Author Topic: governors  (Read 31205 times)

Offline Jo

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governors
« on: October 16, 2012, 07:47:20 AM »
One of those parts of a model engine that used to cause me consternation was the governor :ShakeHead:. The second engine I nearly completed (the first was a Stuart 10V which was completed) was my Mary, I say nearly because whilst I finished the engine and got it running, oh dear nearly 20 years ago, the part that eluded me was the governor :disappointed::



The governor on the Mary is a simple Watt governor, a design that is found on so many engines, including steam and Gas engines:



I suppose the parts that I found so fearful were those spindly links with minute forked ends, the top hat and the lower sliding sleeve:



The links, whilst fiddle, can be easily overcome with a slitting saw and then either side milled. I have found it easier to break the top hat and lower sleeve down into easy to make components and silver solder them.

Another challenge with governors are those pivots that hold the arms together. I have gone away from using nuts and bolts to using a male and female pin through the pivot points, which you can see an example of these in this picture:



The final scary part is those thin links with big ends. Again a bit of thinking and they to become easy, from cutting the end from a piece of plate:



Silver soldering it to a long thin shaft:




And then filing to shape:



Of course then there is those bevel gears :hellno: ... but thankfully they are relatively cheap to buy, so if you don't want to cut them you don't have to.

--------

But to really explain how to make a governor I really should go back to the beginning. So please stay with me I first have to draw up the one for my Stothert and Pitt(s) and then over the comming week(s) I will make them  ;).

Jo
Usus est optimum magister

Offline Pete49

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Re: governors
« Reply #1 on: October 16, 2012, 11:22:46 AM »
Chairs set up the chips & fizzy drink getting cold ...ready when you are  :Lol:
Pete
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Offline zeeprogrammer

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Re: governors
« Reply #2 on: October 16, 2012, 11:34:00 AM »
I'm watching too.
Thanks for taking the time Jo.

I noticed the 'male and female pins'. I can't tell in the picture...are they threaded? I'm using several of those (threaded) on my current project and am glad to have a name for them.

What material was used to make the thin link you silver soldered?
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Jo

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Re: governors
« Reply #3 on: October 16, 2012, 11:48:07 AM »
I noticed the 'male and female pins'. I can't tell in the picture...are they threaded?

What material was used to make the thin link you silver soldered?

No they are not threaded, the good ones are a press fit, the bad ones are kept together with superglue or something stronger ;) .

The links are just boring old mild steel. I keep thinking of moving over to 303 stainless but that can be tricky to get the silver solder to stick and it has a habit of bending :ShakeHead:

Jo
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Offline steamer

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Re: governors
« Reply #4 on: October 16, 2012, 12:03:18 PM »
Oh well and truly strapped in for this ride.....note book out....lots of sharp pencils......... :cheers:
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline mzt

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Re: governors
« Reply #5 on: October 16, 2012, 12:20:23 PM »
I've already written down the first note, about those press fitted pins.

Marcello
This is a fitting job,
not a production job that can be measured in.

Offline gbritnell

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Re: governors
« Reply #6 on: October 16, 2012, 12:27:36 PM »
Hi Jo,
Here's a shot of my Mary governor if it helps.
gbritnell
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Offline smfr

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Re: governors
« Reply #7 on: October 16, 2012, 04:59:58 PM »
Pulling up a chair!

Jo, you mentioned using 303 stainless, but I seem to recall reading somewhere that it was to be avoided on "authentic" scale models because the color is wrong. Material snobbishness, or genuine concern?

Simon

Offline Jo

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Re: governors
« Reply #8 on: October 16, 2012, 05:12:43 PM »
Sorry Simon  :old: my eye sight is not good enough to notice the difference, especially in these small sizes. I suspect that the commercially brought small nuts and bolts are not high tensile either.

Jo
Usus est optimum magister

Offline Don1966

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Re: governors
« Reply #9 on: October 16, 2012, 05:26:18 PM »
I am diffinally in on this thread. Pulling up my chair as well.  :DrinkPint: I will be watching the commericals till the next reply. This should be very interesting and educational as well.

Don

Offline Jo

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Re: governors
« Reply #10 on: October 16, 2012, 07:28:04 PM »
Here is an example of a lost wax governor, that came as part of a casting set:



It is a very nice casting, whilst it will twirl it won't go "balls out" :ShakeHead:.

This is the governor I have chosen to build for this thread:



Ok this is a very simple drawing, so lets look at the governor in detail:

From the bottom, it is mounted on the engine plinth using this simple casting:



There is a pair of 16 tooth bevel gears ( I must calculate the DP of these). Then we come to the governor sleeve:



On most engines it is this sleeve that has a collar onto which the linkage that goes off to the throttle valve mounts but this engine was originally built for an exhibition so they didn't bother adding the collar. Either side you will see a pair of links, we will be doing these "en-block" 8).

Now to the arms, as normal the balls attach with a little collar, the lower half of the drop links are barrelled with the mount of the links in the middle and the top has a very nice u section.



These arms end on the governor fixed sleeve that has a pretty curve to it:





The governor shaft ends in a bush mounted in an arm that goes across the entablature and ends on a pretty nut (that you will have to wait for the drawings to see ;))

I have started the drawings.....it will keep me busy for a couple of lunchtimes ;D.

Jo
Usus est optimum magister

Offline jonesie

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Re: governors
« Reply #11 on: October 16, 2012, 11:27:12 PM »
thanks jo i will be watching also just what i need one more thing to build. jonesie

Offline Captain Jerry

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Re: governors
« Reply #12 on: October 16, 2012, 11:27:32 PM »
Jo

This could not have come at a better time.  My "Notacorliss" is going to need one soon so in anticipation, I knocked off a pedestal for the mounting.  Six flutes on a tapered column. 





I'm sure to learn some useful stuff here,

Jerry
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There are things that you can do and some things you can't do. Don't worry about it. try it anyway.

Offline steamer

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Re: governors
« Reply #13 on: October 17, 2012, 12:01:59 AM »
Man this is an awesome thread!.....

Dave
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Damned ijjit!

Offline Jo

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Re: governors
« Reply #14 on: October 17, 2012, 10:07:42 PM »
Jerry, I fear you are much faster than me at this (or do you get more time?)

I am half way through the drawings 8). The bevels are keeping me awake, the large pair are 16 teeth, 16.5mm O/D... that is about module 1 (and all my cutters are DP :Doh:,), the smaller pair are 8mm o/d, that is 48DP. My smallest gear cutters are 32DP but the observant amongst you will have noticed that I already have the bevels for the smaller governor. :whoohoo: so only one pair to cut and that will be in phosphor bronze or brass. Must do the calculations for those bigger gears....

Jo
Usus est optimum magister