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Member postings for SillyOldDuffer

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

Thread: Which is better Thompson or er collets
14/08/2021 10:09:56

Ways to abuse an ER Collet!

  • Fail to insert the collet correctly into the holder. (ArcEuro's description is good)
  • Don't tighten the collet enough (the professionals apply a lot of torque.)
  • Force oversize items into the collet. (Causes permanent damage.)
  • Don't use the full length of the collet to grip the item (Collapses the far end)
  • Consistently use the collet clamped fully down at the minimum end. (encourages failure to tighten enough)
  • Fail to understand ER Collets are replaceable. (Industry chuck them out ruthlessly so beware second-hand 'bargains'.)


Edited By SillyOldDuffer on 14/08/2021 11:25:54

Thread: Unusual Go-No Go Tool?
14/08/2021 09:47:34

The non-linear scale implies the gauge is for measuring intensity rather than a physical dimension, and the peep hole and squared top suggest a simple optical assembly is missing.

As the instrument is a pocket tool, it's used by someone walking about. The peep hole suggests she eyeballs the target. Sound and light, hence heat, are perceived by humans on a logarithmic scale. I think it's for judging the temperature of a furnace or flame for making glass, normalising steel, welding, or melting without boiling etc. Possibly confirming a lighting system is performing to specification.

Any sign of anything mechanical missing at the top? If it's a visual intensity gauge I'd expect the control wheel to adjust an aperture between the peep hole and the lens carrier, now lost.


Thread: Which is better Thompson or er collets
13/08/2021 18:52:52

Can't comment on Clarkson holders from experience, but one advantage to us of the ER system is it can be used for both work holding and tool holding. The same ER32 collet set is used on my mill, lathe, and rotary table (with a Stephenson Block.)

For what it's worth, not much in my workshop, ER collets seem to rule on CNC systems, I guess this is because ER suits automatic tool changers: no need for the mechanism to faff about with a screw thread. They also have wide gripping range, plus the lighter weight/smaller diameter supports high speed Carbide, 30,000rpm woof, woof!


Thread: er25 collet
13/08/2021 11:58:51

I agree with Ian. The ER series are a tool-holding collet normally expecting a shank to go all the way through. I think work should be long enough to do the same. When the holder is tightened, the collet is pulled into a taper which compresses it equally on to the shank. If the shank is too short, the collet collapses unequally, losing grip and tipping the work in the collet, causing poor run-out. Might even damage the collet.

I sometimes use a stub-mandrel to save metal, supergluing the blank to it, and detaching the job later with a blow-lamp. Superglued joints are remarkably strong apart from a sharp sideways blow.


Thread: Centec 2B - New arrival and Q&A
13/08/2021 10:20:09
Posted by JasonB on 13/08/2021 07:10:04:
Posted by William Ayerst on 12/08/2021 21:56:15:

Looks like either someone has tried to enlarge the keyway or it has become seriously worn where the pulley has been moving about on the shaft. Worth sorting out so it does not allow the pully to start moving again.

Worth making a new one I think. Considerable damage can be done once worn components start flopping about. And not just to the worn part itself - shock forces hammer through the drive train, taking years off the life of bearings etc and causing poor cutting finish.

Decent challenge for a keen beginner too!


Thread: Hole diameters for single point threading
13/08/2021 10:00:11

Fools go where angels fear to tread, but it's never stopped me before!

The form of a metric thread, and relative dimensions, are defined whether or not the diameter is a preferred size or not. Details in Machinery's Handbook, and similar tomes. I pinched this chart off the web:


Internal Thread at top, external thread below. For all metric threads H = 0.866 × pitch. It's usual for metric threads to be cut or rolled rounded at top and bottom rather than sharp as shown in the diagram.

Thread tolerances are somewhat complicated, ranging from very tight to downright slack, such as threads that are going to be plated. More info on Tolerance Positions and Tolerance Grades here, but I don't think Joe need read it!

A thread made as shown in the diagram would be an uncomfortably tight fit, hard to assemble, and any error in it's manufacture would cause it to jamb. Force fits aren't acceptable if the joint is meant to be unscrewed, so practical threads are cut with slightly oversized 'V's, in effect broadening the bold line. The difference can be seen by comparing DIY store zinc-plated studding with the same sized thread on an Allen Bolt. Studding is crudely made and slack; the Allan Bolt should be much cleaner, well formed and tight fitting in it's socket.

I think Joe can control how tight his thread fit is simply by cutting less deeply than normal. Cutting less than 0.866 × pitch will create an over tight thread, exactly 0.866 × pitch will fit with difficulty, and cutting deeper than 0.866 × pitch will create an increasingly slack fit. I'd make the internal thread first getting as close to 0.866 × pitch as I can measure (not sure how I would do that!), and then use the internal thread as a gauge to make the external thread a tight fit. Could be very tight, needing a strap wrench, or hand tight, as required.

EN8 may not be a good choice because a smooth surface finish is vital for a tight thread fit intended to be screwed and unscrewed, and EN8 often tears roughly when cut.

A precision collar preventing slop might be an alternative to hard to make precision threads.


Thread: Vise/Vice advise
12/08/2021 10:37:05

I have two vices, both supplied by Warco:


I don't require them to 'last a lifetime'; I'm past my 'Before Date', and the hobby doesn't require me to thrash my tools. I'm sure they will last longer than I do!

The vice on the right is an ordinary 100mm machine vice. That in the centre is a DH1, with 80mm jaws. Note both vices are removed from their turntable bases. Swivelling is rarely required, and the bases take up space and reduce rigidity. Turntables are almost unnecessary in my workshop, and many others agree. For the same reason I'm suspicious of Angle/Swivel vices - bendy!!!

Although the DH1 is only 80mm wide, it's holding capacity is greater than the 100mm vice. Its jaws can be unbolted and moved, providing much wider jaw opening. I mostly use it in the plain 80mm configuration, but every so often the wider grip is handy.

The 100mm vice has a couple of vices, ho ho! There's a slight tendency for the jaws to lift on tightening, which is so common that it's respectable in professional workshops to tap jaws and work down with a mallet to correct the problem. More serious is a design compromise. The rear jaw has a stress-relieving gutter, also serving to collet swarf. Unfortunately spacing parallels tend to fall into the gutter and making sure they haven't is a time-waster. Not a problem with thicker work, but I mill lots of stuff under 10mm thick, which is spaced carefully to height.

There's no doubt the DH1 is a better vice, but 80% of what I do can be done just as well with an ordinary one!

I think both vices are about the right size physically for a WM18. Wider jaws come with a disproportionate increase in size and weight. A 100mm vice weighs about 10kg, 125mm about 15kg, worse as they get bigger!


Edited By SillyOldDuffer on 12/08/2021 10:39:03

Thread: Knurling tool
11/08/2021 10:00:15
Posted by Steviegtr on 11/08/2021 03:07:27:

Posted by JasonB on 07/08/2021 07:11:48:


Maybe it's not the tool that is "not fit to use" wink 2



I do not know why you support some not so well made imported, far eastern tools & continually belittle me for trying to point out the shortfalls of such pieces of equipment.

I will be doing a complete build video of the Hemingway to the best of my poor ability, I just hope some will like what i am going to do. Sure you can slag my work,.

But you must remember i am an Electrician by trade . With knowledge of many things & a master of none.


With respect Steve, perhaps the problem is you! No shame in that, because everyone has to start somewhere, but in engineering it's never good to rush to judgement before understanding the problem.

Poor results in the workshop are due to Tools, Material, or the Operator, usually in some new situation. Of these the biggest problem is the operator, because he is responsible for planning the job, choosing materials and tools, setting machines up, and optimising feed-rate, depth of cut, cutting speed and much else. It's not easy, requiring a steady hand and applied judgement. Learners cannot assume tools 'just work', they have to be used appropriately, which comes by reading, training, and practice. Learning has to be approached with a degree of caution. Perhaps the worst training material available to the home machinist are the Internet videos made by amateurs who don't properly understand machining yet. Lots of good machining advice on the internet, but also far too much third-rate junk: videos just as flawed as the cheapest, nastiest, Chinese tool. Over-confidence is no substitute for skill.

I'm on the forum to learn and to share what I've learned. Happy to be told whenever I get the wrong end of the stick because everyone on the Forum benefits from the correction. It's not about my ego and fantastic* work! For me the forum is about improving what Model Engineers know and do. Better for posts to be politely honest, rather than agree with SillyOldDuffer's latest faux pas in hope of sparing my delicate feelings!

Doesn't help when bad workmen blame their tools. Leads to beginners fretting about 'quality' and flapping around the second-hand market when they would be better off learning for themselves by cutting metal.

Anyone who thinks I'm wrong about anything I say on the forum is free to say so, Please do, if the explanation is good, I should change my foolish ways! If it's any consolation, I've lost count of the number of times Jason has put me right. And he's not the only one, blush. Done me the world of good.


*Fantastic can mean 'extremely good', or 'absurd, crazy'. Readers choose which applies to my efforts, not me.

Thread: Colchester Bantam Lathe
10/08/2021 11:34:10

One way of getting it across a lawn, or other rough surface, is to lay temporary track of hefty boards (1" thick plywood).

Difficult to advise on moving heavy unbalanced equipment because there's a certain amount of skill in it, and skills are best learned bu doing easy moves first. Worst case is a bunch of over-confident enthusiastic amateurs crushing someone under the machine. If it topples, it's natural to try and stop it: bad move - wrong! Top priority is to get out of the way! That said plenty of big machines are moved successfully, with simple equipment: rollers, levers, ropes, and a small team of fit blokes.

As they are taught in the Army 'Prior Preparation Prevents Piss-poor Performance'. Assemble a team and choose a leader; this shouldn't be the most gung-ho person available; be suspicious of anyone who wants the job. Drum into everyone they do what the leader says, when he says it. This is because teamwork is essential: lift together put down together. Plan the route, and rehearse it, paying special attention to awkward bits: doorways, steps, slopes, tight corners, and obstacles. How much planning depends on the geography. My workshop has a concrete garage door, accessed from a flat tarmac drive with a short ramp over the public pavement down to the road. The main danger is the tarmac, because it's surprisingly soft, otherwise rolling a big lathe would be 'easy'. My garden shed is far more difficult: steps to garden from road. Sunken path with steps to shed, or lift lathe 300mm from patio to soft lawn and then manoeuvrer machine across grass past goldfish pond and somehow swing past a tree surrounded by a low stone wall, and through a narrow shed door. Lathe in shed needs a lot more thought than lathe in garage.

Be good if you could take photos of the move and share your experiences. Interesting problem, but if it went in it can come out!


Thread: Lathe gears
10/08/2021 10:39:33

Welcome to the forum David,

The Mx210 doesn't seem to be sold in the UK but this picture shows what looks like a WM180


The guide to the fine feed banjo settings is nearly readable, and consistent with NDIY's advice: you can get close by pairing large and small gears. The diagram should help:


I guess this reads:

Gear A=70, gear B=24
Gear D=80, gear D=28
Gear E=85, gear F=H (H is a spacer)

The principle is big gear/little gear pairs chained to turn the lead-screw much more slowly than the spindle. Usually, the normal fine feed is the slowest combination that can be obtained, that is the gear with most teeth is on the lead-screw. The exact ratio may not matter very much, so feel free to experiment for best result.

Much more important to get the gears in the right size and order when threading, but that's another problem.

Perhaps a WM180 owner will comment? Is this the same lathe, and what does Warco's change-gear chart say?


Thread: GigaFactory
09/08/2021 15:05:47
Posted by J Hancock on 09/08/2021 12:52:49:

On the last point , I think you will find all the big power stations in the UK sat on top of the coal-mine.

Killing the mines , killed the stations as well.


Not in my part of the UK! Not always possible to put coal power stations near mines.

I couldn't possibly defend Mrs T's methods, but she recognised UK coal mining was approaching the end of the line as major part of the British economy Disliking Unions was undoubtedly a factor, but she knew the taxpayer was subsidising British Coal heavily, and that it was considerably cheaper to get coal from abroad.

The reason British Coal is expensive is most of our accessible coal has long been worked out: British Coal is deep coal, difficult and costly to extract, and there isn't much of it left. The early Victorians estimated British coal would last roughly 150 years and they were about right. All good things come to an end.

I've no doubt British coal will be mined again when prices rise, but there isn't that much left, certainly not enough to assure the future. Coal is not the answer to the UK's problem, nor for much of the rest of the world. I also argue that coal and oil are far too valuable as chemical feedstocks to be burnt when electricity can be made by other means.

Climate change is a separate reason for burning less fossil fuels. Not to prevent climate change, because it's too already too late, but to reduce the effects. Naysayers have successfully blocked green proposals over the last 40 years by demanding absolute proof. However the evidence has mounted day by day with nothing to suggest it's wrong, and there's a lot of it now. Within 5 years, I suspect it will be embarrassing to deny climate change because the evidence is becoming so obvious.

Time to change. When a technology falters, try something else. Don't cling to the wreckage.


09/08/2021 10:57:03
Posted by Paul Kemp on 08/08/2021 17:30:21:



At the present time I can use as much power as I like as long as I am prepared to pay, governed only by the size of the incoming supply. I like that. In the future it seems there will be some device or external intervention controlling what I can have, when. I don't like that!

I am also wary of 'smart' technology reliability. Looking at a fleet of vessels old and new, the newer ones incorporating smart systems have lower reliability figures than the old and the cost of rectification almost twice as much.


Apart from emergencies, where it might suit the supplier to selectively disconnect ordinary consumers rather than hospitals, I don't think Smart Meters will make any difference to when chaps fire up their lathes, even though Model Engineers are notoriously careful with their money.

A more likely target is ladies who hoover! There are millions of them, all penny proud, and potentially able to vacuum carpets when energy is cheap, and avoid doing it when the meter warns them power is expensive. Same thing applies to EV's: many motorists only travel short distances and their cars spend most of the day and night parked up. They can pick and choose when their cars are charged, and will probably always go for the cheapest rate available. (I used to commute 30miles per day, and do a 100 mile round trip every third Saturday. Even less now I'm retired. My neighbour owns a 4x4, but during the summer he commutes by motorbike; he enjoys riding it and can weave through traffic jams!) Point is, power management is much more about average behaviour than special cases like the 10% who have to drive long distances at peak times, or want to tow caravans across Europe.

As to reliability, all the cars I've scrapped over the years have gone to the crusher with their Radios and other electronics in working order. What got my cars was mechanical wear and tear; coming up to an MOT with a leaking diesel pump, worn brake discs, slipping clutch, corroding brake pipes, and odd knocking noises whilst cornering can add up to a big bill. And although simple mechanics are reliable don't forget complex mechanics, like a Strowger Telephone Exchange, are hopeless compared with the electronic equivalent. (Strowger exchanges filled a large room and were kept going by constant skilled maintenance. The modern equivalent is a small box in the corner, replaced when it eventually breaks.)

A number of posts point out domestic roof top solar panels are a dodgy financial proposition. Maybe, but solar panels are a better bet than all other home-made alternatives. Driving a generator with a car-engine is horribly uneconomic compared with grid electricity. Problem is domestic installations are too small to achieve economies of scale, their contribution will help rather than solve the energy problem outright. The answer is to think big, for the same reasons coal-powered generating stations are huge. Blyth B's turbine room and boiler house were both 206 metres long, and the chimneys 170metres tall. Plus considerable infrastructure for transporting and storing large quantities of coal and ash: not a back garden operation.

My local solar proposal describes a 17MW installation covering 30 Hectares of land, which is a much lower energy density than a fossil fuel or nuclear plant: UK solar takes up a lot of space for not much power. But this is offset by several advantages: no fuel has to be bought and transported to the site; zero pollution; and the site is on poor agricultural land currently used for grazing sheep, who will still have access to much grass because the panels only shade 30% of the land. Doesn't seem unreasonable compared with digging coal in Brazil, shipping it half way around the world, and then moving it to a UK power station by road, rail or barge.


Edited By SillyOldDuffer on 09/08/2021 11:00:13

08/08/2021 15:30:57
Posted by Paul Kemp on 08/08/2021 13:52:30:

... but I may not have properly understood!

Dynamic Containment (DC) is a means of maintaining the grid at its nominal 50hz within the specified limits. ... DC therefore is a means of load balancing by bringing in additional capacity either to deliver or accept load.


So to archive the objective there needs to be assets available to either provide or absorb power. These assets are controlled by power companies (PC) and with regard to DC and the descriptions seem to be battery based?


Is that how it works?



Well reading about Dynamic Containment made my head spin. The information on the web seems mainly focussed on managing the facility as a paying service rather than the technology behind it. It seems to one of several methods intended to manage energy from multiple suppliers rather than any particular generating method.

I don't understand it either! However, reading between the lines, I think DC is a contracted service allowing a provider to raise or lower the output frequency in order to manage energy in or out. I visualise it working the other way round from Paul, ie dropping frequency reduces power output, or accepts power back, whilst increasing frequency pushes more power out. Otherwise as he says.

Imagine two steam turbine generators connected to a grid. If one of them drops frequency the other will feed power into it and drive it's generators backwards faster; thus the low frequency station 'sees' a reduced load and burns less fuel. On the other side of the grid the other power station at normal frequency 'sees' an increased load and burns more fuel. A third source coming suddenly on line might be ultra-cheap electricity from a wind-farm, which it can 'sell' to the grid by raising it's output frequency so that other power stations on the grid work less hard. The overall effect is to balance the load whilst giving priority to cheap sources. Would be done on a grid supporting many thousands of generators, some of which might be able to absorb and store energy by charging batteries, pumping water uphill, compressing Nitrogen, or electrolysing Hydrogen etc. Many generators of different types work in concert to satisfy consumers.

The frequency changes needed to do this seem to be small, about 0.001Hz, so don't worry about electric clocks going mad!

How electricity is sold wholesale and retail is pretty complicated already. DC looks to be another way of allowing the market to cope with peaks and troughs in demand. It's not the only mechanism: real-time tariffs applied by smart meters will encourage consumers to balance the load by increasing prices when capacity is short, and dropping them on bright sunny windy days when renewables are cheap and plentiful.


Thread: electronic cylinder indication
08/08/2021 09:45:15

Excellent work Werner! Good to see the diagrams being used to improve the engine's performance.

I had no trouble translating Biergarten from the video, but what is K_weg (mm) on the graph? I know it's piston distance ('weg', but what's the K_ ?

Impressed: tasty traction engine with sensors producing computerised indicator diagrams explained in both English and German!

And thank you for publishing the Haeder and Powles diagrams.



Thread: Timeing
07/08/2021 16:52:30

Just a thought, but retarding the ignition, to less that 10° of TDC will make the engine easier to start, though it might not do to leave it that way.

It gets harder for a spark to jump inside the cylinder the more compressed the fuel/air mix becomes as the piston approaches TDC. The problem particularly effects old cars with conventional contact breaker ignition. The battery struggles to crank the engine over, causing the volts to drop, and a weak spark. Once the engine is running, there's plenty of electricity and away she goes, but a cold start with a tired battery is likely to fail, particularly if fuel is cold-condensing inside the cylinder as well.

Electronic ignitions are engineered to deliver a fat spark under all conditions, but this can cause another problem which is the spark not happening because of insulation failures. The CD electronic ignition I fitted to my Vauxhall Victor caused a small thunderstorm inside the engine compartment one dark damp morning - 2" sparks jumping randomly between HT leads and to the engine block; a quick squirt of WD40 fixed it.

You can guess how I know, but with electronic ignition it's not smart to pull the lead off a running engine to check for a spark. The insulation on HT leads isn't good enough to stop a nasty shock...

But check the spark on this model engine, too weak and too strong can both cause problems. Try starting the engine in the dark to make sure the insulation is OK. (Safety first!)



Edited By SillyOldDuffer on 07/08/2021 16:52:50

Thread: Milling on a Lathe with a Vertical Slide
07/08/2021 16:26:08

8 to 10mm, and I'd go all the way through.

Though you can convert a taper tap to a plug tap by grinding the taper off, it's easier and stronger to tap clear through a hole, than it is to blind tap it. Apart from anything else, through tapping much reduces the chance of breaking the tap.

If the bolt isn't allowed to go through the hole, ding the last turn of the thread with a centre-punch to jamb it.

Rule of thumb, threaded holes should be the same depth as the diameter of the bolt in steel, 1½ x deep for soft materials, and twice as deep for mixed metals, like a steel bolt into aluminium plate. So 10mm is good for up a 10mm diameter bolt, and comfy for an 8mm bolt.

Studding isn't strong as steel goes. Studding threads are a loose fit in ordinary mild-steel. Loose threads are easier to fit, but weaker. Cheap and handy rather than aerospace! Studding is perhaps a quarter of the strength of an Allen Bolt of the same diameter because Allen Bolts are are made from stronger steels and with tighter threads.

For this purpose, the extra strength of an Allan Bolt isn't required, because mild-steel is good for 10 to 20 tons per square inch, but never a good idea to replace existing Allan Bolts with studding or home-made nuts. In William's case, his 10mm mild-steel plate would fail before an 8mm Allan Bolt, but not likely to happen unless the lathe has a serious accident!


Thread: Aircraft General Discussion
07/08/2021 10:18:27
Posted by Samsaranda on 07/08/2021 09:50:11:
The downside of being on that unit was that we picked up aircraft crashes, both civil and military, could be pretty gruesome. Dave W

Friend of mine bought a badly written off MG Sports Car for parts and found what was left of the driver's foot jambed under the pedals. My mate was a cheerful boy racer, but he slowed down after finding it...

Thread: Knurling tool
07/08/2021 09:58:32

Bit late in the day, but choice of knurling tool depends on what the knurl is for, and how many are needed.

In my utilitarian workshop, I mostly make things for practical reasons. I'm not into fine models, and rarely care about decorative qualities, because what I make rarely needs to look good. I paint to prevent corrosion, not to improve the aesthetics.

Knurling is done decoratively and/or to improve grip. Decorative knurls have to be consistent because the eye is so good at detecting flawed patterns. Cut knurlers are the go to tool for manufacturing these in quantity with minimum rejects. Bump knurlers are fairly consistent but a bigger stiffer lathe is needed than most hobbyists own. Scissor knurlers allow small machines to produce workmanlike knurls, but they're not particularly consistent. There's a bit of a knack to using them, and I wonder how many poor results are blamed on the tool rather than the operator. Maybe psychology kicks in: the beginner having failed to get acceptable results from an inexpensive tool leaps to the conclusion the tool is at fault. No excuses when the expensive replacement arrives: the learner has to learn how to use it, and does!

Consistency isn't important if the knurls only purpose is improving grip. More important that the knurl be blunt to reduce abrasion. As even well-made knurls on heavily used tools damage the operator, knurls are discouraged in industry. Anyone who doesn't believe me is invited to ride a push-bike fitted with knurled metal handles along a bumpy country lane!


Edited By SillyOldDuffer on 07/08/2021 10:00:55

Thread: Moving vice on mill table....
06/08/2021 18:16:00
Posted by HOWARDT on 06/08/2021 12:37:16:

Tee nuts are not tapped fully all the way through. Use a taper tap and only allow the tap to cut a partial depth thread at the bottom, check that a stud tightens before passing out of the bottom. This will prevent you from jacking the tee nut up and locking it into the underside of the tee slot.

Or tap all the way through because it's easier and then upset the bottom of the thread with a centre-punch. Good opportunity for hammering.


Same reason as Howard explains - to prevent the stud screwing all the way through the T-nut and jacking accidentally.


06/08/2021 10:30:34

You say bolts rather than studdiing? Are the bolts passing through the T-Nuts or bottoming on the nuts, preventing the t-nuts from being pulled tight. Always use studding, not bolts, because a bolt can break the table by jacking the slot.


Apart from the T-nuts not being pulled tight properly, are they too small, ie, not bearing fully across the top of the slot.


Edited By SillyOldDuffer on 06/08/2021 10:31:09

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