Author Topic: Two little CHUK's  (Read 7400 times)

Offline Chipmaster

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Re: Two little CHUK's
« Reply #150 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?

t=16s

Andy

Offline Jasonb

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Re: Two little CHUK's
« Reply #151 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:

Online Jo

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Re: Two little CHUK's
« Reply #152 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
Enjoyment is more important than achievement.

Offline Jasonb

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Re: Two little CHUK's
« Reply #153 on: September 26, 2019, 07:22:54 AM »
BB1 time :cartwheel:

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #154 on: February 02, 2020, 04:03:59 PM »
Hmmm, a Red warning label....

After what seems like an eternity, at least 120 days according to the website, the tide has receded from the workshop.

An accident with the bearing yoke before Christmas, dropped from a great height, no just being dropped onto the concrete floor cracked the casting. Being a supplier has its advantages, a replacement just happened to be available.

So with several steps backwards I'm pleased to be one ahead today. I managed to get to where I was 4 months ago. I also managed to machine the flame port slot.

I'll be back out later to do the flywheel.

Cheers Graham.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #155 on: February 03, 2020, 11:47:13 AM »
What a waste of time!

I had around 15 flywheel castings done as the Robinson hot air engine flywheel was pressed into service for the CHUK range of vacuum engines.

I picked out one from the box and proceeded to clean up the flash prior to machining. I cleaned up the boss, centre spotted and provided extra security with the tailsock rotating centre. Cleaned up the side of the rim then turned my attention to the face.

After a couple of passes I noticed a distinct bumping noise, a small hole had appeared adjacent to the remains of the " in gate " .... A " waster " in foundry parlance!

I picked out another and this time put just enough effort into cleaning to be able to turn it. Bump, bump, bump! Another hole. Lights out, lock up and feet up in front of the fire. A wasted evening.

Clearly insufficient  " head " had been used during casting causing a " draw " to form at the runner.

Tonight I'll be attacking the rims with an angle grinder prior to machining, I hope I find a good one!!

Cheers Graham.

Online Twizseven

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Re: Two little CHUK's
« Reply #156 on: February 03, 2020, 12:29:01 PM »
That's a shame.  What sort of size hole are you talking about.

Would be interested to see one of the faulty castings.

Colin

Offline Jasonb

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Re: Two little CHUK's
« Reply #157 on: February 03, 2020, 01:19:01 PM »
Painted Rim or 13 more chances :thinking:

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #158 on: February 03, 2020, 01:52:05 PM »
Painted Rim or 13 more chances :thinking:

Indeed Jason, it's a dilemma.

Sad thing is that I'm suffering the consequences of someone who's " learning the trade " he'll be good in about 30 years time, I can't wait that long lol....

Colin, I'll be out in the shop later with the camera.

Cheers Graham.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #159 on: February 04, 2020, 04:43:16 PM »
Now....

That's more like it !!

            :)

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #160 on: February 08, 2020, 05:54:26 PM »
Whilst Colin has been metal " bashing " on his thread I've been working with some Nylon.

I've always liked the look of the oil box covers fitted to my Barker 1 HP type B, a bit like a Pagoda roof. Having got a few castings still on stock from my restoration days I made a pattern that would sort of go with the cover.

Oh, I'm a little ahead of myself, I never made a pattern for CHUK 2 main bearing carrier so today I did.

With a little luck I'm hoping to cast it in Brass later this evening.

Cheers Graham.

Online Twizseven

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Re: Two little CHUK's
« Reply #161 on: February 08, 2020, 06:30:01 PM »
Graham,

What sort of temperatures do you need to cast brass.  What chemicals/additives do you need, if any, to add to the melt.

Colin

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #162 on: February 08, 2020, 08:06:53 PM »
Hi Colin.

Textbooks will say around 850 degrees C but we've always gone that little bit higher to allow for transfer between furnace and mould. There are proprietary covering fluxes available but before we had them lots of Borax was used to keep the Zinc from " boiling " off.

Well....

Arthritis 1 Graham nill.

I got as far as I could before my knee decided enough was enough.... Tomorrow, as they say, is another day!

Cheers Graham.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #163 on: February 09, 2020, 11:53:00 AM »
A brief description of the photos above.

Pattern placed centrally ready for ramming. ( in the Drag )

Adding the " facing " sand. By pushing it through a sieve you remove large lumps and other " foreign " bodies that might be present.

Firming, gently forming the facing sand around the pattern.

Ramming up, in the larger " Greensand " foundries older tempered sand would be used for " backing out " the mould.

Pattern ready for removal.

Cavity left and ready for the " Cope " to close the mould.

I'm going to drop the metal directly onto this one to help prevent shrinkage, this method is frowned upon because it can cause unwanted turbulence.

If the workshop isn't flooded too badly we'll be out later to cast. Tremendous overnight storm hit us.

Cheers Graham.

Online Jo

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Re: Two little CHUK's
« Reply #164 on: February 09, 2020, 11:54:50 AM »
Looking forward to seeing it Graham  :)

If the workshop isn't flooded too badly we'll be out later to cast. Tremendous overnight storm hit us.

We have still got it down here: 70+ mph winds. I have decided it is not safe to venture out to my workshop  :-\

Jo
Enjoyment is more important than achievement.