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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: Coke for brazing purposes
23/10/2019 10:02:58
Posted by Nick Clarke 3 on 23/10/2019 09:26:08:

In older copies of the magazines it was always mentioned to pack work being brazed well with coke before brazing with paraffin blowlamps. Even as recent as the earlier Don Young and Tubal Cain articles.

Is there any reason why this is not used today? (or is it?) as coke or breeze is still available and as a way to generally heat a workpiece together with more localised heating it seems like it could still be useful.

Is coke generally available? Last time I looked to buy some it was unobtainium in small quantities. (I did find a local coal merchant selling it by the ton.) Coke was common when domestic gas was made by baking coal but we all burn natural gas now. Now coke is specially made for steelworks etc and doesn't seem to be sold as ordinary fuel in bags. Or at least I couldn't find any!

Coke being porous and mostly carbon makes it a good insulator for hot work. Good stuff if you can find it. I'd look at Vermiculite instead, not because it's marvellous or cheap, but because it's available.

Dave

Thread: Changing chucks on Harrison L140
23/10/2019 09:44:39
Posted by David Capewell on 22/10/2019 21:13:15:

I haven’t worked out how to rotate my pictures yet!! ...

That's because it's not obvious! The forum doesn't allow users to rotate photos online so orientation has to be checked and fixed by the user before they are uploaded.

Although it's usually obvious to an intelligent human which way is 'up', a camera has to guess. Any confusion caused is further compounded by digital photos having 4 or 5 different ways of recording orientation which display software can misunderstand or ignore entirely. Mostly it works, but we live an imperfect world.

The cure is to view pictures in an Image Editor before uploading into an Album. If the editor displays wrongly or issues a warning, then the picture can be rotated and saved. Saving writes the human perception of 'THIS WAY UP' unambiguously into the image, and the forum gets it right. Most image editors seem to work, but there's always the possibility of one of them being eccentric too!

Quite a good example why I don't believe in 'common-sense'. Orientation seems obvious to us, but it's not. Right, Left, Up and Down all depend on the ability to sense an agreed frame of reference. If in the UK you believe 'Up' is overhead, then Australia really is upside-down. Or perhaps we are!

Dave

Thread: Two weeks wasted
22/10/2019 15:43:50
Posted by Peter Simpson 1 on 21/10/2019 16:41:20:

Solving problems in one thing, but when plans are not correct what's the point in having them. Building up the valve gear it now appear that the radius rods will not run through the full arc of the expansion links as they foul on the back of the valve crosshead in the lower half of their travel. Should have stayed with stamp collecting !

It seems rather a lot of locomotive plans come with more or less serious errors. LBSC was a genius and tremendously proud of providing all the "Words and Music" necessary to build his designs. Except he didn't! He didn't always do a good job!

LBSC's output certainly includes engines planned and built by him where most of the bugs were corrected before publication. And the plans for his popular engines, widely discussed, are likely to be reliable too. At the other end of the scale, particularly later in life, LBSC published descriptions of engines that may never have been built, perhaps because he was exploring ideas rather practicalities.

Plans for some of LBSC's engines might be incomplete or wrong. Other engine designers seem to have done much the same, ranging from good to bad as time and talent permitted. I suspect many engines were planned with mild errors that were fixed on the job, and the designer never got round to correcting the drawings. And then there's human error - forgetting bits, getting the dimensions wrong, and otherwise failing to translate 3D into 2D correctly.

I'm not unsympathetic to chaps describing engines. It's not easy. Having attempted some design work myself, I'm of the opinion that producing a good design with accurate plans and effective documentation is more difficult than making the object itself.

The forum is a good place to ask before building an engine, and a club should be pure gold. Nothing like the advice of someone who knows the ropes. Not only will they know if the plans are OK or not, they can comment on how difficult construction is and how well the finished engine will perform.

Generally, I don't trust hobby plans much. I often redraw bits of them to confirm my understanding and their accuracy. Nothing massively formal - a quick sketch is often enough to clarify issues. Other times I've been obliged to fully explore parts and their relationships with CAD; modelling in 3D on a computer often reveals details I don't see on the 2D plan.

Maybe dicky plans are all part of the fun. I don't see it that way...

Dave

Edited By SillyOldDuffer on 22/10/2019 15:44:55

Thread: WM 280V lathe with inverter drive advice
22/10/2019 13:11:48

Yes, I upgraded from a mini-lathe to a WM280VF, and it's quite an improvement!

The machine, stand and extras arrived on the same pallet, so quite big, perhaps1300mm by 1000mm and heavy!

The man (a local delivery driver, not a Warco employee) unloaded the package with a manual pallet truck and wheeled it up a short tarmac drive into my single garage. I didn't have to cope with a garden path or steps. Then I broke into the package and dismantled it. Removing the stand parts and accessories leaves a more manageable plywood box about 1300 x 600 x 600mm. The splash back was bolted to the back of the lathe, making lifting it out a little awkward: it can be removed if necessary.

Four strong blokes should be able to safely lift the lathe, but rehearse and take care. I did it all myself with assistance from my daughter. I bought an Engine Crane; you might prefer to hire one. It makes lifting easy and safe but they're not very manoeuvrable. I came slightly unstuck because there wasn't quite enough room to turn the crane through 90 degrees and drop the lathe against the wall. (It would have been possible had I not wasted a foot by temporarily stacking stuff along the wall.) A happy accident, because having the lathe sideways makes it really easy to change gears and get at the controls and electrics through the back access panel.  Think about access to the headstock end before plonking it into a tight space.

Dropping the lathe on the stand was slightly tricky because the lift point is close under the headstock, which means the splay legs of a crane tend to foul the stand bases. Balance is an issue. The lathe is top-heavy, with most of the weight at the headstock end, and the heavy motor tends to tip it backwards. You don't want it spinning or sliding in the sling. One person moving the crane while another guides the lathe into alignment with the stand's bolt holes is much simpler than one person attempting it.

When positioning the sling or ropes, position them under the bed and behind the leadscrew, making sure they won't snag or crush delicate parts like the toolpost.

It's the sort of job that's intimidating the first time, but is much easier the second time.

I'll leave what to do if there's no room for a crane to someone else! Perfectly possible using rollers and blocks...

Dave

 

 

Edited By SillyOldDuffer on 22/10/2019 13:14:52

Thread: Pratt Burnerd 4 jaw Chuck jaw alignment
22/10/2019 12:35:19
Posted by lfoggy on 22/10/2019 12:27:11:

I was planning to position all four jaws the same distance from the centre using a dti, then set the chuck rotating and grind all four jaws at once with a pneumatic die grinder held on the cross slide and rotating in the opposite direction to the chuck. I was assuming that centrifugal force would hold the jaws in position. I only need to remove 0.1mm.

Does that sound reasonable?

Probably not - I don't think centrifugal force is strong compared with the forces applied by a cutter or grinder ploughing into four hardened steel jaws. Never tried it myself but the book method suggests forcibly opening the outside of the jaws into a steel ring. Then the jaws are firmly held whilst leaving plenty of room to get at their gripping faces.

Dave

Thread: Turning a recess in the end of a bar
22/10/2019 12:20:53

I'd drill a 13mm / 1/2" hole of the required depth and then open it out to full diameter with a boring bar. That's assuming the work is short enough to be held in a chuck or the lathe can take a long 40mm diameter bar through the spindle!

If not, to deal with a long bar, I'd take the tailstock off, clamp the bar to height on the saddle, and bore the end recess with a cutter spinning in the chuck. I could probably do a 1500mm long bar that way, before the far end hit the wall, but the method is only limited by the need to support the free end of the bar and plenty of room beyond the tailstock end. (Which I don't have unless I turn the lathe through 90 degrees and open a door!)

My problem is, how does a lazy bloke with no money get someone else to sort out the brambles he's allowed to take over his garden. As it's I nice day I've been forced to tackle it this morning, and I HATE GARDENING.

Dave

 

 

Edited By SillyOldDuffer on 22/10/2019 12:22:50

Thread: Warco GH1224 Wiring Diagram
22/10/2019 11:10:12

Failure of a suppressor capacitor would explain the symptoms. The poor things are connected directly from Line to Neutral and from Line and Neutral to Earth. Although specially rated for this purpose (X and Y), they do go pop.

They fail by causing a short circuit, but it's only temporary because the capacitor's innards vaporise like a blown fuse. The brief short is plenty enough to cause a trip, but because capacitors usually die open-circuit everything appears normal when power is reapplied.

The purpose of the capacitors is to stop any Radio Frequency excrement produced by the machine being broadcast via the mains wiring. They stop the machine blotting out radio, tv and communications services.

It's a good theory, except John Haines' Hinkley's Grizzly Diagram doesn't show any suppression capacitors! Possibly there are some in the Control Panel circuitry.

Dave

Edit, silly mistake corrected thanks to John Hinkley!

 

 

Edited By SillyOldDuffer on 22/10/2019 11:24:53

Thread: Stepper power for autofeed on lathe
21/10/2019 16:56:53
Posted by Neil Wyatt on 21/10/2019 14:04:17:

Note, Dropbox free isn't intended for image hosting in this way. You could end up exceeding your bandwidth limit if a picture gets displayed a lot with the result your account gets throttled or limited.

Neil

Good point!

I believe the bandwidth limit on a Free Dropbox account is 10Gb/day. The photo I used as an example is 1.3Mb, so about 8000 downloads of that would do the mischief. (8000 downloads isn't much in web terms.)

Phil needn't panic though : since he started his thread, it's averaged about 260 views per day, quite respectable but not Top of the Pops. Putting the same Dropbox pictures on a busy thread like 'What did you do today' would be more risky, though I think all Dropbox does is send 404 Errors until next day's ration becomes available.

Dave

21/10/2019 12:59:30

Bit of research into how Dropbox manages images has revealed all. Although Dropbox shared links look just like ordinary web image source URLs, they aren't! They actually activate a management layer inside Dropbox that presents the image, as I suggested earlier, as one of many. In consequence Dropbox links can't be embedded successfully in a webpage because Browsers expect a single raw image. To keep the Browser happy it's necessary to bypass Dropbox's management layer.

One solution suggests it can be done changing the query string from, for example,

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

to

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?raw=1

Didn't work for me, perhaps because the method is historic. Instead it seems Dropbox now provide direct access to embeddable images by requesting them from a different server. Rather than:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

try

https://dl.dropboxusercontent.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

Fingers crossed, that does work. Not sure it's a good way of managing images though. I prefer the forums own Album system for the reasons given by Frances. Although a shade clunky and basic the album avoids many technical issues and is future proof in that it should last at least as long the Forum.

Dave

Thread: Pratt Burnerd 4 jaw Chuck jaw alignment
21/10/2019 10:42:51
Posted by lfoggy on 20/10/2019 20:37:26:

...

runout.both on the periphery and on the face. The clamping surface of the jaws however are not parallel. They are the opposite of 'bell- mouthed' as in the pic below. The taper is consistent on all four jaws...

 

 

 

Sounds like a manufacturing fault to me. If so, probably explains why the chuck is still in unused condition!

Even the best manufacturers have occasional quality problems due to faulty machines or human error. Inspectors don't catch everything especially if they operate a random sampling system and it's far from unknown for factory rejects to be retrieved from a skip and sold privately. Not everyone in 1980's Britain was honest!

But is it the jaws or the chuck itself that's faulty? If the jaws are at exact right angles, maybe the chuck's T-slots are off.

Dave

Edited By SillyOldDuffer on 21/10/2019 10:43:49

Thread: Slideways oil
20/10/2019 16:03:34
Posted by old mart on 20/10/2019 14:43:24:

Don't be put off by modern synthetic motor oil being thinner, the main reason why these oils contribute so much to engine life is their superior lubricating qualities precisely when the greatest wear is present, when the engine is cold.

Can you provide a reference to that Old Mart?

I believe the problem addressed by thin oils is making sure the important parts of a cold engine aren't starved of oil whilst the engine slowly gets hot enough for the oil to flow freely at operating pressure. The thin oil doesn't have to be the best lubricant, it just has to get there! It's a bit like the car is being treated for clogged arteries, thin oil rather than blood thinners like Warfarin and Aspirin.

Wasn't able to find anything supporting my understanding, but I don't think I dreamt it! I could be wrong and not for the first time. However, if I'm remembering correctly, winter motor oils will be inferior on a lathe to bog-standard 20/40. All a tad pedantic though, I doubt the reduced slipperyness would make much practical difference on a lightly used machine tool.

Dave

20/10/2019 14:30:35

As NDIY says, WD40's lubricating properties are temporary and using it might even be harmful: I use WD40 to clean oil and grease off and it's a very thin lubricant at best.

Mostly I use old-fashioned 20-40 motor oil because it's cheap and readily available. I avoid modern types like 5W40 because they're designed for hot engines. These oils are thin at low temperatures (which aids winter starting), but thicken up to lubricate properly as the engine heats up. As Lathes don't heat up like engines, they never get the full benefit! Modern oils are also more likely to contain additives which may not be ideal for a lathe.

ISO32 Hydraulic Fluid is good for lubricating machine tools; I buy it when I see it.

Slideway Oil is better than motor oil on machine tools because it's distinctly sticky. Ordinary oils tend to get pushed off slides leaving them dry, making regular squirting on of new oil advisable. Slideway Oil lasts longer between applications and is less likely to run off the vertical slide on a milling machine.

That said any oil is much better than no oil and hobby lathes really aren't fussy.

Dave

Thread: Stepper power for autofeed on lathe
20/10/2019 11:29:45
Posted by Journeyman on 20/10/2019 10:07:50:

Must be an iPad thing all the images show for me (Linux Mint, Firefox).

John

Not working directly for me on Ubuntu/Firefox. However, I can see the pictures if I right click on the image space and select 'View Image'. (This loads an application to display the image outside the browser, ie independently of the web-site and browser combination.)

Edit: The brilliant theory that follows struck out below is WRONG!  I should have been able to display one of Phil's photos in this post, and it doesn't work...   Back to the Drawing Board in sack cloth and ashes!    

The only peculiarity I can see in Phil's Dropbox links is they all append a query string, query strings being a way of passing extra information to a server. I think it's telling Dropbox that the image is one of many, so that - if called by suitable software like an Image Viewer - Dropbox can download a series of images as from a slide-show magazine. As the forum/browser combo only expects a single image per link, my guess is the extra query parameters are illegal in that context. The Browser expects only one image, not the first of a list.

Assuming my theory is correct, it's not a forum problem. The forum just allows writers to insert links to remote images that are passed unchanged to the readers Browser. It's the writers job to get his external links right! Technically, the missing images are due the readers web Browser not coping with a query string copied innocently by Phil from Dropbox.

However, I think it's easy to fix. An example, with the unwanted query string in bold:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg?dl=1

Removing the ? and everything after seems to create a working link:

https://www.dropbox.com/s/i0ug22ojhy4ajt7/2019-10-19%2020.32.37.jpg

Once Phil's posts are locked, links can only be changed by an administrator. Phil can tweak the links when first inserted and while the timed edit window is open.

Dave

 

Edited By SillyOldDuffer on 20/10/2019 11:37:15

Thread: windoze 10
18/10/2019 15:44:51
Posted by Versaboss on 18/10/2019 14:12:38:
Posted by MM57 on 14/10/2019 20:20:20:

...

"Open Linux shell here..."

And it does as well...so I can ls -l, ps -ef, grep, awk etc in my windows folders from a command line

... when I do the steps above, I don't get a Linux shell, but a window with a "Windows PowerShell".

I'm beginning to think there are different variants of W10 around...

Kind regards,
Hans

There are indeed several variants of Windows 10, plus what's loaded by default on a particular computer depends on the hardware vendor. The bash shell (Linux) is an advanced developer feature, far too scary for ordinary Microsoft groupies. It usually has to be switched on by an Administrator from Settings->Update&Security. This set of instructions describes all the steps.

The bash shell is the Linux equivalent of Microsoft's PowerShell, not a full Linux installation. The extra power bash provides might only be useful to command line and scripting gurus, not the average civilian! Powershell is well beyond most Microsoft users and Bash goes to the next level. Very useful if needed, mostly not!

Dave

Thread: Tapping drill size
18/10/2019 10:26:12

Posted by IanT on 17/10/2019 22:04:24:.

...

Instead I use the 65% flank engagement recommended by Tubal Cain in his ME Handbook (my copy is the 1993, 8th version - page 63) which for an 8mm (1.25mm pitch) thread is given as 7.1mm. These sizes work very well and makes tapping a far more relaxed process - and I've never been concerned about the strength of anything I've tapped using this thread engagement.

...

Oodles of good advice in Tubal Cain's Model Engineer's Handbook. I should read it more often!

In Section 4, he explains that most tap drill tables are designed for tapping machines fitted with slipping clutches and automatic reversers. He says: 'The tables are designed to accept the higher thread engagements found in production workshops are not suitable for hand tapping.'

Therefore his tables of tap drill sizes in Model Engineer's Handbook have been designed to give at least 65% engagement in small sizes (below 3/8", and up to 75% for larger sizes. Thus he recommends 7.1mm for M8 rather than the usual 6.8mm.

There's also a table of recommended engagements by material. This ranges from 50% for Stainless Steel (the nasty tough type, not the free-cutting variety) up to 70% in Brass and 75% in Cast Aluminium. He also points out higher engagements are needed when tapping sheet metal - at least 85%.

Dave

Thread: Be gentle with me.
18/10/2019 09:59:21

Posted by lee webster on 17/10/2019 18:03:43:

... Fusion is supposed to run without internet connection, but it refuses to on mine. ...

Lee

The main thing I don't like about Fusion is it's a Cloud product. Although designs are stored locally - 'cached' - for performance reasons, they're also copied to a central repository on the web. The web copy is the master, most useful when a team is working on different parts of a large project.

Fusion does work off-line, but only within limits:

  1. Installing the product requires creation of an online Account and downloading an installer that does further downloads as the package is built. This stage requires an Internet connection.
  2. In order to start Fusion the first time it is necessary to login with a password. This is validated against the central account and requires an internet connection.
  3. Not having an internet connection later means the product isn't kept up to date. As it is still being developed, Fusion is frequently upgraded with bug fixes and new features, sometimes every day .
  4. Not tested it but this is what I think happens. Once a user has logged in, Fusion remains active for about a month. During this time it's possible to work off-line but Fusion eventually Signs-Out automatically. Then the user can only reactivate Fusion by logging in with an internet connection. Once reconnected, her project is uploaded to the cloud and any backlog of upgrades downloaded and installed.
  5. If a user signs-out manually at any point, an internet connection is needed to log back in again.

The purpose of the arrangement is to allow Fusion to carry on working during temporary network outages and to allowing work to continue on a mobile computer over a short holiday. It doesn't support unrestricted off-line working like Solidworks or FreeCAD.

Thread: Anyone know about buying freehold to a house in the north
17/10/2019 17:55:37

Freehold can also come with strange covenants and conditions. My house deeds state that the pub at the end of the road has the right to discharge sewage across my garden! (The pub is Victorian, built when the area was still fields.) Not too worried because my house is at least a metre higher than the pub and Public Health legislation forbids spraying human effluent about. The minerals rights under the property belong to the Church of England and I'm forbidden from keeping pigs in the house. It's why I had to take up Model Engineering rather than indulge myself in porky pleasures...

Dave

Thread: Fusion 360 Licence Changes
17/10/2019 17:39:43
Posted by Ian P on 09/10/2019 19:53:27:
Posted by SillyOldDuffer on 09/10/2019 17:02:25:

... I also play with a laptop in front of the telly. Previously, both computers 'just worked' but this is now blocked. ...

Dave

I am not using Fusion (I want to, but need more memory and better graphics) but for your dual login problem cannot you use 'Remote Desktop'...

Ian P

Tested accessing Fusion 360 as Ian suggested using Remote Desktop. Seemed good at first, but it freezes after about 10 minutes. Not sure if this is a Fusion problem or an issue with my computers, local network and RDP. More testing needed.

What does work is signing-out of each and every session. I've found not signing out when using two computers also creates a more serious problem - misalignment between components stored on the server and those in the two different local caches, causing 'There's a later version...' warnings and inconsistencies. Might be a bug or because the Hobby Version of Fusion doesn't support multiple users.

None of this is serious: despite some initial confusion I was able to realign my computers without having a nervous breakdown. Apart from confusion due to using the product on two different computers, I haven't found any loss of functionality due to switching to the Hobby Licence.

Dave

Thread: Tapping drill size
17/10/2019 13:23:07
Posted by Martin Shaw 1 on 17/10/2019 12:51:20:

I have a need to tap some M8 holes. From published information it seems the tapping drill can be anything from 6.8mm to 7.5mm. I appreciate the small drill will produce a tight thread and the large one a loose fit, so is approximately the mid point between the sizes the optimum, given that the application is some T nuts. I would appreciate your thoughts.

Regards

Martin

Given the application is T-nuts which can be expected to be stressed, best to go for a small drill leaving the maximum amount of metal for a strong tight fitting thread - 6.8mm.

When strength doesn't particularly matter, and often it doesn't, I generally use a larger than recommended tapping drill because bigger holes reduce the work the tap does. Taps in bigger holes last longer and are much less likely to break, especially in small sizes. But a loose fit also means low strength: don't deliberately weaken load bearing fastenings.

Dave

Thread: Internet searching
17/10/2019 12:40:33

For the ordinary Joe the size of the search result is a hint he should follow Michael's advice and tighten up his search terms.

Not everyone on the internet is an ordinary Joe though - I occasionally use 'Beautiful Soup' which is a Python module for automatically retrieving and parsing HTML pages : it's a tool for mass extraction of web data for offline processing rather than casual browsing, and one application is analysing the results of a large search. Google, DuckduckGo, Yahoo and others build their search indexes by 'spidering' the web. It can be crudely done by reading all the pages on a website and recursively following every link to every other website and all its links.

Website owners can be seriously upset by visits from these tools! I might decide to scan the whole of the Model Engineering site with the innocent motive of creating a better index. Thoughtlessly done, my home computer on a moderately fast internet connection could easily overload MyTimeMedia's servers. Unless told not to, a program doesn't behave like a human user slowly retrieving pages and reading them, instead it requests pages as fast as the network running flat out permits, thrashing the web server with a load equivalent to many thousands of people. (Chances are the web server is programmed to detect and throttle single users submitting multiple fast requests, but even so an inconsiderately written program would block and delay legitimate users.) The size of a search result can be used by these programs to detect an accidentally excessive search, or to deliberately find them with a view to rationalising them: Google do a very job displaying the most likely hits first and this intelligent ordering doesn't happen by accident.

Finding small results is more challenging than big ones. A 'Google Whack' is a two word search request that only finds one hit. Really difficult to do. I'm tempted to bring the internet to its knees by writing a badly automated search...

Dave

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