Member postings for Half centre

That's quite some pump David - it looks great and it works. I think I have found the plans for it and if my Southworth pumps continue to be uncooperative I will definitely give it a go.

thank you

Martin

Hi Noel - Thanks for your reply, I have heard that as well. I have DRO on the mill otherwise it would be well beyond my experience / ability to tackle. I think the basics must be correct because they go like the clappers on air, very frustrating they don't run on steam.

Hi Jon - Thanks for getting back to me. I fixed the shuttle valves at an early stage in the make, but you are right it is a key source of problems if you are not very careful. As for the clacks I did not follow the drawings, they looked very fiddly and rather delicate? I made ordinary type in line clacks with a Nitrile ball (its a cold water feed so Nitrile is OK). By ordinary I mean the type that have a deep groove in one face and the ball is pressed against it in the on position allowing the water to flow around it, through the groove and out. In the off positing the ball presses against a seating to stop water flow. They seem to work well and I have had no problems (yet!) with transient back flow - might be worth a try? However without a spring and with no pressure to close them they do let water through, but as they connect the water tank to the pump and then a boiler clack the whole feed water line can remain flooded. Hope that all makes some kind of sense?

Martin

Hi Simon - Thank you for getting back to me - I am starting to realise that these things are a bit of a minority sport.

The rings come supplied in the bag of castings so I am not sure what they are made of, I will phone Blackgates. Your suggestion of rings expanding and tightening in the heat is an excellent explanation of why they run on air and not steam. I am sure you are right about their inefficiency. I am treating them as a bit of mechanical bling - an interesting feature rather then a serious water feed. They do look good perched on the front of the Pea (vanity, vanity!)

Its good to know they can potentially work so I will persevere.

thank you

Martin

Just tried it and it worked a treat. Gentle tapping with a small hammer and an aluminium rod as a punch. Careful to move it around the circumference to get an even movement. Found 2 raised pips formed on the inner casing I presume deliberately to create grip. Sanded them a little flatter, grip still adequate but now far easier to separate.

Thanks again Zan

Martin

Thanks Zan - That sounds an excellent idea - I will give it ago.

Martin

Hi folks - I was wondering if anyone had any tips for separating the front and back of small pressure gauges. With the two I have the back slides into the front telescopically. This seems to be a very common fitting. The fit is very tight and I have yet to find an "easy" way to separate the two halves to enable me to mark the red line on the scale.

Any thoughts gratefully received

Martin

Many thanks chaps - I think the best thing is to make a ring, perhaps with nozzles which can be swapped and give it a try. Its not at all difficult to go back to the pipe if there is no obvious improvement. I will start with 1mm holes.

Martin

I have noticed how some locos have a simple blower pipe (mine included), others a blower ring. I was wondering what the advantages and disadvantages of the two systems are? A few random thoughts come to mind.

Pipe is relatively easy to build?

Ring truer to prototype?

Pipe less prone to blockages (wider nozzle)?

Does a ring make more efficient use of steam, do you get more draught from a given steam volume?

Has anyone substituted one for the other, if so why, and was it an ‘improvement’?

Looking forward to the forums thoughts

Martin

Interesting thought about the availability and cost of materials. It was the idea of spreading the load and stopping 'flange drag' the which sparked (my not particularly well thought through!) musings. It is also interesting to ponder how often ideas were implemented (or not) for less than fully logical reasons! Thank you for the ME lead – so off to the club library later in the week.

Martin

Very interesting - thank you all. I was wondering why the Victorians thought it was worthwhile? It does sound rather complex and costly?

Martin

Thank you chaps - makes perfect sense!

Martin

I am going to build a slightly elongated drive trolley, long enough for myself and a couple of passengers (grandchildren!). First thoughts were to build a couple of sprung 4 wheeled bogies and have one at the front, the other at the rear – a conventional arrangement. I then wondered about making 4 x 2 wheeled sprung 'bogies' and distributing them along the length of the trolley. The 2 sketches show the alternatives, the X marks the centres of rotation. I would appreciate any opinions as to the advantages and disadvantages of the 2 designs. I have never seen the distributed arrangement so presumably it has significant problems?

Martin

Hi - I would like to buy your Warco Mini Formit but can't find any contact details.

thanks

Martin

Big enginnering, small engineering - all in one place - terrific!

Martin

Some terrific ideas. Spoilt for choice!

I think I will try the 60 degree cone method and then clamp the part down, Put a button / bar in and clock with my edge finder and DRO - should be interesting.

The hole edge might have a very slight amount of uneven wear on it - but using the cone should get me very quickly into more or less the correct position, the button/ bar should allow me to do any correction needed.

Many thanks folks.

Martin

Hi Folks - I have a 5mm diameter hole in a 10mm thick flat mild steel part.

I Need to drill it out to 7mm. I have DRO on the mill and have often indicated larger holes (for centre finding) using my 4mm edge finder, however on such a small hole the finder virtually fills the hole and it is difficult to tell when it meets the edge as the hole constrains the throw. I am sure someone must know a cunning trick on how to centre small holes?

Martin

Thank you very much George - certainly worth try

Martin

I posted this earlier - I think in the wrong place, so I am trying it here –

I was wondering if anyone had any useful tips when tramming the WM16. After using the DTI and finding the correct head position, when you tightening the 2 head lock nuts it pulls the head around spoiling the setting. I end up trying to compensate for this ‘pull’ by setting the tram over to one side by the amount the head will pull. The whole process can be a little frustrating as it is difficult to guess the amount to offset the tram. It can take quite a few attempts before you get it right.

I made and fitted an extra steady for the left hand side of the head to match the one supplied on the right – this helps a little.

Any ideas gratefully received

Martin