Author Topic: A first Engine  (Read 8508 times)

Offline dalee

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A first Engine
« on: October 23, 2012, 04:21:33 AM »
Hi,

I'm a new guy that has started my very first engine. I've been lurking for a while and wanted to finish this little project before showing it. But every time I go out to my shop, I get interrupted, (I volunteer as a Fireman/EMT on a small rural department). Seems everyone knows when I head to the shop. My pager never fails to go off. So I figure if I post my start on this, I will be more driven to finish.

I will be building a simple wobbler, "The David" by Alan Marconett. A simple engine compared to much of the work that is done by all of you here. But I think there is much I can learn from it.

I cut a piece of aluminum to start the upright. I had firmly intended to get it sawed, milled square and to length and all holes drilled and reamed. But my pager went off and I had to stop and do a medical call. So I didn't quite get it milled to length tonight. But I did get one photo of milling my stock square.



I hope to be able to get the upright done tomorrow night. Provided the dreaded pager tones stay silent. ;D

dalee

Offline DavidF

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Re: A first Engine
« Reply #1 on: October 23, 2012, 04:28:33 AM »
Wobblers are a great first build, but they can become addictive and multiply like rabbits on the mantel.  Youve been warned LOL

Bogstandard

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Re: A first Engine
« Reply #2 on: October 23, 2012, 08:01:15 AM »
Dalee,

Don't you worry about showing your first engine build. It takes guts to put yourself in the public eye. :NotWorthy:

Everyone on here has been through that experience, and they all know what you are going through. :wallbang:

It will be a massive learning experience for you, and of course, as you get a little more into your build, people might start to suggest different ways you could have done something. Don't get annoyed at them, they are only trying to help you become a better model engine maker. Just absorb what they say, and use the hints and tips they give at another time.

If you get stuck on how to hold or machine a part, then don't be afraid to ask, I still do after many years in this game. :old:

But one two things above everything else, even if you balls it all up, enjoy what you are doing and learn from your mistakes.


John

Offline steamer

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Re: A first Engine
« Reply #3 on: October 23, 2012, 09:49:27 AM »
Hey Dalee,

Thank you for your service, and welcome to MEM!  We're a good bunch....and we like pictures!....Like John said...if you need something just ask!.

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

Offline b.lindsey

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Re: A first Engine
« Reply #4 on: October 23, 2012, 11:13:09 AM »
Welcome dalee.  I'm happy you decided to jump in and post your build. That first engine will always be special and by sharing it here, you allow us to join in that with you. Everyine here has been just where you are and I think you'll find us a helpful and very supportive bunch.  Its not a race either so take your time and make progress as you can.

Regards,
Bill

Offline black85vette

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Re: A first Engine
« Reply #5 on: October 23, 2012, 03:21:59 PM »
Welcome to the forum.   Does not matter what your skill level is there are always questions to ask and new skills to learn.   So feel free to fire away.  Someone here will know an answer or how to do something.

Offline V 45

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Re: A first Engine
« Reply #6 on: October 23, 2012, 04:04:10 PM »
I'm right there with you !! My first build going on as well. Wish you all the success to complete a fine engine.
  Dave
Never assume the implied task has been completed !!

Offline dalee

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Re: A first Engine
« Reply #7 on: October 24, 2012, 02:45:31 AM »
Hi,

Good to hear someone else is working on their first engine also! I guarantee that I will have questions to ask, in fact I can use some guidance already.

But first. I was setting up to drill all the holes in the upright tonight. When I got to the two 1/16" holes for the intake and exhaust ports, I discovered that I do not own a drill chuck that will grip that small. I have 4 mounted chucks, 2 on MT2 for the drill press and lathe and 2 more for the mill. Who does that?  :wallbang: Will need to run to town tomorrow and see what I can do. Maybe one of those quick change drill bits in the aluminum hex?

Now for some guidance. I went to work on the cylinder. I got to the point of drilling the bore for the piston. Looking at the print, it shows a flat bottom. Is this important? I know that the cylinder shape and volume can matter on more complex designs. I had planed on simply drilling the cylinder, as I don't currently have a 3/8" reamer. I could take a spare 3/8" drill bit and repoint it to a flat profile to finish the bottom. But is it necessary?

Thanks for the fine welcome!

dalee

Offline steamer

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Re: A first Engine
« Reply #8 on: October 24, 2012, 02:47:55 AM »
Hey Dalee,

Can you post a sketch?

Thanks!

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

Offline DavidF

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Re: A first Engine
« Reply #9 on: October 24, 2012, 04:29:27 AM »
I dont think it really matters, my first wobbler was just drilled and reamed. But if you wanted to you could just taper the top of the piston to take up the clearance.
  Heres my first engine, not the prettyest but I only spent a couple of hours making it out of what ever I had and with out plans.

Offline mzt

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Re: A first Engine
« Reply #10 on: October 24, 2012, 11:12:57 AM »
Quote
Now for some guidance. I went to work on the cylinder. I got to the point of drilling the bore for the piston. Looking at the print, it shows a flat bottom. Is this important? I know that the cylinder shape and volume can matter on more complex designs. I had planed on simply drilling the cylinder, as I don't currently have a 3/8" reamer. I could take a spare 3/8" drill bit and repoint it to a flat profile to finish the bottom. But is it necessary?
dalee

Dalee,

I made that same engine as my first, and asked almost that same question.
Best answer I got was a warm advice into forgetting about reamers, boring the cylinder than lapping it to size and finish.
It worked for me, happy to pass it on to You.

As for holding tiny bits, I took a proxxon/dremel chuck and mounted it on an arbor.
I see You're making the upright into alu., I would not make the cyl. into that same material.
That's personal experience: it lasted a few seconds only.

Marcello
This is a fitting job,
not a production job that can be measured in.

Offline steamer

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Re: A first Engine
« Reply #11 on: October 24, 2012, 11:30:30 AM »
OK...Marcello makes a point there.
Though a good finish off the boring bar might be sufficient..

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

Offline black85vette

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Re: A first Engine
« Reply #12 on: October 24, 2012, 01:53:54 PM »
These little engines are pretty forgiving.   It is not an internal combustion and compression is not an issue so the amount of volume at the end of the cylinder is not critical.   No need to drill it flat.  Just don't let the tip of the drill go through the end of the cylinder.   :facepalm2:  DAMHIK

You will need to build your tooling collection as you go.  May not be a bad time to start your reamer set. Just get the most common and you will get a lot of use out of them.  In fact you may change a design based on what sizes you have on hand.   I started with 1/4, 3/8, and 1/2 and get a lot of use out of them.   I also keep drill rod in those sizes.   Very handy to have some drill rod and matching reamer!

There is also the option of a shop made reamer.    Look at page 128 here; 

http://books.google.com/books?id=4ygDAAAAMBAJ&pg=PA128&lpg=PA128&dq=shop+made+reamer&source=bl&ots=Y3OmgT-60r&sig=aPh0w3823Me3QEHe6Ut1zxDYieU&hl=en&sa=X&ei=qN6HUPzOGOfU2AXii4DoAQ&ved=0CGcQ6AEwCw#v=onepage&q=shop%20made%20reamer&f=false

I have seen other examples online but this gives the idea.  Best to use tool steel and harden with heat.

You can also take some aluminum rod and turn it just under size, spit it down the middle for an inch or two.  Put some emery cloth in the slot and wrap around the rod.    It is not precise but it will smooth out a bore that is not critical.   Then make the piston to match the final size of the bore.

If you are using aluminum for the upright AND the cylinder, make sure the surfaces are really smooth and keep plenty of oil on them.  Aluminum tends to gall when rubbed together.

Lots of ways to skin cats in this game.   As always these are just my opinions.  You results may vary.


Offline dalee

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Re: A first Engine
« Reply #13 on: October 29, 2012, 03:36:37 AM »
Hi,

I haven't forgotten this build yet! Just been working through some life.

I appreciate the advice for far. This is has been an enjoyable learning experience. I think this could get to be pretty addicting.

I did get a couple of relaxing hours of machining time this afternoon. So I managed to get the upright and cylinder completed. I took a couple of photos to document.

Drilling and reaming the pivot for the cylinder.


How to drill a 1/16" hole when your drill chuck won't hold that small. I picked up a 1/16" drill meant to be used in a quick change chuck for cordless drills. Only cost me $1.50US.


Edge finding the end of the cylinder to find center for the bore.


I did manage to get a relatively flat bottom hole. I agree with the knowledge here that it isn't really necessary for these engines, but I decided to take the challenge. I rummaged up a damaged 3/8" drill and reground the end to flat. Add a bit of relief at the lips and I was good to go. I used a standard point 3/8" drill to drill to depth and then used the modified drill to flatten the bottom. I had some reservations about re-drilling the hole because the second drill often does bad things to the hole because of rubbing on the sides. I got pretty lucky and it turned out well. Just .002" over the nominal size of .375" and no ballooned out center from side rub. And the finish, while not ground, is pretty good and should clean up pretty easily. I will probably hone it smooth with black85vette suggestion. And my depth is just .0015" short of print. I am quite satisfied.

Old school analog DRO


Completed upright and cylinder. They still need polishing, but the machining part is done.


I hope to try and get a couple of the small parts done tomorrow night. And I think another trip to town is in order for some steel guitar strings to make springs out of. I've never made a spring so now is a good time to learn.

dalee

Bogstandard

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Re: A first Engine
« Reply #14 on: October 29, 2012, 06:44:47 AM »
Dalee,

Sorry about coming in late with a bit of advice.

Almost the easiest way to get your flat bottomed hole is to use a trick that is frowned upon, but can get you to where you need to be.

Drill down as far as the hole needs to be with one size smaller drill than what is needed, then, horror of horrors, mount up a milling cutter of the correct diameter into the chuck and just drill down to the overall depth required. If you take it very steady, that will clean up the bore enough for a little engine such as this, and give you the flat bottom hole that you desire.
I do this a lot when I am putting in counter bores for cap head screws.
I mention this because if you are not taking a lot of material out, then there is not much force on the cutter to cause it to slip in the chuck, which is what would happen if you tried to do full scale milling with a mill cutter in a drill chuck.
Another point, if you do use this tip, if you can, always try to use a centre cutting mill cutter.

With regards to holding small drills. When your finances allow, invest a bit of money in a PIN CHUCK, it will be money very well spent, not just for use on the mill, but on all your machinery that you can drill with, and even by hand using at times, just to do a bit of hole cleaning out or fine countersinking.

http://www.axminster.co.uk/axminster-pin-chuck-set-prod33442/?sessionid=qol

You might also find a set of PIN VICES very handy at times, but not for holding things when mounted into another chuck.

http://www.axminster.co.uk/axminster-pin-vice-set-prod33440/?sessionid=qol

John