Author Topic: Two little CHUK's  (Read 16501 times)

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #105 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.

Online Jasonb

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Re: Two little CHUK's
« Reply #106 on: September 16, 2019, 07:29:51 PM »
Almost there, does it quack yet if you put your finger over it's mouth?

Online Jo

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Re: Two little CHUK's
« Reply #107 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
Enjoyment is more important than achievement.

Online Jasonb

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Re: Two little CHUK's
« Reply #108 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

Online Jo

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Re: Two little CHUK's
« Reply #109 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
Enjoyment is more important than achievement.

Online Jo

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Re: Two little CHUK's
« Reply #110 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
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Online Jasonb

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Re: Two little CHUK's
« Reply #111 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
« Last Edit: September 17, 2019, 06:42:24 PM by Jasonb »

Offline b.lindsey

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Re: Two little CHUK's
« Reply #112 on: September 17, 2019, 06:48:47 PM »
That's looking great Jo. Neat idea of using the blade for the shutter too.

Bill

Online Jo

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Re: Two little CHUK's
« Reply #113 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
Enjoyment is more important than achievement.

Online Jasonb

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Re: Two little CHUK's
« Reply #114 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.

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #115 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.

Online Jo

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Re: Two little CHUK's
« Reply #116 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
Enjoyment is more important than achievement.

Online Jasonb

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Re: Two little CHUK's
« Reply #117 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?

Offline Alyn Foundry

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Re: Two little CHUK's
« Reply #118 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.
« Last Edit: September 18, 2019, 11:36:05 AM by Alyn Foundry »

Online Jo

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Re: Two little CHUK's
« Reply #119 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
Enjoyment is more important than achievement.

 

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