Member postings for Andrew Tinsley

This must be a longshot, but!

Amongst some gear cutters that I have acquired, there are some with no identification on them. Is it possible to work out what DP they are if I can get a good shadow graph magnification of the profile?

They are definitely professionally made and have some coding on them, but nothing that remotely resembles a DP identification.

Regards,

Andrew

Hello Muzzer,

Point taken, I must be more careful about my prefixes!

Andrew.

When I was a teenager, I built a VLF receiver, It peaked at about 20 kHz (sensitivity that is), But it had a very broad bandwidth. I was looking for whistler mode propagation and it worked well for that purpose. However it picked up things I was not expecting. I hooked it up to a super low speed tape recorder so that I could dispense with listening via headphones.

I picked up US and soviet rocket launches (the trail of ionized gas was a perfect VLF signal generator) Similarly I picked up a couple of Russian nuclear atmospheric tests, including the very big "Tsar" bomb. I also picked up the relatively local Rugby GBR signals, I think these morse signals were for nuclear powered submarine communication.

So what has this got to do with meteorite detection in the 100 mHz region? Well I strongly suspect that an ionized meteor trail would radiate in the VLF and would be quite a large if very short signal. No way could it be used directionally, but then you wouldn't have to build a Yagi and point it in the right direction. My non directional ariel was simply a very long piece of insulated wire wound on a very large wooden frame.

Andrew.

Hello Dave,

I would not worry about the effects of String Theory. In 40 odd years of development, it has not predicted a single thing that can be verified experimentally. The inference that any sane person would make, is that the theory is wrong.

However it doesn't cost much to be a physicist who is involved in this folly, hence I suspect its popularity is largely down to needing only a small research grant! The King has no clothes comes to mind.

Andrew.

Jason,

Why on earth bother trying to programme the PID controller to correct the error? I seriously doubt that one could anyway.

10 degrees is 10 degrees error that can be eliminated by using the correct connector, which is in fact cheaper than the specified connector! OK if you are measuring 1000 degrees it doesn't much matter, but if you are measuring a100 degrees it sure as hell does!! Once you have a PID controller, then who knows what you will be controlling in future?

Andrew

Hello Hopper,

Centecs are a nice machine if in good condition. maybe not Rolls Royce, but good for the money, unless you pay £1410. It took me a couple of years to find a good one at the right price and I don't regret the purchase.

However some folk seem to have more cash than sense, bidding wars again I suppose.

Andrew.

Hello John,

It isn't the programming per se that I find complicated. It is trying to find the appropriate bits which one actually needs. I guess that is about 5% of the actual capabilities of the VFD, are the ones I want and I tend to get lost in the other 95%!

Really it serves me right, I should stick to one make of VFD and then setting up the second or third one is easy. I tend to buy VFDs that are good value and that means I never get the same type twice.

Thanks again,

Andrew.

Thank you John,

I shall now take some Paracetamol and see how I get on!

Andrew.

I just noticed that a rather scruffy Centec 2B with horizontal and vertical head but with manual horizontal feed, went for an eye watering £1410. Someone must be desperate.

Andrew.

Thank you John,

Just a quick query, Can I instruct the VFD via the basic operating panel or do I need the advanced AOP panel?

Regards,

Andrew.

Hello,

Just starting to sort out a Micromaster VFD with the basic operating panel (BOP).

I assume that I can construct a remote pendant control for stop/start, alter frequency and jog, by directly connecting the pendant to the VFD? or are you restricted to doing this via the BOP?

I have yet to wade through all the operating instructions which I am sure will reveal what can and can't be done. However I usually get a headache when trying to sort out the instructions. There is so much stuff that I will never need and what I want is usually the last place I look!

Thanks,

Andrew.

Why not buy some cheap Chinese angle plates. In my limited experience. The ones I have seen are not square and the slots are rough. Just treat them as castings and machine them properly.

If the castings are made available then go that route. I don't think that economics come into it. Just a way of gaining valuable experience!

Andrew.

I seem to remember that split lead screw nuts, for the purpose of reducing backlash, were roundly condemned by certain forum members. Perhaps someone could remind me why this is so?

Andrew.

Hm! Maybe not so expensive after all? I shall certainly consider such a solution when I need to replace worn nuts and lead screws.

I assume that wear will be very much slower than a conventional set up?

Thanks again,

Andrew.

Hello Neil and Nigel,

I am not looking to install a zero backlash solution on any of my machine tools. I simply wanted to know how they worked.

I guess that even a "cheap" arrangement would cost half of what my machines cost in the first place and the other half would be taken up by the price of a DRO installation! I am quite happy working in the old fashioned way. In fact I am happier keeping old skills alive, than in jumping on the latest techniques. However it doesn't stop me from wanting to know how the new stuff works!

Thanks for your comments,

Andrew.

Thanks KWIL, that search term worked very well indeed!

Regards,

Andrew.

I have just been reading another thread which mentions using ball screws(?) on lead screws to obtain zero backlash. Can anyone point me to an article which explains this? Seems to be a CNC derived technique, Googling doesn't seem to get the results I am after, probably because I am using the wrong terms.

Thanks,

Andrew.

I purchased one of the Chinese cheapies from Focus when they shut down. £15 and the choice of four. I must have the only decent one they ever made! Quill is still a good fit and apart from the Mickey Mouse depth scale. The only real snag is the table. It is dead square to the axis of the quill, until you start to drill serious holes and then it deflects. Right now I use a scissor jack to keep it square. If only I could fix this problem with a bit more elegance, it would be the best £15 I have ever spent. I use it in preference to my Fobco Star as I would rather wear it out than the Fobco,

I should have purchased all four, a cheap source of pulleys, electric motors and NV release switches, amongst other things.

Andrew

Why not use oil firing? Plenty of full size locos used it and it does work on smaller locos.

Andrew.

Three thou run out on a 3 jaw isn't bad! I cannot emphasize enough that the chuck and spindle nose should be ABSOLUTELY clean. In my early days at using a lathe, I was plagued by variable run out of anything up to 10 thou! Cleaning both the chuck thread, scroll and the spindle nose made the run out about a consistent thou.

If you genuinely have a 3 thou run out, then you can always convert the back plate to a "sort" of Burnerd Grip Tru chuck. I think Commander Barker was the first to describe the mod and then GHT wrote it up. You can buy a kit from Hemingway to convert your chuck, but best read GHT's manual of workshop practice, it is described therein.

Grinding jaws is a last desperate resort for a worn out chuck as far as I am concerned and then it only works for one diameter.

Andrew.