Member postings for David Haynes

Is there any reason why brass should not be used for smokebox door hinge straps? Some materials must not be used, such as aluminium, as the heat might affect it, but what do others prefer?

I want to solder firebox side stays but don't want to damage the existing solder on the tube ends less than 1/2" away. I had thought of using a bit of squashed down soldering blanket but wondered what other folks use.

Thanks,

Dave

hi Julian,

Thanks for that. I have made a 2 part wet header, with the front part that is fixed to the superheater tail bolted to the rear part which is in turn soldered to the smokebox tubeplate. So it is possible to take the superheater completely out of the smokebox, in a theory making a screwed connection possible. In the end, I have gone for a soldered joint for the superheater tail.

Thanks for the comment anyway!

Dave

Hi folks,

If you have a 3/16" OD copper superheater tail going into the wet header, has anyone used a threaded join rather than the often specified soldered join, in order to facilitate easier superheater removal?

Thanks,

Dave

I have a Sieg X3 and wondered how often people take off the top cover and lubricate the gear train from the motor to spindle. Also, with what - I initially used the type of grease recommended by Sieg.

Hi All,

Well, I now have 3/8" OD tubes with .035 wall thickness, so that must be an improvement on .045" or .055".

I think...

There is also of course the 'rule' mentioned by Martin Evans in 'The Model Steam Engine' :-

'Examination of the most successful boilers shows that length of the tubes (between tube and smokebox tubeplate) divided by the square of the internal diameter works out between 50 and 70.  Similarily, it has been found that most successful model locomotive boilers seem to follow the same rule.

… the following formula can be recommended:-  d= sqrt(L/65)' [I shall call this Tube Index]

For my tiny boiler, the 17 SWG tubes (ID .263" gave a tube index of 65, whilst the thinner 20 SWG tubes (ID .319) gave a tube index of 49.  This is even lower for 22 and 24 SWG.

I have thought about how long the hot gases are in such short tubes and knew about the comments about how little the tubes contribute.  This had to balanced against the above relationship between ID and length, with the wall thickness brought it as well.  It also seemed interesting to bet more tubes in.  On balance, I felt the thinner tube seemed the way forward, after all, it may be academic, making very little difference anyway. 

All the best,

Dave

Edited By David Haynes on 06/05/2015 08:31:19

Hi Folks,

What is the effect of boiler tube thickness on steaming properties? If you have a 3/8" dia tube with 0.055" wall thickness, the heat will be a little slower getting across to the water than if you have 0.045" thick tube walls. However, I think the effect must be negligible and as most of the heat transfer is in the firebox, this makes the difference even more negligible.

What are your thoughts on this?

A bit more on this. Presumably if there is an injector feed, as this is warmer, then it is not as much an issue as other feeds; and the height will be so that the top nut is accessible without taking the cab floor up.

On the theme of backhead bushes, what is the preference for blow down bushes? The height will be just above the foundation ring, but cross-wise, do you prefer in the middle or at one side?

All the best,

Dave

What is the basis behind the advice not to have cold feed to a boiler at the backhead? I have my own idea but would be interested in the wider forum.

Dave

Thanks Julian,

Jason, I have corrected the small error - it looks better now.

Dave

Thanks Jason,

I has wondered about reducing the step on the bush to only 1/32". However, as this step is only to act as a register for concentricity and give a greater solder contact area, and not resist pressure, that should not be a problem.

Dave

Edited By David Haynes on 26/03/2015 22:37:02

Hi Folks,

I have asked this question elsewhere but am now able to also post images here to go with the query.

I would like to add bushes to an LBSC 'unbushed' backhead but on the regulator I am a little tight for space. I propose to replace the original 9/16" dia clearance hole with a 3/4" dia hole for a 7/8" dia bush. Whilst this is an improvement on screwing straight into the 13g backhead, it does means that the fixing screws threads are partly in the bush and partly in the backhead.

Thoughts please...

Edited By David Haynes on 26/03/2015 20:19:20

Do a search for alum - it dissolves ferrous but leaves non-ferrous alone, just a little cleaning up after.

Hi Pete,

Good to see someone wanting to start a Tich. Despite the various mixed comments it has sometimes received, covered in this forum and elsewhere, it is a very workable option for many. If you want to get to grips with the valve gear of Tich, without going in the workshop, have a look at the late Charlie Dockstader's valve gear simulations. You have to build your own with his software, but it is fairly straightforward. It is nice to see a valve gear actually running without even getting your hands dirty; although, that will be the ultimate destination I am sure! His simulations are discussed on this forum if you do a search, but you will find it here as well.

Dave

Hi Folks,

Firstly, I am sorry if you have seen my request elsewhere.

Can anyone give any images and specifications for lagging and cleading stationary boilers. I have a 3 1/2" boiler running a Stuart horizontal and an unidentified vertical engine, but there is a lot of heat being lost from the bare boiler. I am interested in ending up with a timber barrel segment exterior and expect that there will be an insulation layer between the boiler outer and wood.
Your suggestions and images would be appreciated.

Many thanks,
Dave

Hi Stephen,

If you are able to look at the Christmas edition of EIM, besides reading about some lucky people who built a portable 5" track on a frozen lake and steamed on it,, Don Ashton has given a bit of a refresher on valve gear.

Also, Curly's Belpaire Tich is pictured in the 'Simple...' Tich construction book with outside Stephenson's valve gear.

Best wishes,

Dave

Hi all,

Do you know about the 3rd Tich boiler? A Belpaire which has a 9% larger grate than the large boiler, but not as simple a build as the other two.

Dave

A lathe with a vertical slide is an approximation of a milling machine but may not be as rigid a set up as a milling machine. The vertical slide introduces another element into the path of fixing the work piece to the machine bed. As many more experienced people here than me will tell you, if you have a high degree of confidence in the accuracy of your lathe operation and vertical slide and take things slowly, it will be fine. A poor milling machine set up could be the worse option. Also, it is not recommended to use ordinary 3 jaw chucks for holding milling cutters, they can screw out during use and the chucks are not designed for lateral milling forces. I personally find I have more control and precision for some jobs with the mill.

Dave

Graham,

Take great care with the ports however you do them, I did mine on a vertical slide in the lathe and was not satisfied with the result, I wish I had the milling machine I have now when I did them. You might find when drilling any 'small delicate/critical hole' that if you start one or even two drill sizes down and gradually work up to size, this can give some chance to recover a mistake. Despite this and what seems like a high amount of errors in my Tich construction, along with my own doubts and expecting it to fail, the chassis happily burst into life with about 20 PSI. A tribute to the robustness of Walchaerts' valve gear and the LBSC design. On the subject of exposed rivet heads in buffer beams, it has been discussed here or elsewhere; they look nice but are a pain to paint and in prototypical practice, many are hidded anyway!

Dave

How much bother is it to put the digital subscription MEs into the format for a NOOK reader?