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Member postings for Andyf

Here is a list of all the postings Andyf has made in our forums. Click on a thread name to jump to the thread.

Thread: De-Magnatizing digital callipers
12/07/2013 10:06:57

On the subject of picking stuff up, I have my late mother's "reacher" - this sort of thing - in the shop, and find it very useful for recovering items which have fallen behind machines or under benches. Mine has a magnet on the end; fairly weak, but can be used to draw a small item into a better position for grabbing.

It also saves a lot of bending to pick up all the twigs my ash trees shed before I mow the lawns.

A bit off topic, but we seem to have picked the bones out of demagnetisers.

Andy

11/07/2013 14:49:45

Mike gave me a small one which he made, as shown here , which is very useful for picking chips off machinery. There's no reason why a much larger version couldn't be made for the floor.

Andy

Thread: Jaguar CUB5A-1 Programming question
11/07/2013 00:15:33

Round figures:

0.25A at 200V = 50W, or 0.15A at 380V = 57W. Much the same; call it 54W (or 0.054kW).

746W = 1 HP, so 54W is about 0.075HP. Less than 1/10 HP.

Andy

Thread: De-Magnatizing digital callipers
08/07/2013 14:34:29

I must say that, had a defunct central heating pump been available, I would have followed Ian Phillip's suggestion of discarding the "wet side" and rotor and using the stator windings in the dry side, under the diaphragm which separates wet from dry. I've read that tip before.

But not having an old pump, I took the modified transformer route. At least the result is lightweight and reasonably compact .

Andy

Thread: What did you do today? (2013)
07/07/2013 23:37:22

Finished off putting wheels on what was to be the heavier end of the stand of a cheap bandsaw I bought last year, so lifting the lighter end by 2" brings them into use. Then assembled the rest of the thing and tried it for the first time. Surprised to find that it cuts square, out of the box. Then watched the tennis final. The boy done good!

Andy

Thread: Cleaning hands.
07/07/2013 21:06:27
Posted by Mike on 06/07/2013 11:27:10:

I've never tried this, but a pal who was a roofer and regularly got splashes of bituminous compounds used to swear by his home-made "Green Swarfega" - a gel formed by mixing washing-up liquid and paraffin. As an angler, I can tell you that a very effective killer of bad smells is lemon-flavoured Fairy liquid.

Thanks for reminding me! I'd forgotten that my brother used that recipe 40 years ago, before he caught Chartered Accountancy and could afford a better car. Must give it a try myself.

Andy

Andy

Thread: would this vintage machine be a basis for building a great little lathe ?
06/07/2013 05:16:51

I have found other pictures of it which its vendor has posted. It looks as though the original spindle with a screwed nose to take chucks, faceplates etc has been replaced with one having a flange to which they are bolted. As it would be a big job to make such a spindle, one from a modern Chinese minilathe using 100mm chucks may have been used, somehow.

Speaking for myself, I wouldn't bother with it, but look around for something which comes with at least one chuck and a faceplate, and is capable of screwcutting. Kitting this lathe out so it can actually do something useful could get expensive. The more accessories you can get thrown in with a second-hand lathe, the better, and this one seems to come with no such dowry..

Andy

Thread: De-Magnatizing digital callipers
05/07/2013 09:57:19

In case you're interested, Ian, I've created a temporary page on my website and put a couple of pics on it here. I'll leave the page up for a couple of days before deleting it. The page isn't in the navigation menu, so if you move to another page, you will have to use the above link to get back to it.

Andy

Thread: Untrue 4 jaw chuck ?
04/07/2013 22:29:19

I had a similar problem with a cheap 4-jaw. I labelled up the jaws 1 2 3 4 and the slots A B C D and tried a few combinations of jaws and slots. The error was always against one particular jaw, so as someone suggested earlier I worked on its gripping face with an oilstone until things straightened up. A bit of a hassle, but probably less than trying to get the chuck replaced and finding the replacement was just as bad.

Andy

Thread: De-Magnatizing digital callipers
04/07/2013 22:21:00
Posted by jason udall on 04/07/2013 17:18:31:
Back to op as some one said simple blue box mag demag available. .I think someone posted a link..oh yeah me...

I'm sure the blue ones work fine for screwdriver blades and lathe tools, Jason, and there's no possibility of electric shock, but calipers might not fit through the holes. Andy. (why, all of a sudden, can I not put my name on a line of its own? Because the software on this forum is *^%! came the chorused reply .

04/07/2013 15:51:35

Right, as promised I've checked my home-made one out. The whole caboodle draws 80mA at 230VAC. I can't remember the specs of the transformer, but its windings are on a former which is roughly a 1" cube, so it was no biggie. I suspect its secondary produced 9 or 12V.

Circuit:

L -------- 2350ohms---------X------------- transformer primary ----------N

L to point X 190VAC, X to N 40VAC. The resistor is two wirewound 10W 4K7 ceramic cased jobs in parallel. These seemed to get a bit hot. They are square in cross-section, so werte clamped to the ally box with a heatsink on top, which keeps their temperature within reason. There is a salvaged neon indicator between L and N, though to stop the thing being left on, the push switch mentioned on the other thread is a good idea.

Andy

04/07/2013 09:32:23
Posted by SLOTDRILLER on 04/07/2013 06:55:26:

....... Andy,
What sort of current have you limited the primary coil to ?
I have an old 230v/12v @ 1amp transformer and under load it draws about 150ma on the primary so i suppose if i stick close to this it would be ok.

Imagine the unit one could make from an old stick welder !

I'm not sure how they became magnetised all i know is it makes them unusable !

Ian

I've got to do a week's worth of tidying up this morning, Ian, 'cos my cleaner is due and I pay her to clean, not to clear up the debris I leave lying around. I'll put the old Avo on it later and let you know. I recall that on full mains voltage, it heated up once the E laminations were all pointing the same way. I experimented with incandescent lamp bulbs of various wattage in series until it calmed down, using an ammeter to measure the current when the lamp was dimly lit., and then substituted ceramic resistors .

The chap on my earlier MadModder link stuck a piece of iron (probably cast iron so it wouldn't magnetise permanently) across the ends of his laminations, but I didn't bother and simply arranged things so they almost touched the underside of the earthed aluminium box which stops the electricity falling out.

I think one way of making a magnet is to hammer steel so that (in crude terms) its internal structure tends to arrange itself north-south along the Earth's field. Maybe the bumpy ride encountered in use by HSS tools might have the same effect? Again in crude terms, the 50Hz alternating field of a demagnetiser disarranges the structure, but as already said the item has to be moved reasonably slowly away.

I don't know how my screwdrivers and calipers get infected, though.

I wonder if you could get the same effect with a row of neobdymium magnets, and drawing the object along the row and slowly away, thus taking it through an alternating field.

Andy

03/07/2013 23:57:59

No effect on any of my calipers, John. They are all just as almost, but not quite, accurate as they were before treatment (most of them came from Aldi/Lidl, so have never quite agreed each other, or with my M&W mics).

If you can build a degausser, it really is a great help with HSS tooling, screwdrivers etc which have been turning into furry monsters when they get near swarf.

Andy.

03/07/2013 21:19:30

If you have one of those Weller instant soldering guns, pulling the trigger and sticking a magnetised object through the hairpin shaped element, then withdrawing it slowly and getting it a few inches away before releasing the trigger will demagnetise it. Caution - the element gets hot, so watch your fingers and the plastic bits of the caliper.

If you are happy working with mains electricity and have an old transformer, you can make a better demagnetiser, as in this LINK. Mine has 10W ceramic resistors (heatsinked) rather than a capacitor, in series with the 230V primary winding to limit the current. The low voltage secondary winding is still there, but disconnected. Again, the object needs to be passed slowly through the field (you will feel it vibrate) and away before switching off the current.

Andy

Thread: Tangential lathe tool holder
03/07/2013 00:02:39

I really must get around to making one.

My bright idea is a snail cam under the bottom end of the tool bit, to stop it being hammered down. Or even a shelf on the toolholder to support the bottom of the bit, if the tool holder is to be mounted on a QCTP which can be set a little higher after each sharpening.

Andy

Thread: Cleaning machines and workshop
02/07/2013 00:21:07

The link goes to Lidl, rather than Aldi. Looks a good machine, though sadly a bit big for my limited space.

Andy

Thread: backpage key
20/06/2013 09:22:12

You are clicking on "Latest Posts" just below the words Backpage Key, aren't you, and not on Backpage Key itself? Apologies if that seems to underestimate your computer literacy, but I tend to think of the silly things I've done from time to time!

Latest Posts is repeated just below the last message and above the Reply box. Does that work?

Andy

Thread: "salt bath" to soften metal
18/06/2013 22:28:08

His name wasn't Uri Geller, was it?

(Very) hot baths of molten salts are used in the heat treatment of metals, particularly during hardening. I expect your friend was describing annealing, and in particular the reference to wingtips makes me think of the way in which sheet aluminium alloys get pretty pliable when heated and allowed to cool, but tend to work harden as they are bent ionto shape.

Andy

Thread: Power feed transformer wiring
18/06/2013 14:59:05

Not sure if that one has a DPDT relay in it, Neil. And if it has, it would be hard to mod because the cheaper ones don't have a get-at-able feedback loop to hold the coil on until the red button breaks the loop. Rather, a plastic arm sticks down from the red button into the body of the relay, with its end bearing on the moving contacts, so pushing the button physically pushes the contacts apart to break the loop.

I've just had a look at Maplins e-catalogue. Can't see anything much there, but by searching part no. N09AW taken from an old paper catalogue, that looks the one. Switches 10A at up to 300VAC, and has a 240VAC coil drawing 14mA . Costs about £5. Might need a plug-in base to go with it.

Andy

18/06/2013 00:29:26

I just hope it works.....

You might get the components at Maplins, if you can stand the prices. You only need a relay capable of switching a few amps at 230VAC and with a 230 VAC coil, the two push button switches, wire, solder (or some choc block connectors) and a box to put it all in. Don't forget to earth everything metal which might fry you if it goes live, like the casing of the box.

Andy

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