Author Topic: CONWAY 0-4-0 3 1/2" GAUGE LOCO  (Read 174382 times)

Offline NickG

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #375 on: March 11, 2018, 08:18:33 AM »
Nicely done Rich, shame about the snap but as you say shouldn’t affect anything. Yes, the larger spacing would have avoided the passages had the pattern been orientated correctly - perhaps that was the intention. Is there a drawing with the pattern of tapped holes on the cylinder or does it ask to spot them through from the covers? On the front covers you could just rotate around to where needed but obviously not on the rears as the slide bars bolt to them. Wonder whether he just has the pattern in the wrong orientation as MJM said. Keeping a real bolt will give Better and more even clamping force but you’ll have to watch your other passage now as it may be closer.


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Offline NickG

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #376 on: March 11, 2018, 08:20:00 AM »
I can’t really get my head around the automatic drain cocks but a lot of people use them. They are on the 5” gauge loco I’ve just bought, haven’t tried it yet but am told by people in club that they usually work ok.


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Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #377 on: March 11, 2018, 08:32:40 AM »
Hi

Martin Evans is well known for errors on his drawings, I have come across quite a few already. Thats all there is in the text re the covers, so I think I will go with the dummy bolt idea.

Heres another similar image for the drain cocks


Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #378 on: March 11, 2018, 11:53:06 AM »
Hi

Just noticed something on the last drawing

E  =  9/16
F  =  5/8

 :headscratch: :thinking: :noidea:

Cheers

Rich
« Last Edit: June 03, 2018, 12:00:17 PM by Firebird »

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #379 on: March 11, 2018, 12:01:17 PM »
Hi

The cylinder covers.

I was going to use brass but my mate julian said I have some bronze that will do.

Well the bronze was a sprue that he acquired from a bronze foundry.



It took a bit of turning to get it down to a usable 2" bar

But once it was there it machined nicely





Heres a neat little trick I picked up. Use magnets as spacers. They are quite accurate and don't fall off





Now come on, is this starting to look like an engine or what



 :DrinkPint:

Cheers

Rich

Offline MJM460

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #380 on: March 11, 2018, 12:10:31 PM »
Hi Rich, that explanation of how the valves work for both purposes makes sense, thank you.  It's time I tried them.  Much simpler than a screw down type or even the tapered quarter turn type.

MJM460
The more I learn, the more I find that I still have to learn!

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #381 on: March 11, 2018, 12:45:48 PM »
Hi

I'll post any drawings that I modify in case anyones interested


Cheers

Rich

Offline Jim Nic

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #382 on: March 11, 2018, 12:48:17 PM »
Hey Rich.  That's starting to look like an engine!   :ThumbsUp:
Jim
The person who never made a mistake never made anything.

Offline Jasonb

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #383 on: March 11, 2018, 01:19:30 PM »
There is no need to rotate the covers to clear the passages, IF the passages are done as per the drawing. Original drawing shows TWO passages 3/16 x 1/8"  with a space between which the stud hole can be drilled into.

You may find your engine is a bit strangled with just the two 1/8" holes which give about 60% of the intended area

Much like this one and a lot of other models

« Last Edit: March 11, 2018, 01:27:48 PM by Jasonb »

Online Kim

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #384 on: March 11, 2018, 02:10:51 PM »
Yes Rich, its definitely starting to look very much like an engine!  :ThumbsUp:

Kim

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #385 on: March 11, 2018, 06:03:41 PM »
Hi

You are quite right Jason  :ThumbsUp:

It looks like I have misread the plans :facepalm: :embarassed: :wallbang:

I will have to remount the cylinders and drill some more holes

Cheers

Rich

Offline NickG

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #386 on: March 11, 2018, 08:08:49 PM »
Ah, it all becomes clear!


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Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #387 on: March 12, 2018, 07:54:15 PM »
Hi

Now then my learned friends, we have to get out of this predicament. :thinking:

By my calculations  :atcomputer: there are two passages each end of 3/16" x 1/8". The original plans call for two 1/8" overlapping holes to give the 3/16" x 1/8". So the total passage area (each end) is 3/8" x 1/8". As I have not drilled the overlapping holes but drilled them side by side I already have a passage area of 1/4" x 1/8".

So my question is can I get away with just drilling one more 1/8" hole which will give me the 3/8" x 1/8"

Cheers

Rich

Offline Jasonb

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #388 on: March 12, 2018, 08:08:21 PM »
You need to remember that the passages have rounded corners and are not simple 1/8" x 3/16" rectangles.

Area of passages as drawn is approx 0.04 sq in

Your two 1/8" holes have an area of 0.024sq in, 3 would be 0.036sq in

So still a bit low, what about adding a third hole but making all 3 say 3.3mm dia which would give just a smidge under the .04

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #389 on: March 12, 2018, 08:26:06 PM »
Hi Jason

Not sure that I fancy sticking a bigger drill down the already drilled holes.  :thinking:

Would it be better to go for 4 holes ?

Cheers

Rich


 

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