Bog's Paddleduck Engine

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kvom:
I can't seem to find a description of the threaded adjuster that connects the eccentric fork to the spool valve. Can you point me to the right spot in the book? Or is iit just a length of threaded rod with a jam nut?

bogstandard:
Kvom,

Here is the description, not much, so that might be why you couldn't find it.

Yes it is just a bit of threaded rod and a locknut.

Bogs

kvom:
I did some measurements and discovered that I indeed have enough brass for both the top and bottom plates, so as of now the only material I am missing, AFAIK, is the correct diameter drill rod for the spool valves.

My first task this morning was to cut the ~6"x3" bottom plate blank out of a 9x4 piece of 1/4" brass. I could have done this on the bandsaw, but decided to mill it out with a 1/8" endmill. It took longer, but in the end I wasted less material. From the cutoff, I then cut out a piece big enough to turn the disc for the 4th crankweb. My boo-boo was to crank it a little too hard and broke the endmill. Luckily it's a double ended mill, so I still have one to go.

I was going to post in detail about another fubar I did, but I'll just summarize it by stating that when tapping a hole, look to see that you do indeed have the correct size tap in the tap wrench. :hammer:

After lunch I tackled the crankwebs, now that I had all 4 discs cut out. Drilled the holes and pressed in the drill rod. I am using 1/4" for both shaft and pin:

My little arbor press was handy here. Milled the first side:

I used a 3/8" ball-end mill to get the rounded inner corner. Then the other side:

All ready to be slit:

I'm not sure whether to drill and tap the lock screw before slitting.

bogstandard:
Kvom,

Wait until after slitting, then just drill all the way thru with your tapping drill, then using your clearance drill, go down until it reaches the slot. Then cut the thread. It save lots of trouble finding the correct depths to drill to.

Bogs

kvom:
Yesterday evening I had squared up the base plate and flycut the top surface. As it was still in the vise this evening I continued to drill the holes in the plate. After center drilling all of them, I came to the conclusion that the scaled metric screw for the bearing blocks was between a 6-32 and an 8-32 SAE. Since these are not visible, I decided to go with the larger screw. I used a #20 drill bit for the 8 inner holes, leaving ~.003" clearance. Since my parallels were under the points for the perimeter holes I decided to defer drilling these. I'm not sure how I will be mounting the finished engine.

I then proceeded to slit yesterdays crank webs using the borrowed slitting saw/arbor. This went nicely and quick fast. I used the same drill rods in the holes to clamp the webs parallel to the top of the vise jaws. The mill was running in back gear at 200 rpm with a feed rate < 1ft/min. The exposed radius of the saw was "just" enough to reach the small end hole.

Having been out and about in the sun all day I decided I was sufficiently tired to call it an evening, before I did something silly.

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