Little Wonder

Discussion of Live Steam locomotives should be located here
Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Mon Feb 21, 2022 9:58 am

I have been spending lots of time on K1 recently which explains the lack of activity on this (and 4420). However I have made the frame stretchers for the inner ends of the bogies:
IMG_2119.JPG
Trevor

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Thu Sep 08, 2022 3:20 pm

It has rained here in West Wales for the last few days so I pulled this project onto the bench again.

I have cut out the frames for the boiler cradle, made the stretchers for the cradle and assembled it. I have also put the pivot stretcher onto each bogie, and made the connecting bolts. So here are a few views of the progress:
IMG_2398.JPG
IMG_2397.JPG
IMG_2396.JPG
I suppose that I will have to start on the cylinders if it continues to rain:
IMG_2401.JPG
Trevor

User avatar
Old Man Aaron
Fireman
Fireman
Posts: 499
Joined: Wed Oct 19, 2016 11:08 am
Location: Sunshine Coast QLD, Australia

Re: Little Wonder

Post by Old Man Aaron » Fri Sep 09, 2022 4:09 pm

The only thing equal in this thing's size, is the sheer amount of effort you're putting into it. :salute:
Regards,
Aaron - Scum Class Works

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Sat Sep 10, 2022 9:51 pm

Old Man Aaron wrote: ↑
Fri Sep 09, 2022 4:09 pm
The only thing equal in this thing's size, is the sheer amount of effort you're putting into it. :salute:
Lets hope the end result is worth the effort!

Trevor

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Sat Sep 10, 2022 10:17 pm

I have been squeezing in time to work on the cylinders (which I hadn't intended to start straight away) - carried away again!

So 4 sections of the block of brass have been parted off in the lathe and turned to size, width, length and height. I have marked the centre of the bores, and bored and reamed them all. Here are two of them:
IMG_2404.JPG
I am carrying out each operation on all 4, rather than finishing one and then starting on the next. There is better efficiency in having the machine set up to carry out the operation and having the right tools for doing it to hand, and therefor doing it 4 times.

You might remember from my drawings that the valve face is an extension on the inner face of the cylinder which passes through the frames into the valve chamber. So the first operation was to mill 4.5 mm off that inside face to make the valve face protrude:
IMG_2406.JPG
The end result required the sharp edges removing and the opening in the combined valve chamber/frame needed slight filing to get a good sliding fit. This is the first valve face and the hole it fits into:
IMG_2409.JPG
The bolt heads holding the frame to the valve chest prevent the cylinder fitting right down to the frame at the moment - and I intend to mill out a pocket in the inside face of the cylinder to swallow the bolt head. I am going to do all the milling first - and then concentrate on drilling afterwards. So here are the 4 cylinders sitting as far into place as they will go at the moment:
IMG_2408.JPG
I think it will be milling the bottom of the cylinders to make the flange for the bolts which will hold it to the frame next.

Trevor

User avatar
SimonWood
Trainee Driver
Trainee Driver
Posts: 522
Joined: Tue Apr 07, 2015 9:46 pm
Location: West Wales
Contact:

Re: Little Wonder

Post by SimonWood » Thu Sep 15, 2022 2:19 pm

This is really starting to take shape. The boiler cradle frames look superb.

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Fri Sep 16, 2022 9:36 am

I keep going back to it!

All of the cylinders are now shaped and fitted to the frames. You can see the cutaway around the valve face and the hole in the frame through which it fits on the nearest cylinder:
IMG_2419.JPG
All of the cutouts for the bolt heads are made, and the cylinder is secured to the frame by 4 bolts. From above the bolts fit from the inside:
IMG_2422.JPG
From the bottom they fit from the outside. I had to make cutouts in the bottom of the cylinders to make room for the nut spinner to reach the bolt head:
IMG_2421.JPG
And of course all 4 cylinders are now fitted to the frames.

On to the cylinder end covers, piston and rod next, and then drill all of the holes.

Trevor

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Fri Sep 16, 2022 12:10 pm

Four front cylinder covers, and 4 rear covers:
IMG_2425.JPG
The basic shape turned, then milled and drilled in the rotating table. That ensures that the milled faces are perpendicular and centralised. It also makes it easy to ensure that the mounting holes are all 60 degrees apart (and on the same radius).

And now to work on the cylinders one at a time. The first piston is made and in the foreground of this photo:
IMG_2426.JPG
As an aside I am finding that having a digital readout has made my work much more accurate. For example I was able to turn the piston blank to a diameter of 11.95mm and find it was a smooth fit in the bore first time. I then turned the groove for the O ring to 9.15mm diameter and 2.0mm width (for an O ring 12mm diameter and 1.5mm cord diameter), just using the readout - no trial and error. The piston with its O ring just fits first time with a nice smooth movement.

Really satisfying!

Trevor

User avatar
FWLR
Driver
Driver
Posts: 3736
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Little Wonder

Post by FWLR » Thu Sep 29, 2022 8:30 am

I bet it is satisfying Trevor. Your'e doing an awesome job. :salute:
Digital really does make things easier doesn't it. :thumbright:
Rod

Life is so easy when I run my trains. :thumbright:

πŸš‚πŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒ

https://gardenrails.org/forum/viewtopic ... 41&t=11364

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Sat Oct 01, 2022 10:07 am

FWLR wrote: ↑
Thu Sep 29, 2022 8:30 am
I bet it is satisfying Trevor. Your'e doing an awesome job. :salute:
Digital really does make things easier doesn't it. :thumbright:
Awesome until I made a mistake!

Drilling lots of 1.4mm holes I broke a drill, leaving 6mm of it in the hole.
IMG_2488.JPG
So in the photo the hole in the end of the cylinder - the one that is uppermost has the drill end in it. I couldn't get it out with tweezers or messing with dressmaking pins. So I drilled a hole from the side ( you can see it) to break into the place near the tip of the drill and immersed it into the acid pickling tank. It took 10 days for enough of the steel to corrode away and enable me to tap the hole most of the way to the bottom. There is probably a bit left in it - and a hole in the cylinder side to fill, but the cylinder is recovered and usable.

I have finished drilling all of the holes:
IMG_2494.JPG
IMG_2496.JPG
The fresh looking holes in the top photo are for cylinder drain cocks, and are linked to the ends of the cylinders with 0.9mm holes. In both photos you can see where I have tapped and plugged the ends of the steam ways. There is a plug to make for the exhaust steam way you can see on the face facing the photo in the second photo.

Trevor

Trevor Thompson
Trainee Driver
Trainee Driver
Posts: 703
Joined: Fri Oct 05, 2018 6:30 pm
Location: South West Wales

Re: Little Wonder

Post by Trevor Thompson » Sat Oct 01, 2022 10:17 am

The first cylinder is test assembled, and holding the air line on each valve port makes the piston shoot from one end to the other (as it should):
IMG_2500.JPG
IMG_2498.JPG
I have turned up ptfe rod into seals for the piston rod. 4.5mm OD, reamed 3mm ID, and 2.5mm long. An idea I got from Tony Bird a couple of weeks ago. Worth trying - If it doesn't work for me I can easily go back to ptfe tape wrapped around the shaft.

I am not sure how to tackle the cylinder drain cocks. The automatic ones seem temperamental. The trick seems to minimise the distance the ball has to travel to seal the drain hole - but I'm struggling to get consistent results. They work on Linda but not on K1 (at the moment). Back to that at a later date.

Just 3 more cylinders to finish. I'll be careful with the drill in future.

Trevor

User avatar
FWLR
Driver
Driver
Posts: 3736
Joined: Sat Aug 05, 2017 9:45 am
Location: Preston, Lancashire, UK

Re: Little Wonder

Post by FWLR » Sun Oct 02, 2022 11:10 am

Easily done, breaking a bit in something. I have done it when I worked in the toolroom for the company I worked for many times. It is one of those things, no matter how much coolant I had running on it.

Still you have managed to get resolve the problem, well done. It works a treat now that's the important thing and it's onwards and upwards now. :thumbright:
Rod

Life is so easy when I run my trains. :thumbright:

πŸš‚πŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒπŸšƒ

https://gardenrails.org/forum/viewtopic ... 41&t=11364

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests