Member postings for Paul Kemp

Ian,

First off, congratulations on having got this far, this is a great thread, really enjoyed reading.

Did you gap your rings? By that I mean set into the bore (off the piston) and measure the gap between the ends of the ring? At a very rough estimate you should be looking for 0.006” to 0.010” gap.

it is not unusual for new rings in a new bore to be a bit stiff, as an example on the full size Avelling tractor I put together it was all I could do to pull the piston through the bore but after a few minutes running when we finally steamed it, it freed up in the first run. Similarly my half size traction engine cylinder is tight but it moves easily on 10 psi air pressure. It has not been erected onto the engine yet only blown back and forth by manually moving the slide valve spindle but even in the few movements it has done on the bench it has got a lot freer than when first assembled.

So in short, if you know you have a gap in the rings and can get plenty of oil in, I wouldn’t worry too much. Just a point on the oil, I wouldn’t use 3in1 if you can’t lay your hands on some 460 bearing oil or 680 steam oil at the very least use motor oil. I can’t remember if you have made provision for a lubricator? A displacement lubricator on the steam inlet to the valve chest would be a good accessory

Paul.

There was intent by the “feds” to produce a UK construction code to compliment the test code some years back but that all fell by the wayside, they had some stuff on copper boilers but steel seemed to fall in the all too difficult box so it never ended up getting published.

Paul.

Safire silicon bronze rods were originally coloured blue on the end, any evidence of colour code on them? The other option is silver braze if sb is relevant, as far as I know they had no colour code. Former melts about 875 deg c latter about 740 deg c if that helps.

Paul.

Well if the media are to be believed many are voting with their wallets and buying second hand cars now, as reportedly prices are going up. Is this a reaction to the deadline for new fossil fuel cars in 9 years time?

My poor old Discovery with the towing capacity I need is getting poorly, not sure what to do, certainly can't afford a new electric even if there were somewhere to charge it so not sure which way to jump!

Paul.

Ok, I see how the figures Sam B1 is quoting could stack up on efficiency but running cost is another perspective that is probably more important to the average householder than efficiency. On the efficiency question the figure Sam quoted for generation efficiency is a little lower than my off the cuff guess but the transmission loss a little higher so ball park around what I was expecting.

In terms of cost the latest averages I can find for September despite the gas price rises put electricity per kWh at around 4.3 times the cost of gas. I also did a bit of digging on heat pump COP and it would seem that yes a COP of 4 or higher is achievable in ideal conditions but the norm is between 2.5 and 3.5 - so considering the high capital cost plus the higher running cost only the most dedicated of greens would be attracted.

In Dave's (SOD) example of heating use a heat pump system considering its apparent average limit of 40 degrees C on the hot side he would need to be running it considerably longer to get the same heating rise in the house?

Seems another example of the gap between environmental sustainability and economic sustainability to me. Granted price differentials may change between energy sources and legislation may drive change but if it's the latter there will be a lot of people driven below the poverty line.

Paul.

Have you any credible figures to back that up? Granted CCGT is pretty efficient but taking into account grid losses and then whatever the efficiency of a heat pump is compared to the efficiency of a new condensing boiler that sounds a bold claim?

Paul.

Before relying on vaccines to protect you from catching Covid consider the following;

Vaccines give some level of resistance to infection, more importantly they offer protection from severe disease that may require hospitalisation or indeed mortality.

In some cases they can increase the chances of a very mild infection such there are no symptoms - this does not mean you cannot pass it on if so infected!

Vacination is a good idea to protect yourself from severe illness and potentially increase your immunity such that your chances of catching it are reduced. Being with another person that has been vaccinated is no gaurantee they are not infected, carrying or capable of passing on to you, in fact in some instances it can increase the risk they may be infected and niether of you know!

Paul.

Hmmm I think you may have mentioned that ........ Once or twice. Ever the diplomat?

Paul.

No idea on that particular machine but I swapped the motor and control board on my Chester mini mill for a 3ph motor and cheap VFD for about the same price as a replacement motor. Never looked back it's far better than the original set up, standard motor used to get too hot to touch in about an hour, new set up will run all day. Lower power than yours but the motor came from inverter drive supermarket I think for about £50 and the VFD from a source unmentionable on here for a similar price, probably a death trap and not approved but it's worked fine and I am still alive! Best mod I ever did to it!

Paul.

About the only really good thing I can say about our internet / telephone provider is we get zero nuisance calls. The first time any number calls us it automatically diverts to the screening process where the caller needs to record their name and purpose, it then calls us and asks to accept or reject, if rejected the number is permanantly blocked. It's a bit of a pain for genuine callers to hold while the process goes through but once accepted they can call freely. Since we signed up for this a couple of years back we have had absolutely zero scam or nuisance calls.

in fact it has made life a bit boring as I used to try and see how long I could lead them on and how much they got wound up when they twigged!

Paul.

As stated, shot peening, common in crankshafts, normally at the fillet radius or other areas of high stress reversal. Idea is to introduce a compressive stress into the surface such that as stress becomes tensile the tensile magnitude is limited. Helps prevent fatigue cracks propogating in the surface of the material. Very important on cranks this process has been used on that the important areas like fillet radius are not machined when undersizing the journal or the benefit is lost.

Paul.

With respect it was a genuine question. However you want to 'play' with fits of the curve the data sets themselves still show a significant trough around 1910 and a significant peak around 1942. You could manipulate the curve according to the data for the trough to be a little deeper and the peak to be a little higher but it's fine as presented, it still shows a larger short term variation than the period of reasonably steady increase say 1962 (ish) to present? Given the efforts to eradicate CFC's over the last 10-20 years coupled with efforts to reduce CO2 certainly over the last 10 years there is no real hesitation in the rate of rise. Hence my question.

Paul.

Whatever was going on between about 1898 and 1910 we need to do more of? What caused the peak around 1942? What happened pre 1880?

Paul.

Just do what the big boys do and use rag or wear leather gloves! Aside from that and following full size practice also, fit wooded handles.

Paul.

You say there was no hydraulic lock, how can you be sure of this? Have you removed the clack valve to the boiler and checked there is free passage? I have seen several boiler clack valves for pumps "fur" up on the boiler side reducing the area of flow, the worst down to a small hole little bigger than a pin, can be particularly problematic on steel boilers using treatment, especially if you add it to the tender. The reduced area significantly loads the pump. The fact you have effectively 2 failures simultaneously (pin and rod) suggests to me there is something else going on. You suggest the rod failure is about half inch from the weld - that suggests it the point of failure is well on the edge of any HAZ. Lastly if your engine has isolation valves at the boiler for the clack I have seen some clowns close these valves when the driver isn't looking! That never goes well if the bypass is closed, I know many people who keep the handles in the tool box to prevent bystanders "fiddling" with them!

Paul.

As ever there seems more behind this story than meets the eye at first glance. Most news articles are blaming this on record high gas prices with little explanation of the reasons for the high prices beyond increased demand due to emerging from the pandemic. However if you dig deeper there is a lot more to it. Gas reserves (gas in storage waiting to be used) are at a low, below 2018 levels, the figures don't show a drastic drop since restrictions have released / enconomy has recovered. But neither do they show a significant increase during the peak pandemic period which suggests there was little down turn in demand either. The lack of decreasing demand may be linked to lower than normal wind speeds across Europe leading to greater use of gas in electricity generation. Apparently reserves are low due to reduced export of gas from Norway and Russia (plus some allegations Russia is holding back supplies!). Norway and Russia combined, supply around 40% of European gas consumed. Previously in the UK and Europe when gas prices were high electricity was generated by coal powered stations - we all know where that has gone - few resources left and reliant now on imported fuel.

This article is the latest (August 21) I found with future predictions tells an interesting story.

https://www.worldoil.com/news/2021/8/6/natural-gas-prices-surge-as-energy-transition-driven-demand-outstrips-supply

For those unwilling or unable to follow the link a very broad executive summary is that gas has been seen as a transition fuel to zero emissions as dirtier fuels are being phased out however not being exactly clean itself there has been unwillingness globally to invest in new projects to increase the supply to meet the demand.

There is some irony here that the drive to green has produced a bonanza for the gas market with other technology lagging in implementation and capacity. The demand for gas is set to continue increasing and in Asia demand due to outstrip supply so the price issue isn't going to change any time soon! With increasing drive to electricity but without an exponential expansion in renewables to support, electricity prices are set to follow the current trend especially considering the steady increase in demand for electricity from ev's and similar initiatives (no gas boilers in new houses). Green hydrogen is no silver bullet either because a 20MW electrolysed only produces 3000t a year and there are not many of those plugged in right now.

Dont expect your bills to drop any time soon! The really odd thing in all this is CO2 is one of the pollutants we are striving to eliminate but is so widely used in the supply chain it is set to become more expensive - unintended consequences?

Paul.

Thanks Andrew, I tried at 06.00 this morning and it wouldn't load, still the same tonight. Hopefully it's not terminal!

Paul.

Anyone else having trouble logging in to TT today? Seems to have disappeared?

Paul.

OP said he had a collet chuck, if that marks the smaller diameter it's not much cop. If the large diameter has run out when held in a collet either the collets are rubbish or the small and large diameters are not concentric anyway?

Paul.

I must be missing something? Assuming the 3 jaw or collet on the lathe runs reasonably true if you hold it on the castellated spigot I don't see why there is significant run out? As the large boss to be machined down is also oversize I would just hold it on the small spigot and machine the rest, then it must be true to the small spigot. There are many instances where large diameter parts especially castings are machined by holding on small chucking spigots so I don't see a problem. If you are worried take light cuts. If you really want belt and braces put a small centre drilling in the face, reduce the large part leaving a small projection with the centre in and last op remove the tailstock and machine off the small remaining spigot. I think you may be overthinking / worrying too much. If it helps the casting (cast iron) for the smokebox door on my traction engine which is 11" diameter was machined holding it on the 1 1/4" chucking spigot with no drama!

Paul.