# A Simple Oscillator (First Project)



## Heffalump (Jan 21, 2014)

Hiya Chaps,

This is going to be the first thing I've built since college, and I'll be re-learning how to machine as I go along.

I'm going to be building the simple oscillating engine found here: http://www.steves-workshop.co.uk/steammodels/simpleoscil/simpleoscil.htm

I started first by making the base plate. As this was the least critical part I thought it would be a good one to get my eye in on.

To start with I found a random piece of Ally sheet lying around and got it clamped down on the mill bed.







Here's the blank cut to size






 And the stub drill bit set to 0,0 (DRO making life too easy)






 Then finally the two holes through which I'll attach the frame.






 It was fun trying to remember how everything works!

 In hindsight, I should have protected the workpiece from the clamps, and I shouldn't have used a file to deburr the edges, so it is quite a messy piece now, but still fit for purpose.

 Thanks for looking


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## Heffalump (Jan 22, 2014)

I started to make the main bearing today.

The plans called for brass or bronze, but I didn't have any to hand, as discussed in another thread I did have some PTFE.

I decided in the end to try with the PTFE as I did have some handy. If it is not fit for purpose in the end I can come back and make another with brass.

I've never used this material before, it's very messy on the lathe!






I've got the majority of it turned out, tomorrows job will be to finish turning down the back now it's been parted off, centre bore and mounting holes.






I'm quite happy with my accuracy so far, I've not used a lathe for 5 years!


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## 4156df (Jan 22, 2014)

Always fun to follow a build. Please keep the photos coming.


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## Heffalump (Jan 22, 2014)

Thanks, it's all going to be little small bits as I am doing this in my lunch times.


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## Heffalump (Jan 24, 2014)

Didn't have time to upload yesterday's progress! I turned the back of the bearing down, drilled the mounting holes, drilled and reamed the centre and cleaned up the edges a bit.











Then cut the axle to length and cleaned the edges up with the file whilst the chuck was spinning.

Here I made a bit of a mistake. I measured the axle at 6.3mm and the ID of the bearing at 6mm, I thought it would be easier to open out the bearing than try to turn down the axle. I drilled the bearing out to 6.5 (the next drill size I have) and now it's a bit loose.


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## bmac2 (Jan 24, 2014)

First of many? Excellent choice for a first build. The plans look well laid out with good documentation for each step. My first engine looks like it was bashed out by a caveman with a dull rock. Ive never used PTFE, but I cant see that 12mm piston is going to beat up and deforming the bearing much, and if it does, make a new one. Thm:


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## Heffalump (Jan 27, 2014)

I hope it will be the first of many! I'm lucky enough to be using mostly off-cuts from around the shop at the moment, but I'm worried about the price of materials I'm seeing!

I've been a bit poor at taking photos of my steps over the last few days but here's the evidence, I next turned out the pivot for the cylinder, threaded m4 one end for the thumbwheel, and m3 on the other for attaching to the cylinder.






Next I needed to make the pivot nut / thumbwheel






And here's the assembly


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## Brian Rupnow (Jan 28, 2014)

Heffalump---Nice first engine---But---You'll be sorry. It all starts with a simple oscillator. You will be so excited when it actually takes off and runs on its own that next you'll want to try an engine with a valve---and then when that works a twin----and then when that works, a beam engine.--And after about 10 compressed air engines, you will cross over to the dark side and build your first i.c. engine---and then you'll be wanting to buy better machinery to build bigger models.--Trust me---it's the road to perdition!!!----Brian


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## Heffalump (Jan 29, 2014)

Hi Brian - thanks! Yes, I fear I will have become hooked, so far I am just enjoying the tinkering time in the workshop, even if my progress is slow (and clumsy). My goal is to build a few boilers to run engines on steam rather than compressed air, if I had the means I'd be building a full size steam engine! I must admit it's the V8 IC engines which drew me to this website, and got me thinking about it to begin with, I definitely want to build an IC at some point..!! I'm quite lucky with the size of the machines in the shop at work. Harrison M250 and a bridgeport series 1.


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## Sshire (Jan 29, 2014)

The bits are coming together nicely. Soon, it will be a runner and then, as Brian said........


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## Tin Falcon (Jan 29, 2014)

Nice stuff. On hint comment. I was taught to keep a file near the lathe to debur sharp corners. It is a lot easier and faster to do  while in the lathe. I even start the parting groove back out the tool take off the bur then finish. just something to add to the note book for next time. 
Tin


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## Heffalump (Jan 29, 2014)

Tin Falcon said:


> Nice stuff. On hint comment. I was taught to keep a file near the lathe to debur sharp corners. It is a lot easier and faster to do while in the lathe. I even start the parting groove back out the tool take off the bur then finish. just something to add to the note book for next time.
> Tin


 
Thanks for that, It's something I actually picked up over the last couple of days, I've started doing that now, wow it makes life much easier!!


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## Heffalump (Jan 29, 2014)

Here's some more bits!

Cutting the cylinder down to length






And milling the flat face






After the exhaust/intake port had been drilled and the pivot mounting hole tapped






Cylinder drilled and reamed, but still needs polishing






Mocked up with pivot and thumbwheel






There's a lot of tidying / cleaning / deburring to do yet.


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## Swifty (Jan 29, 2014)

Hi Jim, your doing a great job there, just thought that I might give you a tip when putting a short thread on a shaft, drill and tap a hole and then put in a screw with a bit of loctite if you wish, then cut the screw to the length required. It allows he thread to be right up to the shoulder. Here's a picture of a M3 thread x 3mm long that I have just done.





Paul.


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## Heffalump (Jan 30, 2014)

Swifty said:


> Hi Jim, your doing a great job there, just thought that I might give you a tip when putting a short thread on a shaft, drill and tap a hole and then put in a screw with a bit of loctite if you wish, then cut the screw to the length required. It allows he thread to be right up to the shoulder. Here's a picture of a M3 thread x 3mm long that I have just done.
> 
> Paul.


 
Ohh that's sneaky!! I love this idea - I will definitely be using it next time... Thanks so much


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## Lawijt (Feb 4, 2014)

I build this one also. Here a picture:






 And offcourse a movie:

 [ame]http://www.youtube.com/watch?v=2DkUCrBrFug&list=UU1BXeMnWzIagQAC7fKYx0_g&feature=share&index=1[/ame]

 Barry


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## Heffalump (Feb 4, 2014)

Hi barry, thanks for posting that! it's very enthusing! It's great to see what I'm building, it really seems to have a good rev range, and it seems to run very slowly!


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## Lawijt (Feb 4, 2014)

A good tip.....In the next picture you will see a other wobbler. You will see that I milled a slot in the middle of the mounting plate..It may be wider.....
 But you will see that there is a lot off movement on the top & the bottom off the cilinder. In the middle not much movement. So when the engine runs , you have wear on the bottom & the top , but not in the middle!! Than the air leaks will come. 






 If somebody want that plan , send me a PB with mail adress...

 Barry


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## Heffalump (Feb 6, 2014)

I haven't posted for a few days - I made a bit of a schoolboy error and ruined my cylinder whilst creating the tapped holes for the cylinder cap. In the end I've now made a new cylinder, which is a much tighter fit on the piston, so I think it's worked out OK.

Milling the new cylinder 











I think I'm getting better, long bits of swarf = good right?


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## Heffalump (Feb 10, 2014)

I keep forgetting to take photos, and I keep making silly errors (including basic maths). Here's some evidence LOL

The cylinder cap now fits snugly on the (new) cylinder






The piston didn't fit into the new cylinder, so it was roughed down to size using a file. We seem to have an absence of ALL emery in the shop, so this has gone on my personal shopping list. The file has left the cylinder grooved - which my friend and I thought may help providing a seal with oil caught in the grooves. I don't know if this is misguided or not...






Here are most of my mistakes, I started making the frame.

I accidentally drilled the bearing hole 2mm oversize, so I will have to make a collar for the bearing to fit into. Alternatively I could make a new oversize bearing, I'm not sure which to do.

Second event taking me up to TARFUN - the two ports above the pivot are both straight through. However, the intake is meant to be at the top of the frame, this hole should have been drilled blind!! I think I will tap the hole part way, loctite a screw in, and continue as normal. I do not think there is enough clearance next to the exhaust port for a steam / air fitting. What do you think?


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## vascon2196 (Feb 10, 2014)

Ha,ha,ha,ha,ha.....welcome to the dark side.

Keep saving your pennies....your going to need them once your hooked!

It's worth it though


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## gus (Feb 11, 2014)

Hi Heffalump,

Will be following your thread on this engine. After this engine and more engines coming???


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## Heffalump (Feb 13, 2014)

I've had another mixture of steps forward and back, I always liked my dessert first;

I plugged the back of the misdrilled intake port and drilled down to meet it from the top







A bit carried away, I had oversized the bearing hole in the frame by 2mm. So I made a new bearing, this time from brass not PTFE.






We decided that we'd like to press fit this into the frame. Thankfully, we have a -41c freezer and plenty of heat guns around. Here's the result before cleaning






and a quick dry lay up


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## Heffalump (Feb 17, 2014)

I've been really terrible about taking photos!! I got all of the parts made and assembled so we tried to get it to run up. I haven't been able to get it running though. I think the main problem is lack of compressed air pressure. We have one compressor that runs all the air lines in the building, the system pressure is around 104 psi. The only thing I can find to get the air into the engine is a damn safety air gun. The back pressure is causing the gun to cut back the output so much I'm barely getting anything out of the end. I need to find away to get air out of the lines ha!


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## barnesrickw (Feb 17, 2014)

Or, a valve between the supply and engine.  Very small valve.  Or run it balls out, even though there is no governor.  140 psi should provide a few seconds of extreme excitement. 


Sent from my iPad using Model Engines


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## Heffalump (Feb 17, 2014)

no the problem is the safety air gun isn't giving out enough air because it's sensing positive pressure


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## barnesrickw (Feb 17, 2014)

Can't bypass the gun?  Safety stuff, always in the way of progress. Or emergency room visits. 


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## Heffalump (Feb 18, 2014)

Well it isn't finished, but it's all together and we couldn't help but run it up to see what happened. I still need to fit some kind of inlet attachment, rather than having my glamorous assistant hold the airline. We managed to bend the crank when we were press fitting it all together so really that should be re-made. A bit of loctite added in a couple of places, waiting for that to dry and we'll have another go. Here's the evidence.

[ame]http://youtu.be/tkFjt0EW7wk[/ame]


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## Sshire (Feb 18, 2014)

You'll never forget your first runner. Each engine adds to the "this worked" and the "I won't do that again" lists. Each one gets better.
Congratulations!!


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## Heffalump (Feb 18, 2014)

Sshire said:


> You'll never forget your first runner. Each engine adds to the "this worked" and the "I won't do that again" lists. Each one gets better.
> Congratulations!!


 
Stan, I think I have more on the "I won't do that again" list than I do the "this worked" list!

looking forward to getting it all cleaned up and running smoothly.


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## barnesrickw (Feb 18, 2014)

Nice runner. How does it feel?  


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## BaronJ (Feb 18, 2014)

Heffalump said:


> Well it isn't finished, but it's all together and we couldn't help but run it up to see what happened. I still need to fit some kind of inlet attachment, rather than having my glamorous assistant hold the airline. We managed to bend the crank when we were press fitting it all together so really that should be re-made. A bit of loctite added in a couple of places, waiting for that to dry and we'll have another go. Here's the evidence.
> 
> http://youtu.be/tkFjt0EW7wk



Its alive !  Congratulations on having a runner.


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## bmac2 (Feb 18, 2014)

Thm:Congratulations! Its a runner! 
The more you can get on the "I won't do that again" list the better. Only making a part once means you have leftover stock. Left over stock means you have a start on the NEXT engine. 
Saves on bandages too.


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## Heffalump (Feb 22, 2014)

Welp, Here's what I think will be the last video of the oscillator, I got it running up to 6.5 BAR even with all the bits that didn't fit properly and it still felt quite comfortable! I've learned a lot whilst cobbling this together, and next I plan to make something that looks OK as well as just running. I'm giving Elmer's 33 a go, so we will see how I fare!

https://www.youtube.com/watch?v=jN1Gp0-_7NM


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## Generatorgus (Feb 22, 2014)

First runners are great. They give you the feeling that you can move onward and upward as well as the comfortable feeling of accomplishment.
Well done.
GUS


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