Author Topic: Props first engine - Elmer Wobbler #25  (Read 24021 times)

Offline Don1966

  • Full Member
  • *****
  • Posts: 6817
  • Columbia, MS
Re: Props first engine - Elmer Wobbler #25
« Reply #15 on: January 13, 2013, 03:45:16 PM »
Prop, those parts all look good to me. Elmer's engines are pretty forgiving in most ways so the oil grooves won't pose any problem and even a reasonably close piston fit will usually work just fine.

Bill

What Bill said, nice work Prop

Don

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #16 on: January 13, 2013, 10:25:00 PM »
Right so, rather a good day today. I made more progress on the piston and con rod assembly, including threading piston and con rod, milling a flat on the big end of the rod, and drilling the pivot hole.



It looks a little beaten up from the extra work - the close up pics really show up the detail and blemishes, but it will polish up OK. In real life it looks much better - damn cameras!

But never mind that - I took the opportunity to test the piston in the cylinder again, and was mighty pleased to feel resistance as the air compressed, per Lees suggestion, and a then hear a little "thop" sound as I quickly pulled the piston out. Yay! It was even better with a light oil coat. I wandered around the shop for a good few minutes playing with that.

After that I drilled the port hole in the cylinder, and did a little dry fit of cylinder and frame. I was pleased to be able to feel pressure in the cylinder again when on the frame, and also pleased to feel the pressure go away as the port lined up with inlet and outlet on the frame respectively - definitely a good thing.

I also turned and drilled the crank disc, leaving over thickness for now, as I will skim it to the correct thickness once it is pressed on the crankshaft. Jury is still out on whether I leave the crank disc as a disc, or cut it out for that "balanced" look. I'll sleep on it.

Here are the frame, crankshaft and crank disc as they stand. Some (plenty) of finishing work needed on the frame. I'll do that during the week after I have drilled and tapped the mounting holes in it.



Moving along - there are plenty of imperfections, but plenty of positives too. Lots of stuff to build on as I progress in the hobby. I am pretty happy about it all.
« Last Edit: January 28, 2013, 04:07:04 PM by propforward »
Stuart

Forging ahead regardless.

Offline vcutajar

  • Full Member
  • *****
  • Posts: 2555
  • Marsascala, MALTA
Re: Props first engine - Elmer Wobbler #25
« Reply #17 on: January 13, 2013, 10:42:41 PM »
You'll have it running in no time.  Keep it up.

Vince

Offline chucketn

  • Full Member
  • ****
  • Posts: 399
  • East TN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #18 on: January 14, 2013, 09:26:52 PM »
propforward,
I had started on this engine some time ago, but life got in the way...
I've dug out the few pieces I had made and am following you along, so I'll be asking questions. First one, did you use the drill guide and locating pins to locate the port holes in the frame? If not, how did you locate them?

Chuck

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #19 on: January 14, 2013, 09:43:44 PM »
Hi Chuck - that is great. I look forward to seeing pics of your build.

I did indeed use the drill jig and pins. I'll take some pictures of that. It's a neat and simple method for locating the holes, because you can then use the same jig to get the port hole in place on the cylinder as well, just about gauranteeing a good match up.
Stuart

Forging ahead regardless.

Offline steamer

  • Global Moderator
  • Full Member
  • *****
  • Posts: 12697
  • Central Massachusetts, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #20 on: January 15, 2013, 12:16:14 AM »
Great build Chuck!....keep it coming!

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline chucketn

  • Full Member
  • ****
  • Posts: 399
  • East TN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #21 on: January 15, 2013, 01:48:50 AM »
Uh, Dave, this is Propforward's build. I just asked a question.

Chuck

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #22 on: January 15, 2013, 01:55:21 AM »
Don't worry, I'll adopt any name going when the compliments are being handed out, it helps me feel good about myself. ;D
Stuart

Forging ahead regardless.

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #23 on: January 18, 2013, 02:50:52 AM »
I'm still working on it. Haven't done much lately, having had to deal with other far more mundane and boring everyday life matters, but I got down the shed tonight, and cleaned up the frame a bit, and made a base for it.



Tomorrow, I plan on making the pivot pin and soldering it into the cylinder, cleaning that whole assembly up, and then making the flywheel (for the third time).

Depending on how it goes I might even have it all assembled tomorrow - I certainly ought to have it complete this weekend.
« Last Edit: January 28, 2013, 04:07:34 PM by propforward »
Stuart

Forging ahead regardless.

Offline swilliams

  • Full Member
  • ****
  • Posts: 896
  • Canberra Australia
Re: Props first engine - Elmer Wobbler #25
« Reply #24 on: January 18, 2013, 03:44:17 AM »
Go Prop. It's going to turn out a beaut  :cheers:

Steve

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #25 on: January 20, 2013, 12:57:36 AM »
Well I've put a bit more time into it. I had a go at cutting the crankshaft disc to shape, but that turned into a hideous failure, so for this engine I'm just going to leave the crankdisc as a plain circular disc. I don't think it will matter. The replacement crank and disc are made, and ready for use. I made little jigs to keep everythig square when pressing the crankshaft and pin into the disc. (I didn't want to use loctite as in Elmers instructions).

I also made the steam connector, and began work on the third flywheel.

Originally I was using aluminum, and making them plain discs, with a hole through from the perimeter of the flywheel, but I don't think aluminum is massive enough for a flywheel really, and I don't like the lock screw right through the flywheel.

So my third attempt is in steel, and I have changed the design to a flywheel with a boss, and the boss will have a set screw in it.

I was also bound and determined to make it look like a flywheel - ie machine a groove both sides. I am giving up on aesthetics on the cylinder and crank disc, in that the cylinder will not have chamfers on the outside edges, and the crank disc will not be cut to look "balanced", so I need to add some interest somewhere, and this seems like the best place.

This is the flywheel part way into machining.



In this picture the groove has been machined both sides. Not to any specific dimensions, but even both sides. You can see some burrs and marks on the flywheel - that's OK, it isn't complete. The next stage is to drill and tap the boss for a set screw, then I will mount it back in the lathe on a shaft, and take the last finish cuts to true it up and clean it up.



It's not the best finish, although the magnification of the camera makes it look worse than in real life (honest). I am actually pretty satisfied. At least it looks like a flywheel, with rim, web and boss. I used a form tool to make the groove, and that is a tricky piece of machining. The bit wants to chatter like mad. Note to self - read your reference works on using the lathe BEFORE starting new to you operations. Turns out that having a rake angle on the form tool was a mistake. It worked much better with no rake, but this time I saved the part and didn't need to trash it.

So progress continues in a two steps backwards, three forwards kind of way. Yesterday, by lunchtime, I had fewer available parts than when I started in the morning.

However, since then things are well back on track.
« Last Edit: January 28, 2013, 04:08:31 PM by propforward »
Stuart

Forging ahead regardless.

Offline Don1966

  • Full Member
  • *****
  • Posts: 6817
  • Columbia, MS
Re: Props first engine - Elmer Wobbler #25
« Reply #26 on: January 20, 2013, 01:10:24 AM »
Starting to shape up nicely Prop, it wouldn't be long now she will be running.

Don

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #27 on: January 20, 2013, 01:14:55 AM »
Thanks Don. Everything takes longer than it is supposed to to make, but I ought to have this running tomorrow.
Stuart

Forging ahead regardless.

Offline zeeprogrammer

  • Full Member
  • *****
  • Posts: 6811
  • West Chester, PA, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #28 on: January 20, 2013, 01:18:21 AM »
but I ought to have this running tomorrow.

Tomorrow? Already? Geez I feel so inadequate.

That means a video then! Looking forward to it.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline propforward

  • Full Member
  • ****
  • Posts: 1656
  • MN, USA
Re: Props first engine - Elmer Wobbler #25
« Reply #29 on: January 20, 2013, 01:25:13 AM »
Heh. I've been working at this model for ages it seems. I have quite the graveyard of parts that have since become "jigs and fixtures" ;D

If it works (and all dry fit testing says it ought to) then I certainly shall post a video! I shall be quite proud of my first little effort. I realise that there are some quite magnificent models on the site, but you have to start somewhere. This is a basic little model, but I'm pleased as punch so far, and shall be very excited when it spins.
Stuart

Forging ahead regardless.

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal