Beam engine at double scale--

[Brian Rupnow]

This was my work for yesterday--I took Elmers beam engine, doubled the scale, modelled it, simplified it a bit, and did a complete set of detail drawings. They are currently hosted in .jpg format on MediaFire, a free hosting site. Click the following link to download them.---Brian
http://www.mediafire.com/?bexmifnnjlu

 

[Brian Rupnow]

Holy Cow!! I just took inventory of all my short peices of brass and aluminum left over from my first two steam engines, and I have enough material to build 2/3 of my "Larger, Simpler, beam Engine".

 

[Brian Rupnow]

Well folks---Here is the first part!!! I chose to make the bearing from aluminum, because that is what I had. I made it as per the drawing, except that instead of 3 1/4" long, I made it 3 3/8" long, and drilled the crankshaft hole out with a 1/2" diameter drill. I pressed and loctited two peices of 1/2" diameter brass into the holes, and will drill and ream them for the 1/4" diameter crankshaft. I set my calculator in the picture to give some idea of scale.--It looks like it is going to be a fair size.

 

[GailInNM]

Brian,
I thought you were going to take a week off so some of us could get a head start on you. ;D

I started at the other end from you and did a cylinder. I made it out of cast iron so I could lap it. The better the finish on the cylinder and valve, the slower it will run. While not impossible, it is hard to lap a blind hole, so I bored the cylinder block out to 9/16 and made a liner out of cast iron to insert in it. Liner is lapped before installation. I cut away part of the cylinder mounting stud so a lap could pass through the block to lap the valve bore. I rough cut some scrap cast iron to make the valve pistons and am planning to make the valve a built up assembly with the cast iron pistons installed on a steel rod. The power piston and cylinder head will also be cast iron. I chose cast iron for all of this as it has a very low coefficient of friction and the only oil it needs when operating on air is enough to prevent rust. I also like cast iron. It machines nice, other than being messy, and is relatively cheap.

Other changes I plan on is to use 10-32 to replace 10-24 threads. I just like fine threads and I also have lots of 10-32 hardware. I will increase the bearing height as you have done so I can put 1/4 X 1/2 ball races in. I have a box full of them from a surplus buy. I am sure other changes will creep in also.

When you get to the cylinder, consider putting a liner in as it will be hard to get a good finish on that deep a blind hole. If you want to take the easy way out, use 17/32 K&S brass tubing for the cylinder liner and 9/32 to line the valve bore. It has 0.014 wall and is very round and has a nice finish on the bore. It would mean that your piston and valve would increase by about 0.003 inch as it is not quite 1/64 wall thickness. I have used in in the past and it works quite well. If you do this, make the bore in the block a slightly loose fit so you don't distort the tubing. Use a stud/bearing mount grade of Loctite (609/640/680 etc) to install them.

Enjoy your time off.
Gail in NM,USA

 

[Brian Rupnow]

Gail--wife and I are going travelling today, I had a few hours to kill yesterday afternoon, while wife made arrangements for 2 of our adult kids to come and house sit. I have never worked with cast iron, in fact I'm not even sure where I would go to buy it. The tooling I have for my mill is off shore stuff, and I find that anything other than brass or steel dulls the cutters amazingly fast.

 

[Bogstandard]

Brian,

I wouldn't worry about cast iron, it cuts really nice, no lube required as the carbon in the iron makes it self lubricating.
But it is filthy stuff to work with, the dust gets everywhere.

If you are buying it from a metal factors it should come ready to go. If from other sources, the very hard outside 'skin' has to be roughed off before you are into the good stuff.

John

 

[Brian Rupnow]

Gail---Or anyone else---Question!!! What is the best way to accurately measure and set up for the smaller (valve) bore in the cylinder block? I understand how to lay out the position of the bore for the cylinder on the end of the block, how to set it up in my 4 jaw chuck on the lathe, and how to drill and bore the cylinder hole. The question comes in when I go to "set over" the block in my 4 jaw chuck to do the bore and ream for the valve. Since there is no measuring dial associated with the 4 jaw chuck, do I loosen off one of the jaws by the required amount and tighten the opposite jaw to slide the peice over and align the center of the valve hole with the drill in the tailstock? If that is the method, then I guess I should lay out the position of the valve hole at the same time that I lay out the position of the cylinder hole, so that I can line it up "by eye" in the chuck. Is this correct, or is there a better method?---Brian

 

[kvom]

Can't you drill it on your mill?

 

[GailInNM]

Brian,
I did my power bore with a boring head in the milling machine and also drilled and reamed the valve hole on the milling machine.

I have done other things on the lathe with a 4 jaw and this is how i did it. I know you are beyond some of this, but a short tutorial may help some one that is not there yet.

Lay out all your holes with what ever you have at your shop. This can range from just a pair of calipers used to scribe lines in a blued surface using the edges of the part as reference to using a surface plate and height gauge. For this engine the location of the holes will not be all that critical, but it will be good practice to try to locate them a accurately as possible so the a project that comes up where the are critical you will know how to do it and have had some practice.

With a very small center punch, lightly prick the scribed intersections. Look at your punch mark and if it is not on the intersection, it can be moved a bit by punching deeper with the punch held at an angle. Once your punch mark are in location, deepen them a little bit. It does not have to be much. Twenty or thirty thousands is more than enough.

There are commercial wigglers made to help locate things, but I just use a piece of 1/8 diameter music wire that has been sharpened to a point that approximates the angle of the center punch. Make it about a foot long. Any sharpened small diameter rod will work, it does not have to be music wire.

To locate the marks on center your 4 jaw, first locate by eye with the jaws tightened lightly. Then put what ever you are using for a wiggler in the tailstock a bring it up to enter the punch mark on the part It wants to seat, but not put much pressure on the part. When you rotate the chuck, either by hand or at low speed under power the end of the rod will move around in a circle. If you are doing this under power, you can touch the rod with a marker, like a Sharpie, to locate the side of part that needs to move towards the center of the chuck. Readjust the chuck, wipe of the mark from the marker and repeat until get very little movement on the end of the rod. Then put a dial indicator in the tool post and rest the end of plunger on the rod near the part. You could also use a dial test indicator here, but it seems easier to me to use a dial indicator. Rotate the chuck by hand and you can see which way the part needs to move in the jaws. The object is to be able to rotate the chuck a full revolution with out the indicator moving. Snug up the jaws to working pressure on the part, but keep checking with the indicator to keep the punch mark centered.

After you have done this a few time it will take you a lot less time to locate a part that it took me to write this.
Gail in NM,USA

PS: Are you home to start work on your toy now? And did you have a good time on your holiday?

 

[Brian Rupnow]

Yes. we came home this morning. This is the first year in about 10 years that we haven't taken a major trip to somewhere. We just travelled around Ontario, went to see a fellow that I started engineering work with back in 1965, went and visited my mother who will be 88 in August and lives about 150 miles from me. Wife and I are both wiped out, didn't sleep to well in Bed and Breakfast---wasn't their fault, just not used to strange bed. I plan on getting into the beam style engine now. I will probably do both the cylinder holes in my milling machine. If I had used my lathe I would have used the method which you described---thank you for the excellent write-up. I will be doing the beam next, probably do the cylinder in a couple of days.---Brian

 

[Brian Rupnow]

Well Dang!!! Ain't we gettin' fancy!!! I think I'm getting this milling business figured out. I still have more work to do on the beam for this engine, (and I know those cut-outs aren't on the plans I posted.)--However, the other dimensions are all exactly the same. Now if I can just do the rest of the required work without frigging up what I've done already------(and Oh Yeah--I used brass because thats what I had)--aluminum would be just as good.)

 

[Brian Rupnow]

Another part done.---No disasters on the last bit of machining on both sides, but I did have to build a fixture to mount the part on in the lathe. There was nearly as much work in making the fixture as there was in making the part. A bit of polishing now, and this part is finished.---Brian

 

[Brian Rupnow]

And for Sunday mornings amazing stunt---a column!! Again, slight departure from the plans that were posted, but dimensionally the same. I used a 1/2" milling cutter to put the slot in the top end, and just left the 1/4" rad in the corners of the slot. I also decided that a taper would look better where the round portion of the column transitions into the rectangular shape at both ends.---Brian

 

[Powder keg]

Looking good Brian.

 

[Brian Rupnow]

We have a cylinder!! And this time, I did follow the drawing exactly. I had one mini-disaster when drilling the 0.080" diameter holes thru to the cylinder bore----the darn drill broke off below the surface when I was drilling the hole closest to the bottom of the cylinder. I was able to drill thru from the other side of the brass block, and pop it out with a very small drift punch. This is not really a big deal, as there are some holes in this cylinder that will have to be pugged anyways. I will put up a seperate post about which holes are plugged, how I do it, and at that time I will show how I attach the inlet steam port to the center hole half way down the cylinder body.---Brian

 

[b.lindsey]

Brian,

This is looking great. I think the cutouts in the beam will add a lot of character as well. Looking forward to following the thread and more pics.

Bill

 

[Brian Rupnow]

I feel a bit like that song that Roy Clark used to sing on Hee-Haw---"If it weren't for bad luck, I'd have no luck at all-----Doom, despair, and agony on me---". Three weeks ago I got the deal of the century on a used 14" metal cutting bandsaw. Last week it quit!! I phoned around and quickly found out that a new 3/4 HP 1750 RPM motor costs close to $300. I took off the motor, hot wired it, and it ran okay.--Then I played detective, and began isolating components untill I determined that the switch was bad. A new $10 switch fixed it, thank the Lord. Today was my first day back to work in my engineering office, and at quiting time I decided to mill out the base for the beam engine from a peice of 3/4" copper plate that I had. Not heavy milling---just squaring up edges which I had sawed out with my bandsaw. Now the friggin' mill has gave up the ghost on me. Lights come on but motor will not run!! I looked for a thermal reset switch on the motor, but there doesn't seem to be one.---It appears to be a D.C. motor with brushes---maybe a brush is hung up in its holder. I will call Busy Bee in the morning and get there insights, as this mill is less than 3 months old, and is guarenteed. I just HATE it when new machinery (Heck, even used machinery) quits on me---

 

[Brian Rupnow]

Things are not good!!! I have to load the mill into my truck and take it to Toronto, to have it repaired. They seem to think that the circuit board for the DC controller may be fried, but they can not diagnose it by telephone. And they don't make housecalls!!! This is definately going to put a cramp into my steam engine building for a while.

 

[CrewCab]

Brian ............... the service/warranty sucks imho............ :-\ .......... or have I missed something

To be fair I can't really comment from experience as unfortunately, most things we buy (if they are going to break down) usually do so at abut 54 weeks old :wall:

Good luck mate

CC

 

[Brian Rupnow]

Well---This is cheap Chinese stuff we are talking about here. There is no service contract. The machine is gauranteed, but only if I deliver it to BusyBee head office in Toronto, and then pick it up after it is repaired. Thank God that I only live an hour outside Toronto.--There are many regions in Ontario 8 or 10 hours from Toronto that have BusyBee sales outlets---I wonder what happens when their customers machinery breaks down??????????