Proposal to design a "First Build" engine

[zeeprogrammer]

Excellent start black85vette!

If I may...

No soldering at all. I'm on my 4th engine (such as it is) and no soldering yet.
In a similar vein (i.e. 4th engine)...no drill press needed.
A 3" flywheel? Maybe too big? I have a 7x12 lathe. The 2" flywheel for the Launch Engine was no problem (okay...was problem...but that was me...not the equipment). The 21/4" flywheel for the Model 2 was a bit more of a problem. Even though 7x12 means 7" swing...it seems to be a matter of what the 3-jaw chuck can handle. Think limit is out-of-box 7x12 mini-lathe...no 4-jaw...maybe no reversed jaws for the 3-jaw.

The manual is key (well was for me). No matter how good you are...a newbie will have a question/problem you didn't think about. Make sure others go through it. (I just had that pointed out to me at work today. Fooey. Young wet-behind-the-ears wannabe programmer. But they were right.)

Oh...and you probably already know this...don't worry about getting it right the first time...if you realize that those guinea pigs are going to improve it...you'll be far happier. I only say that because of today. Fooey but it is an improved idea.

Again, I think this is an awesome project.

 

[black85vette]

Thanks Zee! You have some really good thoughts on this project.

I agree with the limit on the size of the 7x10 standard 3 jaw. I have actually held larger than 3" in mine by drilling a hole in the center and then put a nut in the chuck. "Bolt" the fly wheel to the chuck. Then turn the outside and the recess on that side. Now you have a hub that you can hold in the chuck. Square up the outside and finish the second side. But you are still right. Make it a size that can be done simply.

I am a big fan of not getting it right the first time. I have seen too many projects take way too long trying to fix every potential issue until they were high centered and dead in the water. Unless you are designing aircraft, submarines or medical equipment it is good to get it "about" right quickly and then start to refine and debug. Hmmmm. Sounds kind of like programming (or at least the way I do it)

 

[black85vette]

Had some time last night and got to drawing on my clipboard in my easy chair. Did a little brain storming and using all the ideas that have been suggested. Then I went through a couple of sessions to reduce and simplify. Nothing here is all that original. The general configuration is from one of Elmer's engines. The valve was Brian's idea for one of Chuck's designs. So I "borrowed" on some design ideas from several sources. The valve and piston assembly are drawn to the sides to make things easier to see.

I only have a top and end view because I can't do 3d (just barely got this much done). What I ended up with (if it will even work) is something that you can cut out of 1/4" aluminum 2" bar stock 8.5" long for the base, vertical, crank and flywheel. Then a 2" piece of square aluminum 3/4" stock to make the cylinder and valve bodies. Finally a 1/4" steel rod piece 6" long makes the piston, valve and both connecting rods. So you only have to order 3 pieces of material. The two bores and crankshalf are all the same size so you need just one reamer. All mounting hardware, and pivot points are 4-40 screws. So again just one tap size. I did some on-line shopping and came up with about $5.00 usd for materials and $4.00 for 100 screws. If you can buy the screws locally this gets cheaper.

I am thinking of this as a starting place. But, that does not mean it is the right one. Look it over and see if you have suggestions, corrections or maybe it makes you think of another approach. Let's see where we go from here.

 

[black85vette]

Hi. Welcome to the forum and this thread.

You might like Brian's version of Chuck Fellows horizontal single. It has a number of the features you described. Plus you can post on this forum and hear from others who have already built it. It is a friendly design and you can use several materials to build it.

Plans are here:

http://www.homemodelenginemachinist.com/index.php?action=tpmod;dl=item199

And here is a web site with a bunch of info on basic machine tool operations:

http://www.jjjtrain.com/vms/library.html

But you can always ask on this board and get a good answer. You might consider starting a build and then ask the how to questions as you go.

 

[zeeprogrammer]

Hi black85vette,

I'm a little confused...I can't quite figure out what the material list is from your post...and the drawing seems to indicate the some round pieces will be turned from plate. If that's true...my suggestion is to use round stock for round pieces. Interrupted cuts for the newbie are scary (very scary my first time).

Have you seen the drawings for the 'Rocker'? I thought those were easy enough to use (although the dimensioning...not to mention my math could have been better).

 

[black85vette]

Zee;

Yes I do have 2 round parts made out of the bar stock. I do it at times without an issue but I am willing to hear other opinions on the matter. By making them out of flat stock I eliminated two additional materials to purchase. So I guess it is a trade off. I do have questions for you; if we use round stock how do we order 1 piece of 2" round stock 1/4" thick? Or, do we order a couple of inches and cut off the amount needed? How did you do your flywheels? Personally I tend to order about 6" of any material I need and then use a bandsaw to cut it down, but I don't think everyone would want to do that.

The material list was:
1. 2" wide aluminum plate 1/4" thick and 8.5" long
2. 3/4" square aluminum bar stock 2" long
3. 1/4" round rod 6" long

All the parts were then cut from those 3 pieces.

So what do the rest of you think? Round parts from round stock or square stock? Any ideas on buying stock for a flywheel?

 

[va4ngo]

I prefer the flat stock idea. Reason:- I have just tried making a 3 " diameter disc from a piece of breadboard material I believe it may be Polyethylene or Polypropylene, using the no chuck method with masking tape as the gripping material and it worked very easily and trouble free. The person who described the method ( I apologose for not remembering who) says he could turn up discs up to 2 foot diameter on larger lathe using this chuckless method . I have no reason to doubt the method as being acceptable. It would be very difficult to purchase small lengths of 2" Diameter bar.

Great work on this worthwhile first timers project. Keep up the good work.

Cheers
Phil

 

[Deanofid]

I don't know what you had in mind for the piston and valve, Vette. If aluminum, then it will probably be better to use brass for the cylinder and valve body, and it won't cost that much for a 3/4" square piece. Won't hurt for it to have a little color, too.

The flywheel from aluminum is going to be pretty light. The engine will run smoother and slower if you use a heavier metal for it. Steel or brass. Brass is easiest to cut of course, but costs more. Maybe give the builder the option to use either one?

I'm another one who thinks it will be easier for the new builder to start out with round stock for the flywheel. I've made a lot of square things into round things, so it's not like I have any objections to doing it, but it will be easier to make round things from round, square things from square.

The valve was Brian's idea for one of Chuck's designs.

I think you will have to go back a long ways to credit that valve. It's a good, old, design. Great for a new builder.
Speaking of valves, it needs an intake pipe to go along with it. I would suggest just drilling down a piece of aluminum or brass round stock. Then turning one end down a short distance for a press fit into a common sized drilled hole in the valve body/steam chest.

Dean

 

[zeeprogrammer]

Hi black85vette,

My mistake. I'm so new to this and what I've done has been from kits of materials...I hadn't thought about the need to cut one's own parts.

While you can readily find houses that will provide metal by the inch...it's not the most economical nor accurate. Although a 'thick' aluminum flywheel may give more inertia at the expense of some looks.

But cutting a round part from square is still uncomfortable to me. I think the 2nd or 3rd part I ever made was a machinist jack from hex stock. The noise from the interrupted cuts was very disconcerting. (Although it was steel...I don't know if aluminum is easier.)

I'd like to see what others think too.

The material list is helpful. You might add the specific material type or suggest various. 6061 T6, 1018 CRS or 12L14 steel. That kind of thing. The easier you make it for the beginner to get started the better. For example, it was tough getting started for me. If I had to study a supplier to figure out what material I needed, there was a chance I'd be too confused, unsure, and give up. If I can go to the house and order this one and that one, and be done...that gets me quicker to my goal of building my first engine. Once I have some success, I'm more likely to spend the time to expand my learning.

On that note...and perhaps this is going too far...when I first started several months ago...I didn't know what T6 meant, 1018, CRS, etc. I understand the manual can't tell the beginner everything...but it would be helpful to provide some information or explanation on the materials being proposed. That or some references where they can look if they're interested.

When I was a kid building plastic models, one of the things I always enjoyed was when the instructions provided a bit of history on the subject model. And, if there were tips and techniques...well! I'm not suggesting anything major...but a lot of people don't even know how a steam engine works. I remember the Model #2A...my very first attempt...not a word about how it operates.

 

[black85vette]

Zee;

I agree with the need for a materials list and sources for exact type of metal. I still have some problems figuring out what I need. Fortunately I have a Metal Supermarket near me and they are good about explaining different grades and helping me pick, but not everybody will have that. So when we get a design some of the experts will need to jump in with help on that.

You don't have to cut flat stock from a totally square piece. I keep cutting corners until I get close to round then go for the lathe. Still some noise.

Dean;

Agree about the inlet piece. I didn't show it but it is an opportunity to turn a piece to a correct diameter and drill it on the lathe.

The piston and valve were to be made from the 1/4" steel rod.

I looked at doing the flywheel in brass but the price jumps up. We could give several options on the plans and let the builder decide based on budget and material availability. I thought about doing the flywheel, cylinder, and valve out of one piece of 3/4" brass. (yes the flywheel is still square) Then turn the flywheel down to 1/2" with a 1/4" hub. It would be wider and plenty heavy. Plus it would be another opportunity to make a different type of cut. Another thought I had was to use two thicknesses of the 1/4" stock (yes flat again ;D ) and use screws to hold them together. That would make it heavier but still cheap.

Good discussions guys. Everyone has some insight to this and we should be able to incorporate some experience and expertise.

Everyone is welcome to comment.

 

[black85vette]

Need more input here.

Over the weekend let's try to get our basic configuration and some of layout work done. My ideas are only to start up some discussion. You can go from there or go an entirely different direction.

Maybe we can start with discussing some basic configurations that you have done or seen that would suit a new builder and fit the criteria we have so far.

:idea:

 

[black85vette]

Well, not much activity on this over the weekend.

How about we get a little more specific. What valve arrangement should we use? Should be easy to make and appropriate for a small engine.

BTW: Zee, while I prefer to use flat stock for the flywheel, it occurred to me that we can just leave it up to the builder. If they want round stock they can just order what they need. It really is not critical. We can always have options and alternate ways to do something depending on the builder.

 

[zeeprogrammer]

I like that idea black85vette. Providing options and alternate ways will help prevent beginners getting stuck. Some us (me!) take a little while before we get flexible enough to consider alternatives on our own.

Sorry I can't help with the valve arrangement. I don't have the experience to comment much on design, engine types, etc.

 

[rleete]

Spool valve. It's a simple turning exercise, and fit is somewhat important for minimizing leakage, but not so important that it won't run if it's too loose.

One other point. NO angles! Setting up in a mill is difficult enough, and most newbies won't have any angle blocks to start. That means holes need to be drilled at right angles. Also, minimize blind holes if possible, making them through holes. If the design needs a blind hole - like the bore of a cylinder, for example, it's much easier to make a through hole and cap the end.

I like the design posted on page 2, but I'd rather see round cylinder/valve body with a flat on the side. Yes, it's milling, but brass or aluminum can be hand filed easily enough.

 

[black85vette]

Spool valve. It's a simple turning exercise, and fit is somewhat important for minimizing leakage, but not so important that it won't run if it's too loose.

I have seen spool valves used in some designs and agree that they just require simple turning. I am interested. Do you know how to calculate the basic size and timing? I have never actually used one.

The round vs square cylinder can be another option like Zee and I discussed on the flywheel. Let them make it the way they want according to their skills and IF they have a mill. We can do the same for the blind hole issue. They can make it either way. I am liking the idea of several ways to skin this cat.


Thanks for the good ideas!

 

[Kermit]

The round vs square cylinder ... Let them make it the way they want according to their skills and IF they have a mill.

I wanted to comment on this if I may.

I'm thinking a simple no frills - lathe only - design, with multiple "upgrades" if you will. Many different engines of the same exact design, but with addition frills and florishes that can be used to learn new lathe and mill techniques. So a person could make the crank, piston rod, piston, and bore the cylinder and proceed from there and build the variation he wants according to skill level and equipment. Fancy milling on the flywheel. Radiused edges. Slopes on flat surfaces. Internal threading, or just plain threading.(haven't tried it yet!) I'm scared of it still. Any number of variations. All fitting on the same basic motor chassis.

Am I making any sense with these ideas?

well anyway, I'll keep reading. loving this thread,
Kermit

 

[black85vette]

, but with addition frills and florishes that can be used to learn new lathe and mill techniques. So a person could make the crank, piston rod, piston, and bore the cylinder and proceed from there and build the variation he wants according to skill level and equipment. Kermit

Kermit: When this started I hadn't even thought about that aspect of it but you make perfect sense. I can see a couple of chapters after the basic build and each with some specific machine operation to learn and dress up the engine in the process.

Thanks for the thoughts! Keep jumping in. Thm:

Of course we still need to get this thing designed. Any other input out there on the valve?

 

[Quickj]

Another option for Flywheels for engines you are building are "Found Flywheels"

This picture is two that I found today at the local thrift store. They are the drivewheels from old "eggbeaters" from the kitchenwares department at Goodwill.

Roughly 2.75" in Diameter, 1/4" and 3/8" inch thick, Nicely chrome plated. Interesting gear look to them. and they only cost a couple of dollars. I always shop with an eye towards "Could I use this to build an engine" It is amazing the stuff you can find in a thrift store that will work.

I used a Found flywheel like this on the first engine I ever built 10 or 12 years ago.

 

[Quickj]

I looked at your drawings on page 2, and I decided to do a concept build to see how difficult this would be as a 1st engine. As you can see from the photos, I did not finish it today, but I am close. I have about 4 hours in it.

I decided to build this as if I had limited tools. I hand cut all of the metal plate with a hacksaw. and filed smooth. Once I determined that those processes would work (Although very slow) I switched to the mill to do final clean up. I drilled all holes with a drill press. etc.

I had the most problems with the flywheel. I made the first one from 1/4" plate, Hacksawed roughly to size, and then put it on a mandrel to turn between centers to make it round. This worked well. Then I did the final center bore and ream which made it fit the shaft a little loose. I could have used locktite to secure it, but I thought I would just put a little knurl on the shaft to expand the shaft enough to hold the flywheel securely. I pressed the shaft into the flywheel with my 2 ton arbor press (crookedly, scratch one flywheel).

The second flywheel I made from 2 inch round bar 7075. Parted off a 1/4" thick disc. Drilled and reamed. Close fit this time. Will use locktite.

I still have to make the piston, Valve, connecting rods, and crank disk.

I think that this will work fine. There is many ways that the basic design can be personalized. I will see if I can finish up the build tomorrow, Test run it, and write up a detailed report on the build.

I might redraw your basic plan in CAD and save it as PDF if it is OK with you.

 

[black85vette]

WOW! That's great. :bow: I like what you did on the flywheel side to mount the valve body. I think that could allow a wider flywheel and add some weight. That same technique could be used to go to a larger piston which I think would also work better.

I have one that I am building as a test platform also. Right now I am trying to work out the spool valve suggested by Rleete. I think it will be better than the original one. It seems to have less friction because it does not have pressure pushing it against the side and it has less surface area to rub against the cylinder wall. It ended up being about 2" long because I kept the stroke at .5" and the position of the port the same. Still not sure I am getting it right since I don't understand the math behind it.

BTW; I put the stroke of both the piston and valve at .5" as a starting point because it was easy to locate the pin on the crank and flywheel, not because that is the proper amount of stroke.

I attached a picture of the original valve and the spool valve in its current iteration.

Thanks for your contribution and feel free to modify as you see fit. It was only a concept not a design.