Author Topic: Fixing the how NOT to make an engine  (Read 47746 times)

Offline Bernd

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Re: Fixing the how NOT to make an engine
« Reply #25 on: July 19, 2009, 07:46:15 PM »
Bogs,

I don't know about the rest of the crew here but I find it a bit hard to read the red comments that you put on your pics. Could you try white or maybe yellow on that background?

By the way I like these bits of repairing an engine. I try to guess about what you are going to do to fix it and have hit about 50% of the time. Keep up the interesting articles.

Bernd
Route of the Black Diamonds

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #26 on: July 20, 2009, 12:47:01 AM »
Will do Bernd, without feedback, things can't be put right. I have changed the above pictures, just for you. :thumbup:

Quote
I try to guess about what you are going to do to fix it and have hit about 50% of the time.

You're not the only one, I am guessing what needs doing next most of the time.
As you can see, lots of little things need to be done before you can do the original fix. That issue is a major problem when working on finished engines made by someone else. That is why they take so long. At every turn, you find another part that needs to be put right or replaced.

I am hoping this has now had most of the critical bad bits put right, and I can get on with rebuilding it.


Bogs
« Last Edit: July 20, 2009, 01:16:44 AM by bogstandard »

Offline Darren

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Re: Fixing the how NOT to make an engine
« Reply #27 on: July 20, 2009, 02:27:16 AM »
Great write up again as usual John...

One Q, when drilling the 3 holes in each piece using the RT. I take it that as long as you don't move the mill bed you just drop each piece in, drill, rotate 120 deg, drill etc, and all the parts hole will line up....?

Cool, I wondered how that was done....so simple...as usual..... :doh:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline shoey51

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Re: Fixing the how NOT to make an engine
« Reply #28 on: July 20, 2009, 02:35:23 AM »
great explanation with pictures John the way I like it. Im afraid im not good at description my self :doh:
but hats off to you :bow: :bow:

Offline sbwhart

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Re: Fixing the how NOT to make an engine
« Reply #29 on: July 20, 2009, 03:07:58 AM »
Good Job John

Will it be running tonight when I call round with my Rockers we could have a steam up  :headbang: well wind up realy  :lol:

Stew
A little bit of clearance never got in the road
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Offline Stilldrillin

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Re: Fixing the how NOT to make an engine
« Reply #30 on: July 20, 2009, 03:25:43 AM »
Progressing beautifully John.....  :clap:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #31 on: July 20, 2009, 03:38:49 AM »
You got it Darren, drop the bit in when the RT is centred and if possible zeroed as well, move it in the Y axis towards you (or even the X axis, if that turns you on), the amount you want the hole from the centre, drill hole, rotate to next position, depending on how many holes and so degrees required, drill hole etc etc. No fancy footwork involved.
If you have another thousand parts to drill, all needing to be the same distance from the centre, as long as you don't move the table, just keep dropping 'em in, drilling and turning etc etc etc.

Stew, I very much doubt it. Other things have priority at the moment.


Bogs

Offline NickG

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Re: Fixing the how NOT to make an engine
« Reply #32 on: July 20, 2009, 05:15:50 AM »
John,

I really enjoy this thread. It's like a new engine, a lot of new buts but any critical / expensive castings you've managed to save and kept them nice and neat!

The guy is going to be chuffed, just out of interest, will you be giving him a sit rep on what you had to do to it? He could learn a lot!

Nick

ps. I really want a rotary table and chuck! Is yours a SC 4-jaw or independent?
Location: County Durham (North East England)

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #33 on: July 20, 2009, 09:51:59 AM »
Nick,

The chappie has already had a progress report, and has given me permission to make up a much more complex posting to go onto a model boat site.

For me, fitting a 4 jaw independant chuck to a RT would be like trying to wear a barbed wire thong, a real PITA. If my self centrings run within a couple of thou true, then they are good enough to fit to my RT.

I am not boasting at all, but I have a few of all sorts for both the lathe and RT. If I had a choice, I would always use a 4 jaw self centring, and one main advantage is that they can hold square stock, but on the other hand, they can't hold hex, you use a 3 jaw for that. Swings and roundabouts I suppose.

One definite thing I do do though, if I buy either a 3 jaw or 4 jaw self centring chuck, I always buy soft jaws for them. If soft jaws aren't available, I go elsewhere and buy one that does. For true accuracy, if done correctly, soft jaws just can't be beaten, for RT or lathe work.

Thru my experiences, and I don't know if anyone else has found this, but I have found that, from new, my 4 jaw self centring ones have less runout than 3 jaw ones.

Bogs

Offline Bernd

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Re: Fixing the how NOT to make an engine
« Reply #34 on: July 20, 2009, 10:32:59 AM »
Thanks Bogs, much easier on the old eyes.

Nice write by the way. One can learn some interesting ways to fix things.

Bernd
Route of the Black Diamonds

Offline dsquire

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Re: Fixing the how NOT to make an engine
« Reply #35 on: July 20, 2009, 03:28:23 PM »

John

Thanks for the change on the text in the pictures. Now it jumps out at you instead of trying to play camouflage.  :clap: :clap:

You repair of the engine is also top shelf as usual. Excellent job John.  :D

Cheers  :beer:

Don

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Never let it rest,
'til your good is better,
and your better best

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #36 on: July 20, 2009, 03:40:55 PM »
Don,

I will try and get the earlier pics done as well.

Glad you are liking the article. I just hope it inspires just one person to have a go at salvaging what looks to be a hopeless case.

I have been doing this sort of thing for many years, and when you get a hopeless one up and running, it gives a real buzz.

Nothing is ever really lost until you have tried all ways to fix it.


John

Offline rleete

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Re: Fixing the how NOT to make an engine
« Reply #37 on: July 20, 2009, 04:03:06 PM »
I just hope it inspires just one person to have a go at salvaging what looks to be a hopeless case.

My wife has been trying for years.  I'm still hopeless. 


I, too, like the recaptioned pics.  Being colorblind, I've learned to just deal with it.  The new way is much better.
Creating scrap, one part at a time

Offline CrewCab

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Re: Fixing the how NOT to make an engine
« Reply #38 on: July 20, 2009, 05:06:24 PM »
Just amazing what can be rescued  :clap:

Great work, and a great read John .......... Thank you  :thumbup:

CC

Offline Bernd

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Re: Fixing the how NOT to make an engine
« Reply #39 on: July 20, 2009, 08:29:39 PM »

Glad you are liking the article. I just hope it inspires just one person to have a go at salvaging what looks to be a hopeless case.


John

John,

Over hear in the colonies it would be more like "What is a steam engine" rather than "can you get this beast running". Although we do have models built I'm sure they get thrown away before anyone asks if someone can fix them.

It's the thow away mentality of our "much" younger generation. :(

Bernd
Route of the Black Diamonds

Offline NickG

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Re: Fixing the how NOT to make an engine
« Reply #40 on: July 21, 2009, 04:17:25 AM »
John,

Interesting about the accuracy thing. I've always thought a 4 jaw sc would be really handy.

Nick
Location: County Durham (North East England)

Offline John Hill

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Re: Fixing the how NOT to make an engine
« Reply #41 on: July 21, 2009, 05:02:53 AM »

Thru my experiences, and I don't know if anyone else has found this, but I have found that, from new, my 4 jaw self centring ones have less runout than 3 jaw ones.

Bogs

John, perhaps this is logical in that the error is the average of all the errors.
From the den of The Artful Bodger

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #42 on: July 21, 2009, 05:42:49 AM »
You just might be right John. It is just a thing I have noticed over the years.

Nick,

As I have said before, I always reach for the 4 jaw SC, my 3 jaw has hardly ever been used. Only when I have a bit of large hex to turn, or some large soft jaw work, does it ever come out. This morning, I am just working with a lump of 1 3/8" brass bar, can you guess what chuck I have on?

I am not saying you should rush out and buy one, but if you do ever get the means available, I think they are a great addition to your arsenal, but don't forget to add the soft jaws as well. In fact, soft jaws for your 3 jaw, if available, are more important that a 4 jaw SC. If used correctly, they can bring precision to your work that you only ever dreamed of being able to do, for such little cost.

John

Offline kellswaterri

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Re: Fixing the how NOT to make an engine
« Reply #43 on: July 21, 2009, 06:50:25 AM »
Hello John, speaking of ''soft jaws'' in three and four jaw chucks...I believe that somewhere there is a write up on how to true them up properly before they are put to use...I seem to remember your self may have posted it some where but for the life of me I can not find it...Perhaps some one could post it again.
All the best for now,
                            John.

Offline NickG

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Re: Fixing the how NOT to make an engine
« Reply #44 on: July 21, 2009, 06:57:39 AM »
John,

I don't think soft jaws will be available for my cheap chinese chuck. I did see something in model engineer or model engineer's workshop once though that somebody had made to sort of clamp over the existing jaws then machine them up, not sure how well that would work though? it would have to be a very sturdy setup and you wouldn't get the grip right to the rear of the jaw.

I was thinking making a draw bar for my collet chuck like John Hill did will bring a lot more precision to my work also.

Nick
Location: County Durham (North East England)

Offline kellswaterri

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Re: Fixing the how NOT to make an engine
« Reply #45 on: July 21, 2009, 08:08:55 AM »
Found the write up...''Making a flywheel'' 3/10/09...just what I want.
                                      Cheers,
                                                John.

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #46 on: July 21, 2009, 08:50:47 AM »
Nick,

I read those articles, and very good they were as well. Unfortunatley they went too deep for what we get up to on here. It was ok if you are into spending a lifetime making tooling, like a lot of the 'super engineers', just too much info was given, and it totally confuses the beginner, who just wants to get a basic set of soft jaws and get on with the job.

This sort of thing happens all the time, and I think that is why sites such as this thrive. Basic information is available that takes a person to the next level up from being a newbie. After that, it is up to each person whether he wants to enjoy what he is doing, or go further and start to discuss the coefficient of friction between a locomotive wheel and the rails when driven against a 12mph headwind and a 1.5 degree upwards incline.

John,

In about 10 minutes, I will be attempting to make another flywheel. Depending how I get on, you might see it posted tonight.


Bogs

bogstandard

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Re: Fixing the how NOT to make an engine
« Reply #47 on: July 27, 2009, 09:29:00 PM »
It seems ages since I posted onto this topic, but now I have got the bling out of my system for the time being, I am pressing on with this rebuild.

The engine is now going together rather than having fixes done on it.

Today it was the time for the crank, and I think that this post might be of use to a few of you who build small engines.

This shot shows a normal crank build, and to me is one of the worst types.
What should be done, drill a slightly undersized hole, wack a pin in and hope it goes in straight? Or make a slightly oversized hole so that you have clearance for silver soldering, wack the end of the pin to deform it so it holds in the hole whilst soldering, and again hope it ends up square? There are many ways of doing it, but I will show you how I go about it to almost guarantee that the pin will be square and secure in the hole.




First thing I do is thread the hole, to about the same size as the normal plain hole.
Then I turn the pin up out of silver steel (drill rod) that is rather larger than the original sized pin.
First off you turn the length and size of the crankpin you want to go thru the big end. Make sure you end up with a nice clean shoulder where it joins to the main bar.
Then cut a length off the rod to allow you to form the other end.
Holding the crankpin in your chuck, you turn down the sticking out end to the size that is required for threading, and while you are doing that, form another shoulder, like shown. My integral 'washer' is about 0.025"(0.6mm) thick. Then thread the stub to whatever size that is in the crankdisc. Turn a small undercut on the thread, to ensure it screws all the way into the hole.
After that, turn down the diameter of the 'washer' so that it doesn't overhang the edge of the crank disc.




A little high strength loctite on the thread and it is then screwed into the hole tightly. The small shoulder will ensure that the pin ends up perfectly square to the crank, even if the hole was tapped slightly out of square and the thread isn't too tight a fit.
Dress off the back of the hole so the thread is flush, and put one or two very small pop marks around where the thread and hole meets.
If ever the pin gets worn, a good grip with a pair of pliers or vice grips and you should be able to screw it out, make a new one and refit it.




When I made the basic crank and disc, I made on the back of the crankdisc a 'rubbing face' to reduce friction, I left it overly long because I didn't know how thick my 'washer' would end up being. After the pin was made, I reduced the rubbing face by the thickness of my washer. So now everything has nice small running clearances.
But those damned big ends came back to haunt me yet again.




When I tried to turn the engine over by hand, I was STILL getting interferance, even though they were made to the modified drawings. The pic shows what I eventually had to do. Hack the corners off. Then the engine turned over very nicely thank you.




I just couldn't resist it, the basic bits for the engine were there, no gaskets or cylinder outer covers, so I wacked some oil into and gave it a small dose of air.

You guessed it.

It ran like a swiss watch, both forwards and reverse, and the throttle works a treat, and that was with a tight engine, when it get bedded in, it should run on a wisp of air (or steam).

So now on the run in, just a little work to do and it should soon be winging it's way back to the customer.

I will give you the final update to this post when it is completed.


Bogs

Offline Stilldrillin

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Re: Fixing the how NOT to make an engine
« Reply #48 on: July 28, 2009, 03:35:09 AM »
"I knew you`d get it right in the end".......  :clap: :clap: :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline ozzie46

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Re: Fixing the how NOT to make an engine
« Reply #49 on: July 28, 2009, 07:53:20 AM »

 Nicely done John :thumbup: :thumbup: :thumbup:
 I'm learning oodles here.
 Ron