Kearsarge Windlass Engines

[crueby]

Glad I didn't read those before going in to finish the gear cutting...
So, all the teeth have been pre-cut, ready for hobbing.

Next step will be to turn up an arbor to spin the gear on during the hobbing process.

[cnr6400]

Yep that was what the Gleason reference was about! Fantastic gear cutting machines. There were a room full of them at the big US based controls branch plant I worked at in Toronto. Later I toured what was Westinghouse's gas turbine plant in Hamilton Ont. and they had some of the largest Gleason machines I have ever seen. One could cut 12 foot diameter gearing and curvic (Hirth style) couplings. Great to see. I don't have any idea how much gear cutting is still done in North American industry, but I sure hope there's lots of it. 

[crueby]

And today is Hobbing Day!  With the gear held in an arbor that lets it spin freely, the Acme tap held in the chuck, it was adjusted till the teeth in the tap meshed with the precut gear teeth, such that if I turned the spindle by hand it would advance the gear without much binding. The cutter was set towards the front slightly, since the blank is over-thick still and the back side will be trimmed off. Started the motor on a slow speed, and started to move the mill table over to start cutting. Every few full turns of the gear the table was moved over another few thou, letting it cut all the way around the gear several times for each position. After a while, got down to full depth.

Closer look at the cutter and the teeth


Test fit of the threaded rod on the teeth as I went as well

When happy with the depth, it was set down horizontal again to trim off the second side

Here is the finished (well almost, need to cut a keyway in the center hole) gear with the side plates screwed on:

This gear is too big for my plating tank, may just paint it instead...

[Admiral_dk]

Great result (in more than one way) 

Per     

[Michael S.]

Du hast es mal wieder geschafft. Perfekt 👍

Michael 🍻

[cnr6400]

  Great looking hobulation process, and a fantastic result Chris. The fit looks good. 

[crueby]

Thanks guys!  I was worried when the hobbing started, given how much work went into the parts to get them ready, but it went very easily. The hobbing still seems like magic!
 

[crueby]

This afternoon I shaped a piece of the Acme threaded rod to make the worm gear. The screws will locate it on flat spots on the rod, they need to be shortened.

For those who may be wondering why I 3D printed some of the rope and chain drum parts, this may help explain my thoughts. Here are the pieces for just the chain drums, one set assembled, one set aprt on the table, plus the worm wheel with its printed side panels. They would have required about 18" of 6" bar to make from scratch, not even counting the rope drums shown previously. Also, the shapes needed would have been very hard to do without CNC, especially around the chain path on the drum in the upper left corner of the picture. There will be a number of metal parts added to these to make the ratchets and brake bands. The main drums spin freely on the shaft, while the worm wheel and the flanged plates, like the one just above the '9' on the tape measure, are fixed to the shaft. A set of ratchets will sit inside the slots in that plate, with the open ring in the upper center pushing one end of the ratchets up into recesses in the chain drums to make them move. An interesting arrangement, allowing the chain drum to freewheel when desired, with speed slowed as needed by a brake band around one end. The plans showed all the pieces needed, but it was finding a patent about the mechanism that taught me how it all comes together.


So, next up will be the three upright brackets that sit on bases already on the deck plate, and hold up the main shaft of the chain drum assembly. Going to take some plotting and planning to work out how to make those brackets. Two of those brackets are visible in this CAD view, in pink on the right hand end, either side of the orange chain drum with the handle sticking out the top (which controls the ratchet engagement). The third one is over on the left end but obscured by all the other parts. The brackets have a lot of curves and flanges around the edges, I need to decide what to mill out and what gets bolted/soldered on.

[Kim]

Very nice hobbing, Chris! That is one big worm gear! 

Kim

[crueby]

With the gear set done, next looked to the big support brackets that hold the shaft. After lots of measuring and digging in the racks, I found a chunk of aluminum that I can use for the thick center walls, some thin brass flat bar for the edge flanges, and some steel for the middle bracket base plate. Thought I would have to either order a piece for the two end bracket bases or cut down some sheet, then found a piece of wide 260 brass flat bar that a cousin gave me a couple years ago. Usually I avoid that crap since it cuts/drills so bad, but figured I'd use a bunch of the bar up on these simple flat plates. Well, wound up having the drill break in one of the holes when the 260 brass grabbed on and wouldn't let go!    Did get them finished up, here are all three set in place on the main base plate - the two brass ones at the sides, the steel one in the middle.

Next up will be to lay out the shapes on the ali plate for the upright walls and get them cut out - with luck the upright bandsaw will cut it okay so it just needs final trimming. The walls have a flat bottom, but the sides are all curves. I'll trim them out with the thin brass flat bar, will run in some brass screws into the ali and peen over the ends to form flush rivets to hold them in place.