Chris's Build of Steering Engine

[Michael S.]

Chris, I can only see one groove in your picture.
But I think if you assume one direction of rotation of the crankshaft, the eccentrics of the crank always run 90 degrees behind or 90 degrees ahead in the other direction of rotation.
Your explanation is understandable.

Michael

[Michael S.]

I'm just wondering whether you have to pay attention to the installation position in the base, or does it not matter?
The eccentric and crank are stamped with an S for starboard. That means from the front it is installed on my left. But what is wrong when viewed in the direction of travel? 🤔

[crueby]

Chris, I can only see one groove in your picture.
But I think if you assume one direction of rotation of the crankshaft, the eccentrics of the crank always run 90 degrees behind or 90 degrees ahead in the other direction of rotation.
Your explanation is understandable.

Michael

Exactly, both eccentrics are either ahead or behind the crank, depending on the direction of rotation. If one was ahead and one was behind, then the engine would deadlock

[crueby]

I'm just wondering whether you have to pay attention to the installation position in the base, or does it not matter?
The eccentric and crank are stamped with an S for starboard. That means from the front it is installed on my left. But what is wrong when viewed in the direction of travel? 🤔

Yes, if the crankshaft is installed with the wrong end to the side, then it will run the opposite direction since the eccentrics would be on the other side of the cranks.  Its a little counterintuitive since on a screw, a right hand thread is a right hand thread no matter which end you look at it from. On the model one its a lot easier to see the difference since I can flip it around in my hand to look at it both ways, on the real one you would have to walk around the other side unless you have a very strong helper!
The potentially good news is that if my walkthrough of what part turns the next in which direction this morning was wrong, all I have to do is flip the crankshaft end for end!   

[crueby]

Whee!  As the old textbooks would say, the sequence when the steering wheel is turned to the left is left as an excercise for the reader!

That's OK. I'm just auditing this course, and don't have to do the homework!

You can sit up in the bleachers with the shop elves... 

[Michael S.]

Well, once everything is correct, let the workshop elves mark the crankshaft with punched letters. It's better they follow that so you can scold them if the letters are crooked.
And some industrial archaeologists can properly restore the machine in 100 years.
😂

[crueby]

Well, once everything is correct, let the workshop elves mark the crankshaft with punched letters. It's better they follow that so you can scold them if the letters are crooked.
And some industrial archaeologists can properly restore the machine in 100 years.
😂

Just to mess with the archeologists, maybe I'll mark it backwards!   

For now, its easy for me to keep it in the correct direction since I have kept the left end (as viewed from the engine end of the engine) long so I can put a small drill chuck on it to hand-turn the engine during construction and setup.
 

[Admiral_dk]

That's OK. I'm just auditing this course, and don't have to do the homework!

                Oh man       - Sorry Chris, but   

Archaeologists usually have it hard enough to figure things out when enough years has passed - so consider to be kind .... 

Now where on the rafters are the    and the       - we need to pay attention now 

Per

[cnr6400]

If you want to really mess with the archaeologists , drill a wobbly badly finished hole somewhere completely arbitrary on the crank. Then  stamp the letters "TIMING DATUM" next to it.  The hole and letters should be placed under a hub or inside a bushing. 

Or do as an old diemaker I worked with did - marked 0,0 for the datum on the diagonally opposite corner of the actual 0,0 on the die block. Caused some head scratching if a different diemaker had to do a repair. 

Another one (named George) stamped "MADE BY JUL. CAESAR" under the punch block as a joke, regularly!! 

 

[crueby]

If you want to really mess with the archaeologists , drill a wobbly badly finished hole somewhere completely arbitrary on the crank. Then  stamp the letters "TIMING DATUM" next to it.  The hole and letters should be placed under a hub or inside a bushing. 

Or do as an old diemaker I worked with did - marked 0,0 for the datum on the diagonally opposite corner of the actual 0,0 on the die block. Caused some head scratching if a different diemaker had to do a repair. 

Another one (named George) stamped "MADE BY JUL. CAESAR" under the punch block as a joke, regularly!! 

 

That's evil.   I like it!




Knowing how archeologists think, they'll call it an altar anyway...

[cnr6400]

Or "an artefact probably used by high status individuals" 

I heard that a lot watching Time Team and other BBC archaeological shows!

[crueby]

Today is eccentric day. Um, the ones on the crankshaft, not just me!   
Started out with a short length of stainless round bar, turned the end down to the OD of the eccentrics, and used a parting tool to put in the smaller sections around the center of each eccentric.

Then used the dial indicator to offset the bar to one side:

and drilled

and bored the hole for the crankshaft

Snuck up on the final hole size till it was a good fit on the shaft:

then parted off the two eccentrics and took a light cleanup pass on the cut sides since the parting tool leaves the surface a little rough


A quick trip to the arbor press with the broach, and the the eccentrics are ready. The holes were smaller than the smallest guide block in the broach set, but it worked out fine, since the broach depth at the starting end matched the diameter of the holes, so I didn't bother with the guide block, and made one pass through.

Now I need to make a pair of keys from some square stock, and they will be ready to install. I am thinking that I will add a set screw down through the thick part of the pieces, to lock them in place on the keys. Will see if tapering the key slightly is enough or not...

[RReid]

That's a fascinating looking assembly of parts, and will be fun to watch in motion. For me, there is always something satisfying about any sort of offset turning/boring on the lathe. It almost feels like some kind of magic trick.

[crueby]

Hi Ron,
Tricky part on this one was keeping it centered in one direction while offsetting it the other - the offset was enough that the other two jaws were going down the sides of the rod and I had to do a lot of checking to make sure they were still centered after tightening. The four-jaw chuck is a very handy thing!
Chris

[crueby]

Got the keys made for the eccentrics - was able to get a tight fit with a little filing on the square bar, so I don't think I need to add a set screw. Here is the crankshaft all assembled:

and a family shot:

Next step is to take some measurements under the shaft with it engaged in the worm wheel to see if I need to tweak the dimension for the bearing blocks, and then get the bearing blocks and bearings made. I had milled the engine bed down under the bearings and drilled screw holes to hold the blocks in back when I made the bed. On the original the bearing blocks were part of the base casting, and extended up above the rest of the bed. To keep from having to start with a thicker block and mill most of the top away to leave those 'towers', I decided to make the blocks separate pieces. Sounds confusing, but when I have them made and set it in place it will be clearer.