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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: Free Fusion360 subs ended
26/06/2022 09:35:28
Posted by Nealeb on 26/06/2022 08:19:27:

I do my main CAD work indoors in my office so might leave F360 running there, but quite often want to tweak a toolpath so would also use it on the workshop PC in the middle of a job. Can't do that now without one shutting down - and as it is about as quick to go back in the house than start/restart F360 on the very slow workshop PC, in practice it's not a big deal. Not two at the same time, but close...

Another case where I suspect Autodesk want to make it more difficult for commercial organisations to use the free edition?

I often achieve this in a different way with Remote Desktop Protocol. Briefly, RDP allows one computer to take over the display, keyboard and mouse of another. Software running on the base computer is operated by the second: with something like CAD there's no need to copy files or install another licence on the second machine.

Fusion 360 and Solid Edge are both installed on my main workstation, which is set up in my dining room. Two big screens, comfy chair, roomy table top etc for serious work. However, in the evenings, I often tinker in front of the telly with a laptop connected to the workstation. The laptop behaves just as if it were doing all the work, but actually the action is on the workstation. It lets me do 3D-CAD, browse the web, do email etc. just as if I was sat in the dining room.

RDP clients are built-in to Windows and can be downloaded for Linux (Remmina). Setting up the Windows server is a little more difficult, it's built-in to Pro versions, but has to be installed on Home editions. Howto here.

Dave

Thread: Single phase milling machine recommendations
26/06/2022 09:12:45

Wanting a single phase motor is an odd priority for choosing a machine tool. Is it because 'old ways are best'? If so, it doesn't apply to single-phase motors!

Getting an electric motor to run on single-phase AC is quite difficult, and the way it's done is always a compromise. The advantage is a motor that runs off ordinary domestic electricity, but they come with many disadvantages: unreliable due to capacitors, centrifugal switches, and delicate start windings, relatively inefficient, they vibrate, and don't like being continually stopped and restarted. In short, a poor choice for a machine tool, unless the workshop only had single-phase power.

DC and 3-phase motors both outperform single-phase types but back in the day, it was expensive to convert single-phase power into DC or 3-phase. Today's electronics can do either at reasonable cost and it's unusual to find new machine tools fitted with single-phase motors. Likewise, many faced with replacing a failed single-phased motor on a old machine, choose to replace single-phase with 3-phase powered by a VFD, which provides speed control, low vibration and other significant benefits.

Another point, of all the parts on an elderly tool likely to need replacing the motor is usually, not always, the easiest. Standardised mountings have been used for years so there's a good chance a new one will just drop in. Not so the rest of the machine: bearings and other spares might be difficult to source, while wear and tear can require significant remedial work - time and money. So I'd prioritise the machine's mechanical condition above all else. The motor is bottom of the list, except watch out for machines with special motors and complicated drive arrangements designed to provide variable speed; they can be difficult to replace, rewire, and worn mechanical parts may be unobtainable or cost more than the whole machine.

Not that many different older small milling machines available. Tom Senior seem more common than Centecs, and jig borers turn up from time to time. Industry and education seem to have preferred bigger machines, especially Bridgeports, and horizontals. Mill-drilling machines of the hobby-type are a more recent arrival, and a good thing too, because they provide a choice of size from table-top to big workshop via modest shed.

Dave

Thread: don young piston valves
26/06/2022 08:38:06

An armchair view for what it's worth!

Industrial experience has shown fitting sliding surfaces by forcing one over the other gives poor results.

The idea is that driving the two parts removes the exact amount of metal in all the right places needed to get a good match. This happens, but it doesn't leave the metal in good condition. As neither of the two parts is a cutter, metal is removed by gouging and galling whilst smoothness is achieved by smearing peaks into the valleys and infilling them with debris. The resulting surface is full of microcracks and weaknesses, and galling causes deep damage.

At first a valve or bearing made this way will perform well, lasting long enough to fool the workman into thinking he's done a good job! Unfortunately, the damaged surfaces wear rapidly; bearings slop, and valves leak.

Depending on the application it may not matter: the bearings and slide valves in model locomotives aren't subjected the thousands of hours of hard running, and it might take years until a slide valve made by driving has to be replaced. The inferior method doesn't matter at all if the engine is tested a few times on compressed air and then displayed in a glass cabinet! But it wouldn't do for a hard working engine intended to give reliable service.

In contrast, lapping takes a multitude of tiny cuts with a fine abrasive, removing metal cleanly without much smearing, and the process leaves a high-polish on a mostly undamaged surface. Although lapping increases the working life of bearings and engines dramatically, it too causes enough damage for industry to routinely apply even finer finishing methods.

Remember 'Running In Please Pass' signs on new cars? Necessary because the bores and bearings were imperfectly lapped and gently knocking off the tiny remaining scars and changing the oil after the first 500 miles greatly increased the life of the engine. Still pays to run a new car gently at first, but it's no longer essential to keep under 20mph for a few months!

Dave

 

Edited By SillyOldDuffer on 26/06/2022 08:38:56

Thread: I may be stupid but
25/06/2022 20:38:38

Posted by Andrew Tinsley on 25/06/2022 20:13:38:

...

My main interest is its single pinion and why it was made thus and by whom.

...

Any chance it can be taken apart? It may not be a scroll chuck, perhaps a different mechanism designed to save time because it doesn't need 3 pinions to be tweaked in turn for maximum tightness:

Dave

25/06/2022 18:22:21
Posted by Andrew Tinsley on 25/06/2022 10:25:38:

Thanks Peak 4,

As there is no identifier on the chuck, I would think it is probably Chinese. I must make a backplate for it and see if it is any good.

Regards,

Andrew,

Could be from almost anywhere. If it's last century East Germany or the communist bloc is a distinct possibility, but almost every country in the world with any kind of industry once made or is still making chucks, most of them unbranded, ranging from cheap and nasty to first class.

Where it came from is almost irrelevant. Try it and see - if it turns smoothly and holds work firmly with typical 3-jaw run-out, it's a bargain. Otherwise, poor performance speaks for itself.

Dave

Thread: Loose table on Fobco Star
25/06/2022 18:07:59
...The current setup seems to work well.

I've attached a picture below for reference

clampondrill.jpg

Just as a side note, and this probably is a slightly daft question but seen as the shim is stainless steel and the column now pushes against the front of the clamp assembly, is this going to cause additional wear to the front of the clamp over time when slid up and down the column? Or would this be negligible?

...

Many thanks

Luke

It will wear faster, most likely where the shim rubs, but I'd expect the wear to be insignificant unless you're into loads of drilling and table movement. Just keep an eye on it, and if the stainless starts to cause damage, try replacing it with a softer metal like Aluminium, or Brass Shim. A spot of oil on the stainless would help keep it sliding rather than scraping or galling.

Good fix, far safer than over-stressing the clamp.

Dave

Thread: Myford M - a few random questions
25/06/2022 17:57:43

Alec, once a photo is in the album you can't rotate them. It's annoying but the only reliable way is to make sure they're the right way up by checking on your computer with a photo-editor before uploading.

However, moderators can twirl them in a post, and if I see any and aren't in a rush, I'll fix them. The 'not in a rush' caveat is because rotating photos sometimes messes up the format of the post and the thread it's in, and this takes much longer to fix.

Anyway, for the delectation of Myford/Drummond fans around the world, here are Alec's lathe photos:

Dave

Edited By SillyOldDuffer on 25/06/2022 17:58:42

Thread: Target for This Month: A 3D Printed Engine
25/06/2022 10:35:13

Yesterday's progress was 4 out of 5 parts printed, which I hope to clean up before attending a compulsory family do. As can be seen lots of support plastic to be removed. Usually comes off without fuss, but there are always small imperfections to be smoothed out.

Unfortunately won't be able to print the last part today because I prefer not to leave the printer running completely unattended.

dsc06609.jpg

Dave

Thread: Amadeal VM25L R8 Milling Machine
25/06/2022 09:41:39
Posted by Andrew Johnston on 24/06/2022 11:53:48:
Posted by Howard Lewis on 24/06/2022 01:25:10:

Alignment time is less than 5 minutes, compared to possibly 20 minutes of winding to and fro, tapping to align...

It takes me significantly less than 5 minutes to align my vice just using a DTI.

...

Andrew

How long practical work takes is often down to a mixture of talent and practice. I'm light on both!

I always align with a DTI and the time taken varies considerably. Usually a couple of minutes, but on bad days I keep overshooting and can take up to quarter of an hour. When that happens best to take a break, because frustration undermines what little talent I have.

I suspect bad days are due to slight differences in how tightly I've nipped the studs - too tight and too loose are both bad, and then results are worsened by my somewhat erratic tapping.

Dave

Thread: Reinventing The Real
25/06/2022 09:06:55

Another excellent build thread and result. I've learned a lot from Jason and the gift keeps coming. I've not cracked the big secret though: how does he work so quickly? I'm still collecting materials for his Flame Licker. My theory is Jason is really Santa Claus and all the work is done by thousands of elves in a giant workshop at the North Pole...

smiley

Dave

Thread: Can anyone identify this loco build?
25/06/2022 08:33:27

The photos:

Thread: Chronometer and Barometer Info Required
24/06/2022 17:49:52

Grace's Guide have a page on the lady. A subscription is needed to scan 'The Engineer' and 'Engineering' magazines, which might have more information.

Thread: How to machine out a metal channel by hand?
24/06/2022 17:34:41

Assuming the channel is impossible to remove I'd file the hoop because it's easier to get at than the inside. Shouldn't take too long with a sharp coarse file. I'd roughly file a series of flats to get rather under wanted diameter, and then smooth the untouched parts a little more carefully to a pop fit.

The only good news is it isn't a precision job. The filed hoop doesn't have to be a circle or have an exact diameter. It only needs to fit where it touches and look as good as the woodwork!

If the channel can be removed, it could be spread more open by forcing a larger diameter rod into the slot with a big hammer or a vice. The wedging rod would need to be about 12mm diameter. The main difficulty is holding the job during spreading. The wooden frame it's already glued into would probably do, but it might get damaged.

You have my approval to use Strong Industrial Language. I often make 'nearly right' errors and the resulting extra bother drives me mad!

Dave

Thread: Target for This Month: A 3D Printed Engine
24/06/2022 16:31:45
Posted by JasonB on 24/06/2022 15:50:50:

If you look at a simples single acting wobbler the inlet is open for 170-180deg and similar for the exhaust . Remember when running on air you will not get expansion like you do with steam so even more need to keep things open for longer.

A double acting steam engine with no lap will also be close to 180/180.

I think poking some ball bearings into the flywheel holes would be more effective and look better too,

By popular demand, ball-bearings it is! (Luckily I have some the right size.)

The valve news is distressing because the printer is running and changing the model would have been easy! However, I expect my milling machine will be able to open it up. (Worry beads out: PLA might splinter -it's brittle, the core is a sponge, and I've never tried to machine it.)

Duncan's comment are valid too, though I did think of it. In theory (which means I guessed), the length of the piston flanks will compensate for not having a cross-head. The flanks can be increased if need be, but it's more friction. The idea of the T piston top is to hang a balancing weight on it if need be.

Like simple wobbler's I think the design is a dead-end in terms of scaling up. Blasting exhaust out of the centre of a spinning flywheel would be anti-social, while the towering heavy piston stanchion and bendy con-rod can't be good.

Print progress: cause for concern. I'm printing 4 parts together and it looks as if one of them has no overhang support. Don't think I told Cura to support overhangs...

sad

24/06/2022 14:48:47

Thanks to the forum I had an urgent rethink this morning and designed a second, simpler engine. Despite many lessons learned, the Mark 1 engine has a lot of moving parts, hence friction, and will take about 24 hours to print, with no guarantee of success.

The second engine doesn't solve everything, but the rotary valve is incorporated in the main shaft and there's only one crank. Fewer joints to leak, only one fixing (holding the flywheel on), timing easier to set up, less plastic filament, and it will 'only' take 9 hours to print. Most important, I think it has a reasonable chance of running.

simpleenginefront.jpg

Air enters at the side and is fed to the cylinder via a slot cut in the rotary valve. It pushes the piston up to TDC at which point a groove cut part way round the rotary valve allows air to escape through a hole in the centre of the shaft, exiting at the flywheel. Section shows the slot connecting air to the cylinder while the outlet slot is closed.

simpleenginefrontsectionjustafterbdc.jpg

Thinking about valve timings revealed another huge gap in in my engineering understanding, so I guessed! The exhaust gap is set to nearly 180 degrees, which is probably fair enough, but the input is open for 38 degrees. That seems like a lot, probably allowing more energy in than is needed to spin the engine. Might blow the piston clean out of the cylinder in which case I shall claim to invented an air-gun...

Anyone know what valve timings are suitable for an air engine of this type? I guess they depend on the required power output, which is unquantified, the friction to be overcome, which is unknown, and the amount of energy in compressed air at operating pressure.

Watch this space, I'm about to start printing. We could run a lottery on the results:

  • After mild fettling, engine runs first time
  • After lots of fettling, engine breaks at the first puff
  • Engine can't run because of basic design errors
  • Engine can't turn because the piston stanchion and con-rod bend rather spin the crank
  • Engine quickly seizes due to plastic on plastic galling

Only two cheats intended: although all parts will be 3D printed in PLA, the outer ring of flywheel holes will be loaded with plasticine and PTFE lube will be sprayed inside.

Dave

Thread: A Mystery Stephenson Bridge
24/06/2022 10:58:24

Posted by Tomfilery on 23/06/2022 20:53:49: ...

Perhaps it was just a nice picture which they had to hand?

Regards Tom

A quick run through the Gutenberg HTML version failed to find that picture, and it certainly isn't Montreal's Victoria Bridge. Many of the book's illustrations are by R.P.Leitch, and the style is similar, so maybe someone at the Folio Society got it wrong.

Couple of interesting insights on George Stephenson the man. Probably a drug addict:

He was habitually careless of his health, and perhaps he indulged in narcotics to a prejudicial extent. Hence he often became "hipped," and sometimes ill. When Mr. Sopwith accompanied him to Egypt in the Titania, in 1856, he succeeded in persuading Mr. Stephenson to limit his indulgence in cigars and stimulants, and the consequence was that by the end of the voyage he felt himself, as he said, "quite a new man."

And, an early example of old men always believing youngsters don't know what real work is:

It was while working at Willington as a brakesman that he first learned how best to handle a spade in throwing ballast out of the ships' holds. This casual employment seems to have left upon his mind the most lasting impression of what "hard work" was; and he often used to revert to it, and say to the young men about him, "Ah, ye lads! there's none o' ye know what wark is."

He was criticising mid-Victorian toughs, goodness knows what he'd have said about Baby Boomers!

Dave

Thread: Can a Washer Reduce Friction by Acting as a Bearing?
24/06/2022 10:14:36

Thanks for the replies gents, even though they confirm my fears about running plastic on plastic. At least the washer idea isn't completely bonkers.

However, the answers tipped me into a rethink about the engine: I need to test how the plastic I have in mind (PLA) performs in a bearing, so something simple is in order. Back to the drawing board!

Dave

Thread: I may be stupid but
24/06/2022 09:55:53
Posted by AdrianR on 24/06/2022 08:34:18:

If you think about the forces on the scroll, it is better to tighten all three, ideally, you would turn all of them at the same time.

...

Exactly.

Even new chucks are imperfect mechanically and the fit gets worse with wear. Although the scroll mostly rotates, it also moves slightly sideways and perhaps tilts as well. Although the unwanted movement is tiny, it's enough to stop the jaws from fully tightening. Turning the adjusters in sequence tends to release jambing due to non-rotary movement, and allows the jaws to tighten a little more. Three is enough.

Worth doing because the purpose of a chuck is to grip work and it needs all the help it can get from the operator! Finking it's not necessary is a poor substitute for not just doing it - only takes a moment.

Quite a good example of a workshop subtlety that a maker of internet videos might inadvertently spread as a bad practice. Very easy for newcomers to copy the well-presented misunderstandings of an inexperienced machinist who enjoys making videos. Experienced machinists often develop inadvertent bad-habits too. The problem is usually failing to have work peer reviewed by a few qualified critics before publication. Write 1000 times before publishing anything: "Individuals, especially me, are really, really bad at spotting their own mistakes.'

Dave

Thread: Antivirus and VPN
23/06/2022 17:25:45
Posted by vic newey on 23/06/2022 17:00:05:

Windows built in antivirus works fine...

That's what I use on Windows. In the past, Microsoft didn't have a good security product, and it was well worth paying for anti-virus software. Not quite so important now, but it does depend on your internet habits. If you're the type who enjoys casually roaming the net, visiting off-colour websites, clicking yes to all and sundry, use the same password for everything and download 'bargain' software, then remember poor hygiene usually results in catching something nasty.

If moderately concerned I'd advise buying a computer magazine to see what's 'best product' at the moment. The effectiveness of antivirus software depends on how technically up-to-date it is, and it's not unusual to find last year's hot product is today's laggard and vice versa. However, all the big names do a reasonable job, and I wouldn't worry too much about which one unless I was a high-risk internet user.

Mac and Linux are much more secure than Windows, and arguably don't require anti-virus at all. I don't know about Android.

Dave

Thread: FORUM DOWNTIME AND RESULTING ISSUES REPORTING
23/06/2022 17:00:48

I noticed! Luckily I was out for most of it, though I'd rather have stayed home watching an Error 500 screen than troll round Tesco's. I hate shopping almost as much as gardening.

Dave

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