Author Topic: CONWAY 0-4-0 3 1/2" GAUGE LOCO  (Read 42902 times)

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #345 on: February 17, 2018, 07:28:07 PM »
Hi

The ornamental ring is the bit that joins the smoke box to the front of the boiler



I had a bit of bronze in the scrap box, probably picked up at a steam fair for a few pounds, that will do. Its a straight forward turning job



Then part off



Enough spare material to make another one




A nice fit



Cheers

Rich


Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #346 on: February 17, 2018, 08:00:29 PM »
Hi

The cylinders are going to be a bit of a challenge.  :thinking: :headscratch:

They are available as castings but come at a hefty price, £323.28  :ShakeHead:

They are also gunmetal which is not as long lasting as cast iron. Ok if you are only using the engine occasionally but I expect this engine to do a lot of work so cast iron would be better.

I picked up a couple of pieces of cast iron at a model engineering exhibition for about £60.00 so I am going to have a go at hacking them out of the solid. Here they are with the wood practice piece



To save a lot of wasted material I am going to omit the the stub shown here which is the steam exhaust outlet. I intend to either drill and tap the cylinder for a screw in connector or maybe make a flanged fitting. I'll worry about that later



First job is to bring the block of cast iron to size



Its quite a lump





I would like to offer you all a piece of advice

Cast iron is a lovely material to machine but it doe's have one small problem.

Its a very dirty material



So when the wife shouts quick its raining help me get the washing in either very quickly put on some rubber gloves or pretend you didn't hear her :shrug:

Whatever you do don't grab her best white top :ShakeHead: :slap: :Argue: or you will be in the  :toilet_claw:

Cheers

Rich

Offline mal webber

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #347 on: February 17, 2018, 08:23:05 PM »
Hi, just had a read through on this build did not think I was into locos but really enjoying following along, very nice work  :ThumbsUp:


Mal.

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #348 on: February 24, 2018, 08:22:08 PM »
Hi

Thanks Mal  :ThumbsUp:

The cylinders need to be bored to 1 3/16". I have never done anything like this before so its going to be a bit of a steep learning curve.

From what I can see boring the cylinder with a between centres boring bar and the cylinder mounted to the cross slide is the best way.

So I am going to need a between centres boring bar. After a bit of research I settled on a design by G H Thomas

I had a bit of steel bar 13" long that would do although at 30mm diameter a bit too thick.

To start I mounted it in the lathe 3 jaw chuck and fixed steady and centre drilled



The largest drill I have is 25mm so I turned the end of the bar down to a little under the 25mm



Then turned the bar round and centre drilled the other end

Turn a soft centre to 60° and number stamp the position of number one jaw





The bar can now be held between centres with a dog at the chuck end. The dog is driven by one of the chuck jaws



The bar is turned down to a little under the 25mm



I used the powered leadscrew on my lathe, much easier than winding by hand,.

A bit of video


In the mill the bar is cross drilled 3/16" to take the cutter and a flat machined across



Then drilled and tapped to take an M6 grub screw



There is quite a lot of info on what shape to grind the cutter to. A while back I made some tangential cutters that use round tool steel and have got on really well with them. A very good finish can be achieved both turning and facing so I opted to use the same. I have a little jig I made for sharpening the tool steel





An accurate method of setting the cutter would be an advantage. I started with a piece of ally and cut it into this shape



Then with a series of drills upto the 25mm drilled the hole





The adjusting screw is brass screw cut 40 TPI. which means 1 turn is .025". Turned down 1 end to just under 3/16". A piece of 1 1/4" round brass is drilled and tapped 40TPI. the 2 pieces screwed together and silver soldered



The ally is drilled and tapped 40 TPI through the top and drilled and tapped M6 underneath for a clamping screw



I was trying to figure out how to mark 25 divisions on the adjusting screw so drew it out on the computer



Then a flash of inspiration, print it out on photo paper and stick it on



Thats the boring bar completed which took most of yesterday to make.

Today I set it all up in the lathe and gave it a go

I'll post the results in the next installment

Cheers

Rich


Online crueby

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #349 on: February 24, 2018, 08:32:42 PM »
That boring bar is quite an impressive setup.

Never having used one, makes me wonder what the advantage of that bar over using a boring head on the mill for your cylinders? Is it a question of how deep a hole you can do, or quality of the finished result that makes the between-centers approach a better fit?

Looking forward to seeing this in action!

Chris

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #350 on: February 24, 2018, 09:00:44 PM »
Hi Chris

The cylinder is 3 5/8" long at the moment. I have a boring head which I can use on the mill and in the lathe but I doubt I could get a concentric hole. There would be too much flex in the tool.

Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #351 on: February 24, 2018, 09:21:03 PM »
Hi

I made a guage to 1 3/16" that will sit on the boring bar so I can check the bore without removing the tool





I set the block up in the mill and using the DRO located the front left corner



Then centre drilled the position of the centre of the bore



The vertical slide mounted on the cross slide and checked for square



The block mounted to the vertical slide. A piece of 3/8" flat bar (the width of the T slots) in the bottom slot for the block to sit on. 4  M8 studs and a steel plate hold it securely to the vertical slide. The centre drill in the block was lined up with a centre in the lathe mandrel by moving the cross slide and vertical slide then both were locked in position.

Starting with a long M5 drill



Then increasing drill sizes until I got upto the 25mm







Then change to boring bar



A bit of video


Until the guage fits










That was very satisfying  :cartwheel: :whoohoo:

Cheers

Rich


Offline Barneydog

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #352 on: February 28, 2018, 09:34:49 AM »
Saw this block of cast last night. Very impressive.....looks a good job.


Julian

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #353 on: March 02, 2018, 10:11:37 AM »
Hi

Thanks Julian, a bit of encouragement is always welcome  :ThumbsUp:

Both cylinder blocks machined to size and bored






Cheers

Rich


Offline Roger B

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #354 on: March 02, 2018, 03:43:40 PM »
Excellent  :praise2:  How were you holding the big drill in the tailstock when you were drilling the 1 3/16 ring gauge, some form of collet?
Best regards

Roger

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #355 on: March 02, 2018, 06:09:20 PM »
Hi Roger

I held it in a 1/2" collet with a draw bar

Cheers

Rich

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #356 on: March 03, 2018, 06:55:48 PM »
Hi

There is a lot of machining still to do on the cylinders starting with the valve face side. Machining the square that fits through the frames







The cylinder is 3 5/8" long at the moment which includes the mounting flanges. I need to reduce the cylinder length to 3". To start I need a mandrel. I need the mandrel to be as secure and solid as possible. The bore through my 3 jaw chuck is 1" so one end of an ally bar is turned to a good 1" finish



Then reversed in the chuck and cut to length





The bar is machined down to a perfect 1 3/16"





Drill the end of the bar 5mm and countersink. Then part off about 3/8" to make a thick washer. Drill the washer 6mm and tap the bar M6. Turn a small shoulder on the bar and fit a 1 3/16" O ring







Slip the cylinder onto the mandrel and tighten the countersunk cap head which expands the O ring and holds the cylinder securely





My bodged up DRO for saddle. It was one of those temporary jobs 10 years ago but it works



The turning will be done with a boring bar



Some very careful measuring is required to reduce the cylinder portion to 3" in length. Equal amounts have to be removed from each end







Each end is machined out to 1 1/4" for a depth of 1/8" to provide a register for the covers

Cheers

Rich






« Last Edit: March 03, 2018, 07:00:04 PM by Firebird »

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #357 on: March 03, 2018, 08:11:59 PM »
Hi

A bit of video


Cheers

Rich

Offline Steamer5

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #358 on: March 03, 2018, 08:17:04 PM »
Hi Rich,
 That’s some pretty nice work on the cylinders! Love the boring bar, will be using that idea!

Cheers Kerrin
Get excited and make something!

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #359 on: March 03, 2018, 08:28:57 PM »
Hi

Thanks Kerrin  :ThumbsUp:

The leftover noggins in the corners are machined off in the mill and the mounting flanges machined down to 3/16"
I have a powered X axis on my mill which makes the job easy


After machining each end the cylinders are held at 45° and have the corners machined







And finally today the flanges each have 3 4mm holes drilled



Cheers

Rich