Member postings for Martin Whittle

After having a couple of blades break on mine, and wondering about some of the noises, I realised that the blade was trying to climb off the flat section onto the locating ridge at the edge of the idle wheel (the one you adjust for tension, the opposite end from the motor).

I don't recollect details but the wheel mounting can be adjusted for correct alignment in terms of its angle relative to the blade path.

Hope this helps

So you can use a left hand drill bit to drill out broken or damaged screws - it can help to 'unstick' the screw from the hole.

For when you have fitted the slitting saw the wrong way round

That makes sense. And a woodscrew can conventionally be fitted with a 'Birmingham Screwdriver'

https://www.standingwellback.com/birmingham-screwdriver/

Martin

Edited for spelling!

Edited By Martin Whittle on 27/08/2021 19:52:35

Hello Brian

Thank you very much for this, I shall give it a go!

Regards Martin

Hi Paul

Welcome to the asylum!

I have had the Zyto for some 35 years. I have a larger Warco lathe that is my usual workhorse, but the Zyto is still used for some smaller stuff, particularly when I am disinclined to change the chuck or other setup on the Warco. The Zyto + 3 jaw chuck certainly used to give better runout (centering accuracy) than the Warco, but it seems a bit more 'loose' now. I probably should readjust the bearings, but I am nervous about tightening them up too much - not sure about the degree of danger of cracking the cast iron if overtightened

Martin

Sorry Neil but I cannot agree with that. Despite arguably falling educational standards, most English people still can put a sentence together, in a logical word order!

Different order to Latin, but the order of a Latin sentence could be argued to be more logical. A bit like the difference between Reverse Polish versus Algebraic notataion for computer./calculator operation: introduce the numbers / nouns in the correct order, then state the operator.

The latin words have endings added (remembering school recitations of declensions and conjugations which indicate the nominative, accusative, future present or past, singular or plural etc) which further make the make the sentence unambiguous, and render words such as 'the' defunct.

Martin

Just for a change, I acquired a 6mm Wolf Jahn watchmaker's lathe, one has to find somethinig different to do in lockdown! A bit smaller than my other lathes, at 40mm centre height. Anyway, a 'sensitive' tailstock drill attachment finished yesterday:

Nothing much to locate the attachment to, so I used the taper on the front of the tailstock. The drill spindle screw on the back end is undone to remove the assembly, the screw will get knurled when my fine knurling wheels come in!

Martin

A different take on a similar subject is to make an adaptor to mount the drill onto the quick change toolpost. More flexible in application, and more degrees of freedom to position the tool, or indeed to to get it misaligned!

Note the thread for the Dremel mount is 3/4 BSF, with a short counterbore for the shoulder section. The mounting hole centre is 12mm above the base of the adaptor bar to match my lathe tools, although the QCTP is of course fully adjustable for height.

The same holder can be used to mount the drill onto a rotary tool stand. The picture below is based closely on the design in http://mikesworkshop.weebly.com/rotary-tool-stand.html , so I claim no originality.

I have not tried it in anger yet - it has just been an interesting lockdown project!

Martin

And the universe is getting on towards half of a quintillion seconds old.

Another odd fact: as a rough guide, many animals live for around one billion heartbeats. I suppose we do quite well at usually over 2 billion.

The second image is of a pair of Geissler tubes. These contain gas at low pressure, and are lit using a high voltage between the ends. Basically early neon tubes - or whatever gas you would like to try.

PS you can get any number of ribs on the belt that you want - it apears the dealer just cuts the width you want off a wider belt of the standard length, although multiples of 4 are most common, Most common type for likely 'amateur' applications is the 'J section, 2.34mm rib pitch, I purchased a belt, £9.95 (seemed standard price for almost anything of similar style) with free delivery, from Bolton Engineering Products only today to play with - they have web and ebay sites (BoltonBearings).

No link with the supplier beyond eager anticipation!

For my application (700W motor, 25mm pulley, 5000RPM max) it appears a 4 rib belt is enough. Also good for for 1 kW with higher tension, but 1.4kW needs a 6 rib belt according to the Hutchinson application . My wood lathe, Axminster with 1.5kW motor, at lower speed (higher torque) and higher pulley diameter, (better belt wrapping/grip) uses a 10 rib belt.

NB quoted 'belt width is often that of the pulley top including flat edge areas, not the belt itself, so the 4-rib part you might find having a quoted width of 13.5mm, not the expected 9.36mm. Pulleys found on the web are generally expensive taper-bore fittings, not what I want. So probably buying some 100mm diameter 6082 soon for a bit of machining!

Martin

I have been looking at this myself, and thouroughly endorse Micheal Gilligan's recommendation of the Hutchinson Transmission website application to have a play around with power levels, pulley sizes, speeds etc, having had a play with this recently.

My new application - looking at a belt drive conversion of a Warco WM16 mill. I am generally happy with this, but when I push it (not really that) hard, I get a severe 'shrieking' noise from the transmission area , no idea what this is (some resonance set up between the primary drive step down to the intermediate shaft and the secondary step driving the spindle?)

So, as said I have been looking at belt drive, step down of 4:1 could be a bit of a problem, 5000 to 1250RPM for lower speed range, therefore requiring around 25mm pulley on the motor to 100m spindle pulley, and around 120N or more belt tension. So twice this + overhang factor on the motor spindle, around 240N plus 20%, so 30kg or 65lb sideways pressure on the motor end bearing (at 25mm driving pulley, 5000RPM, 0.7kW), Bit concerned about motor bearing.

But for Bibnah:

My 'middle sized' lathe is a Zyto, and iniitially came with a leather belt which was very close to falling apart at the clasp between the leather belt ends. Many years ago I replaced the belt by a Halfords poly-v fan belt, seen in photo, with ribs down onto flat puuley. It is a little slightly wider than pulley width - abolutely not a problem apart from being to wide for the smallest pulley / highest speed,step next to the bull wheel, which would be too fast a settiing anyway. The poly-v works very well on flat pulley for this light loading, and you absolutely do not need to machine your existing pulley to fit.

Martin

Hi Gents

Thanks for the advice, many interesting comments much appreciated.

I thought I would give an update on this. I was looking around on eBay, and found many PCB drill sets on 3.175mm shanks. There are suppliers in China doing sets very cheaply, below £4 for a set of 10 drills typically in the 0.3 to 1.2mm range. Some sets go down to 0.1mm!

I bought a set from a UK seller, ‘Flux Workshop’, for a set for £5.09, and it was delivered on the second day after ordering, the postage label indicating a 24 hour service. The 0.3 to 1.2mm set was one of the available options under item 113799603202. They are of Japanese manufacture rather than Chinese.

Looking at them, they look well made, with the point ground reasonably symmetrically. There is some variation of the grinding angle on the tip between the various bits, but this of minor importance. The helix angle is quite fast as is usual for a PCB drill.

I briefly tried a 0.6mm bit on the lathe, going into a brass rod which had already been ‘pecked’ with a centre drill, it worked very satisfactorily.

I am not clear on the bit material, the description on this item does not give this, but many similar adverts mention ‘tungsten steel carbide’ which I assume relates not to tungsten carbide but a form of HSS? The bits are strongly magnetic (tungsten carbide is usually just weakly magnetic), and shiny like HSS. I would personally expect a fairly high breakage rate if they were tungsten carbide!

I am very pleased with them, especially at this price.

Martin Whittle

NB Pero asked about sharpening small drills. I have never tried this, but there is a simple jig on https://modelengineeringwebsite.com/Small_drills.html by Graham Howe, which may be worth looking at.

Where would you buy small drill bits, say in the range 0.4 to 0.8mm?

I tried to drill a small brass piece the other day on the lathe with a 0.6mm bit . After an initial location peck with a centre drill, I found the small bit was not at all interested in drilling, but just started to physically spring into an arc with increased tailstock pressure.

The bit was from a set I bought from China via eBay, a few years back, 10 off many sizes from 0.4mm to 3mm or so. On examining the bits with an eyeglass, I was shocked at the tip grinding: I did not expect it to be necessarily that perfect and symmetrical at the price, but the smaller sizes often had a remarkably rounded and amorphous tip, or a very asymmetric one. Or even no sign of a central point! Larger sizes appeared very much better, but I have not actually tried them as I have other drills for above 1mm.

So on to a ‘Microdrill’ set bought at a show. This was better, but nothing to write home about. I than found that I had a few higher quality drill bits stored away in a bag, and one of these worked as perfectly as expected.

Therefore I would like to obtain a set of bits of the size suggested above. Prices seem to have a very wide spread. E.g.

• UK Drills do 10 off individual sizes for prices under £1.30. I have used UK Drills previously and been very pleased, but have not tried them for small sizes.
• Arceurotrade do ‘polished drill bit sets’, 20 piece set, 2 off sizes 0.3 to 1.3mm for £3.47. Sounds absolutely perfect, but how good are they? I have a couple of 1.3mm cobalt HSS bits I purchased from them a few years back, examination shows they look good apart from having the tip a bit off centre, maybe only 0.1mm, but that is a very significant amount on a small drill, and I want significantly smaller sizes.
• Cousins appear very trustworthy and clear: they stock a number of classes of drill bits. They recommend that for metal, use bits from Dormer. No problem with this, although the price is obviously higher for a quality item, generally north of £3 each, rising to £6.75 for a 0.2mm bit (now where did I drop that little bit on the littered workshop floor?). Their other ranges are said to be suitable for soft materials such as ‘wood, wax, and leather'. Fair enough, and also describes the bits I have, fully capable of battering their way through a sheet of balsa.
• Cousins also carry 2 manufacturers versions of ‘jewellery drill bits’, small bit diameter on 2.35mm shank, relevant prices either around £1 or £3.

So I would like to buy a set with more than 1 of each size to allow for the odd breakage. I have probably psyched myself up to paying around £3 per bit for a quality item (either Dormer or A*F parts from Cousins), but would be interested in other’s experience.

Re. the ‘jewellery bits’, these obviously can be used in chucks of greater minimum capacity, have others found them good?

Martin

That may be the case for some. However, for the bulk of our readership who are over the age of 10, the odds are estimated for some representative ages:

• 1 in 500 below the age of 40
• 1 in 250 in your 40s
• 1 in 28 in your 60s
• 1 in 7 in your 80s

See https://www.worldometers.info/coronavirus/coronavirus-age-sex-demographics/, also my emails of 4 March and 22 March on the Coronavirus thread https://www.model-engineer.co.uk/forums/postings.asp?th=150094

Current generally quoted death rates appear typically far higher, but are warped because of under-reporting of cases that were very mild and therefore not tested.

Martin

Edited By Martin Whittle on 29/03/2020 19:59:07

I see that the USA now appears to be the main hot-spot for coronavirus.

Looking at the data currently (11:00 GMT on Sunday 22 March) on **LINK** , and on the pages linked from there for individual countries, USA is making rapid headway up the chart.

Future projected levels must be approximate, but:

China currently has 81,054 cases, daily increase around 0.05%, so expect around 81,200 in 4 days time

Italy has 53,578 cases, increasing around 14% per day, so around 90,000 cases in 4 days time

USA has 27,111 cases, but increasing around 35% per day, so also around 90,000 cases in 4 days time

So by next weekend, the USA looks headed to be the worst affected country in terms of total number of confirmed infected cases.

I suspect the figures are generally very suspect, in terms of unreported (and generally milder) cases. For example, Italy has a very high death rate, implying true infection rates are much higher.

I better not comment about leadership of the USA!

It also cannot help that the USA does not have a modern healthcare system freely available to all, as is available in Europe.

There has been a bit of a run on toilet paper

Also staples such as flour, rice and pasta are being hit.

Hand sanitising gel is unobtainable locally, but I have plenty of meths and isopropanol . Painkillers such as paracetamol and ibuprofen also going fast but seems plenty of supply.

Local Waitrose seems as good as ever on its fresh bread suppies - if you go before mid morning, they have not put it out yet, if you try in the afternoon it it is all all gone.

Based on emails I have sent to my own family over the last couple of weeks:

Interesting plots (look at 'rest of world ex. China' on: **LINK** . Click button below graph to change y axis to log scale (but note the last 3 points on the graph are extrapolated figures for next 3 days)

Also, more noddy graph of same data on:

**LINK**

So over most of February, the log graph is a remarkably straight line showing 10 fold increase over any 3 weeks.. Since around 20 February it has increased to a factor of 10 over 12 days.

So allowing maybe 10-fold increase in cases every 2 weeks, if this continues, most of global population could have been exposed to the virus in around 12 weeks::infected then 1 miillion times more numerous than now, nobody left to infect!. I presume this is where the 12 week figure recently quoted by health secretary Matt Hancock comes from.

Expected mortality at minimum estimate of 1% for near 8 billion population gives around 80 million deaths, near double the 1918 flu pandemic. Note typical recent mortality at nearer 2% is much greater than current general flu of around 0.1%, and is also greatly dependant on age But data is still at very preliminary stage.

Notable age dependence of fatality rate, **LINK** , brief summary extract (ages relevant to various generations of my own family):

• 0-9 years: no fatalities yet recorded
• 30-39: 0.2% fatality
• 60-69: 3.6%
• 80+: 14.8%

Hope it does not continue like this, but I would have to have a good reason to believe so. Can the spread be contained? One hears platitudes on the lines of 'it will all die down in the spring, when we open our windows and get out more'.

I was wondering about sending a message about this to my family back in January based on the Chinese data. The prognosis appeared clearly much worse then with a mortality rate of 4%.and projected infection saturation in July, so not so bad now!

So:

• Scenario 1: the infection cannot be contained, leading to global infection and the global death toll of twice that of the 1918 influenza pandemic, when up to 50 million died.
• Scenario 2: the infection is contained through various measures including self isolation, sanitising measures (personal and public), availability of immunisation vaccine, etc. Hoping that this is is how it goes.

Anyway, I am preparing for the worst, but hoping for the best. Good luck to all!

Martin

It was a plasma cutter so I don't expect it to weld!

Martin

Another follow up: two Lidl stores in the Southampton area that I tried this morning had sold out of the plasma cutter, before 11.15am. I was looking forward to an interesting new toy!