Author Topic: Stuart No 1  (Read 6157 times)

Offline Jo

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Re: Stuart No 1
« Reply #150 on: February 12, 2019, 02:02:57 PM »
Thanks Stuart, hopefully it will provide a bit of a modern view on Andrew Smith's original book which described making this engine on just a lathe  :o


The valve was just on dimensions  :paranoia: So it had to be machined very carefully to leave the sides of the valve square. The slot on the top of the valve was already over 4mm wide but the bottom of the slot was tight enough for the nut. Then the hole for the spindle can be drilled. The later drawing show the hole at 4.76mm diameter    :facepalm: the earlier one as 5.5mm, we need the hole to be bigger than the spindle as we want the valve to float like a butterfly.. If it is tight you will either get the fault that the valve will not follow the port face or that it stick too far out  :toilet_claw:

The valve pocket is also tight  :ShakeHead: and the original drawing show it being cut with a radius. I could see no value in the radius so I went for a normal slot drill cut pocket and squared up on the valve pocket size.

We can now check the fit of the valve in the steam chest and as you can see it is too tight so the inside of the chest needs to be milled out. We can then try the fit on the side of the cylinder to check if the movement of the valve hits the chest at all.

Jo

« Last Edit: February 12, 2019, 02:08:29 PM by Jo »
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Offline Jo

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Re: Stuart No 1
« Reply #151 on: February 14, 2019, 08:54:09 AM »
Some of you have mentioned that I failed to do anything yesterday  :facepalm2: sorry I will try to do better. To that end Eric has challenged me to take along this engine to see him next Wednesday so we can have an engine running session so I will be back in the workshop today trying to get some progress  :)


In the meantime any one visiting should be aware that Surus is camped out by the front door in case I get any 'visitors' who he suspects might have wine/chocolates and castings for me  :noidea:

Jo
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Offline Stuart

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Re: Stuart No 1
« Reply #152 on: February 14, 2019, 09:46:39 AM »
Havenít you received it/them yet

Tell Surus that they may be soft so do not squeeze them to hard


Happy Valentineís Day

My birthday is tomorrow 72 times round the big ball , people ask me how I feel I tel them I do not not how I should feel I have never been this old before

Have a good valentines machining day

88ís

Stuart
My aim is for a accurate part with a good finish

Offline Jo

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Re: Stuart No 1
« Reply #153 on: February 14, 2019, 10:54:07 AM »
Havenít you received it/them yet

 :disappointed: I am having to resort to opening a box of Jaffa cakes to eat on my own  :(

Thanks Stuart, have a nice Birthday for tomorrow  :)


Starting from the bottom surface I machined the 8 degree slope on the bit where the leg needs to go. Then turned the cover over to do the top.

I thought it was prudent to check the alignment once more before drilling the hole at 8 degrees. The drawing shows it is 7.14mm for a 6.35mm thread so there is a bit of wiggle room  :paranoia:

Having checked the distance between the soleplate and the bottom cover it is time to start on that leg  :noidea:

Jo

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Offline Jo

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Re: Stuart No 1
« Reply #154 on: February 14, 2019, 02:38:09 PM »
The starting point on the leg is to get it to length and to check it was right before any shaping up.

In case anyone missed it I repeat again: these forged bits from Stuart are horrible to machine  :disappointed: Turning the taper left a finish like an old gramophone record, which had to be finished by rotating the rod and using a file  :-X

Mounting the leg up in Tgs indexing head meant it was possible to mill the two sides parallel and to width. Leaving two holes to drill at the correct spacing in the end.

The only problem I can see is that the standard size nut for the thread on the end of the leg won't fit so it will have to be made smaller.


That was the last bit of machining...there may be a little fettling to go, the cladding and an adapter for the compressor so there is nothing for it - it is studs and their nuts time :toilet_claw:

Jo
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Online b.lindsey

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Re: Stuart No 1
« Reply #155 on: February 14, 2019, 02:46:33 PM »
Almost there now. Its looking great too Jo. The studs and nuts shouldn't be an issue for you  ;)

Bill

Offline Jo

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Re: Stuart No 1
« Reply #156 on: February 14, 2019, 04:35:18 PM »
Its a shame Bill I can't pick up the cladding for another week so it won't get finally finished just yet  :-\


It might be time to start negotiation on the next set of castings    :cartwheel:

Jo
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Online b.lindsey

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Re: Stuart No 1
« Reply #157 on: February 14, 2019, 04:36:39 PM »
UmmmÖ.would that be from Surus' stockpile or are you bypassing him completely :)

Bill

Offline bent

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Re: Stuart No 1
« Reply #158 on: February 14, 2019, 06:19:33 PM »
Well that was quick!  Looks darn good, too.

Offline Jo

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Re: Stuart No 1
« Reply #159 on: February 14, 2019, 06:57:48 PM »
Thanks bent,

Bill I had hoped that at least one casting set might have been dropped off for me today but  :disappointed: The visit to my supplier next week may bring the odd set to light but I doubt it so we are back negotiating as to what I might be allowed :noidea:

Jo
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Offline Jo

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Re: Stuart No 1
« Reply #160 on: February 14, 2019, 08:18:17 PM »
Some more pics from Eric  :)

Jo
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Offline Roger B

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Re: Stuart No 1
« Reply #161 on: February 14, 2019, 08:25:05 PM »
That leg is really quite a tricky bit to get right  :headscratch: It was quite a common feature though, maybe it was easier/cheaper than a A frame casting (is it a or an  :headscratch: I've been away too long).
Best regards

Roger