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Member postings for Swarf, Mostly!

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: What Did You Do Today 2019
09/03/2019 20:50:26
Posted by Limpet on 09/03/2019 19:54:31:

20190220_154845.jpg

Not just today but last week acquired this ML7, it needed a little TLC

20190309_113702.jpg

It's now in a lot of bits - anyone know how it goes together

Go to the Myford web-site and click on ML7. You will be presented with links to several pages, one for each of the major sub-assemblies of the ML7. Chose one. Scroll down until you reach 'Exploded Parts Diagram' and then click on 'View Page'. You will then be able to download (aka 'save as' ) the Parts List and the exploded diagram. Go back and choose the next sub-assembly of interest, 'rinse and repeat'.

Best regards,

Swarf, Mostly!

Thread: Workshop - indoors or outdoors
26/02/2019 13:30:41

If it were me, I'd research the local geology before committing to the cellar. What is the local sub-soil and at what level is the water table during the wet season?

'Tanking' has been mentioned - I'm sceptical about the efficacy of tanking on the inside of walls & floor, the water pressure from outside can push it off.

Back in the late 1800s & early 1900s houses in some districts were built with 'stock' bricks which are porous. The walls were often built with no damp-proof course but with air bricks and a large ventilated space was left beneath the lowest habitable floor. While there were often pipes and cables down there, it wasn't intended as a cellar. The idea was that damp rising up the walls by capillary action would evaporate from the surfaces of the brickwork and be removed by the ventilation in preference to proceeding further up the walls to the inhabited floors of the house.

A friend of mine was helping clear the cellar workshop of a deceased neighbour. It seemed to be dry. He encountered a piece of paper into which had been inserted several very small (e.g. #61 - #80 ) twist drills, as is often done with sewing machine needles. Over time the paper had acquired enough moisture to completely rust through the drills at the points of contact!

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 26/02/2019 13:33:09

Edited By Swarf, Mostly! on 26/02/2019 13:33:39

Thread: Tauco drill press
08/02/2019 16:59:27

Posted by SillyOldDuffer on 08/02/2019 10:31:55:

SNIP!

Watching those telly programmes about restorations is even more surprising; if rebuilding a Sherman Tank, it seems possible to get new turret rings.

Dave

Off Topic but here goes:

Back in 1969 I needed a 28 Volt dynamo for a project. Watson's Eastern Motors (a long-time ME advertiser) was listing the 'Type O Engine-driven generator, 28 Volts DC 1500 Watts'. (I'm relying on memory there. ) So I drove out to Aldeburgh and stated my requirements. 'Oh, we don't keep them here. Let's go the the other store' was the reply. The 'other store' proved to be a bungalow some distance from the main shop. I was ushered into one of the rooms whose walls were lined, floor to ceiling, with cardboard boxes each containing a Type O and addressed to the CO of some RAF Station. The labels all said 'Rotax'. I purchased a few for my requirement.

Some time later I heard that the proprietor of Watson's Eastern Motors had died and the succeeding proprietors were more interested in house clearance. I still wonder what happened to all those Type Os. I later donated two of the ones I had bought but not used to a restoration group at Duxford.

The type O was one member of a family of aircraft dynamos that had a standardised interface to the aircraft engine gearbox via a splined shaft and a flexible coupling. I wonder whether that equipment practice is still used today?. Some (most? ) were 28 Volts but the family had 12 Volt members. Each type letter denoted a different power rating,

Best regards,

Swarf, Mostly!

Thread: One off castings
08/02/2019 16:39:47

Stephen,

I believe that Stuart Turner are now at the Bridport Foundry.

Best regards,

Swarf, Mostly!

Thread: Tauco drill press
08/02/2019 09:49:40

Hi there, Alan,

I wonder if Wilkinsons provided you with a copy of this:

tauco spares list #001m.jpg

My Tauco has a female spline in the upper spindle extension and a die-cast component with the male spline that sits within the pulley. This die-cast piece doesn't show very clearly in the diagram! When I acquired mine, the male spline had worn paper-thin but I was able to obtain a replacement from Wilkinsons.

Best regards,

Swarf, Mostly!

Thread: Microphone Screw Threads
31/01/2019 10:38:08

Sorry, I quoted AJW but I actually intended to quote Chris Trice.

Best regards,

Swarf, Mostly!

31/01/2019 10:36:05
Posted by AJW on 31/01/2019 09:28:17:
I've always used 1/4 whitworth for all my tripod fittings? Always worked!

Alan

I believe that UNC and UNF threads are NATO-ised versions of ANC and ANF respectively, the 'U' standing for 'unified'.

The threads on authentic (e.g. Amphenol ) UHF and N-type coaxial connectors were/are 5/8" by 26 tpi ANEF but there are some Far-eastern made connectors on the market with 5/8" by 1 mm pitch threads. Some mate - some don't!!!!

Best regards,

Swarf, Mostly!

Thread: Cast Iron Straight Edge
24/01/2019 09:35:54

At the risk of going from the sublime to the ridiculous, here's a suggestion for anyone who has the time but not the money:

Find a neighbour who's disposing of an upright piano, the older the better. The one I dismantled (back in the 1970s ) had a cast iron frame on a wooden frame. The cast iron had a bell-shaped cross section, fairly suitable, I thought, for an engineer's level. Not out of the question for a straightedge either? The material I acquired from this source machined beautifully. The piano could easily have been fifty years old when it fell into my hands so aging was probably not a problem. I still have a piece about 24" long under my bench.

I never did make the base for the engineer's level - a complete level turned up in an estate disposal.

The material of the wooden frame was rather special too, softwood by definition but age hardened in condition, 4" x 5" in pieces four feet long and not a knot to be seen!!!

(Before I get accused of vandalism, the neighbours concerned had made long and valiant but unsuccessful efforts to find the piano a good musical home.)

Best regards,

Swarf, Mostly!

Thread: New collets. Bankrupt now.
17/01/2019 14:14:02

Hi there, Mark,

In my applied mathematics course (many, many years ago!! ) we were taught that 'a couple has the same moment about any point in its plane'.

Best regards,

Swarf, Mostly!

Thread: Model engineers - enlisted in war efforts?
02/01/2019 20:18:04

I seem to remember reading that Edgar T. designed a portable ('luggable? ) steam driven electrical generator used by the 'Chindits' to power their radios in the jungles of Burma (now Myanmar).

Precursor to Drax?!?!

I don't know who would have made them.

Best regards,

Swarf, Mostly!

Thread: USB memory sticks
31/12/2018 11:58:29

Here are a couple of web-sites that might be of interest:

**LINK**

and

**LINK**

I hope these help.

Best regards,

Swarf, Mostly!

Thread: Changes in heating equipment - and what else?
26/12/2018 12:34:13

Posted by Nick Clarke 3 on 25/12/2018 20:21:45:

SNIP!

Do you think anything else has changed more?????

Edited By Nick Clarke 3 on 25/12/2018 20:23:04 to correct typo

Edited By Nick Clarke 3 on 25/12/2018 20:24:00

The effect of 'Health & Safety' on accessibility of scrap metal yards.

Now, before I go any further, I'm not against 'Health & Safety'. Several years ago, there was a nasty accident in a scrap yard some thirty miles from here and I wouldn't want anything like that to happen to anyone.

But still, I miss the sort of relationship I enjoyed with my local scrap metal yard when I lived in Essex. The first time I visited them they treated me as though, if they were to turn their backs, I'd put the whole yard in my pocket! However, after a few visits, I'd be greeted with 'What are you looking for?'. I'd answer and then be invited to browse among the skips. I'd move stuff out of the way to see what was in the nether layers but I ALWAYS replaced it tidily. The scrap yard guy came to realise that he didn't need to supervise my every movement and that I'd always buy something (for 'stock' ) even if I couldn't find anything that fitted my answer to his initial question.

As some say 'that was then and this is now!' .

Best regards,

Swarf, Mostly!

Thread: What's in a name?
17/12/2018 13:26:57

Thank you all for your replies.

In each case the sender's email was as follows: offers@email.model-engineer.co.uk

Best regards,

Swarf, Mostly!

17/12/2018 10:43:57

I've recently received a second pair of emails offering me subscriptions to ME and MEW.

Both sets addressed me as 'Dear Franco'. I use an alias on this forum but the name behind it isn't Franco. Who should I tell so that this (small) wrong can be righted?

Best regards,

Swarf, Mostly!

Thread: Myford taper turning attachment
14/12/2018 16:34:37

Posted by Michael Gilligan on 29/01/2017 10:51:43:

SNIP!

Goldilocks must be crying in her porridge ... 1/4" is, so often, "Just Right".

MichaelG.

.

P.S. ... Yes, I know M7 exists, but it's not preferred.

An off-topic comment!!

I once had a Citroen GS Club Estate on which many, many, fasteners were M7. I guess when you're buying as many fasteners as Citroen do/did, the quantity discount exceeds the non-standard premium. Apart from which, their use keeps most owners as captive customers!

Best regards,

Swarf, Mostly!

Thread: Optical Centre Punch any good?
13/12/2018 14:06:52

Hi there, Mark and Geoff,

I have the Soba version of the optical centre punch. I felt it was a bit of an indulgence when I bought it but I have found that it enables me to achieve a precision that I couldn't manage with the naked eye.

You'll look at it and wonder how on earth there'll be enough light at the bottom of the optic to illuminate your scribed lines but, somehow, there always is. You do need to look DOWN it though, I don't know how one could use it on vertical or inverted surfaces.

Best regards,

Swarf, Mostly!

Thread: ML7 questions
12/12/2018 20:42:42
Posted by ega on 12/12/2018 17:28:09:

This extract from an old Bedford catalogue may be helpful:

SNIP

Sorry about the bleed-through from the reverse!

A trick that usually works to stop bleed-through is to put the target document on the platen of the scanner or photocopier and then lay a sheet of black paper on top of it, then close the lid.

Best regards,

Swarf, Mostly!

10/12/2018 13:52:01

Hi there, Clive,

As nobody else seems to have commented on spanners (aka 'wrenches' ), here's my two penneth:

The rule of thumb on most ML7 machines is that all threads below ¼" are B.A. and all threads of ¼" or bigger are B.S.F.

Best regards,

Swarf, Mostly!

Thread: Horn Antenna for Radio Astronomy
04/12/2018 15:03:54
SNIP

Score so far - Swarf Mostly: 1 Duffer: Nil.

Dave

This type of antenna ... consists of a flaring metal horn with a curved reflecting surface mounted in its mouth, at a 45° angle to the long axis of the horn. The reflector is a segment of a parabolic reflector, so the antenna is really a parabolic antenna which is fed off-axis. ... It is extremely broad-band, has calculable aperture efficiency, and the walls of the horn shield it from radiation coming from angles outside the main beam axis. The back and side lobes are therefore so minimal that scarcely any thermal energy is received from the ground. The antenna has a gain of about 43.3 dBi and a beamwidth of about 1.5° at 2.39 GHz and an aperture efficiency of 76%.

Reference https://www.physicsforums.com/threads/qs-re-aspects-of-the-holmdel-horn-antenna-used-to-find-the-cmb.941032/
This type of antenna ... consists of a flaring metal horn with a curved reflecting surface mounted in its mouth, at a 45° angle to the long axis of the horn. The reflector is a segment of a parabolic reflector, so the antenna is really a parabolic antenna which is fed off-axis. ... It is extremely broad-band, has calculable aperture efficiency, and the walls of the horn shield it from radiation coming from angles outside the main beam axis. The back and side lobes are therefore so minimal that scarcely any thermal energy is received from the ground. The antenna has a gain of about 43.3 dBi and a beamwidth of about 1.5° at 2.39 GHz and an aperture efficiency of 76%.

Reference https://www.physicsforums.com/threads/qs-re-aspects-of-the-holmdel-horn-antenna-used-to-find-the-cmb.941032/

 

Dave,

Please accept that my post was not intended to be adversarial! You drew our attention to an interesting bit of hardware for which I thank you. My post was offered to broaden the discussion, nothing more.

If I remember correctly, the USA end of the Telstar trans-atlantic link used the same type of antenna as the Holmdel one, if not that actual one. (Perhaps it is time I took a Gribbin refresher! ) I believe that the UK end, at Goonhilly Down, used an alt/az mounted complete paraboloid, in a dome. It was an 'if at first you don't succeed' situation - the two teams had different conventions for the direction of polarisation. But it was 'alright on the [second] night' !!!

Best regards,

Swarf, Mostly!

P.S.: I apologise to the original poster for causing topic-creep!!  I think that horn is a splendid job.  How on earth did you hold the first two pieces in position while you fitted the fasteners?

S,M!

Edited By Swarf, Mostly! on 04/12/2018 15:08:14

04/12/2018 12:52:23
Posted by SillyOldDuffer on 02/12/2018 12:12:15:

Very smart!

This is the famous Holmden Horn in New Jersey that promoted the Big Bang to Theory status:

Story is the two guys experimenting with it were baffled by the unexplained noise it picked up and were slow to admit it really was cosmic evidence. Their efforts to eliminate the noise included climbing inside to clean out a gigantic quantity of pigeon poo. It seems Horn Antennas are the avian equivalent of a public toilet...

This is the fate of all engineering.

smiley

Dave

Edited By SillyOldDuffer on 02/12/2018 12:12:33

This episode is described in one of John Gribbin's excellent books - I recommend them.

I believe that the functional heart of the so-called ' Holmden Horn' is actually a segment of a paraboloid. That's the base of the 'scoop' on the extreme right-hand end of the structure. The focus is somewhere just inside the hut.

Modern satellite TV antennae have the same basic layout but don't have the enclosing pyramid (or the hut! ).

As I'm not an antenna guru, it isn't clear to me whether the Holmden pyramid is part of the feed to the paraboloid or a purely mechanical structure to hold the paraboloidal segment and the feed in the correct spacial relationship.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 04/12/2018 12:53:22

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