Making a piston valve engine from mainly junk materials

[derekwarner_decoy]

Hi PD's ....just to add to more confusion    as Sandy said

on real ships, number 1 cylinder is always nearest the bow

well....not always.....the first 100,000 tonne bulk carrier - built [1960] as the Chelsea Bridge in Kobe [Japan] for the Ropner Shipping Company of Darlington [London] - first sailed as the Sig Silver for the Silver Line to Singapore & the chartered by our OZ  :yeah GIANTS  BHP  :respect2 & then sailed as the BHP Iron Sirius   on the Headland to Kembla run for 25 years

Anyway   ....the as built Chelsea Bridge has a 13 cylinder IHI built under licence - Sulzer engine & No 1 cylinder was next to the prop shaft turning gear :rant   to see the engine fire up  :boom   :boom   :boom from each of the 13 bleeders  [      :respect2  = 13]  

[derekwarner_decoy]

Hi PD's -  :hmmm ....not sure Sandy... how we should treat this new member 'Standard John of the Bog'

1) a one legged bandit :?:
2) a one armed machinist  :?:
3) a most competent engineering artisan  :respect2

'and' [ Bogstandard] I am glad to see a couple of your RELLOS found a REAM of A3 paper as there is none left in OZ  

My humble vote would be 10/10 for point 3)....what do you think PD's?

[bogstandard]

Just a word for Derek before I start. Thanks for the compliment. You said you didn't know how to take me.
Bogstandard means in rough terms a basic unrefined article. I am just that, no complications. If I don't know something I ask, if I know all about something I will help if someone else asks, if I'm not sure I try to keep my mouth shut.
I like good honest humour, the nod nod, wink wink type , nothing too deep, it hurts my brain too much. I don't expect praise or sympathy, but if it is given I acknowledge it. Now you know.

Back to the article.
I said last time that we had finished with the blocks for the moment.
I forgot that not all of you will have the means to get a good enough finish on the bore, they will most probably vary from a slightly dull surface, thru what looks like screwcutting to digging out the hole with a hammer and chisel.
If you can borrow a reamer, and your hole is still slightly undersize, use one, otherwise this is how I would get an acceptable finish.
You can go out and buy adjustable laps, but that costs a lot, just to get a couple of holes cleaned out, this isn't the totally correct way but it will be better than what you've got at the moment.
Start with the largest hole, stick the last drill you used through them and wiggle about side to side, the one with the biggest wiggle is the biggest hole.
Mark the largest hole with a felt tip. Now chuck up a piece of material to make the lap out of, have it sticking out of the chuck by 1.5 times the length of the hole plus 25mm (1"), I use hard nylon but aluminium or brass will also suffice, I get better results with the softer materials.
Carefully (no heavy cuts here, material sticking a long way out of chuck) and turn down the rod until it just pushes through the hole for a length of 1.5 times the length of hole (like the pic).
Now we need to spend a bit of money unless you are from the old school and have some in your garage. We need to buy some fine and coarse grinding paste, Halfords is about the cheapest at about £3 and you get a grinding stick with that as well. This quantity will last you for the rest of your life.
Dab a bit if the coarse stuff along the length of the lap, you don't need a lot. Get a piece of hardwood and with a rolling action in combination with turning the chuck by hand (you have stopped the lathe I hope) embed the surface of the lap with grinding paste, what you are doing is making a very accurate round file.
Select the lowest speed on your lathe and switch on. Keeping well away from the chuck feed the hole to be lapped onto the lap, get ready to let go on this initial feed in just in case it bind up and sticks. If all is well the lap will be turning (without you going round with it) in the hole. Now just gently move the block up and down the lap in a sort of rotary twisting motion. You need to keep the lap fully into the hole at all times.
Change the block position 90 deg around the lap every so often, eventually you will get the feel and a rhythm going.
Do this for a couple of minutes, stop machine and check the bore, it should have started to smooth out. Repeat as necessary, wipe off, recharge, turn the block around and come from the other end of the hole, until the rough stuff has gone, then wipe off coarse grinding paste with white spirits and recharge with fine. Repeat the operation.
You should after a while end up with a nice round, parallel bore showing slight scratch marks on the surface, these scratches will help the bedding in process as they retain oil while the pistons and bores are wearing against each other.
Clean off the grinding paste and turn down the lap to fit the smaller hole, and repeat the process again. When finished give the bores a very good clean out to get rid of any remaining grinding paste.
If you remember from before, the pistons are going to be made to fit the bores, so they don't need to be the same size.
Put the lap you have just made in a safe place, you might make something else where you can readjust the size and use it again.
I will do the pistons in the next article, it will give time for the batteries to recharge on my camera.

John

[AlistairD]

 
 

 
Hi PD's ....just to add to more confusion as Sandy    said

on real ships, number 1 cylinder is always nearest    the bow

Are you    saying a paddle steamer is not a real steamer then? With a compound diagonal,    triple expansion diagonal. or even an oscillating engine all three cylinders    are equidistant from the bow  
   
Alistair

[derekwarner_decoy]

Oh dear PD's... looks as though I have offended    another newer member as John posted.....

"Just a word for Derek before I start. Thanks for the compliment. You said you didn't know how to take me.........
I like good honest humour, the nod nod, wink wink type , nothing too deep, it hurts my brain too much. I don't expect praise or sympathy, but if it is given I acknowledge it. Now you know"

Bogstandard....in my defence   ...all I can say is that both the Sir Sandy of ArgYile & I as convict stock 20,000 miles distant have enjoyed great fun & banter over the past years along with many informative postings re STEAM to & from  Sandy - I have many direct postings from other PD's  :gather asking that we keep the show going...........

Your postings along with those from....typically.... our member  'Engineman' show how you guys can produce quality products and :kewl

[bogstandard]

Hi Derek,
You haven't upset or offended me in any way, you just asked a question and I gave you a straight answer.
I find jovial banter very amusing and interesting, it is just finding the level where I could join in, it is a steep learning curve.
By the way, I have been got at before by professionals, so I have no problem with an amateur like yourself.

John

[sandy_ACS]

       

Hi PD's,

Don't you just love it when a plan comes together.....

AlistairD......

Are you saying a paddle steamer is not a real steamer then? With a compound diagonal, triple expansion diagonal. or even an oscillating engine all three cylinders are equidistant from the bow

1st point......Not in the least Alistair...in fact I consider these the truest form of the term 'Steamer'...with in line steam driven ships a close second.

I deliberately chose not to include paddle engines in the argument......I felt this would really add to the confusion...and our John is already confused enough.....  :music  :music

Whilst I was, of course, referring to in-line steam engines (rather than modern diesels or diesel/electrics) I do accept your point, however, even here what you say is not always the case.....some compound diagonal engines and oscillators for that matter, only have 2 cylinders, whilst others have 4 or more....and a triple expansion engine can have 4 cylinders and a 4 throw crank, but they are not commonplace I agree, especially in paddle vessels.
Regardless of these minor trivia though....a compound engine, however many cylinders it had, would normally have the 1st HIGH PRESSURE cylinder designated as number 1....and on an in-line arrangement this would be ,normally, closest to the boiler, which generally was ahead of the engines...however, I accept that there are exceptions even here.

As for DEREK and his 13 cylinder 'SUCK-SQUEEZE-BANG-BLOW SWISS CHEESE engine......well this just goes to show the Japs and the Europeans (excluding the UK) just have to be different/awkward and anyway these are not REAL engines....they just make a lot of noise and cause GLOBAL WARMING........How the hell do you expect to balance a 13 cylinder engine?.....no wonder ships suffer from heavy vibration these dddayys.....      

John.... :birthday ......I just LOL when I read the notes on your 'LAP' JPG sketch.....

'Having it sticking out to keep your hands safe'.... only works if your holding IT....and even then it's debatable!!!..... as for the other statements...I will leave them to the other PD's to ponder....but not when the other half is looking over yer shoulder..  :music  

BTW....aks the dog which way the paper goes...he/she is bound to know....failing that, stick it in yer printer...don't ask me how, but these nearly always manage to work it out....if a sheet jams...you, and/or the printer know it is the wrong way round/up... :music      

Keep Happy.

Sandy. :vacat  :computer    

[bogstandard]

Hi Sandy,
Glad you liked a few of the explanations, I myself prefer the hands on and get it done approach rather than very technical terms, that's why I try to keep it slightly humorous, more enjoyable to read.
Marvelous these Japanese, being able to get the printer to recognize which is the right way up, but I've now got it sussed, if when I'm writing,  the words come out upside down, the paper is the wrong way up. I haven't come across one yet, but I am sure I will one day.
No build sequence tonight, have been getting ahead a bit to make it a lot easier for me, top caps, stuffing glands, pistons and rods are now done, just need to get a few pics taken.

John

[derekwarner_decoy]

Hi PD's....so Sandy asks..."How the hell do you expect to balance a 13 cylinder engine?"

Well lets go back 20 years to real units  :music = shaft horse power...

so if 13 cylinders produced 50,000 SHP, each cylinder contributed 3846 SHP

but a modern 5 cylinder producing the same 50,000 SHP, each cylinder contributes 10000 shp

Therefore each  :boom is near three times as great - critical engine speeds are those that   must not be maintained .... eg., like 22.5 to 23.0 RPM may be a  :rant or 47.0 to 48.0  :rant & the engine room  :computer just racks additional fuel to the engine when approaching these critical speeds

The only thing that critical engine speeds were good for was EXICITING the 20 year old wrist watch to keep it wound up  

Just to keep this from being   ...I think they has steam powered turbo chargers back then TOO  :nah - only kiddin

[bogstandard]

Hi All,
Sorry no posts recently but body bits wouldn't allow it.
Anyway, remember how I said in the first posts about scrap materials and turning nothing away.
A friend (yes I do have them) came at weekend and dropped this lot off (pic 1), they were moving to a new factory and were dumping old fixtures, so he thought of me and brought the metal and delrin off them, the bottom plate is about 15mm thick and 600mm square. So as I said, tell everyone what your hobby is,  and sometimes christmas comes early.
The next pic is some hex bar offcuts from the scrapyard for less than £1 and turned down to 18mm for top caps and stuffing glands, there is enough here for 4 or 5 engines.
The last pic is a tip how I get all my holes to the same depth. This can be used anywhere you use a twist drill. Get a piece of tube just a bit bigger than the drill and slip it over the end, then adjust the position of the drill to the correct depth sticking out of the end, so when you get to the correct depth the tube is trapped between the drill chuck and the job so stopping the drill going any deeper.
Hopefully in a couple of days I will be able to post more pictures of where I am up to.

John

[Eddy Matthews]

Now we're starting to get onto the bits that really interest me John, so I'm eagerly awaiting your next posts....

Making the pistons, conrods, crank, etc etc....  We've done the basics, now we move onto the bits that baffle me totally!

[bogstandard]

Hi All,

There's no stopping me now, a pack of real paper and when I went to the bank I found a brand new pen, but some idiot had chained it to the counter, but being a prepared engineer I just happened to have a set of bolt cutters in my inside pocket.
So here is what Eddy has been waiting for. You never know what pleases some people!!

I am not going to go thru all the operations from now on, just tips when they are being machined, if you need to know how to do it just ask.

First pic shows top caps, packing (stuffing) glands and raw pistons (always make more than you need).
Pic 2 is the finished packing glands.
Pic 3 shows piston rods in blank pistons.
Pic 4 are the finished pistons with one having had an o-ring fitted.
First tip is for packing glands, make the screw in bit first, do not drill any holes thru them until you get to the stage where they can be screwed together with the main part still chucked in the lathe. Then screw them together and drill your hole thru them, this will keep them concentric. Keep them together in matched pairs.
For the top caps, you can have them as high as you want, on the picture there are two different top profiles.
I left the pistons until last, the sketch shows the finished size but make them initially to about 10.5mm diameter and 6mm long. The recess in the piston thread is to allow the thread to screw all the way in and sit against the shoulder on the shaft. Assemble the two together with loctite and leave for 24 hours. Your chuck must run very true for turning the piston OD., it has to be as concentric as possible. If this is not possible, ask and I will draw a sketch to show a very easy way to do it.
DO NOT remove the piston assembly from the chuck until it is finished. Turn the piston to length first (if you make the thread a little longer as well you will end up with a nice flat topped piston). The OD is turned down in minute cuts until it only just fits inside the cylinder (no floppy fits here, if so start again), stick a piece of very fine wet or dry paper or emery to a flat stick of wood and hold this against the side of the piston (no heavy pressure) until the piston just starts to slide nicely in the bore, you are looking for a clearance of about 0.02 - 0.03mm(0.001"-0.0015") if you can.
The groove is put in half way along (I make mine to fit a viton o-ring) and can be left empty so it uses collected oil to form the seal or it can be packed with either gland material (messy) or twisted up plumbers PTFE tape (fiddly) or like myself an o-ring.
Keep these assemblies matched to the bores.
IMPORTANT - ALL sharp edges on the piston need to be 'knocked' off with a file while still in the chuck, this will allow the oil to penetrate correctly for lubrication, but more importantly the sharp edges actually break down the oil preventing it from doing its job properly.
All holes that ANY shafts on the engine pass thru should have a small chamfer at each end, this is to allow oil penetration.
Please take note of the sketch with the block on it, this is nowhere near finished at the moment so you have to avoid certain areas if you want to start putting the end caps and packing glands on.
The rods on the pistons are not finished yet, I am still designing and making the middle part of the engine, so these will be finished off when all this area is proven to work.
The rest of the sketches are self explanatory.  

John

[Eddy Matthews]

Okay, I'm confused John - Hey it doesn't take a lot!!

From what I can see, the pistons are basically solid brass machined with a groove for the oil ring and a threaded hole in the bottom to take the conrod. But what about the little end bearing to allow the conrod to swing from side to side as the crank rotates? I don't see any sign of that...

I'm sure I'm missing something here, but clarification would be appreciated...

[bogstandard]

Hi Eddy,
Because we are going to make a double acting engine (that means we have power on both up and down strokes) we cannot have a little end on the piston as we can't seal a swinging con rod, a car engine as we normally know it is only single acting, power on the down stroke only, so has a little end going thru a con rod to the crankshaft. But we are a lot more efficient and because of that we have to move the little end away from the piston and convert linear motion into rotary motion(crankshaft) so I have done a little sketch of how we are going to do it.
Also is a picture of a real life steam engine showing what I am on about. But if you look at this engine it is totally naff the way they counteract side thrust (you can see two bars sticking out of two of the columns), this is the area I am working on at the moment.

John

[Eddy Matthews]

AHA!! I knew there had to be a simple answer, thanks John.

Because I was thinking about a single acting engine I hadn't thought about the problems (and solutions) for a double acting engine.

But remember, I did say that I knew nothing about making a steam engine, so please be patient with me if I ask seemingly silly questions!