 PM #5
WOW!!! Really impressive.
03-05-2009, 12:24 PM #6
03-05-2009, 12:32 PM #7
I'm intrigued but probably not inclined to buy your technique file from you. Would a video of yourself cutting a tooth on the saw totally kill your sales or is there more to it that would inspire would-be gear makers to contact you for the knitty gritty details?
03-05-2009, 05:20 PM #8
I think a video clip like that would kill sales. The pictures and video of the finished gears working together should be enough. How would I make such gears if my technique didn't work? I have posted on my site a few emails from customers expressing their opinions about it. As far as I know everyone has been very happy with it, and nobody has complained or asked for their money back. The simplicity of the technique is what makes it work so good, but hard to market.
03-05-2009, 07:09 PM #9
I don't know how Steve does it but
- Set up your saw for elliptical coving
- Attach a sheet of ply or MDF to the table top for a work surface
- Attach a cone the shape of the cove to the work surface off set from the centerline of your wood round
- Start pushing a wood round through the guides. It's going to cut a spiral.
Coving is a lifting process and a lot of blade is in contact with the wood so there's a lot of opportunity to screw the pooch. Start small.
Here's some coving sites.
03-05-2009, 08:25 PM #10
Cutting coves is a great way to make molding with elliptical arc sections. To do the same thing with a router would take a rather hefty and expensive bit and you would be stuck with one profile per bit. The tablesaw would be more versatile for that job.
My technique makes the involute tooth profile based upon the pitch, pressure angle, and base circle diameter of the gear being produced according to AGMA gear formulas - not a circular or elliptical arc that approximates it.
03-05-2009, 08:43 PM #11
My first reaction was scepticism, but we're told it exists, so at guess and if I remeber correctly!!I'd say it works on the same principle as the old Sunderland Gear planers, where the blank is both rolled and offset in relation to the cutter.
03-05-2009, 08:51 PM #12
A way to make involute teeth on a table saw is the same as when making them on a shaper. In this video you see a shaper cutting a gear. As the table moves from right to left, a flat tape is unspooled from the shaft the gear blank is mounted to. You can just make it out near the tower of the shaper. It is anchored at one end. It represents the pitch circle diameter of the finished gear. In fact a shaper would do a fine job of making wooden gears using a section of saw in place of the usual cutter.
Using a skid in the table top guide slot, the gear blank is run repeatedly over the blade and then both shifted and rotated. A feed screw would move the work and the tape would rotate it. A rack and gear can be used in place of the tape for rotating the work as it is shifted over the blade. Cutting blanks in gangs would get a lot of gears made in a hurry.
03-05-2009, 11:55 PM #13
thats amazing, really cool, and pretty. Nice work
03-06-2009, 12:05 AM #14
I was really impressed by the first picture back in the first post...so I showed it to my wife who commented: "it looks like something from Leonardo da Vinci".
03-06-2009, 12:46 AM #15
03-06-2009, 12:56 AM #16
I'm impressed. Wooden machines have always fascinated me. But, the cynic in me asks: Are you posting this here to share something, or to sell something?
03-06-2009, 01:08 AM #17
Thank you everyone for the compliments. The helix forms I believe are related to helical gears mathematically. I have been compared to Leonardo DaVinci before, but have no plans for a helicopter.
03-06-2009, 04:17 AM #18
Not to worry, gentlemen, this isn't rocket science!
Actually Stephen Fry has just done a BBC film on the Gutenberg Printing Press where the wooden gears were cut by hand with a chisel.
Again, wood was used for presses in wine making both in France and UK( there may well be other areas)
Furthermore, the masons cut spirals in stone pillars in Durham Cathedral.
But, gentleman, pillars were cast in bronze at the time of Soloman
03-06-2009, 06:14 AM #19
Nobody said rockets,they said gears .
Nice work sir.
03-06-2009, 06:26 AM #20
Gears or Rockets
So what? Rockets or gears--- both are SO-----------------------------------------Old!
Just that some of us can't do history