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Member postings for Swarf, Mostly!

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

Thread: Painting on old galvanize
05/08/2020 10:41:36

Hi there, all,

I don't know what process is used for the galvanised sheet steel from which garage doors etc are made. Maybe it's an electro-zinc process.

I doubt that it's a hot dip process unless it is configured rather in the shape of a float glass plant.  (Long and narrow and hot in the middle! )

The following is my understanding about hot-dip galvanising - I welcome correction from any members with first-hand experience. I understand that hot-dip galvanisers float a thin layer of molten palm oil on the surface of their molten zinc vat/bath. When the item is removed from the bath it gets coated with a film of palm oil on top of the zinc - it is this that makes the item difficult to paint until the weather and any passing microbes have removed it.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 05/08/2020 10:43:00

Thread: Today's delivery
29/07/2020 16:31:52
Posted by Henry Brown on 29/07/2020 14:15:26:

I had this 200mm grinding wheel come from Cromwells yesterday. I was somewhat alarmed at how it was able to bump about in the box as the air bags weren't doing much.. The wheel rings ok so all's well but I'd expected better from Cromwell, I chose to buy from them but the local store but no stock of this wheel so had to go on-line.

20200729_140131.jpg

Hi there, Henry,

Sorry if this is off-topic.

I was told by the guy in my local branch of Cromwell's that I'd have to buy grinding wheels via their web-site - they didn't stock ANY grinding wheels in the shop because they have a shelf life?!?!

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 29/07/2020 16:32:37

Thread: DTI accessory threads - Mercer - Verdict etc.
19/07/2020 18:58:34

Hi there, Rik,

I don't know if it's in the latest edition but the MSC catalogue used to have a couple of pages devoted to screw-on accessories for DTIs. There were two series, one with a metric thread, the other with a USA inch-based thread. (The listing says what the threads are. )

I haven't checked lately but you might find their on-line catalogue still lists that information.

Best regards,

Swarf, Mostly!

Thread: Fiber change gears
17/07/2020 12:05:35
Posted by Circlip on 17/07/2020 11:41:31:

Nylon absorbs water and even the "Low" absobtion rated Nylon 6 or 6-6 does to a lesser extent. Tufnol should not be lubricated, it's a layered material.

Regards Ian.

Hi there, Ian,

Are you suggesting possible delamination?

Best regards,

Swarf, Mostly!

Thread: cateracts.
12/07/2020 13:10:21

Hi there, Clive,

I had one eye 'done' on 24th January. When friends learned I was going to have the procedure, a surprising number of them revealed that they or someone close had also had the surgery. All were reassuring.

In the event, the worst thing I remember was walking into the operating room and being confronted by a huge machine reminiscent of the bad robot in RoboCop!! smiley smiley smiley

The reassurances were completely justified as to the actual surgery and my subsequent experiences. The only down-side is that, following my post-op assessment on 24th February, the arrival of lock-down prevented my getting an eye test until a couple of weeks ago - I have an appointment to collect my new glasses this coming Tuesday.

Best regards,

Swarf, Mostly!

Thread: whats this socket used for?
29/06/2020 13:41:09

That 'resistor' looks like a 'Brimistor' to me. I can't remeber whether they were NTC or PTC but my now-vague memories associate them with the heater chains of themionic valve radio receivers of the 'AC/DC' variety. The high tension supply was derived by half-wave rectifying the mains and the heaters of all the valves were connected in series, including a suitable Brimistor, across the mains but with a 'dropper' resistor included to make the chain match 230 volts. Valves were available with high voltage heaters for use in such receivers - they were designed and manufactured to have high cathode to heater voltage ratings. The temperature coefficients of the various components in the heater chain were chosen both to limit 'inrush current' while the valve heaters were yet cold and to stabilise the heater current once the set had warmed up.

I do have a copy of the 'Brimar Valve Book' in the bookcase downstairs - the Brimistor is probably included. I'll have a look later this afternoon.

Best regards,

Swarf, Mostly!

P.S.: I apologise for any typos - I'm due to have my post-cataract surgery eye test tomorrow - it should have been in mid-March!!! Dang lock-down!!!!!!!!

Thread: Hello from West Sussex, looking for ID for my first lathe
01/06/2020 19:27:51

James:

You have a PM.

Best regards,

Swarf, Mostly!

Thread: Method of joining for chuck key?
28/05/2020 13:22:52

At least one well-known brand of padlock uses a brass pin through the brass body to secure the assembly of its 'innards'. The brass pin is driven in and then filed and linished flush on both flanks of the body. If this is done properly, 'you can't see the join'! (I and my fellow pupils actually had to assemble such a padlock as part of a 'Locksmithing Acquaint Course' several years ago. )

You could use the same technique but polish the handle rather than settling for a linished finish.

Of course, the shaft of the key would need to be a good fit in the handle and the pin should be the same grade of brass as the handle so that their colours match.

Best regards,

Swarf, Mostly!

Thread: Contacts in a Parkside Charger from Lidl's.
23/05/2020 13:50:03

Hi there, all,

My thanks to everyone who has contributed to this thread.

I did quote the charger part number in my original post - perhpa I should also have stated that it is a member of the Parkside X 12V Team series, i.e. 12 Volts.

Ady: to sew the matter up completely, which two positions in the charger? Plus (+) and minus (- ) or Plus (+) and the other one? Just out of interest, is one of your chargers the type that charges two batteries simultaneously?

Best regards,

Swarf, Mostly!

23/05/2020 10:38:27

Hi there, Roy,

My, you were quick off the mark!!

As to 'does it work?' well it appears to work but the User Instructions say the battery is supplied 'part-charged' and advise that it will require several charge/discharge cycles before it develops its full capacity. I have not yet got the feel of the red & green LED charge signalling facilities.

I'd like to resolve this apparently missing contact topic before proceeding further.

Best regards,

Swarf, Mostly!

23/05/2020 10:24:41

Hi there, all,

Many years ago, I was taught the 'First Rule of Electrical Engineering', namely that 'Everything in Electrical Engineering must have a "come from" and a "go to".

I recently bought a Parkside tool from our local branch of Lidls. These are supplied 'bare' so I bought a battery and charger to go with it. The charger part number is PLGK 12 A2.

Before I go any further, I want to emphasise that my experience with the Parkside brand has been very good. What I am about to describe is no exception to that - it is a matter of curiosity rather than displeasure.

The battery concerned, has three electrical contacts, positive, negative and a third. This third contact is common with rechargeable battery packs and is, I understand, used by the charger to sense battery temperature.

Imagine my surprise, then, when I discovered that the charger (well, my charger) has only two electrical contacts. Let's see if I can insert the photos:

parkside charger #02.jpg

and

parkside charger #01.jpg

The positive contact is there as is a contact with an unfamiliar symbol, but while there is clearly a provision for a negative contact, that position is empty!

I addressed an enquiry by email to the address given in the User Instructions booklet for service matters, namely grizzly@lidl.co.uk, but my query has been intercepted by Lidl's customer services department who have given a non-technical response!

I intend to persevere with my attepts to reach some Grizzly techie but, knowing that members here often patronise Lidls, I wondered if anyone else has bought this charger? If so, how many contacts does your charger have? Is mine unique?

Best regards,

Swarf, Mostly!

P.S.:  I'm suddely afflicted with doubts concerning apostophes!!!
 

Edited By Swarf, Mostly! on 23/05/2020 10:29:18

Thread: Failure of Brass Bolts
05/05/2020 13:13:58

It just so happened that, last evening, I also watched the video concerned. To be sure of what I'm about to post, I've just watched the opening minutes again.

The actual earth rod is clearly copper-coloured so it's either solid copper (unlikely) or copper-clad steel. The actual clamp looks to be tinned, only the securing bolt & nut look to be brass.

As already stated, there's stainless steel and then there's stainless steel! Some varieties of stainless are actually weaker than mild steel. Also, stainless steel can be either anodic or cathodic (but, of course, not both at the same time wink ), depending on the local environment, including the oxygen availability.

I like the suggestion to use bronze fittings in lieu of brass but I've no idea where one would obtain them in small quantities!

One of the books on my shelf is 'Earthing', published by the Copper Development Association, it may be available on-line nowadays. It shows earth rods being driven by an early form of Kango hammer. BICC (whatever happened to them? ) used to sell an earth rod of copper or, maybe, cadmium-copper, that came in sections with driving points, driving heads and couplings as accessories. The rods were star-shaped in cross section to maximise contact area vs length. The driving head protected the coupling thread from damage so the next section could be attached without difficulty when required.

Best regards,

Swarf, Mostly!

Thread: An Odd Screw
20/04/2020 20:53:25

Hi there, Robert,

One purpose of screws like that was/is to secure loudspeakers to their baffle board. The coarse left-hand screw engages the plywood baffle board and the machine screw portion takes washers and nuts to secure the loudspeaker. Tightening the machine screw nut also, because of the left-hand thread, tightens the wood-screw part.

Best regards,

Swarf, Mostly!

Thread: "I'm gobsmacked", Mi' Duracell's leaked.
15/04/2020 19:18:25

Hi there, Sparks,

The mess from the leakage can be cleaned up with either white vinegar or citric acid. You can obtain citric acid in fine crystalline form from eBay or (in virus-free times) from some food suppliers. Maybe also from other web suppliers. Dissolve in warm water and apply with a brush or a cotton bud. Wipe away with a piece of kitchen roll and rinse with plain water. Dry by brushing on methylated spirits, surgical spirit or vodka!

Best regards,

Swarf, Mostly!

Thread: Removing drill head assembly from column
09/04/2020 15:42:07

Hi there, Adrian,

Just a suggestion:

When I got my Tauco drill I anticipated that weight of the head and of the table might give handling problems. (The table on the Tauco doesn't have a lifting rack. )

I machined up a couple of rings of engineering plastic that were a snug fit on the column. I machined a groove round their exteriors and split them. One fits beneath the table knee bracket and one beneath the head and each is tightened by a Jubilee clip in the groove. Each one limits how far the head or table can drop if they should try to escape from control. (Obviously, I don't move the head very often. ) If I'm lowering the table, I slacken the ring first and lower and re-tighten it so as to determine the lower limit of table position for that adjustment.

If your drill has a table lifting rack this suggestion is not relevant, though you might find a safety ring under the head of value when the head needs to be removed or fitted. The head is heavy and reaching up that much higher might make lifting its weight that much riskier. Such a ring is completely out of the way most of the time.

I made my rings from Ferrobestos, that's obviously a no-no material these days (once machined and varnished, leave it alone. ). If I were making them nowadays, I'd look for some fabric-based Tufnol.

Best regards,

Swarf, Mostly!

Thread: Percival Marshall gramophone message?
08/04/2020 10:07:49
Posted by Oven Man on 08/04/2020 09:57:14:

I've still got a pile of old shillings. A use for them at last?

Peter

Before 1921, sterling silver, 1921 to 1947, some silver but I don't remember the proportion.

I just mention it for information, I don't advise defacing the coinage!!!

Best Regards,

Swarf, Mostly!

Thread: 2TB USB drives.
03/04/2020 19:56:07

Hi there, OM,

There is a small programme on the web somewhere that will check the true capacity of either flash cards or USB sticks (aka 'thumb drives' ). I guess the writer wrote this programme in response to the high incidence of counterfeit devices from less-then-conscientious sellers.

I can't immediately give a link here - by the time I find it you could well have scored with some trial key words on Google.

Best regards,

Swarf, Mostly!

Edit:  I put the following search phrase into Google and got lots of hits.  'software to check flash drive capacity'
 

Edited By Swarf, Mostly! on 03/04/2020 20:04:07

Thread: Lathe levelling
23/03/2020 17:01:32

Hi there, Howard,

Thank you for your response to my post.

What you wrote is fine UNLESS the slope is so great that the level goes into saturation, i.e. it's so far beyond its range that its reading is meaningless.

If the position of the level line is known to be close to level, one can proceed as you wrote without having to iterate through many off-scale steps.

Best regards,

Swarf, Mostly!

23/03/2020 14:42:39

Hi there, all,

I hope that I will not be censured for an off-topic post but this post isn't about 'lathe levelling' - it seemed like a good place to interject an observation about engineers' precision levels and their calibration.

Half of my offering is from Stan Zinkovsky's channel on YouTube (He of the Bar-Z Bash fame). The rest is my idea but probably not original.

An engineer's level is accurate if it reads level both ways round when on a level surface. How do we determine if a surface is level with a 'wonky' level? Not all of us have more than one level! But many of us do have a surface plate.

Stan pointed out that somewhere on a non-level plane surface, there is a line that is absolutely level - it is at right angles to the line of maximum slope. It obviously helps if the plane surface (e.g. surface plate ) is fairly close to level. So, how might we find this level line? If we can find the line of maximum slope, we're only a single step away.

One way to find it is to use an ordinary ball bearing. Put it gently in the middle of the plane surface, it will roll down the line of maximum slope. If the ball doesn't know which way to roll, that's useful information. We're nearly there but we'll get a better result if we repeat, placing the ball at the top edge of the plate. We know where that is now. Mark the path of the ball with a Sharpie and repeat a few times to get an average. Then use a square to draw a second line at right angles to the first.

The level to be calibrated can then be aligned with our level line and adjusted until it reads level both ways round.

Have I confused everyone? If not, let me know and I'll try again!! smiley smiley smiley

Best regards,

Swarf, Mostly!

Thread: Internet crash
19/03/2020 13:29:21
Posted by Bazyle on 18/03/2020 00:25:10:

Posted by Steviegtr on 17/03/2020 23:37:10:

teaches swimming on an evening.

You'd think being dunked in dilute bleach would be quite a safe option at the moment.

SNIP

Edited By Bazyle on 18/03/2020 00:36:16

In my younger years I used to spend a lot of time in swimming pools. In the process I had some contact with Pool Managers and technical staff.

'Oh, no, it's not chlorine that stings your eyes, it's too low a concentration. It's the ammonia that stings your eyes.'

'Why do you put ammonia in the water?'

'We don't - it's the swimmers that put the ammonia in!'.

I underatand that the modern technique is either to irradiate the water with ultra-violet light or else to inject ozone.

For reasons that have nothing to do with water treatment chemistry, I don't swim these days.

Best regards,

Swarf, Mostly!

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