1916 65 HP Case Traction Engine 1/16 Scale

[raveney]

RE steering gears. I've found this image of the worm and gear. Appears to be a coarser pitch and note that the chain roller has a spiral feature that would not only keep the chain from tangling, but also increase the amount of chain per rotation? SPD stated a 20:1 ratio for worm to gear on the ones Rudy suggests. Im going to "freehob" a 3/8-16 tap into a brass gear blank and see what happens....

 

[raveney]

Used a short 3/8-16 bolt for the worm and hobbed the gear using a tap. Infeed 0.040" seemed to work good. The rest of the spur gears got some fancy yet time consuming detail work to mimic the real ones. Then small hub spacers were soft soldered on using a well blackened SS rod to keep everything concentric. I also made some 1/16" spacers to push the gears out away from the wheel spokes. Had planned on making the cross braces inside the rims, but not so sure anymore. Next I will make some brass bearing blocks and rivet them to the horn plates. Shifted the forward crankshaft hole for the pinion gear as expected to clear the flywheel and mesh well with the new gear ratio.

Thanks for watching!

 

[Rdean33422]

Very nice work all around.
I have used the same hobbing process when I made my rotary table years back. I used a 1/2" tap to make the 90 teeth for the worm gear.
Ray

 

[gbritnell]

It's coming along nicely!

 

[Steamchick]

Nice bit of clockwork to drive the wheels!
K2

 

[raveney]

Thank you for the generous compliments

I have an idea that I would like to bounce off you all.
I would like to be able to start and steam the tractor while stationary, and the full size tractor uses a friction clutch to do this. Do you think a small cone clutch would work as sketched below?
The shaft and flywheel would be keyed together, but the small pinion gear would have a outer cone attached that would slide against the shaft driven inner cone when the rest of the gears need to turn. I have a similar arrangement on my Grizzly mill for the quill downfeed. The pinion and outer cone would freewheel when resting to left, and rotate with shaft when the cones are forced together. Maybe brass on brass so they are grabby?

Any thoughts or suggestions to improve?

 

[johnmorley7]

Definitely an interesting concept. It would allow for stationary PTO like function ( generator mounted as in Showman's type engine). I'm still making wheels and reading feeds.

 

[Steamchick]

I cannot see a lot of benefit from the cone... (Unless a clever person can explain?). A direct flat-on-flat surface is as good as anything needs to be, as you are not transmitting a great deal of torque to drive anything are you? You can surely find an old brake pad (I can post you one?) so you can even make a disc with friction surface to impinge on an equivalent flat face of the driving gear?
The "worry" in using a cone is that it may slip/heat/seize - after which it won't release... A flat clutch has better heat dissipation if it slips and heats-up. A flat disc can have "proper" friction material that won't seize, and need less force (pressure on the plate) to make it grip? A simple thread on the shaft for the disc to screw along should suffice to engage/disengage the drive. With 2 holes in the back for a twin-pin spanner to tighten/release? I assume you won't be engaging or disengaging when the engine is running? Just set it when static and then run the engine?
K2

 

[krypto]

Yeah, you definitely want to be able to kick the traction engine out of gear for stationary running of accessories.

The Wilesco engines use a lever to slide one of the gears in the cluster in and out of engagement by sliding it on the shaft. Simple, but very effective. I can try to get some pictures if that would help.

 

[raveney]

Thank you John, K2 and Doug
I doodled a bit today and then modeled something different using the flat disc friction clutch and a clutch fork design. This revision 2 would permit some leather as the friction face if needed and also align with the idea of using a Johnson bar and linkage near the steering wheel. It is still simple enough to fabricate at this scale I think.

 

[krypto]

Can't wait to see what you make! Not much room in there at this scale.

You might find this video interesting. It's on my 3 lifetime long build list.



Look at one of his other videos to see it working.

 

[kwoodhands]

I have set of wheels like yours I'm intending to build sometime. My plan of the moment is to solder the spokes to the hub,
then when all is cooled, red Lock-Tite the spokes to the rims.
Or solder only one spoke at a time, hub and rim and let cool.
Just my thoughts.
As I'm basicly a self-taught machinist, I got several good ideas from your pics.
I like the idea of the setscrew access thru the rim.
I did build a flywheel about 4" in diameter one day, that I used only red Lock-Tite on.
As you say a bit of truing up afterwards, it is still working today.
Thanks for sharing your pic's!!

I tapped the hub 3/48 and soft soldered the spokes at the rim. I made the hub with a set screw instead of the set screw thru the hole in the rim. The hub is a bit larger than the drawings. The axle has a flat spot milled for the set screw. Rear axle is longer than Rudy shows, I did this on purpose so the wheels can be adjusted for single row or double row cultivation. I used to farm , that's why some modifications were done.
I am stumped over the " humidifier valve Rudy mentions. I took the book to a plumbing supply and they never saw a valve like the picture. This valve is also supposed to show water level in the boiler?
I have seen steam driven tractors at the county fair in Mays landing. The boilers were filled from a valve on top . I think this method would work on the Case model instead of pumping .
I looked at many types of humidifier valves online, none resembled the picture.
Hopefully someone can find this for me.
mike

 

[Charles Lamont]

I don't know about US practice, but the normal UK arrangement is a sliding gear on the crankshaft or second shaft so that only the crankshaft revolves for stationary work.

Pretty much all British traction engines, even agricultural ones, as well as road rollers, have two different drive ratios, three for a road haulage engine. The axle usually carries a winch drum on one side and the differential on the other. Final drive to each rear wheel is by means of a pin through the oval wheel hub. Drive can be disconnected by pulling the drive pin out of the hub to allow use of the winch. On the other side, an extra long pin can be used instead of the standard one to provide a diff lock.

 

[Charles Lamont]

The problem with a plate clutch as suggested by Steamchick, is that you need a considerable amount of axial force to make it work. Without a clutch thrust bearing, friction from the engagement force needed on the fork in the CAD model would probably absorb most of the engine's power. A cone clutch needs much less axial force.

[I have driven several hundred miles in a (1902) car with a cast iron to cast iron cone clutch. It certainly takes some getting used to, but is one of the most reliable things on the car.]

 

[johnmorley7]

From my very limited expertise, I value the keep it simple approach of sliding a gear on the shaft to engage wheel drive or disengage to drive flywheel only.

 

[raveney]

I am stumped over the " humidifier valve Rudy mentions. I took the book to a plumbing supply and they never saw a valve like the picture.

I remember seeing these used 40 years ago when a tin-knocker connected a water line to the forced hot air heat ducts in basement. The water humidified the dry hot air. They were more typically used to connect ice maker tubing. I think most codes banned their use as they pierce the copper tube and seal using a rubber gasket. Better off with compression or sweat fittings

You can buy online or hardware stores
https://www.amazon.com/4001-Aprilaire-Replacement-Humidifier-Tapping/dp/B0195UR7N8
I haven't gotten that far, but it makes sense as they are pretty small and cheap

 

[raveney]

The problem with a plate clutch as suggested by Steamchick, is that you need a considerable amount of axial force to make it work.

I was thinking of that also and went a different route. The original tractor uses this arrangement.....
which I modeled as this.....

it looks like once the thrust bearing and pinion gear is slid over that there might be some "camming" action wedging the clutch shoes in place? Not sure why I am obsessing with this whole clutch idea when my original plan was to just slide a gear over like others have done. I envision some satisfaction of using a small lever to engage and disengage while the engine is running. It's a challenge for sure in 1/16 scale but I'm up to it I hope.....

 

[raveney]

Hello again,
Before starting the clutch and flywheel I had some unfinished business on the gear train. Made the brass bearing blocks and replaced the socket head screws with hex head on the stack, side plates and smoke box cover frame. Filled an "extra" hole on the horn plates as I used a different gear ratio than original. I used TIG weld brazing rod because the heat input (amps) is lower on thin sheet like this. Used a dirty piece of brass as backing. This is an old auto customizing trick when filling emblem holes on fenders.


The flywheel is fabricated and brazed like Rudy suggests, but I added a inner rim part to avoid seeing the spoke holes and also give a hard stop surface for the clutch shoes. All steel construction. Also made the front piece to tie together the horn plates so the bearings are solid and all axles and countershafts rotate freely.



The shoes were made from a scrap threaded coupling using my brand new Eccentric Engineering tangential tool on the lathe. It leaves a superior finish compared to inserts, but extends too far to be very useful on the 7x14 lathe which lacks rigidity.
It works fine on the 9x20 lathe.
Made the shoe sector arm out of 1/8 hot rolled plate. Shoes attach to the plate using 2-56 screws. Made four shoes because of PI, and so I could adjust the design without starting over from scratch.



Made tiny Heim joints using 2-56 threaded rod and 3/16 round bar drilled 0.086 through.
Used 3/16 hex tapped 2-56 for turnbuckles. Didn't finish, but it's looking good so far.

 

[raveney]

The clutch works but still needs refinements

 

[johnmorley7]

great design and well done