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Member postings for Pero

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

Thread: Drilling brass
24/07/2020 09:14:08

I've not drilled a brass screw but have drilled a 1/16" hole through a 1/8" stainless steel screw a little over an inch long. The trick is to back the drill completely out of the hole about every 1/16" of an inch of cut otherwise the cuttings jam the hole and tragedy ensues. Use constant pressure when the drill is cutting and don't allow it to rub.

Pero

Thread: Is This a Tooth?
24/07/2020 04:21:14

Is that the tooth, the whole tooth and nothing but the tooth?

Sorry, but it is relevant ( more or less ) as the somewhat bulbous ( photo 2 ) bottom section ( the blunt end ) bears some similarity with the claw structure of modern birds - think ostrich or emu.

However, I am guessing and an expert opinion is called for.

Pero

Thread: Overview of fitting variable frequency drive (VFD) to a Myford ML7
21/07/2020 08:53:03

Ahh. Thems were the good old days Hopper. When things were made to last and cope with a bit of a hard life.

Just think what todays elf and safety would do with a treadle operated lathe - RSI of the ankles for a start!

What they would make of a pole operated lathe just doesn't bear thinking about.

Nothing against elf and safety - particularly my own - I just like to have the right to make may own assessment of risk and work from there.

Not to cast any nasturtiums but I have a suspicion, in my local jurisdiction at least, that there is a certain degree of self interest in the electrical standards and regulations, which is to say: maximising the sales of electrical fittings and accessories and promoting and protecting the work of the electricians who fit them.

Running for cover now.

Pero

Thread: Overseas Distribution to restart
21/07/2020 05:59:27

Apart from not receiving the subscribed issues, the main problem here seems to have been a distinct lack of clarity as to what the publishers were proposing to do with respect to the missing issues. The April email was certainly not clear in this respect and subsequent discussion in the forum has also been vague.

If fact the comment by Jason ( and it is certainly not his responsibility to do so ) is the first unambiguous statement I have seen. The responsibility here lies with the publishers.

With respect to the digital access ( for which I have already paid and only use for looking up individual articles ) I really dislike using it and would be much happier if I could have received pdf files for the missing issues which I could have printed ( potentially professionally ) in whatever format suited me so that I would have my preferred hard copies to read at my leisure.

Hopefully MEW 295 will be arriving soon - possibly on the next tea clipper.

Pero

intensely dislike

Thread: Overview of fitting variable frequency drive (VFD) to a Myford ML7
21/07/2020 05:16:10

I hope I am being calm ( as in keeping CALM and CARRYING ON ).

I have a number of VFDs - Newton Tesla on the Myford and a variety of others, large and small, to be fitted to various machines, so I am very interested in the technical / practical discussion on the installation of same.

The following comments reflect my ( undoubtedly limited ) understanding of VFDs and points I would like to clarify so if anyone would like to respond CALMLY, I would be very grateful.

Firstly - Enclosures. VFDs are designed for air cooling. Some with internal fans and slotted case, some with just slotted case and some with an exposed heat sink. Placing these into a closed secondary enclosure would appear to severely limit the capacity for air cooling. Unless the secondary enclosure is vented in which case we are back to the beginning. It is possibly something you could get away with in a cool climate with a large enclosure but probably not in a hot climate.

Sounds like a straight forward case for not using an enclosure provided it is out of the line of fire of heavy objects and swarf and cooling fluids. However some VFDs have exposed wiring terminals, usually on the lower front of the case which, although designed to minimise the risk of accidental finger contact, do give rise to some concern. Fitting a cover to such terminals could be sufficient to address any issues here.

Secondly - EMI. Most of the documentation I have read suggests this is not an issue where cable runs ( VFD to motor ) are short. Unfortunately I have not seen anything which indicates how short is short. In the good old days we would place the multi band radio in close proximity to the item of concern, run it through the bands and if no interference was detected it was deemed good to go. These days with so many bands in use this technique may not be totally successful. My understanding of EMI filtering and the remedies is not so good. If the typical low cost filter installed on the mains lead is sufficient then there is not a real case for not using one. Total cost for the filter, a bit of additional wire and perhaps a small case being only a few dollars. If however it is a relatively high power three phase filter on the motor side of the VFD costing potentially more than the VFD and Motor combined, the you need to be fairly certain it is required before running to this level of investment.

How effective is the use of shielded cable in preventing EMI issues and could this be the reason that some VFD instructions recommend earthing at both ends of the shield?

As in most things i would seem that one size does not fit all and systems should be installed after a consideration of all relevant issues - as long as you understand them.

Tranquilly yours

Pero

Thread: Small drill bits, <<1mm
13/07/2020 02:08:50

Hi Martin

Bit late getting back on this but thanks for the comment on sharpening. I have seen the photos and plans for one of these (or very similar). OK for the larger small drills, if that makes sense, but the problems that I have are being able to see the tip that I am working on and supporting the tip being sharpened. I can check the tips using a dissecting microscope but don't have a way of seeing what is happening as I am trying to sharpen.

I have come to the conclusion that the answer is to treat them as disposable items and it they are not working move onto the next one. One possibly bright note is that some of the manufacturers on the Alibaba site sell in small quantities so the quality may be better than the reject stock on Aliexpress - or possibly not!

I'll give one a try next time round.

Pero

Thread: Carbon fibre pendulum rod
07/07/2020 10:53:37

Hi Alan

Yes, it can be turned but ideally you need very sharp carbide tools for the task. It's murder on HSS. You could use a brazed tip tool specially sharpened for the purpose or alternatively an indexable tip designed for aluminium.

It generates a nasty black abrasive dust but it shouldn't pose much of a clean-up issue with the small amount you would be doing.

Cheers

Peter

Thread: Small drill bits, <<1mm
06/07/2020 05:07:22

I have a range of small carbide drill bits ranging from 0.1 to 3.0 mm. These are mostly ex China and principally advertised as PCB drills. The sharpening on these is generally good, i.e. accurate ( visually at least ) but quality ranges from good to bad with frequently chipped cutting edges. Usually you will get a few good ones in a set of ten, which at the price is probably reasonable. Unfortunately I am yet to find a seller who will supply consistently good ones, even at a somewhat higher price.

Given that the drills themselves seem to be of reasonable quality - does anyone have method of accurately sharpening them? I note that this probably also means being able to see them, especially in the very smallest sizes.

Pero

Thread: Pickling brass after silver soldering.
25/04/2020 04:03:40

Steve

Most likely hydrofluoric acid. As far as I know ( which is probably not much ) it was only ever used for passivating stainless steel, mostly after welding. It is, or was, also used for etching glass.

It was very effective but is very nasty stuff. I still have some, probably enough to see me through my lifetime, but I have also had training and have used a lot of particularly nasty chemicals so I am fairly comfortable, but careful, in using it.

I don't know the concentration when used as a pickle, but did go to university with a geological laboratory specialist who died after spilling concentrated acid on himself when a vessel broke. That knowledge reminds me to be extra careful in using it.

Pero

Thread: Holding glass lens for grinding
20/04/2020 08:55:36

The traditional glue for optical glass is balsam ( Canada Balsam ). There are probably more modern synthetic materials but I am not familiar with any of these.

Balsam was used because of its similar properties ( clarity and refractive index ) to optical glass. It can also be removed without damage to the surface of the glass.

Microscopists will be familiar with the use of balsam in the preparation of mineralogical slides and for sealing the edges of biological slides used in permanent collections. It is also used in the art world in the preparation of varnishes.

Pero

Thread: Hardened and chromed steel rod
20/04/2020 06:18:41

Price and availability may be the limiting factors, but 440 stainless may be preferable if opting for stainless. It is high carbon and harder and stronger than most of the commonly available varieties. It is also available as precision ground rod ( if that is a requirement ).

In chromed steel there is a lot of options available ex China and probably many other places as it is sold for guide rails for 3D printers and CNC machinery. Supply ex China ( Aliexpress ) may be problematic at the moment but some suppliers with warehouses may be able to help. Checking with local suppliers to confirm that they have the material in stock would be recommended.

Pero

Thread: Australian Crayfish?
08/04/2020 05:03:47

Lots of confusion here - not surprising as many Australians are also confused by the terminology.

Australia's crayfish/lobsters can basically be categorised into freshwater and seawater species.

The freshwater species all look quite similar but range in size from a couple of centimetres to the giant Tasmanian species which can weigh in at over two kilograms. The appearance of these species with their large claws is somewhat similar to the marine lobster of North American and European waters, however these are actually all crayfish.

The marron ( same spelling for singular and plural ) is a native south-western Australian species of freshwater crayfish. It can be cultivated in dams and there is a small aquaculture industry built about it. They have a sweeter taste and are preferred by some people to the marine lobster/crayfish.

The wickedly overpriced marine crayfish/lobsters are neither crayfish nor true lobsters. Traditionally called crayfish by the locals, the name was changed ( in the face of some antagonism ) to Rock Lobster to market them first to the Japanese market and more recently to the Chinese. They are actually spiny lobsters and lack the large claws of the northern hemisphere true lobsters. The industry is very tightly regulated - to protect the stocks - and prices paid overseas very high, hence the ridiculous price which puts them out of reach of most Australians. They are now most commonly marketed as Southern Rock Lobster.

The superficially similar spiny lobsters of northern Australian waters are badly behaved ( they don't readily go into traps ) and most are caught by divers. As a result the industry around these is small.

I trust that this adds to the confusion. My only excuse is that I didn't have anything else to do. Well I do but it's hot outside and in the workshop - 33 degrees C today. Must go, I think the dogs are destroying the lounge room.

Keep well

Pero

Thread: What is it with the fit of old slotted screws?!
07/04/2020 01:40:58

I have to agree with Steve, although I tend to grind mine rather than filing them.

The only 'specification' I have ever seen on a flat blade screwdriver is the width of the blade, which is not usually of much help, although the right width will assist in preventing damage to the slot.

Getting a perfect fit is essential on tools, clocks etc. where the appearance of the head needs to be protected. It is especially necessary on brass screw-heads which are easily damaged and cannot be repaired, apart from by cutting a wider slot that looks just about as bad.

As Steve has suggested, get a screwdriver of the correct width and file or grind to the correct slot width. If it is one you will be coming back to label it and put it aside - possibly keeping it with the tool for the next occasion.

Taper ended screwdrivers are still readily available - but are of the old manual type, i.e. with long tang and a handle, rather than the modern replaceable type.

A similar problem can occur with cross-head screws, usually because the center part of the slot is too shallow. Grinding a small amount from the end of the screwdriver tip will usually allow the driver to fully engage with the screw, minimising the risk of damage.

Pero

Thread: Coronavirus
27/03/2020 03:55:54

Thanks Duncan

It may well come to that. Still suffering a little from my polite upbringing but I doubt it will last much longer.

Biggest problem seems to be small children saddled with brain-dead mothers. Allowing a small child at any time to approach an unfamiliar dog has got to be a recipe for disaster, with the ultimate consequences likely to be greater for the dog than the child, unless perhaps it's a rottweiler.

At the present time it simply should not occur.

Time to express my inner grumpiness I think.

Cheers

Pero

26/03/2020 12:38:58

As an introverted miserable old git with no ( geographically ) close relatives I have no personal problem with social isolation, or anti-social isolation as I prefer to call it. My biggest problem stems from my two miniature dachshunds who are very social and a magnet for everyone from small children to fellow geriatrics.

We are still allowed out in public here ( Western Australia ) although that may change. I will be perfectly happy with less outside time but the dogs definitely will not.

So while I am desperately trying to keep my distance the dogs keep stopping for their admirers, who still keep on insisting on patting them, aided and abetted by the dogs themselves.

While a long lead generally keeps me at a safe ( ? ) distance ( current recommendation is 1.5 m ) the possible transfer of the virus from an infected person onto the dogs fur and thence to me is of some concern.

I do try to pick times when there are few people about but how do you get the message across to people, especially to small children, that they should not approach the dogs. An also how do I get across to the dogs that they are no longer allowed to approach strangers and friends alike.

I'm sure there must be an engineering solution to this so if anyone has any good ideas I will be pleased to consider them. Dipping the dogs in alcohol at the end of each walk is a possibility but I doubt that they would approve!

Keep well all

Pero

14/03/2020 02:12:14

Concerning news from the Western ( Australian ) Front. There have been adequate supplies of toilet paper in the local supermarket for the last two days running.

Obviously this is very concerning for the desperately needed toilet paper-led economic recovery. Our only hope now is for a flow-on effect from the increased sales of baked beans.

Fortunately we live in an effluent society but I am uncertain how others will fare. Perhaps the government could issue senna pods on a daily basis to those bunged up with surplus rolls.

Hopper is right to be concerned about the economic effects. These are likely to last for up to a decade ( or more ) and the associated indirect death toll could well exceed that of the virus by an order of magnitude. The worst affected will be those in third world countries where on income equals on food and there is no social services back-up.

Obviously it is up to us to keep on shopping so don't delay on the new mill Hopper!

Keep healthy everyone and do follow the medical advice. This is not the time for silly bravado.

Cheers

Pero

Thread: Powder coating
04/03/2020 07:55:33

Definitely plastic.

But as Joseph Noci points out there are plastics and there are plastics.

I have seen the outdoor furniture were the coating falls off in a year or two of outdoor use but I also have aluminium framed windows on my workshop ( exposed to sun and rain ) where the powder coating is as good as new after some thirty odd years ( well a bit grubby but it is the end of summer after all ).

As with all other surface finishes I assume it comes down to preparation, the quality of the coating material and the application and finishing procedures.

A slightly related grumble ( and apologies - I do not mean to hijack the thread) is the Chinese paint which quickly turns to a dull finish and then comes of as a powder on anything that touches it - namely me. If anyone has a suitable method for stabilising it ( in preference to reducing affected parts to bare metal ) and recommendations for a suitable finishing coating I would be very interested to hear.

Cheers

Pero

Thread: Coal being phased out
29/02/2020 08:02:49

On the right track Dave but no cigar.

Being north of the equator the extraction of water about India is not having a big impact.

It is the export of iron ore from Australia and Brazil ( about a billion tonnes in 2017 ) that is causing the problem.

Although a lot of it is exported as iron and steel, not that much of it comes back south of the border ( equator ).

Thread: Explosion in Ophiuchus galaxy cluster
29/02/2020 07:55:23

Well. At least we now know the reason for climate change!

A little further confusion - I thought that once black holes went bang they stopped being black holes and just went back to being space. Very odd.

Thread: camlock back plate
19/02/2020 07:33:54

Excellent video, thank you.

I had thought of trying to do something similar but the cost of a slab of steel for a D1-6 backplate is higher than the cost of a 250-300 mm ready machined one! Not the first time of have experienced this.

Pero

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