Bog's Paddleduck Engine

[spuddevans]

"Well done that man" 

 


With all the work that you've put into this build, there must be a huge sense of achievement to get it running.

Well done 


Tim

[Stilldrillin]

Very well done Kirk! 

 

 

David D

[Stefan Pynappels]

Good on ya Kirk, lovely to see something you built run, I'll get to that stage eventually!

Well done.

[kvom]

Looking back on this thread I see that the first part (eccentric) was made on April 29, so it was just shy of 3 months from start to getting it to run.  I estimate I have about 150 shop hours so far.  I purposely limit myself to 4-6 hours max. time in the shop at a time to avoid getting burned out.

I have to give John props for the design, plans, and construction book, as well as the ongoing advice on this forum.  I can definitely recommend this build to anyone looking to "step up" from wobblers.  None of the parts is very difficult to make given some care and accurate measurement.  My having DROs on the mill and lathe definitely made things easier/quicker.

I don't have any pics like shred's of the practice parts.  I remade the pistons and rods 5 times, mainly because I couldn't get them straight enough    Having a tailstock mounted diestock for the lathe is really a must.

I still have a ways to go to get this finished and polished up.  Stay tuned.

[NickG]

Well done! Fantastic result! 

[kvom]

Today, following Bogs' recipe, I dosed up the air supply with 10w-30 motor oil and ran the engine intermittently for a little over an hour.  At the same time, the exhaust and leaks lubricated my milling vise quite nicely.   

There were any number of things that would cause it to stop:

1) The mounting screws for the guide rods would vibrate loose, allowing the rod to fall down and jam the crank.

2) The piston gland nuts would vibrate loose.  I had to cinch them up tight with a wrench eventually.

3) One of the screws holding the #2 steam chest loosened, allowing the steam chest to tilt slightly and jam the valve stem.

Nevertheless, after an hour the engine was running nicely on 30 psi.  It needs enough air to cause the compressor to run continually, so 1 hour was about all I could stand.

After the last run, I noticed that the jam nuts on the valve stems had vibrated loose, so I suspect that one of the valves has rotated to a sticky position.  That's something to check the next time I run it.

[Brass_Machine]

 

Nice job Kirk! I remember when you started posting over at HMEM... You have come a loooooong way since then eh? 

You deserve a banana!

 

Eric

[CrewCab]

And have another banana on me Kirk, nice job 

CC

[ozzie46]

 Kirk
  You might try putting a piece of dental floss in the piston and valve packing gland with the end sticking out, then install the gland nuts. Sort of a poor mans friction nut. It might keep them from loosening up as you run it in.

  When I made my QCTHs I put some in the height adjustment screw and it keeps it from free turning when I change out holders.

   Ron

[kvom]

I finally was able to get the columns made on the CNC lathe at school.



On the left is a temporary column, followed by one that's been tapped and the others I need to drill and tap.  To get the same profile manually would have required grinding some form tools, plus cutting the taper either with the TA or the compound.  This was my second project for actually making a part, and the first that I designed myself.  There were two g-code programs:

The raw material was 5.5" lengths of 1" 6061 rod.  For the first program, the rods are clamped in a 1" collet with 2" exposed.  This program faces the rod and turns the 1st .5" down to a diameter of .49".  It then centerdrills to form a 60 degree chamfer, then drills 3/4" deep with a #36 drill for later tapping 6-32.

For the second program, the pieces are clamped with 4.5" exposed.  A live center is used in the chamfer created in step 1.  The program turns the profile using a 3mm round tool, then parts off the column at a length of 4.16", a few thousands overlength.

To finish for mounting, I chucked the column on the lathe using a rubberflex collet, with the bottom exposed.  I could then face the bottom and drill and tap for the 6-32 mounting screw.  I then tapped the top end at the workbench.  Once I do all 4 I'll use the height gauge to measure each one, and then face so that all 4 are the same length to with .001.

[NickG]

That should finish it off nicely! 

[ChooChooMike]

VERY VERY NICE !! Always like seeing multi-cylinder engines being built and running.  Double the eye-candy with double the cylinders !!   

Mike

[kvom]

Getting a little more done on this.  I drilled/tapped/mounted the new columns, and also made a pair of flanges for the input/exhaust pipes.  I decided to make 1-piece flanges rather than separate, and I think that will make the fitting a bit easier when I finally get the little tube bender finished and can attach the valve assembly.

[chuck foster]

looking good kvom 

i have looked at the plans for this engine and would like to start building one but i have so many other things to finish.
it will likely be next winter before i can start building it 

keep up the good work 

chuck 

[arnoldb]

Kirk, the little 'ducks is coming along really well.  Looking very good 

[kvom]

After some weeks where shop hours were dedicated to automotive chores, I got some time in to get onto the project backlog.  Unfortunately my photo site, pbase.com, has been down for the past 3 days, so I won't be able to share visuals until they come back up.

The first task was to finish the mini tubing bender that had been languishing as an incomplete box-o-parts for several weeks.  I made the last few minor parts, cobbled it together, and was able to bend 4 lengths of 1/4" copper tubing that are to serve as the connections from the spool valve to the engine.  I also made the two small flanges for the input and exhaust tubes.  And as the last part needing fabrication, I made the valve handle.

Now I pulled out the silver solder "kit".  First, I needed to plug the two holes in the top and bottom of the valve body.  I turned a couple of small brass rounds with a flange to ensure they stayed put during soldering.  The solder job went smoothly, and I then milled the plugs flat to the top and bottom of the valve.

Then, like Bogs, I used the engine itself as a jig to hold the air tubes in place while I solders them to the valve.  One all four were soldered, I proceeded to solder the other ends to the flanges.  Here I had a couple of problems, in that some gaps remain around the tubes.  Seems the solder stuck to the tubes rather than falling into the cracks.

So now I need some advice on how to seal the gaps.  Should I just apply some more flux and some pieces of solder and reapply heat, or is there more to it?

[bogstandard]

Kirk,

Once you have some pics up, show us the problem joints.

It might just be a case of putting the job into the pickle for an hour or so, drying off completely with a flashover with your torch, then a little more flux and solder on the joint. You need to get rid of any old soldering flux deposits before proceeding, otherwise the joint will be contaminated and the fresh solder might not 'take'.

John

[kvom]

Here's the photo log of progress on the engine.

First, the mini tube bender for making the 90 degree bends in 1/4" tubing:



A trial fit once the tubes are trimmed:



The side flanges with some temporary tubes for fit:



The top/bottom plugs soldered:



And them milled flush:



The tubes soldered into the valve body:



The handle for the valve:



Valve after soldering tubes to the flanges:



And the problem gaps where the tubes enter the flanges:

[bogstandard]

Kirk,

Very nicely done indeed, there is not much wrong with your soldering technique at all, in fact it is spot on.
You have soon picked that up.

For those semi soldered joints, just do as I suggested, pickle them for a while, reflux and wrap a bit more solder around the pipe, say 1.5 turns. Don't let the main heat touch the pipes, just the flanges.


John

[kvom]

I finally got around to resoldering the flanges and finishing the reversing valve.  Only took 4 months since the last post.   
But here is it, ready for disassembly and some polish.  I am going to remake the blanking plates.

[spuddevans]

Well done Kirk, that's turned out well. I look forward to seeing what it looks like when polished up

Tim

[madjackghengis]

I've been wondering what a "paddle duck engine" was ever since I first wandered across the reference, and I have to say, having seen it, you are making a serious job out of it, and your's is looking great.  Your tubing bender picture is an improvement on the one I was going to make for the tubing for my radial engine, so I think I'll use your design and get better results.
    I was once a certified micro miniature electronics repairman, while serving in the Marine Corps, and was taught the secret to soldering is 95% cleaning, and the remainder careful workmanship.  When soldering for strength as opposed to electrical work, tinning the whole site which you want solder sticking to, is the best preparation, both the bar, with its hole tinned, and the ends of the tubing.  Once this is done, you will never have an inclusion or break in the soldering job.  Chalk can be used to limit where the solder runs to, including the sticks sold for marking out steel or rusty metal.  This works with pretty much any kind of solder including "hard" silver solder as well as soft.
     That's a great looking engine, I can't wait to see and hear it run!!
mad jack