Author Topic: Elbow Engine (Read 81932 times)

sbwhart · « **Reply #50 on:** March 23, 2009, 02:38:44 PM »

You chaps who've been paying attension would have noticed that I hadn't skimed any of the cylinders down to take the fly wheel or bent all of the elbows, well that all part of the cunning plan

. Now that i've got four cylinders made I've spent some time matching them up to get the best fit,

when I got the best combination and best position for each pair I put an axle in them and an unbent piston then I put the hand reamer through the other bores this took of just a whisper of metal, and gave me a set of cylinders that lined up perfectly.

I marked each pair and assembly position with a small centre pop so that I can match the cylinders up exactly when I assemble the engine.

I was realy pleased with this process I can assemble the cylinders with an axle and three pistons as shown in the pics by hand without any undue force and the pistons are still a nice popping fit in the bores.

One happy Stew

shoey51 · « **Reply #51 on:** March 23, 2009, 02:51:54 PM »

looking beter all the time
patience is a virtue ive been told

sbwhart · « **Reply #52 on:** March 23, 2009, 02:59:07 PM »

Quote from: shoey51 on March 23, 2009, 02:51:54 PM

looking beter all the time
patience is a virtue ive been told

A bloody big hammers even better

and a lot of lucks better still.

Thanks for your comment

Stew

Darren · « **Reply #53 on:** March 23, 2009, 03:12:35 PM »

I have a feeling you'll make this work

Keep going, I want to see this finished....

Bernd · « **Reply #54 on:** March 23, 2009, 04:23:50 PM »

Ah Stew, those cylinders are to be 90 degrees to each other, not straight.

Nice looking so far. Interesting method of making all the cylinders fit. Hoping it'll work for you.

Bernd

sbwhart · « **Reply #55 on:** March 23, 2009, 05:55:57 PM »

Thanks Chaps

I'm planning to visit John tomorrow

to see if I can scrounge a bit of 4 inch square ally plate off him enough to complete two frames, its getting close to the moment of truth, I'll get him to have a look at the cylinders.

Its bin fun so far

Stew

bogstandard · « **Reply #56 on:** March 23, 2009, 05:59:19 PM »

No problems Stew,

Just give us a call first, so I can hide the au pair.

John

Divided he ad · « **Reply #57 on:** March 23, 2009, 08:06:00 PM »

I like your thinking Stew.... Can't wait to see how this all works!!!

John..... "Just give us a call first, so I can hide the au pair." And I thought it was all the extra machining that put you out of action!!!

Ralph.

NickG · « **Reply #58 on:** March 24, 2009, 04:35:03 AM »

Looking great Stew, good luck!

sbwhart · « **Reply #59 on:** March 27, 2009, 03:59:27 PM »

Elbow

Black Thursday

Had the day off work on Thursday spent the time in my shed.

First job was to finish off the fly wheel set it up in the three jaw clocked it up and found that I could get the run out down to 0.05 mm plenty good enough. Bored the hub out to give 0.02 mm interference on the cylinder and pressed it in using the vice supporting the hub on scrap roller bearing, the darn thing went and cracked, on top of that it wobbled like a drunken sailor (no disrespect to sailors) I guess the hub bent as I pressed the parts together, no amount of tapping and adjusting could make it ½ way acceptable. Using scrap pistons to make the hubs was not such a good idea the material is far to brittle. The composite fly wheel looks great so plan B is to make some more hubs using some ½” ally plate John gave me.

Note use of chim cut up from beer cans to stop damage to rim

Polishing rim with lapping stick to avoid twisting fingers into a corkscrew

Looks nice doesn't it pity the hubs scrap.

That was the good part of the day in the evening we had some friends round for a meal, and I went a spilled a glass of red wine on the carpet, it was the first glass of the evening so I had no excuse, normally the boss would have gone spare at me, but no she was very stoic about it she just said “ho well we needed a new carpet any way” bugger that,s my new lathe money gone.

Started on the frames these are being made out of ½” thick ally plate kindly donated by John, this plate is from a recycled assembly fixture and machine real nice. First job was to work out how best to cut the plate to get the bits out I needed, then it was an hours work with an hacksaw and an aching arm to get the bits cut out.

Note use of guide block to keep cut straight and to support plate.
Blade kept lubricated with Bog water WD40

I did a quick check to see if the table edges of the mill were square, by putting a DTI in the chuck and running it along the edge, they were spot on,

knowing this I can use an engineer square to set thing up square on the table.

I set a parralel clamp square across the table, the plate was put on parallels and the best edge butted up to the square clamp, and with an 18mm end mill the face was cleaned up (milling the full depth of plate with up to 2mm deep cut) this clean face was butted up against the square clamp and cleaned up this was repeated until all faces were cleaned up.

Thats all for now

Stew

shoey51 · « **Reply #60 on:** March 27, 2009, 04:11:37 PM »

im liking this thread it is giving me ideas on how to setup and use a mill.
swmbo has agreed to let me by a small one

havent told her about the costs of tooling yet

great work Stew

Darren · « **Reply #61 on:** March 27, 2009, 04:26:11 PM »

Stew, didn't you break this before

It looks so superb, I want to make one and I'm not building an engine

Got to be worth another go....

NickG · « **Reply #62 on:** March 27, 2009, 05:10:41 PM »

Stew,

The bits are looking great, I have every confidence!

Like your idea of taking a day off to do some work, but if I did that I'd probably get dragged off somewhere else ... besides, I only have 8 hours leave left to last until the end of April!

sbwhart · « **Reply #63 on:** March 27, 2009, 06:01:42 PM »

Quote from: Darren on March 27, 2009, 04:26:11 PM

Stew, didn't you break this before

Yes that the second I've broken the material just not up to it.

Thanks for your coments Chaps

Stew

bogstandard · « **Reply #64 on:** March 27, 2009, 06:29:11 PM »

Even though I have used it before now, I am not a great fan of heating and cooling parts to get them together, especially big lumps going around flimsy centres, something usually gives way because of the stresses produced.

I prefer just a slight interferrence fit, pressed into place, or a bit of loctite.

But I am sure you will get it right eventually Stew.

Bogs

Darren · « **Reply #65 on:** March 27, 2009, 06:39:00 PM »

I have to admit I find it difficult to imagine piston material being fragile?

sbwhart · « **Reply #66 on:** March 28, 2009, 02:14:18 AM »

Quote from: Darren on March 27, 2009, 06:39:00 PM

I have to admit I find it difficult to imagine piston material being fragile?

Yes It came as a surprise to me perhaps fragile is the wrong description it could well been the fact as John said that the design of the hub was all wrong In that I'd made the spokes too thin for achieving a press fit, I may have been better having a loser fit with loctite: still I'll just put it down to experience with what I've learnt from this little experiment I'm shure my next attempt will be OK.

Cheers

Stew

NickG · « **Reply #67 on:** March 28, 2009, 10:35:21 AM »

The aluminium piston is most likely cast so it will be brittle. I agree with Stew & Bogs, probably too much interference.

Nick

sbwhart · « **Reply #68 on:** March 31, 2009, 03:50:25 AM »

Just a quick update as to why I've not posted the weekend progress. No I've not kicked it into touch, got one base machines up and fitted together just needs a bit of bling, got the cylinders fitted to it as well.

Spent an hour Sunday night righting it up when I read it realised it was total gibberish, I'm finding it quite difficult to put into words the process, I've had another think about it so I'm going to approach the right up in a different way, it's a matter of finding time this week.

Wifes Birthday, remembered card

, so avoided that dog house, went out for a meal,

another dog house avoided,

Dads 84th Birthday, remembered card

, day out arranged

Dads sister down from Scotland to ''see younger brother'' meal out arranged with them.

Etc Etc

A Busey

Stew

Stilldrillin · « **Reply #69 on:** March 31, 2009, 03:57:24 AM »

Stew,

"Life gets in the way"........

Enjoy!

David.

sbwhart · « **Reply #70 on:** March 31, 2009, 04:34:16 PM »

Assembling the base.

The important thing with the base is keeping everything aligned and square.

First job was to do some crib sheets for holes centres and co-ordinates this required a bit of adding and subtracting and devision easy with a calulator
pic shows the hole centres and the co-ordintes used to drill the base, the vertical treated in a symilar way.

To get the correct position of the holes its important that you locate the edge of the plate, there are a number of diferent ways to do this, I use the cigerette paper method this is the way I was shown when I was an apprentice:- its best to use the method you are happy with.

The base was the first to be drilled M3 clearance and countersunk for cap screw heads, the air way holes were only centre drilled at this point.
The vertical was then set up on an angle plate taking care that the angle plate was square to the table and the fixing holes drilled and tapped.

The base and the vertical were screwed together and the assembly clamped on the angle plate. One edge was set up level with the edge of the anlge plate as a datum.

The air ways were drilled with 1/8 long series drills. When drilling long holes its important to keep clearing the drill out of the hole (pecking) to clear away the swarf otherwise is will build up and break the drill. WD 40 was used to help the drill cut clean.

On the centre line the fixing holes for the cylinder was drilled, with an additional clamp over the top giving additional support

Keeping the same datum edges the base was flipped over to drill the fixing holes for the other cylinder this way everything was on the same centre line.

At this point I've enough bits for a trial assembly this is what it looks like with the wobbly wheel

Its a pity I've got to remake the wheel hub as its getting close to a trial run, it needs a bit of bling on the base and a bit of final fitting elbows squaring up etc.

I didn't find that an easy to right up hope you chaps under stood it

Cheers

Stew

NickG · « **Reply #71 on:** March 31, 2009, 05:19:04 PM »

Stew, your write up makes perfect sense to me.

The engine is looking TOO good! If it assembles with the wobbly flywheel hub, how good is it going to be with a striaght one!

Nick

Darren · « **Reply #72 on:** March 31, 2009, 06:41:38 PM »

Yep I understood what you meant so it must be ok..

Stew, I only hope I can make something to your standard one day, that is looking real good and so methodical

Divided he ad · « **Reply #73 on:** March 31, 2009, 07:53:19 PM »

Loud 'n' clear Stew

I am really glad your showing this too.... I've got a couple of angle plates that were donated by a not so anonymous benefactor ( Hi John

)
I haven't used them yet but I'm sure learning ways and methods of doing so

A quick flywheel remake

And it'll all be down to the fiddling and faffing about

(a representation of moods expected in smileys

)

As long as your still having fun it's all good ehh!?

Ralph.

cedge · « **Reply #74 on:** March 31, 2009, 09:21:05 PM »

Stew
Here is a little trick I discovered when my first flywheel wobbled. Since it is a press fit, it can be straightened. Chuck the flywheel in your lathe and get your hands on a piece of 1/4 or 5/16 inch wooden dowel rod. Mount the dowel in your tool holder and move it over so that one end touches the inner section (at high point of wobble) of the flywheel. (we'll assume the central hub is already running true)

Turn on the lathe and slowly but gently move the dowel rod into the face of the flywheel. Watch until it runs true. Then move to the outer rim and repeat the process. You might have to move back and forth a couple of times, but you will quickly kill off the wobbles.

So far it's worked great for me.

Steve

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Author Topic: Elbow Engine (Read 81932 times)

bogstandard

bogstandard