Here is a list of all the postings Swarf, Mostly! has made in our forums. Click on a thread name to jump to the thread.
|Thread: Ancient Skills|
Hi there, all,
This thread was prompted by my reading today's posts relating to the Antikythera Mechanism. However, rather than posting 'off-topic' there, it seemed better to start a new thread.
A few years ago, a hoard of Roman coins was discovered - I think it was on Jersey. It was a major find, lots and lots of coins.
Large as it was, this hoard must have been small by comparison with the number of coins in circulation. It seemed to me that, in order to achieve adequate production rates, the Roman mint must have had more than one set of dies to strike each denomination of coin. Each coin would have had the Emperor's head on the obverse - I don't know what they put on the reverse.
Now, even today, die-sinking is a far from easy business. How did the Romans produce multiple sets of dies that would each strike anything close to the same impression??? (I don't believe that the Romans produced their coinage by foundry methods.)
Edited By Swarf, Mostly! on 28/02/2021 15:06:16
Edited By Swarf, Mostly! on 28/02/2021 15:07:52
|Thread: I want a telescope|
Hi there, Tim,
I seem to remember that astronomical telescopes give an inverted image.
|Thread: Skynet is Coming|
Hi there, all,
I hope the following won't be judged too far off-topic!
Our ISP is Virgin Media. We're fairly satisfied with their service but we received an email from them yesterday that has prompted a clutch of reactions.
Their basic message was that they have doubled the speed of our wi-fi. To enable them to do this, they say they monitored our wi-fi usage over a few days and then tweaked our frequency to optimise our achieved performance (or psudo-techie words to that effect).
Now, we have 'his' and 'hers' computers and two printers. I can access either printer via ethernet. My wife has to communicate with one of our printers via wi-fi but hasn't printed anything for weeks. We do also have a lap-top equipped with wi-fi (aren't they all nowadays? ) but I haven't used the lap-top for a couple of weeks either. We do have a mobile phone, I'd say it rates as about 1½ G, definitely far from smart. So, just what wi-fi traffic they thought they were monitoring, I don't know.
Their email didn't actually say we're now connected to the turbo-encabulator, maybe that comes next?!?!?!
|Thread: Pipe bending|
If the material didn't have to be mild steel it would sound like an application for electro-forming.
|Thread: ML7 left to run for 72hrs accidentally - what to check?|
Hi there, William,
I hope that your ML7 has not suffered any irreparable damage.
It sounds as though you need to install a motor starter that incorporates no-volt-release.
|Thread: New Hampshire member|
Hi there, Clay, welcome.
I'm the other end of Hampshire.
Regarding metalwork vs. woodwork: metal work is usually more neighbour-friendly than woodwork because the cutting speeds are slower. The grain structure of wood also contributes to the noise. My ML7 doesn't make anywhere near the noise level of my 1300 watt Bosch router!!
Mind you, hacksawing sheet metal can get a bit screechy.
|Thread: Myyford gearbox strip down|
Hi there, Stephen,
I'm very sorry to hear of your lathe's mishap.
Do you have the Myford User Instructions booklet (that's not its proper title ) ? There are 'exploded diagrams' dealing with the major assemblies comprising the ML7 or Super 7 (it's the same gearbox for both lathes) .
If you don't have the booklet then the exploded diagrams and parts lists are available in down-loadable form on the Myford web-site.
To give would-be helpers here something to work on could you take a few photos and up-load them here?
|Thread: Oil Blackening and other Oil Issues|
Hi there, all,
Some time ago I was given an assortment of (threading) taps. They were rusty so I treated them to a couple of days in an Evaporust bath.
After rinsing and drying, I was surprised to see that some of them were bright and shiny (presumably HSS) while the others had developed a blackish colour (presumably carbon steel).
In my opinion, the blackish colour would be an acceptable long-term finish for some components but I have not yet had the opportunity to test its durability.
|Thread: Where do the parcels go ?|
Hi there, all,
A couple of years ago, I sent a parcel via Hermes. The experience was stressful for a time but had an amusing component.
The parcel disappeared into 'Hermes-space' - the tracking facility froze. In this particular case, the recipient was the holder of the relevant Hermes account so he had to liaise with Hermes. After a few days of perseverence, he managed to achieve phone contact with a real Hermes Human.
The Hermes Human asked for a description of the parcel, adding 'PLEASE don't say it's in a brown cardboard box secured with brown tape'. The poor chap was obviously a bit harassed and surrounded by lots of lost parcels, all visually similar!
Before sending any more parcels I equipped myself with several rolls of luridly coloured Gaffer tape including a roll of fluorescent pink!!
The original parcel did turn up eventually, undamaged but a bit dusty. Subsequent parcels all beat their delivery forecasts.
|Thread: Wiring for Parvalux Geared Motor|
Hi there, Brian,
Suffering three motor failures is a bitter portion! I can't add anything to the technical advice you have already received from other members.
However, I am moved to offer you words of encouragement:
Thanks to this forum, you are not on your own. Hang in there and keep trying! These things can usually be fixed. Remember, tenacity tells.
|Thread: microscope graticule cleaning - recommendations required|
Hi there, Gerry,
A retired professional microscopist * I used to meet at club meetings advised me that he used 'spit' (i.e. saliva) for cleaning small areas. Just make sure you haven't recently been eating liquorice! Oh, and toothpaste is abrasive too!
He applied his 'spit' on a cotton bud BUT BEWARE!!! Standard cotton buds can contain sharp silica particles. You can, however, find grit-free cotton buds if you search diligently. A friend with optical interests advised me that ordinary paper tissues can also contain sharp particles - he advised me that kitchen roll is free of nasties (I presume that is because kitchen roll is made from recycled paper fibres). Then there are special lens-cleaning tissues available from some opticians, laboratory suppliers or eBay. One well known make to look for is 'Whatman', the same people who make the filter papers.
* He wasn't originally a professional microscopist but an amateur. When it was realised that asbestos was a health risk, his manager appointed him as 'the asbestos man' and the search for asbestos fibres took over the rest of his career!!
|Thread: flexispeed lathe/chuck problem|
Hi there, all,
My apologies for being a bit late to the party.
I just thought it might help to mention that the old Imperial electrical conduit threads were 16 tpi (Whitworth form), certaily for the ¾" and 1" sizes - I'm not sure if that's also true for ½". Conduit threads were 'borrowed' by some machine builders, e.g. my Coronet Minor woodworker mandrel was ¾" conduit thread.
And I seem to remember that British Brass thread was 16 tpi while some (Imperial) cycle threads are also 16 tpi though one or both might not be Whitworth form.
|Thread: Myford ML7 Cross Slide adjustment|
Hi there, Alan and Brian,
Alan, I suggest that you investigate the cross-slide handle and scale. Excess clearance there could give at least some of the 'perpendicular' back-lash of which you complain. Lock the cross-slide and then examine how much free angular movement there is in the handle & screw.
Look up under the bracket attached to the front end of the cross-slide and find a way to hold the shank of the feed-screw without graunching it. Then turn the cross-slide handle counter-clockwise to loosen it. From memory, the scale and the handle act as nut & lock-nut. They need to be adjusted so the handle & screw can together turn freely but with minimum slack. Again from memory, I believe there is a fibre washer in there, simple but effective.
If you don't have the Myford User Instructions booklet, have you down-loaded the parts lists and exploded diagrams from the Myford web-site?
Also, have a look at the modifications to fit thrust bearings in that part of the machine, see Arc Euro web-site.
Another possibility is wear in the cross-slide feed-screw and/or nut. Again, you can explore this by locking the cross-slide and waggling the handle. You might need to remove the top-slide to see what's going on.
Do, please, come back and tell us how you get on - it's very frustrating to make suggestions and never to hear the conclusion!
Edited By Swarf, Mostly! on 29/12/2020 19:15:45
|Thread: Workshop temperature - cold|
Hi there, all,
Thermal comfort is a complex subject. Even if the air temperature is warm, you can still feel cold if the walls are cold. The body is sensitive to transfer of radiant heat as well as to conducted heat.
Fortunately, it isn't necessary for ALL the walls to be warm - you just need enough warm wall area for the radiant gain to balance or exceed the radiant loss. That's why those infrared bathroom heaters with the spiral element inside a quartz tube (preferably backed by a gold-plated reflector) were effective.
I guess it helps if there is some warm surface both aft as well as fore - otherwise you could be warm in front but chilly behind! (Am I allowed to write 'behind'?? ) Thinking a bit more about that, I guess a radiant heat source will raise the temperature of the other walls faster than will heat conveyed by the warm air?
And I guess the radiant heat source doesn't have to be wall - one of those free-standing oil-filled radiators works for me.
Edited By Swarf, Mostly! on 29/11/2020 16:41:49
|Thread: What am I?|
Hi there, all,
Either Rolls or Royce (not the financial partner) denied being an 'engineer' - he claimed to be a 'mechanic'.
By the way, I think that in the UK it's an 'Institution' not an 'Institute'. If that matters.
And don't get me going about non-technical managers preferring the advice of an inexperienced colleague with a degree over mine based on lots of experience plus a degree-less C.Eng.!
|Thread: Ball ended handle - how to|
Hi there, all,
I thought I'd better have another search and, this time I found the thread. It's on the Mad Modders web-site, here:
The thread is dated 2014. The problem is that the videos are all unavailable. He showed the process in use for a three-ball handle as well as the tear-drop type. (So my previous post wasn't all that off-topic after all! )
If anyone is interested in the process, there are some still photos there that are interesting.
Hi there, all,
I hope I may be forgiven for a slightly off-topic post. Well, it is to do with handles.
In the background of Evan Lewis' post you can see what I describe as a 'tear-drop handle'. Somewhere on the Internet there is a video of one of these being turned using a form tool so arranged that only part of the tool is in contact at any time. If I remember correctly, the top-slide (aka 'compound' ) is set at a slight angle to the cross-slide and is mechanically driven. Again if I remember correctly, the technique is named as 'skiving' (until I found this video I thought that was the process for producing a thin sheet of leather, such as is used to surface a bureau writing flap) .
I found this video fascinating but my recent searches for it have been unsuccessful!!!
Maybe one of the members here is familiar with either the video or the machining technique or both?
Edited By Swarf, Mostly! on 22/11/2020 17:40:22
|Thread: Cutting copper tube square|
A common method with cutting plastic pipes, e.g. underground waste pipes, is to wrap a piece of paper around the pipe so that the edge lines up where the paper overlaps. On your 54 mm copper the same method would probably work. Once positioned, hold the paper from moving and go over the edge all round with a Sharpie. Then remove the paper and cut at the edge of the Sharpie mark. I reckon the result would be accurate enough, assuming that you're going to fit an end disk with a soft or hard soldered joint.
If it had to be a lathe job, the fixed steady rest could help but I'd regard cutting thin copper tube with a parting tool as quite an adventure!!!!!!!! Filling the tube with a wooden bung (or maybe even Plaster of Paris) sounds like a good idea.
When you've done the job, please come back and show us a few photos of the result.
|Thread: Temperature control when grinding HSS tool-blanks?|
Hi there, Peter,
I have a modern two-wheel grinder that actually specifies a duty cycle on the motor rating-plate.
|Thread: Brass Founder vs Brass Caster|
The French verb meaning 'to melt' is 'fondre'.
However did Kelly's Directory manage before the Norman Conquest?
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