Another Paddleducks build log

[spuddevans]

I got a little more done today, started off by hacksawing a piece of 2mm brass for the baseplate, then sized it up on the mill. Then I slathered it with layout dye and marked it up.



Then it was over to the mill and I drilled all the 3mm holes and then all the 2.5mm holes, then I mounted the bearing blocks and marked up for the cutouts. Over to the mill again to mill out the cutouts.



The obligatory posed shot



Th-th-th-that's all folks ( for today anyway )

Tim

[CrewCab]

The obligatory posed shot

Love it

Progressing nicely there Tim 

CC

[chuck foster]

excellent build 

i was wondering were i can get the plans for this engine??

chuck 

[NorthOf40]

Hi Chuck,

Bogstandard posted a couple links to his engine in this tread http://madmodder.net/index.php?topic=1261.0

[chuck foster]

thanks jim 

chuck 

[NorthOf40]

Yer welcome

[arnoldb]

Good looking build Tim 
Cheers, Arnold

[spuddevans]

Thanks CC, Chuck and Arnold for your comments 

I got a little more done today, somewhere inside both of these lumps of brass there are 4 crankwebs and a flywheel, my mission, should I choose to accept it, is to find them.



So I hacked off a length of the long bar and chucked it in the lathe, faced it and turned it down to 28mm. Then I centre drilled and then drilled through progressively to 4.9mm drills, then finished it off with a 5mm reamer. (I guess this was a little overkill but I thought is would result in a good fit for the crankshaft)

I then chucked a 4.5mm drill in the tailstock the wrong way around and just positioned it so that it just stuck into the hole in the brass bar. Then I parted off a 5mm section, and rather than it dropping into the swarf it just got caught on the backwards drill. Then repeat for the other crankwebs.



Then, after de-burring the parted off crank-webs, it was time to make another jig for drilling the holes for the big end pin and the little compression-hinging-hole-thingy. I made the jig as per the instructions in the plans. I drilled all the 2.5mm holes first, then using the pin to lock the disc I repositioned the x-axis and drilled all the 4mm holes.



And so I ended up with this,



You may notice that one of the crankwebs is not as good as the others. When parting off the carriage moved slightly, but it's not too bad ( a blind man on a galloping horse would never notice  ) I think I might be able to salvage it.


Next I will be milling the crankwebs and also turning the flywheel.


Tim

[Stefan Pynappels]

Good job Tim!

Hoping I'll get back out for a little more shop time before you finish this build!

[spuddevans]

Good job Tim!

Hoping I'll get back out for a little more shop time before you finish this build!

Thanks Stefan, you know you are always welcome to come and play with use the machines 

Tim

[NickG]

Tim, this is really coming along nicely!

[spuddevans]

Thanks Nick  I'm really enjoying this build, I'm learning so much. I'm also learning a lot about the limitations and flaws in my mill and lathe. I think once this is finished I will be doing a few mods to both the mill and especially the lathe.

Oh oh!!  strikes again 

Tim

[rleete]

You may notice that one of the crankwebs is not as good as the others.

Put a healthy chamfer on all of them, and you'll never know.  We will, but we won't hold it against ya!

[spuddevans]

Got a little bit more done today, spent a bit of time hunting around for a 0.5mm shim for setting up for milling the balanced areas of the crankwebs. Spent about 15mins, but came up with nothing. Then I remembered the set of feeler gauges that I got years ago when I was building some guitars, ok they were imperial, but with the help of a digi-mic I was able to sort out 2 pairs of feeler gauges that equaled 0.5mm.



After milling both sides I cut the slot on each crankweb. Then I drilled, counterbored and tapped M2.5 for the clamping screw.

Then I turned down some brass to make the flywheel.



Next is finishing off the flywheel, I'm a little undecided as to doing a lot to the visual design of it as, looking at pictures of the finished engine, the flywheel is not as obvious as some other engines.

So that's as far as I got today.

Tim

[Darren]

God damn you Tim.....why do all your parts look so good......

Stanley blade is 0.5mm thick, that's what I used....

[spuddevans]

God damn you Tim.....why do all your parts look so good......

I think someone needs to go to specsavers 

Stanley blade is 0.5mm thick, that's what I used....

Now where were you a few hours ago, I've got about 4-5 packs of them sitting on a shelf. 


Tim

[Darren]

To be fair to me Tim, gotta be fair to me....it's in my project log......

But glad you found a way, gives others a second option dunit.....



(walks away shaking his head thinking "who doesn't have a pack of new Stanley blades"    )

[kvom]

If your experience will be anything like mine, you will eventually spend a lot of time turning/adjusting the crank by pushing on the webs.  So my advice is to debur all the sharp edges on those webs.  Your fingers will thank you.   

[spuddevans]

To be fair to me Tim, gotta be fair to me....it's in my project log......

Ahh, I see. ( where's the embarrassed smiley ) But to be fair to me, and you know you just have to be fair to me  , I do have the memory capability of a "mentally challenged" goldfish.

But glad you found a way, gives others a second option dunit.....

(says in a loud authoritative voice) "And that's exactly the reason I did it"

( walks away hoping everyone believes it   )

If your experience will be anything like mine, you will eventually spend a lot of time turning/adjusting the crank by pushing on the webs.  So my advice is to debur all the sharp edges on those webs.  Your fingers will thank you.   

Thanks Kvom, my fingers thank you for that wise tip 

Tim

[CrewCab]

where's the embarrassed smiley

He's here Tim .........  

and just in case ............. here's his mate, "Foot in Mouth" smiley ............  ............ which is one I need a lot 

Nice work btw, as usual 

CC

[spuddevans]

where's the embarrassed smiley

He's here Tim .........  

and just in case ............. here's his mate, "Foot in Mouth" smiley ............  ............ which is one I need a lot 

Nice work btw, as usual 

CC

Thanks CC, I could make use of those smiley's a lot. 

Tim

[CrewCab]

No prob's Tim, I try and keep a few in stock, just for special occasions etc ..........     

CC

[bogstandard]

Tim,

The flywheel is small on this engine, in fact, flywheels are not really necessary on most of these small double acting engines.

It is there just to help it thru any self induced dead spots (timing not set up perfectly) and assist in keeping the engine at a constant speed when being loaded by say a propellor. But on a single acting one like a wobbler, they are necessary to get the engine onto the next power stroke.

It does help having the flywheel lightened towards the centre, as it then puts more force into the outer periphery of the wheel, similar to a gyroscope. So even a few holes or recesses do help.

John

[spuddevans]

It is there just to help it thru any self induced dead spots (timing not set up perfectly)

In that case a flywheel on my engine will be essential, especially when I start setting the timing, I've never timed anything before.

It does help having the flywheel lightened towards the centre, as it then puts more force into the outer periphery of the wheel, similar to a gyroscope. So even a few holes or recesses do help.

Enough said, I'll see if I can drill a few holes to move the weight towards the outsides.


Thanks John 

Tim

[NickG]

Presume the crank journals set 90 degrees apart on this engine? Do you have a method of achieving this or just by eye?

Nick