CONWAY 0-4-0 3 1/2" GAUGE LOCO

[Firebird]

Hi

Thanks Carl 

I forgot to show the table locking device

Looking around my stock of phospher bronze I found what I think is a brake shoe. I must have picked it up at a steam fair for a few pence but it would yield the die blocks.

Screw it to the table

Move the mill table over the required amount and machine the inside face

There is enough material for three die blocks. Drilla nd ream the 5/32" holes

Move the mill table again and machine the outer face

Cut out the three die blocks and finish to size

Cheers

Rich

[crueby]

That worked great! Gotta love ingenuity!   

[Firebird]

Hi

Thanks Chris 

The expansion links are machined in a similar way. Print out and stick a template to a piece of 1/4"  X  1 1/4" gauge plate. Drill 3 holes. 2 are part of the link the 3rd is in the waste area

Cut the first link off the bar and use as a drill guide to drill the second piece. Screw them to the rotary table as a pair. Machine the slot first then the outer profile.

After machining

Testing with a die block. The die block hasn't been finished to size yet

Cheers

Rich

[Firebird]

Hi

The brackets are machined from 1/2" square BMS

Profiling

Not exactly the shape on the plans but they can't be seen and this isn't a show standard engine

The studs I made as one shaft, pushed through with a bit of loctite in the bracket then the centre part hacksawed out. The links are drilled and tapped M3 and the brackets drilled 3mm

Cheers

Rich

[Firebird]

Hi

Moving onto the crossheads.

Once again gun metal castings are available but at nearly £40.00 its worth making them. I am using cast iron because I have a bit. Cast iron and the steel of the slide bars are a good combination of materials.

Firts job is to machine the block of cast iron to size

Then each side has a 5/16" wide slot machined

Testing with a bit of 5/16" square. Aiming to get a good fit

My usual method of printing out exact size and gluing to the work piece

In the mill and machine away some of the waste. I have enhanced some of the print out with a marker pen

Cheers

Rich

[b.lindsey]

I have missed a few posts Rich, but the progress is amazing and as has been said, the photos are excellent as usual.

Bill

[Firebird]

Hi

thanks Bill 

The two cross heads are seperated and some more material machined away

Then the slot

Drill and ream

Then open out one side and countersink

Cheers

Rich

[Firebird]

Hi

A bit of experimental work. The gudgeon pin looks like a right tricky little so and so.

Start with some 1/4" silver steel and drill

Machine the end

Part off

Turn round and countersink

These 2 are M5 and 2 BA. The M 5 might be too big on the head. I am going to try M4 next to see which is the best fit.

Cheers

Rich

[zeeprogrammer]

Nicely done.

I know it would be tricky for me. What made it tricky for you?

[Firebird]

Hi

Carl, I just don't get on too well with really small parts. I doubt I could get a good enough finish on the shank part of the gudgeon pin. Using a bit of silver steel that is already finished to a high degree seemed a better option.

I'm not going to do any more to the crossheads for now. Some more fettling will be required to get the con rods to fit nicely so without further ado lets get on with the con rods.

I bought the con rods as laser cut parts. At £8.46 each its not bad. To make them myself I would still have to buy the material.

Here they are

A quick measure up first. there is not a lot to spare. The big end needing only 6 thou off each side. It was then I noticed they are not straight.

I am assuming the heat generated by the laser cutting must have warped them. So a bit of gentle persuasion in the press  was called for

Set up in the mill using the DRO to accurately drill the holes

Drill the holes

A  bit of scrap something or other to make a jig

2 short pins are drilled 6mm so that the studs and T bolts fit through. Extra clamps that can be moved around as nec

Machine the big end

Change the clamps around, machine the con rod then the small end

Machine the big ends as a pair. drill for the oil hole

Some more filing will be required to clean them up. I have drilled the small end 3/8" because I have some ball bearings that size. I might still go with the bronze bushes for now. If they wear quickly I will change them for bearings

Cheers

Rich

[Firebird]

Hi

The con rods are given a polish up

The coupling links are similar to the con rods but slightly shortly

Measuring them I found they are .230 thick which is under the 1/4" on the plans. Thats not even 6mm. Its not a problem as the bushes are the critical width. I have decided not to machine the width but leave them flat.

After machining and polishing which is similar to the con rods I gave them all a dip in the zinc plating kit

After plating

Bushes for the con rods are straight forward turning jobs

In the text it says not to make and fit the coupling rod bushes until after the wheels have been quartered so I'll leave them for now.

The intermediate valve rod cross heads are machined as per the plans

Cheers

Rich

[Firebird]

Hi

Some more bits

The weigh shaft bearings, a simple turning and drilling job

The plans show them as lozenge shaped, I assume castings are available.

They fit here

They can't be seen so I am not going to spend time machining them to shape as per the plans.

The valve spindle couplings are also fairly straight forward and are machined as per the plans except I am tapping one side M5

Start by preparing a couple of bits of steel to size

Drill and tap

Then machine out the corner and profile

Cheers

Rich

[Firebird]

Hi

The reversing lever and stand has some small fiddly bits so I'll show a bit of the detail

Starting with a couple of bits of 1/8" steel plate drilled as per the plans

A couple of washers on each bolt as spacers

My home made rotary table being centred and squared under the quill

Move the table over 3 1/4" and position and mount the stand

Machine the outer then the inner radius

Machine the outer faces to size

The stand fits here

The reversing lever starts as a piece of 3/8"  X  1/8" steel flat bar. I used the DRO to accurately drill the holes

Roughly shape the handle leaving oversize

You can see on the plans that the handle is 3/16" at the top but the steel is only 1/8" thick.

Heat up then hammer until its 3/16" thick

Square up in the mill with extra support from an angle plate and centre drill

In the 4 jaw and centre with a Dti

Turn the top slide a few degrees and carefully turn using a tail stock centre to support

Turn a couple of spacers 1/8" thick

The trigger starts as a bit of steel in the mill and carefully shape

Drill 2 holes

Cut off and file to shape

A 1/8" slot is milled across the bottom, sorry no photo I forgot 

Thats it so far

Cheers

Rich

[zeeprogrammer]

Nice job on that handle. It wouldn't have occurred to me (lack of experience) to heat and hammer to make it thicker. Nice. 

[Firebird]

Hi

Thanks Carl

Some good news today. I took the boiler to our club and had the initial hydraulic test done. This is carried out at twice working pressure 160psi. I 'm happy to say it passed 

A major milestone reached and passed 

Cheers

Rich