First engine, the little machine shop oscillating engine.

[Twmaster]

What a great idea for surfacing that flywheel!

*sigh* More tools I cannot buy right now...

 

[metalnwood]

Well, I sure didn't think I would be showing you something interesting!

As I say, for a small flywheel like this - 2.5" my tool on the lathe is too big to get in there easily and I couldn't be bothered grinding something to use. All my tooling is the insert type on a 3/4" holder.

I was tempted to try and put curved spokes on it as I have seen around here but I thought better about ruining another piece just now.

Just about finished another piston but had to stop to give the kids dinner..

I had a small piece of bronze just over .5" diameter so I decided to use that rather then turn down the much larger diameter steel I had around. I hope bronze isnt an issue for a piston.. maybe a waste though.

 

[metalnwood]

Hi all, I have a bit of a question. I have done the piston and I am not really sure of what is a good fit..

The cylinder is bored to .5" and it reads exactly that (.5000) with my calipers. The piston is reads .0015" under. The movement is nice but the air pressure is my only concern, probably no concern at all given the psi it will likely be driven at..

it will fall under it's weight ,1oz, and take about 8.5 seconds to fall 1.4" with a quiet hiss of air passing by. Would I be ok with this?

Oh, and the pic..

 

[Tin Falcon]

You should be fine go with it
Tin

 

[metalnwood]

Thanks Tin, hope so, not far away from finding out.

It was a little longer then expected because I couldnt put in the chuck of the dividing head as I wanted. The only way I could do it is if I held the piston by the head which I didnt want to do, I was bound to scratch it..

I ended up putting it on a v block but even then the clamps were too big to let me get at the end so I had to make a quicky from a bit of aluminium.. I have found that the quick change tool post things from the lathe make good V blocks

Now I have a bit of measuring to do because the cylinder block doesnt clear the crank wheel, very strange as everything was measured and looked good. The only thing I didnt measure was on the upright as I just used the DRO on the mill, if thats the problem then operator error

 

[metalnwood]

And it turns out that is exactly what the problem is.. I must have transposed some number or something..

Too late to look at it now.. Thankfully it's a rather easy piece but I am getting worried that I have almost built two of these engines now and will only have one to show for it :big:

 

[ozzie46]

Only 2, A lot of us probably have almost 4 or 5 of the same engine. :big: :big: :big:

Ron

 

[metalnwood]

Oh boy, I milled to size the new upright and before I started to drill I thought I would re check the old one to see where I went wrong and not do it again.. I thought perhaps I had not adjustedm for the diameter of the edgefinder..

When I looked at it again it was correct.. ??? ???

It turns out when I checked it last night I used my vernier calipers which I dont use often and read the inside value, not the outside value..

So what was wrong? I dont believe it, it's the cylinder block.. Again. I measured and drilled from the wrong end of the bore so the pivot is in the wrong place..

Did I mention that after all of that cutting 2" square stock down to 1" I found so just over 1"? So I guess it will be easier this time.. oh boy.

 

[Kermit]

I once had to remove and reinstall the connectors on ten seperate identical cables. 12 conductors each. One of these was a ground, shield wire that soldered onto a tab attached to a thin washer that went on the connector before the shell was put back together. I got everything taken apart easy peasy. Made the changes to the cables and started putting it all back together. Got all the wires soldered into a connector and the ground ring is there hanging in the breeze. soldered it on no problem. except ALL the wires needed to pass through the center of the damn thing BEFORE the other wires get soldered back on the connector. I un-did and re-did all the solder joints and finally got it put together right.

I did the very same thing on the next cable I picked up. ;D

 

[ttrikalin]

I did the very same thing on the next cable I picked up.
[\quote]

Hahahahahaha it took me a while to understand -- :big:

What a day you were having then!

t

 

[metalnwood]

Hmm, I had a missing post somewhere. No matter.. I do the same thing all the time when making up cables!

I am only saved if I havent done the other end yet so I can slip it on there.

I put it all together and put some air through it. To my surprise it ran and then it didn't..

It took a little bit of tweaking and I am still not sure what to tinker to have it running better.. I might try putting a solid diameter throught the upright for the pivot pin. It's threaded all the way at the moment and that might be letting it move a bit and bind..

Anyway, here it is..

[ame=http://www.youtube.com/watch?v=AjYdGS5Q4Io]http://www.youtube.com/watch?v=AjYdGS5Q4Io[/ame]

 

[ttrikalin]

It took a little bit of tweaking and I am still not sure what to tinker to have it running better.. I might try putting a solid diameter throught the upright for the pivot pin. It's threaded all the way at the moment and that might be letting it move a bit and bind..

I bet this is it. (Also a bit of thin oil never hurt anyone -- just don't run it on a white table cloth... I did but my wife was not around... and put a coaster on it... it's 1 day and 10 hours and still going well 8))

:bow:
Nice smooth running mate -- sure you haven't done this before???

 

[Maryak]

I might try putting a solid diameter throught the upright for the pivot pin. It's threaded all the way at the moment and that might be letting it move a bit and bind..

Congratulations and I think you may have nailed the problem. :bow: :bow:

Best Regards
Bob

 

[metalnwood]

I guess this type of engine is never going to be as smooth as others with a big cylinder block rubbing against an upright.. I suppose with a bit more polishing it could run better. I put some oil between the cylinder block and the upright but it doest take long for it to get blown out.

It seems critical to get the spacing between the crank and the flywheel right, to much play and the piston can sometimes bind , to close and the wheels rub against the upright.

I might take off the crank wheel and give it a good file where it touches the upright to make sure there isnt anything spoiling it there..

Oh well, this was just to waste some time until I cold get some money for the next one..
\

 

[ttrikalin]

This is a nice concept - continuous improvements...

"Pimp my steamer"

 

[metalnwood]

ok, so I did a new pin.. I dont usually deal with anything smaller then M6 so I dont have any dies for m4 or m5. The cylinder block is tapped for M5. I had some old 5mm silver steel around so I needed to cut a screw on it for m5.

Then I find my lathe doesn't do m5 or m4!! I have never needed to so I didn't know. it will do smaller screws and finer pitches but somehow misses these..

This lathe has a leadscrew for screw cutting but uses a seperate rack and pinion for the carriage feed. There was a feed which was .79mm/turn which matched the .8mm pitch so I did it this way. It worked out ok as well..

 

[metalnwood]

I put it back together and gave it a run. I little tinker with the spring tension and it's now a runner ;D

Thats one under my belt hehe.. Now to find some good plans for a horizontal factory/mill type engine.

 

[arnoldb]

Good job metalnwood - Nice feeling isn't it?

There are some good free plans on the john-tom site.

Regards, Arnold

 

[metalnwood]

Thanks Arnold, I had a quick look there a week ago and must go back.

I have one more very poor quality video done on the phone.. its really ticking along nicely now.. the vid is two minutes because I start to see how slowly it will go.. It really needs the oil though, I am using the light oil for my air tools.


[ame=http://www.youtube.com/watch?v=qub0VDMmE1A]http://www.youtube.com/watch?v=qub0VDMmE1A[/ame]

 

[Tin Falcon]

A week and 20 + posts on the board and you have your first runner. Good going mate. As far as those practice parts you made. se la vi. I have told people the home shop is like a university engineering lab . No mistakes just lots of learning experience gained.
Looks like a big fat A on yours first assignment buddy. Now you can go onto bigger and better things or Make a couple of those for the kids for Christmas. and hone the basics a little more before moving on.
Again good going.
Tin