Author Topic: Class 4 tank  (Read 12956 times)

Offline Stuart

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Class 4 tank
« on: July 22, 2012, 03:48:42 PM »
Here are a few random shots  I have some earlier one but cannot get them off the server yet
cylinder and part motion



more of the motion


reversing gear box this is a fully working gearbox, and drivers pedestal


up front
My aim is for a accurate part with a good finish

Offline Stuart

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Re: Class 4 tank
« Reply #1 on: July 22, 2012, 03:53:30 PM »
 safety valve

this is one of the pair  the small holes or number 80 36 in a ring the second ring is offset by 5 deg  again number 80 drill  the bolts at the top are no. 12 ba the ones at the bottom are just dummies as these screw in no bolted as per full size

these are mild pop valves



if any on wants a peep inside let me know and I will post a stripped down view

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

Offline Dan Rowe

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Re: Class 4 tank
« Reply #2 on: July 22, 2012, 04:22:28 PM »
if any on wants a peep inside let me know and I will post a stripped down view

Stuart,
Of course we want to see what is inside. Picture a guy jumping up and down with a sign that says WE Want Pictures.

Very nice work is it 1" to the foot scale?

Dan
« Last Edit: July 22, 2012, 04:25:37 PM by Dan Rowe »
ShaylocoDan

Offline Stuart

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Re: Class 4 tank
« Reply #3 on: July 22, 2012, 07:20:28 PM »
Dan

I will get the valve stripped down tomorrow and get the canon 7d and 17 -40 L out then


it is infact 1 and 1/16 to the foot that give 5 inch gauge true scale if it was 1 inch to the foot the full size would have a 5 foot gauge not 4 foot 8 1/2 inches

its just me and the heap of plans that dictate the sizes


where we have to deviate is the boiler fixings bolt on would not be robust enough

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

Offline Dan Rowe

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Re: Class 4 tank
« Reply #4 on: July 22, 2012, 07:36:47 PM »
Stuart,
I often wondered about the scale for 5" gauge. I see that I am not the only guy building to a unhandy fraction.

Dan
ShaylocoDan

Offline Stuart

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Re: Class 4 tank
« Reply #5 on: July 23, 2012, 11:29:00 AM »
Here is the valve in bits for a 100 psi valve
with all the small holes and the larger ones the escape area far exceeds the calculated requirement in fact the very centre ring would be OK but its not scale

operation
the ball seats on a reamed hole and is held in a carrier this is the positioned in a counter bore, this is the critical bit and the reason why they work the gas ( steam ) lifts the ball then when the ball has lifted a few thou it the impinges on the under side of the carrier ( the fine lip ) this then helps the valve to lift further and reset without to much pressure loss.
The most important thing is the spring they are not a bit chopped off a long length as some do the end would not be square nor would the compression force be the same they are made by Lee springs and are made to a specific length and poundage from memory they are only about 7 llb. to solid

the original work on the mild pop valve in its various  form was done by Gordon Smith who did some article in EIM about this subject I have one done as an open valve for a 14xx with two valves in one body

all the parts




inside bit together

the ball carrier is counter bored to hold the ball but with a specific amount protruding
you have to make up the lower valve body just with the inlet bore ,offer the ball and carrier up and use a feeler gauge to get it correct

inside the body
the body cavity is critical for its shape the lower part is related to the ball carrier and has to be correct to 0.001 "


bits and bobs


the above is a size comparison  the big drill is 1.2 mm the tap is a 12 ba and the small drill in a no. 80 i do get down to 16ba for other parts such as window frames

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

Offline arnoldb

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Re: Class 4 tank
« Reply #6 on: July 23, 2012, 05:51:53 PM »
Thanks for showing the disassembled valve Stuart  :) - quite a bit more detailed than the couple I've made so far!

Kind regards, Arnold
Building an engine takes Patience, Planning, Preparation and Machining.
Procrastination is nearly the same, but it precludes machining.
Thus, an engine will only be built once the procrastination stops and the machining begins!

Offline lazylathe

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Re: Class 4 tank
« Reply #7 on: July 23, 2012, 06:11:49 PM »
Hi Stuart,

That looks great!
How long have you been working on it for?
It looks like a lot of time has been spent on this project and it looks awesome so far!

Andrew
A new place to hide my swarf!

Offline Stuart

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Re: Class 4 tank
« Reply #8 on: July 23, 2012, 06:28:30 PM »
Arnold

yes they have a bit more than most but the lift well and reset about 5 psi below setting not 15 or so with the simple type and they pass the accumulation test with ease


Andrew

there is about six and a half years work , but i have done 3 stirling engines and a vertical boiler and I have a triple expansion on the go now , I use these to break up the long job as it can get bogged down, inc the 6 1/2 years is the boiler , I have the tank shells beaten out they are not straight sided but follow a large rad in the horizontal plane like the boiler only much bigger rad they will take about a year to do along with the cab .


the drawing pack runs into 15 sheets of AO

the lubricator you see is a dummy the one on the other side is the working one the box is about 3/4 " by 1" and contains the pump , very simple one with two o ring separated by a spacer though which the plunger passes alter the space to alter the feed. This then feeds an atomiser ( steam fed ) .

as you said a lot of work and a lot of 1/16 od pipe work for the oil lines then fitting have to be made out of 3/32 hex with small ss on nipples , just realised I have to make up the swab boxes


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

Offline Stuart

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Re: Class 4 tank
« Reply #9 on: August 05, 2012, 09:25:41 AM »
managed to get NTL to sort out my home page ( they had screwed up the permissions )

here are a few more pics from an earlier time










note the loco is on its back in these pics

the second one shows the ex pipes


thats a 6 inch rule on the frame for scale

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