ET Westbury Side Paddle Engine

[kvom]

Here's a pic of the mill:

[kvom]

No CNC work at all as I try to make a conrod to ET's plan.

Rather than steel, this is some 1" diameter brass rod, of which I have 7' and thus enough to screw up many times.  Mounted in the lathe, I turned the following piece:



Not having a ball turner, I used Marv Klotz's ball turning program to output a schedule for turning a 1/2" diameter ball using 5 degree angle increments.  The shaft was turned to 3/8" with the neck nearest the ball grooved to 1/4".  From the end of the ball to the end of the shaft is 3.25".

Next the piece was mounted in the Bridgeport vise held between two V-blocks.  A 1/4" endmill was used to make a flat on the side of the ball plus cut a flat that will be the finar form of that end of the rod.  The ball was then center drilled, drilled, and reamed to 1/4" diameter.



A second flat was milled on the large end to provide a reference for clamping to bill the large end on the opposite side.



The next operation will be to put it back in the lathe and use the taper attachment to taper the shaft from 3/8 to 1/4 over its length.

*** edit ***

Looking at the drawing and doing an eyeball fit, I realized that the sides of the ball end need to be milled flat in order to fit the crosshead.  Luckily it is easy to do this at this stage this morning.  Had I waited until assembly chucking might have been a problem, and certainly I would have needed to do it by filing.

[kvom]

Thanks for lookig ariz.

Today I decided to try to finish the first conrod, so after a much needed vacuuming of the machinery I set up the Monarch's taper attachment. Setting the little indicator on the 2-degree mark, I measured the actual taper angle as calculated from the XY DRO reading: 2.02 degrees, close enough!

After cutting the taper as close to the ball end as possible, I gave the shaft a quick polish with some 320 grit paper and than Scotchbrite.  On this machine it's better to cut a taper toward the large end to take up any backlash in the crossfeed screw.



Earlier I had been worried about whether I could easily clamp the conrod vertically to drill the mounting holes and mill it to length, as it's over 1" longer than the jaws are deep.  Luckily the vise jaws overhand enough to do so.



Finished with the big end bearing attached:



I thought it interesting to find that Reeves in England still sells casting for this engine (at 550 pounds, $800   ).  Their website didn't saw which parts are included.

[kvom]

Yesterday I made the second conrod taking advantage of lessons learned in making the first.  The main change on the lathe was turning the shaft to 1/2", the diameter of the ball end, rather than the final major diameter of 3/8.  So after cutting and filing the ball as before, I could place the shaft into a 1/2" 5C collet and the square collet block.



The 4.10" workpiece was just long enough so that the ball and part of the end were visible.  Then I was able to mill flats on both ends, taking 1/32" off the ball and .200 off the end.  After drilling and reaming the hole in the ball, I could flip the collet block and mill matching flats on the opposite sides.



Next I reversed the piece in the collet so that the large end was fully exposed, and used the height gauge on the surface plate to set the milled flat horizontal:



Now I could mill parallel flats to form the sides of the large end of the conrod.  Then it was back to the lathe to reconnect the taper attachment and turn the shaft taper as before.

The remaining tasks were to mill the large end down to final length and drill the mounting holes.  I discovered that it was easier to clamp the piece between two parallels than to use the tops of the vise jaws.  In order to keep the parallels tight against the jaws, I inserted some pieces from my gauge block set in the opposite end.



Final result:

[Stuart Badger]

I'm really enjoying this thread! Keep it coming please!

All the best

Stuart

[kvom]

I goofed off all afternoon, so after dinner I decided to knock out the 4 cheek plates of the crossheads.



The CNC  milling/drilling took only a half hour.  Squaring the pieces, milling the jaws, and tapping took a couple of hours altogether.  While the 5-40 SHCS are good for now, I think either studs/nuts or hex head screws will look better in the end.

[kvom]

I was supposed to go on a 2-day offroad event, but tweaked my back and decided it was not for the best  to go.  Since I can stand without discomfort, I spent the afternoon in the shop.  Today's goal was to make progress on the cylinder covers.

Having obtained a length of 1.5" brass rod, the process on each of the 4 covers was to start on the lathe:

1) face
2) facing cut to create a .75" spigot .06" deep, to serve as a seal for the cylinder bore
3) part off

The rest was done on the CNC mill.  A 1.5" round pocket .100" deep was milling in the soft jaws of the vise to hold each cover and to ensure that each was centered.  From then on it was a matter of milling and drilling.

The end result of the days's effort is shown here:

[derekwarner_decoy]

Hi PD's...... personally I suggest that kvom's effort  ... in his machine shop is far better time spent than any two day jaunt tracking off road  ...... but him  - Derek

[kvom]

I have about as much invested in the Jeep as I do in machinery, so it should get equal time to be fair.   

Nevertheless, it was back to the shop.

This afternoon's effort was to make the two slide-bar brackets.  These attach to the inner frame and secure the far end of the bars on which the crosshead slides (the other end of the bars attach to the cylinder cover).



The machining sequence was as follows:

1) square 2 pieces 1x1.5x.375 inches on the manual mill
2) CNC the main "pocket" using a 7/16 endmill
3) CNC the inner profile with a 1/8" endmill
4) Back to the manual mill to make the outer 45-degree cut.
5) Drill the clearance holes for the 5-40 screws that will attach the bars.

To be done:  file the edges of the inner slots where the bars attach, and drill/tap holes in the sides to attach to the frame.  This latter operation will be done once the positions of the brackets are known exactly (i.e., the crosshead slides smoothly between the bars with no  binding).

[kvom]

I had been trying to decide which thread to use for the cylinder gland nuts.  ET specified 1/2-26, which is not a unified thread.  The choice is between 1/2-20 UNF and 1/2-28 UNEF.  I recently acquired a 1/2-28 tap, and it appears that a finer thread makes for easier adjustment of the gland.  But not having a matching die, I needed to know if I could cut a good external thread for the nut on the lathe.

Today I decided to do a little experiment before cutting any metal in anger.

I chucked up a small piece of aluminum rod, drilled it 31/64, and used the thread-forming 1/2-28 tap to thread the hole.  This was the first time I'd used such a tap, and in aluminum it worked great.  No chips to clear, and with such a small thread depth in softer metal it went rapidly.  So now I had a "nut" to test with.

The second part of the experiment was to cut some external threads in steel to  match the nut.  In the past for small threads like 5-40 and 6-32, I'd cut partial threads on the lathe to ensure that they were straight, and then finish them with a die.  Since I don't have a 1/2-28 die, I'd need to cut the entire thread on the lathe.  I turned some 12L14 rod down to .500" and cut the thread in about 6-7 passes, with the last couple being a thousandth DOC.

Here's the result:



So it looks as if I ought to be able to make the gland nuts with this thread.

[kvom]

Latest parts made are the two valve forks that connect the valve rod to the die block, which slides inside the link.



The screws show where the threaded valve rod attach via 5-40 threads, plus a lock nut for adjusting the valve travel.

[kno3]

Nice work!
Regarding this engine, some suggested to me that it would be better to build it so that the cylinder valve covers face outwards. This allows much easier adjustment and maintenance and should be easy enough to do at this stage.

[kvom]

You couldn't just move the cylinder to the other side of the frame.  But you could switch the two engines left to right so that the outer frame  becomes inner and vise-versa.  Then the cylinder is on the inside and the valve/eccentrics on the outside.

On the face of it that could work.  You'd need to change the staybolt and weigh shaft lengths.  The downside is that the engine would be quite a bit wider and might not fit well in a typical boat.

Today's parts are the valve rods and the valve buckle.  Rods are 1/8" drill rod threaded 5-40.  For the setscrew on the buckle, I drilled and tapped for a 2-56 screw and countersunk for a SHCS.

[kno3]

You couldn't just move the cylinder to the other side of the frame.  But you could switch the two engines left to right so that the outer frame  becomes inner and vise-versa.  Then the cylinder is on the inside and the valve/eccentrics on the outside.

That's exactly what I meant.

[kvom]

My task for the past two days was to make the two cylinder gland nuts.  No CNC work for these.   

I had a short piece of 3/4" diameter brass, so the first task was to turn down the outer ends to 1/2" and thread them 1/2-28.  By doing the threads at each end I was able to have a nice amount of material held in the lathe collet, and as well I knew the DRO DOC settings for the second thread once the first was done.



I had previously tapped an aluminum "nut", so I had something to test when the thread was good.  Next each end was parted off:



The nut now comes in handy again.  I parted off each end, then threaded the gland into the nut so that the parted end could be cleaned up:



Now the nut/gland/collet were transferred to the hex collet block on the mill to drill the 6 radial holes for tommy bars (used to tighten the nut onto the gland):



The drilled nuts:



The hole for the piston rod will be drilled with the nut screwed into the cylinder cover to ensure concentricity.