Chris's New Steering Engine

[crueby]

So today its on to start making the control nuts, as shown in the diagram in yesterdays post. Started with the shorter one that goes on the end of the outer shaft, on the left in the diagram. This one has a hole in one end that will fit on the shaft, so that was drilled first:

Then bored out the end to be large enough to fit over the Acme threaded rod section, leaving one end sized for the shaft:

Here it is test fit on the shaft. It will get a keyway and a set screw to lock it to the shaft and keep it from turning. More shaping to be done on the end of this piece, that will be done together with the other nut.

Then on to the longer control nut. First drilled a hole through for tapping the center for the Acme thread.

As you can see in the diagram from yesterday, there is a section at the center that gets the threads, and the rest is bored out to fit over the Acme rod. So, both ends were bored out for that, leaving the center section to be threaded.

Then tapped with the Acme tap. A very coarse thread that takes a lot of force, so the part was held in the bench vise - the scroll chuck couldn't grip the brass hard enough.

This shows the threaded section with the larger bore around it at the ends

Next will set up to mill away half of the bored out sections to make the overlapping sections between the two pieces. The flats on the first piece extend over the end on the shaft to let the two pieces come close together but extend out farther too. I'll show that next time.

[cnr6400]

 

[crueby]

[crueby]

Finished up the control nuts today. First milled away one side of the shorter one that fits on the outer shaft to spin with the worm wheel:

The part had to be held on an arbor to continue the step up to the end, so the other piece can extend all the way back.

A keyway was cut into it to lock it to the shaft rotation, as well as a set screw to keep it from sliding off. Here it is on the shaft:

and with the middle shaft slid into place

Then started shaping the other part, with the threaded section in the middle. Also cut away one side, but leaving one end full:

To fill in that end and reduce it down to just fit over the smallest shaft, a plug was made to fit the end. This will also keep the ring from crushing in the chuck in the next operation.

Here it is pressed into place:

Then continued on with the shaping on the other end. I am using the same general steps as what I use on the bearing block caps, setting the end mill height to the outer diameter of the arc, and making a series of cuts, rotating the part 5 or 10 degrees between cuts. Here it is with one side rounded off:

and the other side finished:

The finished control nut, threaded onto the middle and inner shafts:

and it all in place on the model, after making the stop collars that let the nut move the inner shaft, which is the valve rod itself. The valve rod will have a threaded section on the other end with pairs of jam nuts either side of the valve slider. That will let the valve rod rotate if it wants without effecting the timing.

Next I think I'll make the rudder chain drive sprocket, since that acts as the stop collar for the middle shaft. For the chain, I will be using more of the same chain that I got for the first steering engine. This stuff is just like bicycle chain but a lot smaller, it has a 0.1445" pitch. Got it from McMaster, along with the master links to assemble loops of it. I need to make a drive sprocket to fit the shaft, as well as several other sprockets to turn the corners down at the floor level. I'll make them all in one set.

But, getting nice outside, so thats all the playtime in the shop for the day! 

[Kim]

Very interesting mechanism, Chris!   

I love watching your projects come together! 

Kim

[crueby]

Very interesting mechanism, Chris!   

I love watching your projects come together! 

Kim

Thanks Kim!   

[cnr6400]

  Tricky nut parts to machine ! They look great.

Keep an eye on your .1445 pitch chain and links...I overheard one of of my shop gnomes talking on his Elfricsson flip phone with someone about changing the final drive on his mini hog motorbike with some chain he "found" ! might have been one of your shop elves...

[crueby]

Tricky nut parts to machine ! They look great.

Keep an eye on your .1445 pitch chain and links...I overheard one of of my shop gnomes talking on his Elfricsson flip phone with someone about changing the final drive on his mini hog motorbike with some chain he "found" ! might have been one of your shop elves...

I THOUGHT I heard a tiny phone ring...   

 

[crueby]

This morning I got the chain sprocket made, started with a short length of 303 round bar larger diameter than the sprocket will be, turned the hub on the end, and drilled the holes for the pins to fall into. For dimensions, I downloaded the .STEP file for a sprocket for this chain size from McMaster into Fusion, and printed out a dimensioned drawing.

Then moved the chuck over to the lathe and turned the OD of the sprocket teeth section down to the finished size, which just broke into the holes.

To open up the ends of the valleys to the proper width and taper the ends of the teeth, I got lucky and was able to use a 1/8" end mill fed in from the side, which gave the proper opening. The cutter was only fed in enough to just reach the center of the teeth sides. As you can see, the teeth are much taller than needed - I am making two sprockets at once.

Back to the lathe, where a parting tool was used to cut in the outlines for two sprockets, and form the hub for the second one.

The sides of the teeth were tapered in with a file with the part spinning, then the first one was parted off between the two sets of teeth, and the second one back on the other side of its hub. A little filing on the tips of the teeth to remove the burs left by the parting tool, and it was ready to test fit against the chain. Perfect!

Drilled/tapped for set screws, and the sprocket was ready to mount on the outer shaft...

With the sprocket (and a spare to use later) done, I turned (pun!) to the steering wheel. First turned/drilled the hub

finished the profile and parted off back on the lathe

The outer end is solid, it fits on the end of the shaft without the shaft sticking through. Then found a chunk of brass very close to the desired size on the 'yet-to-be-used-scrap-pile', and mounted it on an arbor to drill the spoke holes

and back on the lathe to finish shaping it

Here it is ready for spokes!

A very productive few hours playing in the shop. Getting warm outside, time to head out...

[cnr6400]

  Sprocket and steering wheel parts look great Chris! Are you thinking of hiring a spokesman to do the spokes or will you measure up a pirate's wooden leg and make em yourself?        (worst puns this week, and it's only Tuesday)

[Kim]

Love how you made those two sprockets, Chris!  That was Kozo level genius there    

You guys and your puns!   

Kim

[Michael S.]

It's nice to see the engine grow.
The mechanism is always ingenious!

Michael 

[crueby]

Sprocket and steering wheel parts look great Chris! Are you thinking of hiring a spokesman to do the spokes or will you measure up a pirate's wooden leg and make em yourself?      (worst puns this week, and it's only Tuesday)

The Pun Police have been notified, they are on the way to hit you over the head with a rubber chicken...

[crueby]

Thanks Michael/Kim!

[cnr6400]

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The Pun Police have been notified, they are on the way to hit you over the head with a rubber chicken...

[/quote]

Again?