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Member postings for mgnbuk

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

Thread: Stepper motors
26/07/2021 19:20:29

I have some 4 pin plugs and sockets connecting the steppers back to the control cabinet.

This isn't intended to be critical of you, Steve, as what you have done is what appears to be done often on DIY builds - but did you actually need a quickly detachable connection here ?

From a reliability perspective, every connection is a potential problem - your plug and socket introduces two soldered and one mechanical connection between motor and drive. Putting a gland in place of the chassis socket and routing the stepper motor wiring directly to the drive connector without any intermediate connections would have eradicated 3 potential trouble spots. This would obviously make removing the motor a bit more of an effort - but how often would you be doing that ?

On the drive systems used on industrial CNC machinery, it is not unusual for drive manufacturers to specify thet intermediate connections are to be reduced to a minimum, but preferably to connect the motor cable to motor at one end & drive at the other directlly. The fewer the breaks between the two the better & any joint that can be designed out can only be a good thing - particularly with soldered connections, which (in my experience) cause more problems than crimped.

In my previous employment (CNC retrofit & rebuild), warranty visits reduced when the drive manufacturers introduced pre-made & tested cable assemblies that were installed in one piece. Prior to that introduction, most issues when we made up cables ourselves (frequently broken at terminal strips for ease of wiring) had been caused at terminal blocks or soldered multipin connectors

Nigel B.

Thread: Leveling machines
26/07/2021 18:57:29

The "levelling" when used in relation to a lathe is a poor way of simply making sure that runs true whatever length of work is machined.

How did the machine tool industry get it so wrong for so long ? And as they continue to do so, they mustn't have a clue. I guess I'll be making work for myself when I use a level to check out the lathe I'm cuurently working on before it goes into production.

Questions: Are boats level, when at sea? If they needed to be precisely level to the planet Earth surface, how did the navy cope with all those Drummonds during the war?

I have a recollection that the lathes on ships are mounted on a "neutral axis" that is isolated from the usual twisting and other movement that ships exhibit while at sea. But the lathe would have been checked while it was being bult using a precision level. And as ships are built "out of the water" on supports in dry docks, it would not be difficult to check the lathe for twist with a level at the point of installation, before the ship was launched.

Nigel B.

Thread: Royal Mail Tracking Numbers!
23/07/2021 13:30:21

RM are certainly having problems due to staff shortages. Talking with the postman at work yesterday (we share some interests, so have a quick chat most days), he said he was working 11 hour days to try and catch up as they had so many off - 10 absent on Thursday.

Also having issues with ParcelForce - checking the tracking on a "Next day" delivery of parts required to complete a repair, I found that the parcel had been "Out for Delivery" twice & "Returned to Depot" twice before it was finally delivered. Confirmed despatched last Friday, delivered 5.30pm Wednesday. If the drivers don't get all the packages delivered by the end of their shift, they just take them back to the depot.

Some of the RM & PF tracking (particularly for items supplied & tracked via Ebay) just doesn't get updated - most items I get at the moment are delivered while the tracking has not moved on from "Parcel collected".

Interesting times.

NigelB .

Thread: Keeping the workshop cool
23/07/2021 12:17:13

You might consider those ice-cooler machines from on Amazon

Two main issues with evaporative coolers - they don't work well when the ambient humidity is high & they increase the humidity if they are working. Do you want to raise the humidity in your workshop ?

Nigel B.

Thread: Hydrogen
23/07/2021 12:07:34

that the total cost of ownership of electric cars is already lower than the total cost of owning an IC vehicle.

Where do you get that information from, Dave ?

One of the car magazines (Car IIRC) ran a comparison test recently using an current IC car & the equivalent BEV from 3 manufacturers - in all cases the total cost of ownership of the electric version was higher than the IC version. Considerably higher in some cases.

This may change in future, but right now BEVs appear to be an indulgance - those who can afford them do so & then crow about their supposedly "green" credentials. For some they are a genuine alternative, but for many not so. The only electric car I have seen so far that I may actually consider buying (and could afford to do so) is the Citroen Ami - a very different solution to urban mobility than just trying to replicate the performace of an IC car. Very basic, limited performance (28mph max) and range (5.5KwH battery gives around 30-35 miles & recharges overnight form a 13A socket) ) but cheap (around £6K in France - not available here yet) and made to suit a licence-free category of vehicles in France that makes driving one available to 14 year olds after limited instruction. As my weekly shopping trip is around 20 miles, mostly in built-up areas, such a vehicle would work for me there.

As to the power of big oil, it's fading.

I don't think that is the case. There is more to our use of oil than just burning it for fuel. One of the ingredients of lithium batteries is needle coke - an oil refining by product. Needle coke & pitch are the primary ingredients of manufactured graphite - used in many areas of manufacturing that you are probably unaware of (I know I was before I stared working with the stuff), particularly in metals manufacture (arc furnace electrodes etc.). Carbon black (oil product) used for rubber manufacture. Plastics for pretty much anything (mainly oil product). Carbon fibre starts out a s PAN yarn - oil product. Graphite felt insulation (used in vacuum & semiconductor furnaces) starts out as rayon fibre mixed with phenolic resin (oil products).

The list goes on - we are heavily dependant on oil at some point for virtually everything we make or use today & I don't hear much about finding "green", oil-free alternatives to those. There is a much bigger issue than what we use for a transportation energy source that does not appear to have been addressed by the "sound bite" politicians.

Nigel B.

Thread: Autolock stuck drawbar won't screw in
15/07/2021 15:06:17

I would not be hitting the spindle of an FB2 (clone, by the look of it). Light duty parts & IIRC a "strange" bearing arrangement for the spindle and indeterminate parts situation - easy to damage something you may not be able to easily replace & when parts were available they were pricy.

If you got all the tools with the machine, there should be a thin sheet metal spanner to fit the flats on the end of the spindle nose - hold the spindle against rotation with the spanner & use a tommy bar in the support ring on the tool holder to jack the tool out of the spindle. It may well go with a bang, so have a piece of wood on the table to prevent damage when the tool is ejected. The drawbar should be axial restrained under the nut at the top of the spindle & this usually jacks the tools out. IIRC the original drawbar was M10 (actually an M10 socket head cap screw) - I can check when I get home if that helps.

Nigel B.

(who has a similar machine)

Thread: GigaFactory
14/07/2021 14:34:31

But the real issue is the particulates … but they weren’t trendy

Check out the latest Euro 6 emission levels for both petrol & diesel cars - the particulate levels are the same for both. And a major source of vehicle related particulates is not engine related - brake & tyre dust - EVs will also produce these. By all accounts, both sources are less than particluates from burning wood ineffieciently in wood burning stoves in built-up areas.

One of the things that came out of VW cheating situation was a more detailed examination of what actually comes out of tailpipes in "Real World Driving" rather than during "official" test regimes. One suprise was that many direct injection petrol engines were worse for particulate emissions than some earlier generation diesels, but they were not at that time tested for such. If you look at the current Euro 6 levels, you will see that particulate levels are set for both diesel & DI petrol engines now.

I had (for a while) a Euro 6d Ford Transit motorhome - a not particularly economical vehicle, but after 5600 miles (when I got rid of it) the exhaust tailpipe was clean to the point that when a white paper towel was wiped around the inside of the pipe it was barely discoloured.

Nigel B.

14/07/2021 13:47:31

I’m actually just as interested in the decline in Diesel cars as we really need to get them off our streets as soon as possible. Luckily the message is getting across. Hopefully the complete ban on using Diesel cars can be brought forward by ten or fifteen years.

As a modern diesel car is no more polluting than a modern petrol car, but is more efficient - why the hate ?

Diesel car emissions are not the problem in cities - it is diesel lorries and busses that cause the problems & their contribution is reckoned to be less than wood burning stoves.

If the real issue is CO2 (as we were told at the time diesels were being popularised), modern clean diesels would appear to be still a major contributor to reducing CO2 emissions until something really game-changing comes along WRT to battery technology (less weight, longer life, less environmental impact).

I will miss diesel cars when they are no longer available - modern diesels are more economical, have longer service intervals & are better to drive (IMO) than modern petrols & no more polluting.

Nigel B

Thread: Which was the better design of Airship: R100 or the R101?
16/06/2021 20:05:30

Thanks to SoD for the link to the R101 Inquiry report - far more than just the bare bones of the accident & suprisingly readable.

All rather sad - the desigers seemed to have tried very hard to use modern (for the time) methods to calculate stresses & loads, wind tunnel test to determine drag etc. but still ended up overweight, lacking lift and underpowered, with many technical issues that, while addressed in part, never seem to have been properly sorted out.

The unfortunate ending appears to have been, like many "accidents", a combination of several unfortunate circumstances (which, individually, may have been survivable) coming together. Insufficient testing after a major modification, over-confidence by the crew & designers, politically induced time pressures, imperfect weather forecasting, material deficiencies - a long list of the wrong factors.

I have read several of Shutes books, but not Slide Rule. This, and Stanley Hookers book, are en-route for holiday reading. Thanks for the reminders.

If anyone interested in airships finds themselves in or near Friedrichshafen - home of Zeppelin, amongst other famous "names" - there is a Zeppelin Museum in the building that was built in the '30s as the Zeppelin departure building. Unlike most of Friedrichshafen, this appears to have escaped being flattened in the war & is an interesting way to spend a day. There is a replica section of one of the observation decks of the Graf Zeppelin that gives an idea of the size of the things.

The current Zeppelin is based at the airport nearby & is often seen out on sightseeing trips. There is also a Dornier museum (Claude Dornier worked for Count Zeppelin before setting up on his own) at the airport which it is OK, but not great.

Nigel B

Thread: GigaFactory
15/06/2021 08:52:17

And if we want China to get rid of all their coal fired power stations then they get first dibs on the rare earth metals

I was under the impression that China was the largest supplier of rare earth metals , the extraction & processing of which cause huge amounts of pollution.

But that pollution is "not here" - so that seems to make it OK.

Nigel B.

Thread: Machin guards
15/06/2021 08:39:14

Doesn’t it depend on what one is guarding against?

No, not really.

The OP requirement was for a clear plastic material & for a machine tool application polycarbonate sheet covers all bases, so why consider anything else ?

The only real disadvantage to it is that it scratches if you are not careful cleaning it. Some polycarbonate is available with a scratch resistant coating & industrial machines sometimes use a safety glass / polycarbonate / safety glass sandwich to give more resistance to scratching, but the downside to that solution is that an impact from a broken tool or job coming out on a lathe cracks the glass & replacements are expensive. And heavy.

Nigel B.

Thread: Advice on moving an Archdale radial drill
04/06/2021 10:13:40

The company that I started my apprenticeship at in 1977 had several radial arm drills - as a heavy duty valve manufacturing plant there were a lot of flange bolt holes to drill. There were a couple of semi-automatic multi-spindle drills, but most flanges were drilled on the radials with guide plates clamped to the flange containing hardened bushes - no marking out or pilot drilling, just straight in the bush with the finished size drill followed by a countersink on the front & a back counterboring tool to touch up the back face.

All were fitted with wand operated Jet Brakes (DC injection brakes) & one of my early tasks was to regularly check that the wands were undamaged & that the spindle was properly braked to a stop when the wands were touched. IIRC the spindle stopped in less than a revolution when the wands were tripped. I also have a recollection that it was a legal requirement for radial drills to be fitted with such devices, so I am a bit suprised that an ex-industrial machine doe not have one.

"Nuisance" tripping due to long curly swarf when the wands were set close was an issue, though the machines usually restarted with a press of the button when the swarf was cleared. On one occasion that I recall, this didn't happen - the machine would not restart & I was sent to investigate. Turned out that the motor had restarted, but the drill wasn't going round - the motor shaft had sheared off inside the drive end bearing at a circlip groove. DC injection braking can be pretty brutal !

Nigel B.

Thread: What are these morse taper collets for?
01/06/2021 11:11:12

Split drill driver

Had a bit more of a dig around & found the above link. These also seem to be referred to as "automotive drill" holders in some accounts & appear to require a drive square to be put on the end of the bit, with the parallel bore just to hold them concentric.

The "Use 'em up" repair sockets I initially thought of are not split.

Nigel B.

01/06/2021 10:00:44

I have a vague recollection that those are "saver sockets" that allow further use of tooling that has a damaged Morse taper. I can't find any further descriptions of the type at the moment - maybe have something in an older engineering book at home.

Nigel B.

Thread: A smoking M300
20/05/2021 16:15:58

This Ebay listing shows a KM switch with the same part number. It appears to be a straightforward 3 pole cam switch. Handily the listing shows views of the original swicth instruction sheet & various views of the switch itself. As this particular switch is in the USA, shipping is probably prohibitive.

But this similar item from RS components should do the job. The RS site has datasheets & an installation guide showing the mounting hole layout, dimensions etc.

A 4 pole version is available on Ebay for £12.25 delivered. Chinese manufactured - UK supplier. You would just use 3 poles & leave the extra one blank.

A known brand name unit on Ebay is £23 delivered if you would rather not trust Chinese quality (though the RS Components swicth is probably made in China).

Nigel B.

Forgot to say that Klockner Moeller are now known as Eaton. RS Components list Eaton 3 pole switches that may be a direct replacement - run out of time to look further into this now.

Edited By mgnbuk on 20/05/2021 16:31:02

Thread: What is a Lug Sweater?
20/05/2021 14:18:53

See example below.

Cable Lug

I order those with a different description from a popular industrial source - and crimp them on.

Soldering electrical terminations is so last century - "sweating" possibly the century before that ? smiley

Nigel B.

Thread: ebay’s inconsistent presentation of prices
20/05/2021 10:46:58

The discounted offers seem to be a discount on some sellers prices before Ebay add the Vat to it, Michael - I have seen the same on several items, but it does just seem to be sellers whose origin is outside the UK where Ebay applies the Vat. Offers from genuinely based in the UK sellers appear to be a discount on the Vat inclusive price, as was the case before the recent changes to Vat enforcement.

Still, any discount is a good discount to me.

Nigel B.

Thread: What is a Lug Sweater?
20/05/2021 10:37:30

Sweating is an old term for soft soldering & lugs an old term for cable end terminations, so maybe an electricians tool rather than a plumbers ?

This link to a passage printed in an old "how to" manual describes the process, but doesn't mention any special tool to accomplish it. Given the apparent age of the description, the heat was probably produced by a parafin blowlamp.

Not something that was taught as a skill in the "first year off the job" part of my electrical apprenticeship - such lugs were crimped on by 1977.

Nigel B.

Thread: Hydrogen home heating
19/05/2021 19:10:01

I've read that Germany uses excess wind power to make hydrogen which is pumped into the gas main.

Germany also has a pretty catastrophic (for the land & crop diversity) subsidised biogas production regime, the product of which is also added to mains gas.

Nigel B.

19/05/2021 19:07:23

Hydrogen as vehicle fuel is a new thing

Really ?

BMW had a fully functional hydrogen 7 Series saloon running in the '80s. One of it's features was a hydrogen sensor in the cabin that automatically opened the windows to prevent a potentially explosive concentration of gas if there was a leak - unsuprisingly the insurance industry were not too keen on this safety feature !

Hyundai have had a test fleet of hydrogen fuelled cars (iX 35s IIRC) running in the UK for several years. Wider roll out will be limited by the cost & the scarcity of refuelling points (17 at the moment, apparently). Given that some have struggled with refuelling LPG cars at around 7 Bar, 700 Bar for hydrogen would be a much greater challenge.

As stated earlier in respect of fusion - hydrogen is fuel of the future ..... and always will be.

Nigel B.

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