Member postings for Andrew Tinsley

Just had a panic call from a friend. He has broken a 6mm HSS tap in a brass terminal which is connected to a VERY expensive capacitor! The hole is blind and tapped I think a BSF thread. He is a metric person so decided to tap the hole 6mm. Bang first tap broke. Then to show what an idiot he is, he does exactly the same on a second capacitor Aagh!!!!!!!!!!!!!!!!!!!!!

I seem to remember that hydrochloric acid can be used, sufficient to loosen the tap. I also remember that alum can be used. I have seen the acid treatment work , in fact done it myself years ago. But I can't remember if it was hydrochloric or some other acid?

Failing the above maybe a carbide drill might be the modern recommended way of doing things?

Anyway HELP he is up against some serious time constraints and needs the capacitors urgently!

Andrew.

I originally came from the Black Country and have never heard that expression before. If it were a common word, I certainly would have!

Andrew.

I have a couple of these, that don't work. I have stripped them down and it is the Nylon / ptfe "piston" that has failed. This is simply a piece of round bar material partially bored through and a suitable hole for the retaining bolt. The other end has a slight flair to produce the seal.

Now I can replicate the Nylon / ptfe arrangement. But as all these jacks seem to fail in this mode. I wondered if a metal piston and maybe a couple of good quality O rings might be a better bet. Or whatever the hydraulic people use for seals. I don't know much about that side of things.

Now I suspect that most people would simply bin them.However having got them apart I might as well effect a safe repair, whatever that may be. Any suggestions, including binning them?

Andrew.

A green wheel will not give a good enough finish for a really good surface, you will need to hone the cutting edges to get rid of the grinding marks.

Andrew.

It isn't only metals that were made in stars anything above hydrogen helium and lithium in the periodic table) were made in stars that eventually exploded.

The big bang supposedly created the above 3 elements. But that theory (Bbg bang) has had to be propped up by so many ad hoc props that I believe it to be highly suspect.

Andrew.

Well said Duncan! Use green energy when available, but the base load has to be either gas or nuclear, unless all these greens want the lights to go out at inconvenient times!

Andrew.

Well said Duncan! Use green energy when available, but the base load has to be either gas or nuclear, unless all these greens want the lights to go out at inconvenient times!

Andrew.

Renewables are not going to replace conventional or nuclear sources. Until we learn to do without a significant amount of power, that we currently use, then conventional and nuclear will still be required. All these electric cars will once again place a huge strain on generating resources.

When the lights start going out, then people will stop complaining about nuclear and conventional generation. That is the way of people!

Andrew

Ah! But nuclear keeps generating even when the wind drops! Something these clever renewable people conveniently forget.

Andrew,

You would be better off drilling and tapping a hole in the shaft and using a screw, rather than use plastic or brass. If this is for fixing a pulley onto a motor, then definitely not plastic.

If you cannot broach a slot in the shaft, then file one! With a little care, it is feasible to get a good fit. Good practice at filing too!

Andrew.

My choice is the chuck guard interlock. I have had this go open circuit, twice on a friends lathe.

Andrew.

Good idea John, now why didn't I think of that!

Andrew.

Thanks Mark,

The first link gives what looks like a slightly modernised version of my Rabone, at 3.5 thou per foot, I think that will do me.

Thanks,

Andrew.

Thanks Mark,

The first link gives what looks like a slightly modernised version of my Rabone, at 3.5 thou per foot, I think that will do me.

Thanks,

Andrew.

Hello Clive,

Thanks for your input. I have indeed checked it end for end and it is accurate in that respect. I was feeling quite good about it until your last sentence "Never trust a bubble"!

So is it accurate enough for the job in hand? Or should I get a clinometer? Interesting that you mention "Speed" I think I understand what you mean by that. However I have seen some Engineers levels that do give an accuracy of so many thou per unit length, or does my memory fail me yet again?!

Mark,

Thanks for your encouraging post. After I had levelled the bed and setup the tailstock, accuracy improved a goodly amount!

Andrew.

I have a Rabone 12" Engineers level, which I believe was carried over to Rabone and Chesterman era.

There is no identifying number on it, apart from the Makers name, it is utterly without any information. Usually such a well made level would have its accuracy marked somewhere on it, but not with this one!

So what would its accuracy be? I have used it to check and adjust for zero twist in a Myford lathe bed. I am now wondering if it is good enough for this purpose? Or should I purchase a clinometer for such jobs?

Andrew.

Thanks Sam,

Your information is extremely interesting! I never knew about the grade of copper pipe that came in coils. Looks like a good solution!

Anthony,

My friend has been building Teslas for about 10 years. he is very familiar with the big coils in the US, but that wasn't the reason he started building. I think he got fed up with his Wimshurst machine and wanted something more spectacular.

I suspect the coil in the video is probably the largest in Europe. It operates at a 100 BPS (breaks per second) and uses a rotary spark gap to do the switching. The toroid is really too small hence the need for a 5ft replacement. With that, it should be even more spectacular and the larger diameter would help to make strikes on the machine base less likely. As it is the device is really very impressive, but the whole set up is really rather too dangerous for my taste!

Andrew.

OK, so what is underground copper and why does it bend more easily?

Andrew.

There are plenty dotted about the countryside, anywhere there is an 11,000 volt distribution line, you will find them on the poles feeding maybe a farm or an isolated house!

Seriously they are much rarer than hens teeth in captivity. This one came off Ebay, so at least we didn't pinch it!

Andrew.

Thanks Duncan,

It is indeed the dying throws of the Tesla. I didn't realise that you had to copy and paste a U tube link. You live and learn!

I think we could get away with a three penny bit type of shape. If you look at the "toroid" on the video, it is made up of what we think are some form of air ducting components , That one cost my pal £400 about three years ago from a guy in Switzerland. He said he would not make a crate for it to be transported to UK, so a Polish guy did a round trip (via Poland!) to pick it up with car and trailer and that was another £400. Glad I am not paying for my friends Tesla hobby!

As a matter of interest we were using an 11,000 volt pole transformer. Feeding the 240 volt "secondary" with 260 volt AC (via a huge variac), The Tesla was pulling about 50 amps on the 260 volt AC input to the pole transformer! The whole thing is bloody lethal! I kept well away I can tell you, having earned my keep as a high energy accelerator physicist, I know how to keep clear of high voltages.

The final few frames show the path of a globule of molten copper, as it was ejected from the beautiful secondary coil that I and my friend wound together!

Andrew.

Edited By Andrew Tinsley on 08/09/2017 21:44:28