Author Topic: A "Little Wonder"  (Read 4454 times)

Offline alanl

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A "Little Wonder"
« on: December 30, 2017, 01:57:27 PM »
As I mentioned in my introduction... I've decided to have go at making an IC engine...

This is a casting kit for the "Little Wonder" from The Engineers Emporium, ( http://www.theengineersemporium.co.uk )
It comes as a kit of 14 aluminium castings, and 6 A3 drawings... I bought mine at the Midlands Model Engineering Show.

After turning the castings over in my hands for a fair while... I decided to start by machining the base.
This was done by first dressing the bottom using a file, then milling the mounting studs for the crankcase, turning over and making the bottom cleaner.
It will be mounted on a wooden base (of some sort, yet to be decided...)
The sides were just cleaned up a bit.
I'm going to paint it... and filler primer will smooth the rest off...

The photos show the kit, the base before machining, and the base set up on my micro mill ( is the size ok...??)

Next will be the crank case... a bit more awkward...

Alan


Offline b.lindsey

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Re: A "Little Wonder"
« Reply #1 on: December 30, 2017, 02:16:50 PM »
Should be a nice project Alan. With castings, a lot of looking and mulling things over is good, just as you are doing, before cutting metal. Where and how to hold things and the order of operations are key to working with castings.

Bill

Offline Jim Nic

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Re: A "Little Wonder"
« Reply #2 on: December 30, 2017, 04:49:50 PM »
Hi Alan
I'll be watching with particular interest as a Little Wonder could well be my next but one project.  The photos are fine.
Jim
The person who never made a mistake never made anything.

Offline alanl

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Re: A "Little Wonder"
« Reply #3 on: December 31, 2017, 11:05:47 AM »
Thanks for watching...

So... Moving on to the crankcase...

The base of this was pretty square to the front standard where the water hopper fits, but there was a major difference in level between the two side of the base, and front to back.
Working out how to hold this to flatten the base took a few days turning around in the hands, until it became fairly obvious that the rear of the 'well' was a suitable flatish place to set up against, whilst holding the front standard in the vice, between some thick brown wrapping paper (I'd also taken the major pimples off with a file).
This was milled, and produced a flat base, with the mounting lugs all very close to being the same thickness.

The casting was then held in the vice, on a wide parallel, to machine the crankshaft uprights flat across the top, and down to the correct height.

I could now hold it on its side, to square up the two sides, which are now square to the base, and parallel to each other.

That now leaves the front standard to machine flat to mount the water hopper on to, and to reduce its thickness, so that there is enough space for the studs and nuts to fit at the front (plenty of room at the rear..).

The gap between the two uprights also needs to be cleaned up, and made wider.

Before machining the space in the 'well', I decided that it would be a good idea to fit the upper crankshaft bearing caps, and then machine them at the same time, so that it all looked as though it fitted properly... That's currently being done..

The photos show the crankcase before I started, and during... and the crankshaft bearing shells.

Alan



Offline Jim Nic

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Re: A "Little Wonder"
« Reply #4 on: December 31, 2017, 11:25:59 AM »
The joys of castings.  It seems that figuring out how and where to hold them is a large part of the challenge, your way turned out well.  :ThumbsUp:
Jim
The person who never made a mistake never made anything.

Offline Jo

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Re: A "Little Wonder"
« Reply #5 on: December 31, 2017, 12:04:03 PM »
Making good progress  :)

The base of this was pretty square to the front standard where the water hopper fits, but there was a major difference in level between the two side of the base, and front to back.
Working out how to hold this to flatten the base took a few days turning around in the hands, until it became fairly obvious

This is know as Casting fondling  ;D

Jo
Enjoyment is more important than achievement.

Offline alanl

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Re: A "Little Wonder"
« Reply #6 on: December 31, 2017, 05:27:40 PM »
AH!!!

I'd wondered what this "casting fondling" was...! Now I know!

The main bearing caps have been milled to the correct height, and then the mounting holes drilled 5BA tapping size.
The casting was plenty wide enough, so I split it using a hacksaw... It will all be cleaned up later...
They were then stuck onto the crankcase using double sided sticky tape, so that the hole positions could be spotted through... I'll use a small carbide centre drill from Eternal Tools ( https://www.eternaltools.com/carbide-micro-centre-tool ) which should stop the sticky tape from moving.. (!) , before drilling and tapping for the studs...

Now to make some studs... It looks like I need 18 to start with... but 4 will be ok to be going on with... (tomorrow...)


Offline alanl

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Re: A "Little Wonder"
« Reply #7 on: January 02, 2018, 03:05:14 PM »
A little more done...

4 x studs made to hold the bearing caps in place...

They're a bit long at the moment, as I'm waiting for some 5BA nuts to arrive...

Picture shows everything in place so far...

Alan

Offline b.lindsey

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Re: A "Little Wonder"
« Reply #8 on: January 02, 2018, 03:53:42 PM »
Nice progress Alan!!  The castings appear to be of good quality as well. Still following along here :)

Bill

Offline alanl

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Re: A "Little Wonder"
« Reply #9 on: January 23, 2018, 11:32:21 AM »
Its been a little cold in the workshop here... so not a lot of progress!

Yesterday was warmer though... and I did a bit more to the crankcase...

First, machined the outer sides of the bearing caps to match the already machined outside of the crankcase
(photo 1). This was held in the vice, resting on a parallel, and pushed against the fixed jaw with a piece of wood.

Second, the inside of the crankcase was machined parallel to leave a width of 1". This left the bearing caps at 3/8"..
as specified on the plans. (photo 2).

The rear of the crank upstand is sloped.. so this was machined at an angle, with the bearing caps sloped to match.
(no photo...)

Finally... the front face was machined flat and at right angles to the sides and the base, by holding in the vice, (supported on a parallel )
and setting the base vertical using a small square.
The sides were gripped by wide parallels, to increase the height of the vice jaws.
(photo 3).

I now have the sides, base, and front square to each other...  :)

Bearing shells next... and making the holes through the crankcase for the crankshaft...
I've a few ideas about how to do that, but making them parallel to the front seems to be a possible problem (!)....
Does anyone have any hints please..??

Alan

Offline alanl

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Re: A "Little Wonder"
« Reply #10 on: September 17, 2018, 07:54:32 PM »
Gosh...!

Where have spring and summer gone to..?

Too much else to do, and only a little progress on the engine... But I've started again, and made some tools to help...

First up... photos of the tools...

Photo 1 is hand crank for the Cowells lathe... copied from a design that I found on this community...
Photo 2 is a die holder for the Cowells lathe... this fits over the tailstock
Photo 3 is an ER16 collet chuck for the Cowells lathe....

These will now make making studs a lot easier..!!

And finally...

Photo 4 is a shot of the latest engine progress... I've made the bearings and the oil cups...

Hopefully more progress soon...!!

Alan

Offline alanl

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Re: A "Little Wonder"
« Reply #11 on: September 21, 2018, 05:41:24 PM »
A little more progress today...

I made a start on the crankshaft...

This is an aluminium casting, and so quite an awkward shape to hold for machining...

I decided to attack with files and emery paper.
It took about 30 minutes to clean up all over, and now I can machine the crankshaft boss, to get it down to the specified 3/8 inch.
I'll do that after I have split it.

The drawings call for 2 holes to be drilled no40, to hold the two halves together, but don't specify what to hold with..!!
Now 42 is clearance for 8BA, and all of the other threads are BA... so I'll see if I have any 8BA nuts and bolts, and see if they look ok...

Picture 1 shows before filing..

Picture 2 shows after filing..

Alan

Offline b.lindsey

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Re: A "Little Wonder"
« Reply #12 on: September 21, 2018, 10:11:55 PM »
Good to see you back on it Alan. Nice additions to the Cowells too!!

Bill

Offline alanl

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Re: A "Little Wonder"
« Reply #13 on: September 27, 2018, 05:52:48 PM »
Now comes..... machining the crankshaft...

Having taken all of the casting mess off the connecting rod using files and emery paper (still needs a bit more cleaning up...), Its now time to drill some holes, and to split the big end...

The holes to take the bolts to hold the big end together are marked as no 40 on the drawing, which is an odd size, not being clearance size for anything!
I decided that there was enough room to use 6BA bolts (or studs..), and so marked and drilled for this. I'm not sure whether to use a bolt or a stud at the moment, and so drilled 6BA tapping size.

The cast boss on the big end is an oval shape, so marking the centre line in both axes, and marking .573/2 from both ends gives a gap that can be sawn down. When bolted back together, this should give a circular boss, .573 in diameter.

The central hole for the crankshaft can then be marked, drilled and reamed 1/4 inch.

The width of the big end needs to be 3/8 inch. At the moment it is .447, so some needs to come off both sides... a bit more off one side than the other to even it up.

The little end looks as though it needs a bit of a clean up.. The casting is at a bit of an angle to the rod! This probably doesn't matter, as it will be hidden inside the cylinder. I just marked the centre, and drilled and reamed for 5/32 inch. I'm fairly certain that the two bores are parallel!

Photos...

Photo 1... Drilling for 6 BA bolts
Photo 2... Slicing the big end
Photo 3... Sliced off
Photo 4... Thinning the bosses
Photo 5... Finished conn rod

I'm not sure which bit to do next... Probably the crankshaft, as then I'll have a large part that looks like an engine..!!
This has a taper to hold the flywheel on each side, so I'll have to do those as well, so that the taper is not disturbed.

Next report may be some time..!!

Alan


Offline b.lindsey

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Re: A "Little Wonder"
« Reply #14 on: September 27, 2018, 06:14:04 PM »
Nicely done Alan  :ThumbsUp:

Bill

 

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