Model Engine Maker

Engines => From Kits/Castings => Topic started by: Alyn Foundry on August 30, 2019, 07:13:38 PM

Title: Two little CHUK's
Post by: Alyn Foundry on August 30, 2019, 07:13:38 PM
 Two little CHUK's.
 
Those that follow Jo's Seal thread will know that Surus recently acquired a set of CHUK 2 castings from eBay. Included was a bearing housing for a CHUK 3, this I found intriguing because I must have sold this along with the other castings. Intrigue aside, despite hours of thinking I couldn't remember who!
 
CHUK was originally designed as a kit of castings to be sold alongside the various machine tools marketed by Chester UK, now Chester machine tools. I worked for them for several years as head of the engineering department.
 
My inspiration came from a deal with a friend who twisted my arm for a recently completed A&T engine, cash and an Ernst Planck vacuum engine came my way. The Planck was a non runner initially, it would draw in the flame, partially rotate then stall. Upon closer examination I discovered that the taper pin that located the crank web onto the shaft had sheared internally   so that when the vacuum occurred the valve timing would alter to stall the engine. Within a few minutes the broken pin was removed and replaced, I had a runner.
 
The Planck is a lovely piece of engineering lots of parts pressed together, my job was to simplify its composition to ease construction.
 
I decided upon a simple " A " frame to support the cylinder, probably helped by my recent IF Allman build, I cut down a pattern to suit. CHUK 1 was born.
 
CHUK 2 quickly followed, I have a " thing " for inverted engines and a gravity aided design seemed obvious. This engine was never sold openly nor sketched so only a handful of them exist. Over the next few weeks Jo and I will make a couple more to swell the ranks.
 
Cheers Graham.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on August 30, 2019, 07:26:59 PM
The first picture above is a Gas fired Ernst Planck vacuum ( flame licker/gulper ) engine from the late 1890/1900's that was the inspiration for the CHUK engines.

The second picture is of my original CHUK 1 and CHUK 2 engines, CHUK 1 was redesigned with a smaller, deeper and lighter base.

Photos below are of my initial progress with the new castings and a nasty surprise!!

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on August 30, 2019, 07:32:15 PM
Two little CHUK's.
 
Those that follow Jo's Seal thread will know that Surus recently acquired a set of CHUK 2 castings from eBay. Included was a bearing housing for a CHUK 3

I though Jo bought a CHUK 1 (A Frame) and also got the support for a CHUK2 (as per my CHUKY) with CHUK 3 being the horizontal  :headscratch:
Title: Re: Two little CHUK's
Post by: Alyn Foundry on August 30, 2019, 07:56:02 PM
Two little CHUK's.
 
Those that follow Jo's Seal thread will know that Surus recently acquired a set of CHUK 2 castings from eBay. Included was a bearing housing for a CHUK 3

I though Jo bought a CHUK 1 (A Frame) and also got the support for a CHUK2 (as per my CHUKY) with CHUK 3 being the horizontal  :headscratch:

Check out the fifth picture here Jason.

http://www.modelenginemaker.com/index.php/topic,9113.msg205335.html#msg205335

Definitely a CHUK 2 but with a bonus bearing housing from CHUK 3.
Title: Re: Two little CHUK's
Post by: Jo on August 30, 2019, 08:15:48 PM
Nice to see you have started work on your CHUK 2 Graham. I showed your pictures to Surus and he thought that he would like his CHUK 2 done in parallel to yours  :mischief:

So I have been allowed to have a little fettle of the base casting and having returned it to him have bribed him with a Snickers so hopefully I will be allowed to do a little swarf making tomorrow   :pinkelephant:

Jo

Title: Re: Two little CHUK's
Post by: b.lindsey on August 30, 2019, 10:53:36 PM
Hope you don't have the same issues with the base casting Jo.

Bill
Title: Re: Two little CHUK's
Post by: Alyn Foundry on August 31, 2019, 11:11:04 AM
Hope you don't have the same issues with the base casting Jo.

Bill

Good morning Bill.

It's highly unlikely that Jo will find any problems, that's good old Welsh Iron from the Rhuddlan foundry.   ;)

Just imagine that my base had been a flywheel rim? It's one of the reasons why I didn't push sales!!

I'm going to have to skim at least an 1/8" off to loose the broken edge, with a very sharp Carbide tool.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on August 31, 2019, 01:29:07 PM
Jo has the little fellow been trying out your new sandblast cabinet on that base casting or have you just been busy with the wire brush as it looks a lot more pristine than in the e-bay photos now the Welsh wonder coating has been removed?

Graham, will you be building this one in much the same way as your first one or will there be any tweaks and alterations that you have found improve performance over the years?

J
Title: Re: Two little CHUK's
Post by: Jo on August 31, 2019, 02:57:03 PM
Jo has the little fellow been trying out your new sandblast cabinet on that base casting or have you just been busy with the wire brush as it looks a lot more pristine than in the e-bay photos now the Welsh wonder coating has been removed?

That special coating proves it is an Alyn Foundry original  :ThumbsUp: No aftermarket copies here  :hellno: But I had to take it off before Surus turned brown during our casting fondling sessions :facepalm2:

I decided that the base surface was so good it did not need skimming. I could just face and bore the top by holding it is a three jaw chuck.

As some know there are no finalised works drawings for this engine so all of them are a variation on the theme  ;) I chose to counter bore the top 3.5mm deep by 50mm diameter, after I shimmed the base so that the curved central section was running nearly true. I now think the 50mm would have been better if it was smaller as that way I could have used bigger screws to hold the cylinder down. 

No problem I already know smaller ones will be needed in the top so I can keep them all the same size - I'll use M3.

Jo
Title: Re: Two little CHUK's
Post by: b.lindsey on August 31, 2019, 03:01:45 PM
Off to a nice start already I see Jo. Should be an interesting build.

Bill
Title: Re: Two little CHUK's
Post by: Jasonb on August 31, 2019, 03:34:15 PM
You will probably have to make the flap valve larger too as that is located sideways by the hole you have bored, the notes suggest 40mm between faces so about 44 dia
Title: Re: Two little CHUK's
Post by: Jo on August 31, 2019, 04:05:52 PM
You will probably have to make the flap valve larger too as that is located sideways by the hole you have bored, the notes suggest 40mm

The notes with this engine identify it as 43.75mm A/F which is the same diameter as the spigot on the cylinder (43.75 A/F =  48mm diameter ). The Flap valve Spring is shown 51mm A/F but as I mentioned before there would have less to put the cylinder mounting screws through  :facepalm:


The important item missing is the bottom off a container of Cheese or salted Pringles to make the valve out of :P  I wonder which one is better  :thinking: Is the lack of the original items going to degrade the aesthetics of the engine  :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on August 31, 2019, 04:30:29 PM
Peking Duck  :P would be my choice if not parting off a disc of CI
Title: Re: Two little CHUK's
Post by: Jo on August 31, 2019, 04:37:51 PM
They do Peking Duck flavour  :o and I see Waitrose have them on special offer  :naughty:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on August 31, 2019, 04:42:13 PM
They are very nice, but my dogs don't like me having them as they are too good to share ;)
Title: Re: Two little CHUK's
Post by: Jo on August 31, 2019, 04:47:26 PM
Have you tried offering them a Snickers while you eat the Pringles?

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on August 31, 2019, 04:51:28 PM
Chocolate is not good for dogs so I get to enjoy those too, though Double Deckers are my prefered bar.
Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 11:12:01 AM
The cylinder is a fairly big lump to hold at 63mm diameter over the fins. I managed to hold it over two fins in Big C's three jaw chuck to face the bottom of the cylinder (forgot to take pic  :facepalm2:).  The important thing here is to make sure that the cylinder is square to the chuck and held nice and firm then the bottom can be machined flat. With a squared off base, the flat for the inlet port measures 27mm tall which leaves 1mm still to take off later  :ThumbsUp:

Time to swap over to the four jaw chuck and using the tailstock to secure the casting against the chuck all the jaws can be tightened up and everything checked to run true before looking to machine the top spigot. I'm going to follow what Andy did with his CHUK and use a fixed steady to secure that casting before boring :paranoia:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 11:16:52 AM


Graham, will you be building this one in much the same way as your first one or will there be any tweaks and alterations that you have found improve performance over the years?

J

Pretty much the same Jason.

However I really liked Andy's ( Chipmaster ) use of a cast Iron exhaust valve in his build. It might be a little more time consuming to do but the " lapping " time is greatly reduced. It also alters the sound, less metallic.

I'm keeping one little secret hidden for a while, associated with the inlet port shutter. This adaptation gives the engine a fraction more of a Gnats appendage to output power!

Second nasty surprise....

One axis, well it happens but two axies, unforgivable!! A whole new meaning to " on twist "

Cheers Graham.

Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 11:28:30 AM
That looks like a candidate for the Forest engine with it's helical fins ;)

I also went with the CI valve, easy enough to part off and good for Jo's figure too as she won't have to buy those Peking Duck Pringles after all :LittleDevil:

Look forward to seeing what the shutter improvement ism maybe a slight amount of free play in the vertical movement?
Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 11:29:05 AM
 :o

We didn't find any problems on our original Cylinder like that. There are a couple of drops on the fins where the Iron didn't flow right, which should turn out.

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 11:49:16 AM
Jo,

As you're at the boring stage, you might like to go " large " ?

Because of my association with Chester UK I attended a few exhibitions where I demonstrated their Model
" B " multipurpose lathe. At one event I met Bob Sier who had recently completed a CHUK 1. He said, Graham, make the cylinder bore as large as possible because you get more oomph!

He hadn't used my piston casting as he felt it was too small, this prompted me to make a new pattern, perhaps you have one of the larger diameter castings?

I felt quite proud watching one of my engines running at a show and more so, with who had built it!!

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 12:41:42 PM
Just checked my piston Graham: 40mm at the small end. If I was going to use it I could only go out 1mm or so. The major advantage I can see going large is that it will reduce the wall thickness on the cylinder and take less to heat it up  :thinking: Plenty of time (1/2 a day  ::) ) to think about bore diameter. The other option is to make the fins deeper. I have plenty of 2" CI if we want to go large :naughty:



Using tailstock support the outside of the top of the cylinder has been turned round (but still over sized) to take the fixed steady.  While looking to set up the steady I realised it had been growing mushrooms while in the cupboard  :ShakeHead: So that had to be removed before adjusting the fingers so that they first clamp then backing them off so they support the casting without rubbing too much. A dab of Anti Scuffing Paste doesn't do any harm  ;) And before boring, one thing I often forget is to tighten up the grub screws that clamp the fingers to stop them moving  :facepalm:

With a boring bar sticking a little way out of the holder the end can be faced off square: we don't want any lumpy bits catching the bring bar when we start the bore in anger. Speaking of which a 16mm diameter boring bar looks a bit long and skinny when it is extended out far enough to do the boring  :paranoia:

Jo



 
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 02:07:14 PM
OK Jo.

Sounds like you have an earlier piston casting then, it's up to you how you proceed.

I'm a little ways ahead of you at this time, it took a little time to clean up the cylinder to become presentable. I'd normally leave the fins " as cast " but had little choice with this one!

We've ground to a halt now, the boring bar hit something on a pass and broke the Carbide tip. My bar is an early Sandvic with " brazed tip " so its over to the forge to repair it.

Cheers Graham.

Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 02:39:03 PM
I might take it out to 40mm, which should allow me to use the piston casting, the bottoms of the fins are measuring 48mm so that will leave 4mm walls.

Edit: Just checked the dimension of the bearing stand and 40mm is just on the limit of the internal dimensions for where the vertical part of the support goes up. And it will leave a 5mm wall for some more screws to secure it to the cylinder.

Thinking further this is a vacuum engine so do we want mass to cool the hot air it gulps? Or more fins to disperse the heat? I seem to recall seeing someone playing a flame on the fins of a flame licker to get it running  :headscratch:

Jo 
Title: Re: Two little CHUK's
Post by: b.lindsey on September 01, 2019, 03:00:41 PM
They seem to need some heat in the cylinder mass to get going, but then you want to dissipate as much as possible at least for longer run times.

Bill
Title: Re: Two little CHUK's
Post by: b.lindsey on September 01, 2019, 03:04:58 PM
Have you thought about using a graphite piston at all?

Bill
Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 03:11:25 PM
Last time I ran Chuky he stated on the second flick of the flywheel from cold.

I have found it picks up a bit as it comes upto running temp but will start to drop off if it gets too hot but playing with flame sizr and position seems to prolong the run time if you don't suck too much heat in.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 03:19:33 PM
Hi Jo.

Hmmmmmm, I'm glad you mentioned the bearing support yoke.    :)

We might have ended up with a problem, perhaps the new tip can wait. I seem to remember partially machining mine to allow the piston entry into the cylinder. A good call and hopefully in the nick of time!!

Yes these engines rely on a cool cylinder to " condense " the working fluid, heated air. Obviously the heat transferred to the cylinder walls and then dispersed via the finning try's to keep the differential. Ultimately the cylinder gets too hot for them to work properly.

I've never understood why some needed preheating, possibly because the cylinder to piston fit was too close? Or incorrect valve timing?  My engines have always run beautifully from cold and slowed down as the cylinder temperature increased.

With CHUK 2 the cam disc is screwed directly onto the flywheel, inside boss removed. Timing is achieved by rotation with respect to the fixed crank web.

Thanks again for the timely reminder.

Cheers Graham.

Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 03:43:09 PM
Big bore, it ain't!!

See photo.

CHUK 1 or 3 for bigger bores.
Title: Re: Two little CHUK's
Post by: b.lindsey on September 01, 2019, 03:43:39 PM
With some, there is a tendency for moisture to condense on the inside of a cold cylinder which adds drag. Getting the cylinder up to  some lower starting temp negates that. That is my explanation but they do have very close tolerances .

Bill
Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 04:14:54 PM
I don't think the piston comes out of the cylinder on the Alyn version, does not on my smaller one so would it be possible to leave the ring of the bearing support the 40mm and bore out the cylinder allowing the bracket to overhang?

You would have to assemble the piston and rod and put in the bore before fixing the bracket but can't see that being an issue
Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 04:44:14 PM
The piston TDC is 6.5mm below the top surface of the cylinder.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 05:06:52 PM
Could be a goer then unless Graham knows something we don't.

What do the drawing show the bracket being fixed to the cylinder with, I can't see any fixings on Grahams original maybe just the magic coating was enough? Does have a special bolt hole pattern for the base to cylinder joint though :o
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 07:03:26 PM
The bearing yoke was a slight heat and press fit onto the cylinder.

I'll leave it to you regarding bore size but being able to remove the piston from the cylinder easily, does have its merits.

A cold start!

  VywFtk5SqDQ
Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 07:06:26 PM
Can't ask for it to start much better than that.

Do you think that placing the exhaust holes radially around the opposite side to the inlet would have any benefit as regards to it not disturbing the flame?
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 07:18:13 PM
Can't ask for it to start much better than that.

Do you think that placing the exhaust holes radially around the opposite side to the inlet would have any benefit as regards to it not disturbing the flame?

I'm not sure what you're referring to Jason?

As you're aware the exhaust is through the diaphragm at the bottom, in this case. Are you referring to the string of small holes that can be seen?

If so that was an idea for gas firing that didn't work.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 01, 2019, 07:26:36 PM
Ah, I thought that once the exhaust has passes the valve you may have had it coming out there rather than the big hole in the base. None of the photos of yours that I have show whether they are through or blind holes.

I can now see why there is a hole at the side which I assume was where the gas went in and the holes acted as a row of burners
Title: Re: Two little CHUK's
Post by: Jo on September 01, 2019, 08:17:21 PM
Runs nicely Graham but what do I need to do to get my engine to go "Quack"  :)

I noticed that your inlet shutter goes below the port rather than above does that make any difference  :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 01, 2019, 08:26:31 PM
Runs nicely Graham but what do I need to do to get my engine to go "Quack"  :)

I noticed that your inlet shutter goes below the port rather than above does that make any difference  :noidea:

Jo

Ah.... That'll be the " Peeking Duck " I guess.... :)

It's down to the diaphragm Jo, a thin metal one rings. I recently changed mine for a cast Iron one.

Regarding the shutter I discovered that opening that way disturbs the flame much less as any exhaust left in the cylinder goes up rather than down.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 03, 2019, 03:37:57 PM
Hmmmmmm.

I must stop with the " corny " jokes, put the thread on hold!   ;)

The last pass at nearly 41 mm.

Very handy, if you have one!!

Had to fight for metal here to get the lip for the diaphragm. Now ready for the Delapena.

Cheers Graham.

Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 03, 2019, 03:39:48 PM
LOL

 :lolb:
Title: Re: Two little CHUK's
Post by: Jo on September 03, 2019, 04:10:51 PM
I decided I didn't like using that titchy little boring bar for such a long bore so as soon as I could upgraded to Big Bertha  :) For the last cuts I bored once at 39.5mm, then twice at 39.8mm, which even with a 30mm diameter boring bar after the final cut I found the bore had creeped up to 39.92mm - it is now ready for honing. Sadly unlike Graham I don't have all the parts for my Delepena hone at that bore  :wallbang: so I will be honing another way  :-\ While the cylinder was still supported by the fixed steady I faced to top to the correct height.

Two suitable washers were made to fit one of my 25mm arbors and the cylinder was set up for turning the outside of the fins, the outside at the top of the cylinder and the lip for the diaphragm. I chose to give the cylinder two lips one fits the base casting and the other is the correct height for the diaphragm lip but importantly I have increased the diameter of that lip to 45mm to take account the larger diameter cylinder bore. (The base casting has had its pocket made slightly deeper to allow for this  ::)

Time to take it in to the inspection department to see what Surus thinks of it  :pinkelephant:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 03, 2019, 07:18:19 PM
Special jobs....

Call for special tools....

Last used, quite probably, to do the last CHUK 2!! 20 years ago.

It's coming together nicely now.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 03, 2019, 08:06:07 PM
Graham, I can tell someone has done this before  :thinking:

Jo
Title: Re: Two little CHUK's
Post by: Johnmcc69 on September 04, 2019, 02:20:04 AM
 :ThumbsUp:
Nice work!

 John
Title: Re: Two little CHUK's
Post by: Jo on September 04, 2019, 07:52:31 AM
I've been thinking about the fit of the bearing yoke support. The base of the casting might clean up to 8mm deep which is the depth that the ring on the top has been machined to, So there will be an odd sized gap above the top fin  - I think I should have left that ring at 14mm tall :wallbang:

The cylinder fins have about 7mm between them so a 1mm deep counter bore could be done to allow the bearing yoke support to fit on the top then be bolted into place with plenty of metal to secure it and it would look like there is an extra fin on this engine  :thinking:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 04, 2019, 12:42:31 PM
Any chance you could post a photo of the two bit sitting one on top of the other to make it a bit clearer to see what you are saying.

Provided the groove does not go too deep and meet the fixing PCD I can't see why it could not be done and will help loose a bit of heat even if at the cooler end
Title: Re: Two little CHUK's
Post by: Jo on September 04, 2019, 01:07:23 PM
A pic of the two together.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 04, 2019, 01:13:19 PM
So you would cut the top spigot of the cylinder a little smaller dia leaving a fillet and then machine away the bottom of the bracket ring in a similar way so that when they go together it looks like an extra groove. Can't see why not unless Graham knows something we don't.

Poor green lines :-[
Title: Re: Two little CHUK's
Post by: Jo on September 04, 2019, 04:45:15 PM
Holding the bearing Yoke is a bit of a challenge  :thinking: as the foot is too long big to be able to hold it in a three jaw chuck.

You can hold it with the foot out but even then there is not a lot of space and there is no way it could be bored out to 40mm safely  :-\ It is possible to get 20mm in there to use to secure it on a mandrel.

Once on a suitable mandrel it is possible to turn the outside and to face the bottom, but while it is secure it can be turned round and the top of the bearing mount machined  :)

Which means I still need to do the boring bit  :Doh: But I can still change my decision on the depth for the counter bore if I want to.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 04, 2019, 06:35:28 PM
Could always be bored etc on the mill or try your new welder out with greedy jaws like Graham.

Another option is to drill amd tap the fixing holes and then you just need a plate and a few standoffs
Title: Re: Two little CHUK's
Post by: Jo on September 04, 2019, 06:58:29 PM
I am not saying I expect there to be any problems boring it  :hellno:

I am saying there are lots of other things to get on and do before I get round to doing the boring as once I have done that it is not as easy to hold it for those other jobs. And I was hoping that Graham might have confirmed before I do it that there is no reason not to leave it with a shallow location bore  ::)

Jo
Title: Re: Two little CHUK's
Post by: b.lindsey on September 04, 2019, 07:19:46 PM
This one is moving right along Jo even with the few challenges so far.

Bill
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 04, 2019, 07:49:49 PM
A pic of the two together.

Jo

Like this per chance?

 :)
Title: Re: Two little CHUK's
Post by: Chipmaster on September 04, 2019, 08:49:15 PM
Hi Jo,

I think you're keen on the Chuk sound. When yours is running lift the base slightly to get the reverberating quack type sound. For this video I've undone the holding down bolts and used a small screwdriver as a wedge.

m6Sesuut7hc
My engine would benefit from a de-coke. When its clean I get a better tone right through the rev range.

Andy
Title: Re: Two little CHUK's
Post by: Jo on September 05, 2019, 06:28:35 AM
Thanks Andy. So it looks like the trick to getting these little CHUKs quacking is all to do with amplifying the exhaust valve. Something to try later. :thinking:

Like this per chance?

Yes. It would be nice to be able to see in the picture how you did that. Your earlier pics seemed to show a slight gap above the 7th fin  :noidea:

And Graham you did not respond to the question about does it need to slide onto the top of the cylinder for a secure fit or would just the screws be sufficient. In which case I can machine a slight register in the bottom of the bearing yoke and do that with mine. My preference if I was to do it again would have been to modify how I machined the top spigot.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 05, 2019, 07:26:21 AM
It's a noise you get from most atmospheric valves to some extent as they open, some quack some are more flatulent like the Robinson

S4Vnfcvv7bU
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 11:02:00 AM
Dear Jo.

I'm awfully sorry, I completely misunderstood your question from yesterday; rather preoccupied.   ;)

The spigot at what is the top of the cylinder on CHUK 2 is machined to a clean diameter. This diameter is made as large as is possible from the " cleaning " cuts. The bearing yoke is then counterbored to this diameter to almost the full depth that the casting will allow.

For myself, I like to make this an interference fit. Once the two parts are pressed together no fixings are required and it looks, to all intents and purposes, like a single casting.

Regarding fixings.

There's no need to go overboard on either size or number. We are talking " fractional "  power here. The maximum size I used was 2 BA for securing the bearing carrier to the yoke, all others were 4 BA studs and nuts.

Oh, and a division of 3 was used throughout.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 05, 2019, 11:22:59 AM
This photo of Graham's may help Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 11:31:23 AM
This photo of Graham's may help Jo

" A pictures worth a thousand words "

Thanks Jason, I seem to remember talking photos for you to build CHUKY but am unsure who, and with what device took them.

Perhaps you could post others, if the need arises?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 05, 2019, 11:38:36 AM
Thank you Jason. If you recall Graham showed us his casting earlier and it had 7 fins (black arrow), it shows how the bearing yoke fitted on top of the cylinder leaving a small mount left which over lapped bored the same as the cylinder (red arrow) and the gap between the top cylinder fin and the bearing yoke was less than the spacing of the remaining fins (blue arrow). Later things changed and the gap above the top fin got larger  :headscratch:

So the spigot on the top of the cylinder is actually longer than the base of the bearing yoke  :-\

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 05, 2019, 11:39:36 AM
I think Andy sent them to me so may have taken them, happy to post others if needed but best not show the special bolt hole spacing for cylinder to base ;)

EDIT don't have one of the top of cylinder with the bracket removed just these
Title: Re: Two little CHUK's
Post by: Jo on September 05, 2019, 11:48:34 AM
 :headscratch:

I have been on about getting over this gap (black) and the odd spacing above the top fin (red) on the original engine.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 05, 2019, 11:57:04 AM
As I said yesterday put most of the groove into the thick top of the cylinder as sketch and the remainder into the bottom of the bracket's ring, probably have to be a bit shallower as graham's latest engine is particularly if using fixings.

Not drawn that well but the height gap should match the gap between other fins which will deal with teh red arrow.

Black arrow is simply getting your lengths right so there is no gap.
Title: Re: Two little CHUK's
Post by: Jo on September 05, 2019, 12:10:56 PM
So you are saying turn the top spigot on the cylinder down further and reduce the bearing yoke to make it look like another fin :noidea:

Turning a 1mm register on the underside of the yoke strikes me as easier/quicker and lets the spigot be thick enough for the mounting screw threads

Jo

Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 12:19:08 PM
So you are saying turn the top spigot on the cylinder down further and reduce the bearing yoke to make it look like another fin :noidea:

Turning a 1mm register on the underside of the yoke strikes me as easier/quicker and lets the spigot be thick enough for the mounting screw threads

Jo

Hi Jo.

Yes, this time I tried to make it look more aesthetically pleasing. The original was literally " thrown " together!!

Perhaps Jason should post the picture of the " hidden " horror story lol.

Edit.

On closer inspection of your picture of CHUK B I can now see why you're confused. The bearing yoke is, quite literally sat on the top lip of the cylinder having just been prised away for the previous picture.
Title: Re: Two little CHUK's
Post by: Jasonb on September 05, 2019, 12:30:05 PM
Jo, I don't have the castings or the drawings that you are working from so can't be exact in what I say but doubt it makes much difference where the metal comes off of. You could even assemble the two and turn the additional groove as one. Do note the position of Grahans shutter rod guide, may need moving if the groove is now going to be where the guide fits.

Graham if you insist. Now I have posted the pictures you can tell the tale. :) Also does the eccentric valve face give the quack a Welsh accent?
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 01:07:13 PM
Thanks Jason.

We're all prone to making mistakes, haste, in this case. Luckily all hidden away!

Whilst at lunch with my wife and the CHUK's I suddenly noticed where some of the confusion arises from.

See attached picture of the original and the new, side by side. Where did that extra fin come from?   :)

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 05, 2019, 01:45:21 PM
Where did that extra fin come from?   :)

I have given in asking that question  :disappointed:
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 02:46:51 PM
Where did that extra fin come from?   :)

I have given in asking that question  :disappointed:

LOL !!

Because fin seven was part machined and " blended " into the underside of the bearing yoke on my original engine. For what reason, I've no idea now? Perhaps the casting was rough?

With the new one I was able to fully use the end spigot and effectively blend the underside of the yoke casting to create the " look " of fin eight.

We have an extra few millimetres of bore to play with Jo, I wonder if we can increase the stroke length a little?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 05, 2019, 04:30:02 PM
Is that enough shine for you?

 :)
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 07, 2019, 12:00:24 PM
Good morning.

It seems I have pleurisy, my GP said yesterday afternoon. I'm feeling rather rotten at this moment.

I have the piston casting set up in the Le Blonde with the chucking stub all machined up ready for the next exercise. But I fear it might be a few days before I set foot outside again, hell of a temperature and chest pains.

I've run out of bearings so have ordered some at 0.99 each from eBay.

Jo, perhaps you might consider getting some ball races for the conrod and shutter whilst I'm unable to contribute?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 08, 2019, 01:16:51 PM
Hope you feel better soon graham and that Jo has not caught your illness as her progress seems to have come to a halt if postings are anything to go by?
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 08, 2019, 02:51:32 PM
Thanks Jason and to all who have sent messages.

I'm still feeling really rough with a high fever. Thank goodness for the multi fuel stove, I don't feel so cold!!
Wish I had one in the workshop.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 08, 2019, 04:01:51 PM
Join the gang: I have costrochondritis but today it has been compounded by the arrival of giant Hun-Yuns.  :paranoia:


Why is it that every time I hear someone else has Pleurisy I am reminded of the pleurisy joke on I'm sorry I haven't a clue..Why is it that every time I hear someone else has Pleurisy I am reminded of the plural-I-say joke on I'm sorry I haven't a clue  :slap:


Jo
-----
P.S. Rumour has it that these Hun-Yuns have the potential to contribute to global warming   :o

P.S.s For those of you who know nothing of the great british institution of I'm sorry I haven't a clue, some of the best games are on this page: https://www.bbc.co.uk/programmes/articles/4pfSTqkKVLNyVfr8MjPyRy0/the-five-funniest-games-from-im-sorry-i-havent-a-clue I am not sure if it will work outside the UK  :noidea:
Title: Re: Two little CHUK's
Post by: Jo on September 08, 2019, 04:53:11 PM
Having faced off the surface I discovered its a long way down milling that slot  :paranoia:  Thankfully I had drilled either end before starting which made life easier.

It was not possible to get the measurement on the drawings from the bore to the valve port face as the casting was already below that measurement so it was necessary to mill a bit off the base so that it was a nat's whisker below the valve port face distance.

Having sorted out my thoughts on the mounting of the bearing yoke it could then be bored. You can see how close 40mm is on the vertical - it just scrapes. The final bit that needed milling was the stand for the bearing block, which once machined I had the working dimensions for the block itself, which was a simple boring exercise.


Family shot: The bearing yoke and base have also been attached to the cylinder  :)

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 08, 2019, 07:05:02 PM
Blimey Jo....  :o

You're way ahead now!!

I think it's time I let you know about an improvement that was tried on CHUK 4. This engine is still not finished, but the idea is sound.

Instead of the cam pushing against a roller and spring to operate the shutter CHUK 4 lifts the roller that is mounted to some 1mm by 15mm Flat Ground Stock. This has a 10 mm slot milled lengthwise ( Scotch yoke like ) and uses the crankshaft as a guide. The improvement lies in the fact that a compression spring isn't there to sap energy from the system.

The choice is yours however Jo, but that's what I'll be doing.

I'd suggest using small precision ball races for the roller, big end and gudgeon pin as it makes quite a difference to the overall output power that's pretty low from the start.

Almost the home straight in sight Jo, pretty sure you'll win.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 08, 2019, 07:16:08 PM
Graham, I assume you would go for bearings without seals or remove the rubber seals if they have them to keep drag to a minimum.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 08, 2019, 07:32:55 PM
Graham, I assume you would go for bearings without seals or remove the rubber seals if they have them to keep drag to a minimum.

I never got around to a casting for the main bearings, Jo's solution looks fine.

Yes I'd suggest removing the inner seal of each and perhaps fit an " ornate " polished  Brass oil cup to finish. By replacing the grease with a light oil would definitely reduce drag however I never tried it myself.

As for the rollers, I wouldn't worry about those.
Title: Re: Two little CHUK's
Post by: Jo on September 09, 2019, 07:40:30 AM
Instead of the cam pushing against a roller and spring to operate the shutter CHUK 4 lifts the roller that is mounted to some 1mm by 15mm Flat Ground Stock. This has a 10 mm slot milled lengthwise ( Scotch yoke like ) and uses the crankshaft as a guide. The improvement lies in the fact that a compression spring isn't there to sap energy from the system.

I had been thinking about a pull rather that a push shutter mechanism: I would like it to have a look/feel more like the original Planck mechanism and have been reviewing some other Flammenfresser designs but none were a inverted engine :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Bluechip on September 09, 2019, 09:03:51 AM

P.S. Rumour has it that these Hun-Yuns have the potential to contribute to global warming   :o



Indeed they do ........  :embarassed:  :embarassed:  :embarassed:

Anon.
Title: Re: Two little CHUK's
Post by: Jasonb on September 09, 2019, 09:21:03 AM
Are they not carbon neutral having taken in all that CO2 while growing before the methane gets produced
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 09, 2019, 11:38:32 AM

 but none were a inverted engine :noidea:

Jo

As I've stated many times, I have a " thing " for inverted engines Jo, look at my Avatar. CHUK 2 is a
" ME " engine.

Ultimately the choice is yours, the compression spring offers little resistance to the overall running.

My friend Mike Rodgers from Nantwich had several cam discs produced via the relatively new CNC process, where the profile was milled as a slot. A small roller was made to follow the slot, we called it a " Desmo " drive. He nearly died when he went to pick up the finished parts, never got a price, nigh on 200.00 for 10 cams. A small fortune 20+ years ago! Backyard stuff these days.

I'll be back with you when I can.
Title: Re: Two little CHUK's
Post by: Jasonb on September 09, 2019, 01:09:33 PM
The slot option sounds good Graham, I was wondering how the lifted shutter would close again if there was no spring to pull it back down onto the cam. Jo you can send me a drawing if you want a CNC groove

For the scotch yoke option is the horizontal slot larger than the pin to give some time where the shutter is stationary much like you had on Nattie
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 09, 2019, 04:05:38 PM
The slot option sounds good Graham, I was wondering how the lifted shutter would close again if there was no spring to pull it back down onto the cam. Jo you can send me a drawing if you want a CNC groove

For the scotch yoke option is the horizontal slot larger than the pin to give some time where the shutter is stationary much like you had on Nattie

Ah, but there's no need for a slotted cam on CHUK 2 Jason. We have good old gravity acting for us, the mass of linkage, shutter and roller all help to reclose the port as the cam rotates.

I'm wondering if my term " Scotch yoke " is perhaps a little misleading here? I'll try and get out to the workshop and grab one to photograph.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 09, 2019, 04:19:51 PM
Graham, if you mean that the slot is vertical to go around the crankshaft and keep the rod vertical then I know what you mean. Very similar to this arrangement on my RMC engine except the pin or roller would be on the left of the crankshaft to lift it rather than as shown on the right where it is pushed down.

You can stay in the warm now ;)

(https://img.photobucket.com/albums/v156/jasonballamy/Engineering/RMC/20190909_1614301_zpsushabqih.jpg)

(https://img.photobucket.com/albums/v156/jasonballamy/Engineering/RMC/20190909_1614151_zps8k0ahjng.jpg)
Title: Re: Two little CHUK's
Post by: Jasonb on September 09, 2019, 04:34:24 PM
Or even this
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 09, 2019, 06:58:51 PM
Or even this

LOL

That's exactly what I meant Jason, spot on.. :ThumbsUp:

Title: Re: Two little CHUK's
Post by: Jasonb on September 09, 2019, 07:02:58 PM
So the next question is will the shape of the cam need altering?

That cam would have held the shutter down for longer when pushing but will hold it up for longer now it is lifting.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 09, 2019, 07:19:46 PM
So the next question is will the shape of the cam need altering?

That cam would have held the shutter down for longer when pushing but will hold it up for longer now it is lifting.

I'm not sure it makes any difference Jason. It's just a reverse action. The " dwell " is determined by the outer diameter of the cam the difference in the top and bottom radii determine the stroke of the shutter.

Title: Re: Two little CHUK's
Post by: Jo on September 11, 2019, 01:44:41 PM
A little more swarf has been made and the rattle cans have been exercised.

The flywheel casting was very nice and hardly needed any fettling  8) Mounted on the outside surface of the three jaw chucks the outer surface on either side of the flywheel was made to run nearly true before the rim was skimmed and the outer rim. While mounted up the centre was drilled, bored and reamed for the crankshaft.

Now that the paint has gone off on the bearing block the two bearings have been pressed in and it has been mounted on the bearing yoke. Finally I am able to work out if the stroke could be extended and the length of the connecting rod  :thinking:

I have also started machining the piston. The main body of the piston was very tapered so it was necessary to mount it in the three jaw chuck using tailstock support with the casting jammed against the chuck body.

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 11, 2019, 02:28:50 PM
Hi Jo, wonderful progress.

I'm assuming you've guessed the origin of the flywheel you've just machined?   ;)

That's how the other should have been.... Amateurs!!

My engine has an R.L.E. flywheel, I changed over to the Robinson to reduce production costs as we had 2 patterns on a single plate and that considerably reduced the price.

I know you've painted but you might want to consider the overhang and perhaps remove the inner boss completely? That's up to you however.

As you're now onto the piston try to remove as much metal as you can, I'm suggesting down to as little as 1 mm all over. I was most generous with material because it has the effect of reducing " chill " that dogs most thin section Iron castings.

Carry on, I'll meet up with you somewhere down the line.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: b.lindsey on September 11, 2019, 02:46:58 PM
Having been out of action for a few days what with moving and such, its good to see your additional progress Jo. Finally, now that the shop is just a short walk down the drive, I hope to  find my way there and start contributing again.

Bill
Title: Re: Two little CHUK's
Post by: Jo on September 11, 2019, 04:31:56 PM
Hi Graham,

I have just looked at the alignment and yes I think there is a bit of balance to be gained by reducing those flywheel bosses.

The crank web is too short to allow for a 28mm throw. Which is the maximum throw if the piston is keep in the cylinder casting rather than using the spare extension of the bearing yoke, which I think might cause some drag  :paranoia: That would need a crank rod with centres at 125mm   :thinking: I've found a bit of scrap-bin-inum complete with look-a-like special coating from which I can make a new crank web. The coating isn't properly aged   :-\

Having been out of action for a few days what with moving and such, its good to see your additional progress Jo. Finally, now that the shop is just a short walk down the drive, I hope to  find my way there and start contributing again.

 8)

Looking forward to it Bill, I am sure you'll find it great to be making swarf again  :cheers:

Jo
Title: Re: Two little CHUK's
Post by: Jo on September 12, 2019, 04:18:20 PM
The piston has been turned to have 1.5mm walls for now  ::)

The outside of the piston and the cylinder have been honed until the piston is a firm push fit through the cylinder. To work out just how much polishing is required I need to first properly clean the bore. Brake cleaner is ok for this but the ultrasonic cleaner filled with boiling soapy water is even better  ;)

I might not want that noisy thing running in the kitchen while I eat my dinner  :thinking:. 

Jo
Title: Re: Two little CHUK's
Post by: Admiral_dk on September 12, 2019, 09:50:46 PM
You're really moving quickly with this build Jo and the last picture tells me that it is a lot bigger than I thought. Finished parts are looking good  :ThumbsUp:

Quote
I might not want that noisy thing running in the kitchen while I eat my dinner  :thinking:.

On mine there are big warnings about not running it near any living being (bugs excluded  ;) ) as it can have hazardous consequences ...!  so please do not eat near it when it is running !!!!
Title: Re: Two little CHUK's
Post by: Jo on September 13, 2019, 08:23:29 AM
Thanks Per  :)

... and the last picture tells me that it is a lot bigger than I thought.

Its not a cute little one like Jason's, this is an Elephant size one  :pinkelephant:  ::)

Jo
Title: Re: Two little CHUK's
Post by: Admiral_dk on September 13, 2019, 11:19:24 AM
 :o  Ok, that monster should have a "Quack" loud enough to scare all the cats out of the neiborhood  :Director:
Title: Re: Two little CHUK's
Post by: b.lindsey on September 13, 2019, 01:25:11 PM
Beginning to look like a proper engine Jo. Were you able to get the entire bore cleaned in the ultrasonic by flipping it over?

Bill
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 14, 2019, 11:37:16 AM
 I finally ventured out to the workshop yesterday evening, there's a distinct chill in the air here.

The piston casting was waiting for me in the Le Blonde ready to be reversed with the chucking stub held firmly. It was at this point I noticed that the stub didn't want to centralise, my method is to gently rotate the casting against the lightly tightened jaws. Try as I might I couldn't seem to get things true. I eventually found a position that came near and locked the jaws tightly, knowing that I could get concentricity whatever.

I use a large diameter end mill to " rough out " the inside and then follow up with a boring bar, using a drill bit can sometimes overshoot your depth. Several noisey passes later began to reveal a clue as to why I'd been having trouble earlier.

The swarf kept changing in its characteristics from dust to large curls, I'm a little embarrassed with the photo presented.

Needless to say, patience ruled and I finally found the piston from within the mess. A fit worthy of the time spent. I will, however heat treat it before final fitting. A 4 mm hole was drilled and tapped to 2BA for the small end yoke before gently cutting off the stub with a hacksaw.

My bearing housing will come next.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 14, 2019, 03:46:11 PM
Thanks Bill,

Were you able to get the entire bore cleaned in the ultrasonic by flipping it over?

Yes, just  :)

I've been looking to get the rod done and be able to attach it to the piston. For both the rod and the attaching fork I have used HE30 aluminium, I can't see this engine putting the sort of stresses through the rod that it needed HE15 to be used.

The rod had its big end bored to fit a bearing I had and the small end was reamed 5mm for a bush, the rest is just milling and filing. The small end bearings are a pair of dinky rollers for a 3mm shaft which have been fitted to the piston adapter thingy  :noidea: . The great thing about doing it this way is that the bearings are a good fit on the 3mm shaft so it holds in place on its own so there is no need for nuts, circlips etc.

The only thing to watch now is not to knock the rod against the side of the cylinder as I do a bit of up and down testing (there is a spring currently helping the piston back up the cylinder in this important testing phase ::) ).

Tomorrow I need to make the crankweb and a crankpin  :wine1:

Jo
Title: Re: Two little CHUK's
Post by: Jo on September 15, 2019, 04:07:18 PM
A Crank web was found inside a piece of hard as  :censored: come-in-handie-um. I should have spotted the obvious clue from the amount of rust on the outside of it that it was going to have a high carbon content that enhanced the experience of hacksawing off the two unwanted bits ::)

There is nothing exciting about the crank pin, it is just threaded 2BA to screw into the crank web, which is in turn held onto the crankshaft by a 6B grub screw hiding behind, I might also Loctite it later.

Initial round and round testing is showing up that the piston is still dragging a little so requires more round and round testing, this could be done with an electric drill  :facepalm2: or my preferred manual technique of flicking it over every time I walk by  :) . The piston seems to dangle about 1mm into the port at BDC.

I need to get the cam in place to discourage the crankshaft from sliding in the top bearing when it is flicked over

Jo

Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 16, 2019, 12:03:11 PM
The " home straight " is in sight Jo.

The cam and a few " fiddlely bits " to finish. I wouldn't worry too much about the position of the piston at TDC, it'll be fine.

I didn't reply yesterday as we were waiting to hear some news, finally came at 7:32 PM. A granddaughter at a little over 7 Lbs entered the world. Both mum and daughter are doing fine.

I was looking at the gauge plate that I bought the other day for the cam follower, perhaps a prime candidate for the shutter? My use of a " Stanley " knife blade originally was perhaps inspired by the shape and thickness of the one fitted to my Planck engine. This however needed a lot of fine lapping to get it flat after Silver soldering the pivot, the gauge plate shouldn't.

Don't forget to lap the cylinder port Jo, I can see it looks a little rough at the moment from your last photos. ;)

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 16, 2019, 04:58:33 PM
The " home straight " is in sight Jo.

Thanks Graham, congrats on the new member of your family  :cartwheel: You will have to design another engine to celebrate  ;)


I've been making the cam, I worked out that with a 62mm diameter face I needed to set the boring head at 65mm diameter to cut a profile that gave me 8mm of movement. Hopefully this is sufficient to allow for a clean opening and closing of the valve.

To cut this the mill head was run in reverse and I used the vertical power feed (which also had to be reversed due to the spindle motor reversal ::) ). I decided that removing the cam surface would make the crankshaft out of balance so added some lightening holes on the opposite side.

The final stage was to turn a 2mm long 16mm diameter boss on the inside of the cam to fit next to the main bearing and to reduce the boss on the other side down to 4mm long so that I can bring the flywheel in a bit later  :)

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 16, 2019, 06:41:11 PM
Thanks Jo, that's number eleven!!

I absolutely love the cam " adornment " !   In fact I'd forgotten that the Planck also had a couple of
" windows  "  as cast to help with the balance. Did you manage to use the casting for it?

Hmmmmmm, a new design eh? Perhaps have a competition to find a name from the first letter from each of the grandchildrens names? For the future?

So just the shutter to go, I'm looking forward to seeing what you come up with?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 16, 2019, 07:29:51 PM
Almost there, does it quack yet if you put your finger over it's mouth?
Title: Re: Two little CHUK's
Post by: Jo on September 16, 2019, 07:53:03 PM
I have not yet made the flap valve/spring or done any of the lapping ::)

Did you manage to use the casting for it?

Yes I used the original casting to make the cam  :D

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 16, 2019, 08:00:40 PM
I have not yet made the flap valve

You mean to say you have not got to the bottom of that tube of Pringles yet?  :P
Title: Re: Two little CHUK's
Post by: Jo on September 17, 2019, 01:06:45 PM
You mean to say you have not got to the bottom of that tube of Pringles yet?  :P

They did not have any in stock  :toilet_claw: Alternatives will have to be found   :noidea:

The activating arm has been made of brass and has a slot to fit around the crankshaft. I initially positioned the threaded hole for the follower for when the arm was low and the cam was high  :Doh: Thankfully the amount of movement in the slot allowed for the hole to be drilled and tapped in the right place and the offending hole was filed off  ::)

I've done a bit of shaping up and added a threaded block on the bottom. Now I can start thinking about the bottom end  :thinking: It will need a support to pull it in towards the port face and to stop the rod moving sideways due to drag on the cam.

Jo
Title: Re: Two little CHUK's
Post by: Jo on September 17, 2019, 04:14:35 PM
While I decided if there was something better to make the shutter out of I decided to start off with trying the original Stanley knife blade with its edges ground away. the trickiest bit of the shutter was getting that boss to silver solder in place as the pressure of the propane flame kept blowing it over. In the end I held it in some tweezers as I silver soldered it in place.

It needs a guide just above the port  :thinking:: But the open and closed positions look ok  :)

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 17, 2019, 06:38:22 PM
Jo. was the pivoting block on the drawing or your own thoughts to allow the shutter to lay flat even if rod is a bit out of vertical?

Edit, no need to answer just looked at the video of Graham's again
Title: Re: Two little CHUK's
Post by: b.lindsey on September 17, 2019, 06:48:47 PM
That's looking great Jo. Neat idea of using the blade for the shutter too.

Bill
Title: Re: Two little CHUK's
Post by: Jo on September 17, 2019, 07:42:20 PM
Thanks Bill, I am a little worried I might have the shutter on upside down  :facepalm:


I am still thinking about where to put the missing rod guide. Ideally it should be near the bottom but I want a bit of "freedom" so the shutter is pulled tight by the vacuum rather than needing to be held against the face which might cause drag   :thinking:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 17, 2019, 08:02:44 PM
Would an L shape work with the top fixed to the ring of the bearing support, this would get it lower depending on length of L and give a solid place for a screw. Bit of brass angle with one leg cut down would do.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 17, 2019, 08:24:09 PM
Some lovely engineering Jo, well done!

Your shutter appears to be fine, by the way.

You could mill a small vertical slot in the Brass just below the cam bearing and have a peg sticking out from near the top of your main bearing housing to keep the assembly from moving sideways. This might also allow you to fit a nut to put a bias against it to keep the shutter gently against the port face.

Just thinking out loud here.   ;)

These CHUK's are VERY individual!

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 17, 2019, 09:14:21 PM
I was thinking more around a doughnut of brass like on the original Plank engine to guide the rod but where should it go and how to mount it :thinking:


A higher mounting allows for the spring in the rod to be used to hold the shutter against the port face. A lower one (its difficult to fit anything alongside the fins that is in keeping with an engine of this period ) needs to mount on the top or sides of the port face, where it can provide a bit of adjustment to the pressure :noidea:


I'm going to sleep on it...

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 18, 2019, 07:09:32 AM
Something like the tow bracket on the back of your BB1 fitted to either side of the port maybe?
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 18, 2019, 11:32:49 AM
I was thinking more around a doughnut of brass like on the original Plank engine to guide the rod but where should it go and how to mount it :thinking:

I'm going to sleep on it...

Jo

Good morning Jo.

A doughnut? I'm not sure of what you're referring too?

I've attached a picture from the www, you can see the pushrod is guided through a hole drilled into the burner support bracket.

Both of my first " generation " CHUK's 1&2 have a Brass guide fitted into the casting that becomes the cylinder support " A " frame ( 1 ) and bearing yoke ( 2 )

I can add some photos if you want me to?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 18, 2019, 01:57:53 PM
Thanks Graham that pic has confirmed my choice of where to put the support and how I am going to do it  :)

One cannot have too many pictures of model engines  :embarassed:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 18, 2019, 03:40:41 PM

One cannot have too many pictures of model engines  :embarassed:

Jo

Happy to oblige, Jo....   :)
Title: Re: Two little CHUK's
Post by: Jo on September 18, 2019, 04:06:30 PM
Thanks Graham  :D

The design criteria for the guide was simple: it had to support the rod but not cause drag, it had to be in keeping with a model made of castings  :Love: and it had to not be a pain when it came to dismantling the engine .

So we have a guide, once it has been in the paint shop no one should even give it a second glance  :)

What's left  :thinking:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 18, 2019, 07:29:31 PM
Absolutely wonderful Jo.

I have to agree, you've made something that really " fits " with the casting theme, well done.

So....

Is it a " Pringlebottom " or a disc of cast Iron/Steel?

The " Quack " awaits.... Raucous or mellow?

                          :)
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 07:33:24 AM
Thanks Graham,

I was yet again unable to acquire the original Pringle bottom  :disappointed: So alternatives are being sort, what ever happens I was a good Quack out of this engine as I know the kids enjoy the sound  :D


I am also thinking about burners: A gas bottle can be a big lump to move around  :thinking: were the originals paraffin powered? In which case I have some 28 second burning oil to use up :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 19, 2019, 07:43:03 AM
Camping gas bottle will fit in your handbag. Or do like the model boat boys do and make a refillable gas tank though that would need testing for public display.

No liquid to spill and no hard to see flames and easier to adjust gas than meths.

There is always the lighter option but not so easy on this layout.

S13wymzV0po
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 19, 2019, 12:08:05 PM
Good morning Jo.

Nothing beats " shim Steel " for a sharp metallic quack, it's that simple!

Looking a the few available pictures of Planck survivors most were " fired " by an adjustable Paraffin and wick arrangement. My own is quite rare as it was fired by a small gas flame but the " flame spreader " must have been lost way before my acquisition. Liquid fuel can have its own problems however, if the wick guide is too short the heat can be transferred to the tank causing vapourisation.....

During an exhibition of models Alyn Foundry put on a display at a venue in Oswestry Shropshire.

I was joined by Vincent Salter, Martin Lorenzo and Mike Rodgers. We took up 3 tables  with our collection and many were running. Sometime during the early afternoon I noticed that the other exhibitors were quietly leaving the room, some carrying their most prized possessions.

Strange, thought I. Why such an early departure? It wasn't 4:30 for a long time! Upon turning around the reason for this sudden evacuation became stunningly obvious. My MK 2 CHUK 1 which I'd chosen to run using Paraffin with a Copper tank was on fire. Most of the other exhibitors had noticed this way before we had and by now the flames were well over a foot high! Nothing daunted I picked up a large cleaning rag and dropped it over the burning engine. The fire was extinguished immediately.

We never understood why no one came and mentioned anything to us but that episode became an " in house " joke for years to come.

So.... Liquid fuel can present its own problems, the moral. Don't use conductive materials for a fuel tank.

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 12:37:31 PM
Initial testing is showing the follower is sticking. The engine seems bouncy. I'm going to try a return spring  :thinking:

Jo
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 01:55:54 PM
The return spring seems to have done the trick  :ThumbsUp:

The Wick burner for the 28 second burning oil is covering the engine with soot   :facepalm:  and the flame from it is a bit cool.  Next up a gas burner...

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 19, 2019, 02:38:34 PM
Not so fast Jo.

What's your timing?

The port should just be just closing at 20 past the hour of crankpin position. And reopening at towards 10 to the hour.

I'm surprised you're not getting any action, with mine a small flame causes a back and forth bounce effect and as the flame is increased full rotation begins.

My cameraman is back from his recent sojourn in Greece, he might be persuaded to make a video if you like?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Jasonb on September 19, 2019, 03:10:22 PM
That's the opposite to mine Graham when looking from the flywheel side :headscratch:

Closes at 10 to

Opens at 20-25 past.

Jo, it should also be much harder to turn backwards as the piston is trying to suck against a closed shutter and closed valve and creates a vacuum.

Even an orange propane flame will soon earn this engine the name "sooty"
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 03:23:07 PM
I've had the engine running off the garden wand weeder. But the gas burner was not burning right   :-\ then I discovered I had a no 5 jet in it rather than a no 8.

While I wait for it to cool down I am having a cuppa and Surus is letting me watch him eat a Snicker Ice Cream :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 19, 2019, 03:31:55 PM
That's the opposite to mine Graham when looking from the flywheel side :headscratch:

Closes at 10 to

Opens at 20-25 past.

Jo, it should also be much harder to turn backwards as the piston is trying to suck against a closed shutter and closed valve and creates a vacuum.

Even an orange propane flame will soon earn this engine the name "sooty"

Yes, but what's your rotation Jason?

I was quoting from a clockwise rotation, from CHUK 1 my CHUK 2 runs anti clockwise. You're quite correct about the vacuum being created when trying to turn the engine in the wrong direction however.

We discovered that a Yellow flame works better, possibly due to it having unburnt fuel that continues to burn within the cylinder? A point for debate perhaps?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 19, 2019, 03:34:31 PM
Posts have crossed, congratulations Jo, a runner!!

 :cheers:

Video to follow??

Edit.

So a finished engine in roughly 20 days, but how many hours Jo, did you keep a log of time?
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 03:57:19 PM
Still having problems with the burner  :ShakeHead:

So a weed wand run, which went a bit sideways :facepalm:

mlWeZoUqKMg
Its late in the day maybe I'l try again in the morning.

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 19, 2019, 04:05:17 PM
Does your exhaust come straight out the bottom Jo, raising it up off the bench so it can breath may help and could even get a quack out of it.

Graham, that was clockwise on mine. I now see yours runs the other way As to flame I meant anything other than blue is likely to cause some soot.

Get your dancing shoes on after tea and snickers :pinkelephant:
Title: Re: Two little CHUK's
Post by: Admiral_dk on September 19, 2019, 05:33:31 PM
And we have a runner  :cartwheel:  congratulations Jo  :cheers:

Fine tuning will come as you work try other combinations.
Title: Re: Two little CHUK's
Post by: Jo on September 19, 2019, 05:49:36 PM
Thanks Per,

Its going round and round on its own but the burner  :headscratch:

Jo
Title: Re: Two little CHUK's
Post by: Zephyrin on September 19, 2019, 05:57:22 PM
wow, this is an awesome engine, beautiful.

Quote
We discovered that a Yellow flame works better, possibly due to it having unburnt fuel that continues to burn within the cylinder? A point for debate perhaps?

I think that no unburned fuel could survive in the yellow flame, which contains mostly incomplete combustion products, mainly carbon monoxide.
It is necessary to raise the temperature and give more oxygen to make them burn completely.
this does not happen in the closed cylinder in my opinion.
 
Title: Re: Two little CHUK's
Post by: b.lindsey on September 19, 2019, 06:49:19 PM
It running....great Jo. Some fine tuning and it will be even better no doubt. Nicely done   :ThumbsUp:

Bill
Title: Re: Two little CHUK's
Post by: Jo on September 20, 2019, 08:09:19 AM
Thanks Guys  :)

Its back to playing around with that burner today. I think it needs a meatier set of flames, maybe I could open up the jet holes  :noidea:

Jo
Title: Re: Two little CHUK's
Post by: Chipmaster on September 20, 2019, 11:34:41 AM
Hello again Jo,
picking up your last post on the Stuart Major thread here's a picture of my Chuk 1 castings.

Andy

Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 20, 2019, 12:10:05 PM
Hello again Jo,
picking up your last post on the Stuart Major thread here's a picture of my Chuk 1 castings.

Andy

There's " now't like rubbing salt " eh, Andy?

But, you're missing a couple of " vital " components!!   ;)

Can you spot them?

Cheers Graham.
Title: Re: Two little CHUK's
Post by: Chipmaster on September 20, 2019, 12:40:26 PM
Hi Graham, I couldn't resist that one   :LittleDevil:

Now for your poser,
I don't have a piston, that will be machined from a cast iron bar so I'm guessing that I don't have castings to support the Chuk 1 crankshaft, is there one in the top right corner of your picture?

Cheers
Andy
P.S  Is the gas valve casting for the Allman on the way?
Title: Re: Two little CHUK's
Post by: Jasonb on September 20, 2019, 01:24:23 PM


Cheers
Andy
P.S  Is the gas valve casting for the Allman on the way?

Looks like it is still on the table unless that is Jo's along with her Sphinx nameplate.

That A frame looks easy enough to fabricate, maybe a little Chuky 1 could be on the way, should not take long to knock up if the other ones 12 day build is anything to go by.
Title: Re: Two little CHUK's
Post by: Roger B on September 20, 2019, 02:04:39 PM
I've just caught up with this rapid build after various bits of travelling and life. Looks excellent and runs  :praise2:  :praise2: How much power would this produce when you get the burner sorted? It seems to be quite a decent size.
Title: Re: Two little CHUK's
Post by: Alyn Foundry on September 20, 2019, 03:21:34 PM
My goodness, you two stirring the proverbial.  ....   :)

Andy, I'll message you later.

Yes, 12 days in the making Jason but I wonder how many " actual " hours in total?

There's rather a lot of serious distraction going on in the background of my life at the moment, just waiting for normality to reappear, if ever.

TTFN.
Title: Re: Two little CHUK's
Post by: Jo on September 20, 2019, 03:45:52 PM
That's done it  :facepalm: I thought he had forgotten about his missing CHUK 1 casting set. I won't hear the end of it now  :ShakeHead:

Yes, 12 days in the making Jason but I wonder how many " actual " hours in total?

If you noticed he hasn't been in his workshop of late building model engines, he's been working  :stir:

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 20, 2019, 04:27:16 PM
Yes and I was also working when I made the Chuky so would have only been weekends and the odd evening so far less than you retired types can manage :LittleDevil: Plus I did not have castings as a short cut all had to be machined

Jo, what did you end up using for the valve?
Title: Re: Two little CHUK's
Post by: Jo on September 20, 2019, 04:50:14 PM
Being retired means we have lots of important things to do and model engine making only one of the items on the list  ;)

And of course your CNC milling machine takes its time  :facepalm:

Jo, what did you end up using for the valve?

The centre of a jam jar lid  ::)

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 20, 2019, 04:58:42 PM

And of course your CNC milling machine takes its time  :facepalm:


But not having any handwheel does leave your hands free to eat a magnum while it's working away in the background. Don't think I have done anything on it yet that I could have done faster manually :) Once I get air/lub sorted I won't even need to attend to it much while cutting so can do other things.

It would have made Chuky quicker, Rod (Tangler) did some of his on the CNC that came out well.
Title: Re: Two little CHUK's
Post by: Chipmaster on September 25, 2019, 09:26:56 PM
I intend to take my inverted Chuk2 along to the Winterbourne event on Saturday but it hasn't been running so well lately because it was in need of a thorough clean and decoke. The shutter and diaphragm valves also needed a bit more lapping because they were coated in a tough black layer of burnt oil. Finally the engine was treated to a new return spring for the shutter. With my shutter drive arrangement the return spring gets roasted and gives up eventually.

Jo - Here's a video of the engine featuring the wholesome exhaust sound after its service, have you tuned your Chuk yet?

OvVYFZbRB-ct=16s

Andy
Title: Re: Two little CHUK's
Post by: Jasonb on September 26, 2019, 07:05:09 AM
After watching listening to that I think the thread should be changed to "Two Little Ducks"

I did hear that Jo may be working on the triples again :lolb:
Title: Re: Two little CHUK's
Post by: Jo on September 26, 2019, 07:19:26 AM
Jo - Here's a video of the engine featuring the wholesome exhaust sound after its service, have you tuned your Chuk yet?

Hi Andy, I am sure the little (and big) kiddies will enjoy listening to the unique sound of your engine. It may even be one of those memorable items that encourage them to start making their own model engines  :ThumbsUp:

I hope to get back to engine (sound) tuning after I sort out the burner..

I did hear that Jo may be working on the triples again :lolb:

As I mentioned to you: I need to finish off the Triples so that I can get the centre bench back to enable me to make larger models  :-X

Jo
Title: Re: Two little CHUK's
Post by: Jasonb on September 26, 2019, 07:22:54 AM
BB1 time :cartwheel: