Member postings for Sam Stones

Oh, I forgot!

There's the issue of your milling cutters grabbing swarf and needing to be 'demagged'.

Hi Chris,

From a sufficient number of years of toolroom experience with surface grinders, both chucks with either permanent magnets or DC electromagnetic, I would expect that the rapid, intermittent cutting forces from millng tools, could slowly dislodge/move a work-piece out of alignment. Clearly, this would require some positive means to stop this in the X and Y directions.

I would also suggest that you'll need a de-magnetiser, to reduce the annoyance of (carbon steel) work-pieces remaining magnetic. On that score too would be the collection (and removal) of swarf around the 'vice'.

Using a dial indicator for 'clocking up' near such a vice is also likely to introduce issue with immediate/residual magnetism.

I'm sure this thread will attract other views.

Good luck,

Sam

Ross, I sent you a short PM.

Sam

Hi Noel,

Those were quick replies.

I'm only too pleased to help where I can. Especially having so much help from others on this site.

John Stevens' skeleton clock article commenced in Model Engineer in Jan '72 and ran for five editions. I started cutting brass for it in about '73.

However, I haven't seen his article in book form.

Regards,

Sam

Hi Ross,

Starting my tool-making apprenticeship in 1950, I've never found any need to worry about cutting tools being 'hollow ground'.

It's what happens at the point of contact with the work-piece that is important. The angles are meant to provide clearance and chip control without compromising the strength of the cutter tip. No doubt you'll get more advice shortly.

A very old toolmaker who operated the 24" shaper, finished his cutters on the side of the grinding wheel. Personally, I'm not in favour of recommending that, especially if you are new to workshop practice.

Regards,

Sam

Hi Noel,

Although I’ve only built one clock, there are clever people who contribute here that will offer you a great deal of help.

However, I can’t resist mentioning that the 2” radius nominated for the fusee  does not compensate for the variation in spring output (Mr Wilding’s shows 2.2” radius). If you are looking for good timekeeping, you may have to carry out some torsion test beforehand.

You can see from my crude graph(s) at the bottom of this page the sort of variability which resulted.

**LINK**

By the way, I used a similar cam approach on my ML7, by way of parts from the taper turning attachment.

On the same page of photographs, you can see that I first used fishing line (yellow). It broke after three years, so I replaced it with twisted steel.

A chain would look even better.

If you are a contributor to Model Engineer, I wrote a seven-part article about building John Stevens’ skeleton clock.

It commenced with #4526 dated 22^nd Jan 2016.

Good luck,

Sam

Edited By Sam Stones on 11/06/2018 01:28:05

In answer to your two questions SB5,

IMO watter as fot ger'out u't way fre front pair, and not much gets past tut backuns cos front un's push it for'ard.

Them front brackits stop watter cumin up.

Please excuse my poor version of a Lancashire accent. I don't get much chance to practice down er.

Sam

By the way, that's a damned good link. 

Edited By Sam Stones on 10/06/2018 03:00:44

WARNING - For insomniacs and people like me.

Readers may recall that back in 2015, I introduced a string of somewhat poor quality images of Concorde. See here about halfway down the page …

**LINK**

Taken in 1979 at Heathrow, the first picture showed the final stages of loading and, for what it’s worth, the visor was in the ‘up’ position. (Presumably, this latter aspect was part of pre-flight checks ?) My remaining pictures stepped through the few minutes of push back.

Not obvious at the time, I was quite surprised later to discover (from the paper prints), that the aircraft featured dual livery.

By that time (2015) I’d lost the negatives and was obliged to re-photograph the prints. With the help of Neil’s fairy dust, (ie. Deconvolution in Astra Image), one of my images (further down the page) cleaned up surprisingly well.

However, while reading the late Brian Trubshaw’s book ‘Concorde; The inside story’, I was pleased to read that G-BOAD was indeed painted with Singapore Airlines livery. With whetted curiosity, I scanned the Net and next found this chunky piece of text and photographs about G-BOAD.

**LINK**

The history record shows it was registered G-BOAD on 9th May 1975 to BA.

Scroll to the photograph, 3^rd from the bottom.

Singapore livery except its registration is six characters not the five of G-BOAD. [ZOOM TIP; (if you have a scroll wheel); to zoom in, hold down <ctrl> and <alt> while scrolling.

Zoom to the registration on the tail.

With more of Neil’s influence, thank you Neil, it is clear that the plane in my ’79 photograph was six characters – i.e. G-N94AD

Then on 5^th Jan 1979 this aircraft was re-registered as BA / Braniff Airways.

Further reading showed yet again that Concorde (210) was the only BA Concorde to be painted in another livery; it had Singapore Airlines’ livery on one side and that of BA on the other.

But what’s going on here?

**LINK**

Two photographs, both Singapore livery. The first plane has a six character registration, and the second clearly G-BOAD.

Then the pieces finally fell into place when I turned this one up.

**LINK**

For me, it wasn’t the end of the story because G-BOAD was soon back in full BA livery. It’s also practicing with the Red Arrows for the Queen’s Golden Jubilee Flypast seen in this next link.

**LINK**

And, in conclusion, details of the flypast.

**LINK**

If you are not asleep by now, there’s nothing more I can do.

Regards to all,

Sam

Beware the error in the Wiki reference where it says …

Spark testing is a method of determining the general classification of non-ferrous materials.

The rest is good stuff, especially the diagrams.

Regards,

Sam

XD 351 said ...

I wonder how many square wheels were made before they worked out that round ones roll better !

Not long really. Once the corners had worn off

Gentlemen,

Thanks for all your replies.

I was prompted to start this thread because … in eight years (from when I was getting help with my skeleton clock), and after more than a hundred PM interchanges, only recently have messages remained as ‘unread’.

I’m guessing we are becoming more sensitive to, and less tolerant of - unsolicited mail.

One solution I'll use next time will be to remind posters via the particular thread.

Thanks again.

Sam

What do you do when you receive an email saying …

‘New Private Message Received From Model Engineer’

noreply(at)model-engineer.co.uk

You have a new message waiting, subject xxxx

Go to message centre to view

(?)

I've sent two or three PMs in recent times, and they have remained in my sent box as 'Unread'. I therefore presume they are deleted from the recipients mailbox.

Any other members experiencing this?

Regards,

Sam

I missed it too, Michael.

Brett says it ... has 14 div. with id of 1.000.

id = Inside diameter !

Sam

Edited By Sam Stones on 18/05/2018 19:55:09

Hi Brett,

This ('scape) wheel was cut from silver steel using a single point fly cutter similar to Russell's setup.

The cutter was (also) silver steel, hardened and tempered. With a dividing head in a mill/drill, I cut the teeth in two distinct passes to get the angles right. In other words, the cutter was not full-form. You can get an idea of this from the roughness at the bottom of the teeth.

Initially, this profile was cut a short distance along the bar of silver steel before parting off. Subsequently, the wheel was itself hardened and tempered

The diameter of the wheel overall is 3/4" (19mm) and the eventual thickness 1/16" (1.5mm)

Hope this adds more confidence re cutting the teeth in steel.

Regards,

Sam

Duncan, I'd reckon you could. Mr Stevens used an old 1/16" slitting saw blade.

Loosely wrapped around a central boss however, the spring Derek is making becomes rapidly stiffer as torque wraps it around the boss.

The spring shown in Mr Stevens' drawing is only supported sideways; nothing in the middle. Also, and as I found out from my (one and only) clock, there isn't sufficient stiffness in Mr Stevens' maintaining spring to keep the clock running for more than fifteen seconds. This is ample for its purpose, but the point being that the spring has to be stiff enough.

That would bring us to simple beam theory (thickness cubed) to determine the correct spring thickness, shown as 1/8" in Mr Stevens' drawing.

Sam

Sorry about the double link. Sometimes it's automatic, sometimes not.

Now I can't edit.

Perhaps Neil will step in and fix it. Thanks Neil!

Hi Derek,

Doing a Model Engineer Forum search for the word 'Tempering' produces four threads. I haven't read them all but would recommend practicing watching colours 'run' as you warm up a piece of scrap.

Aiming for a uniform colour is perhaps the hardest part, especially with simple home workshop equipment.

My preference for tempering silver steel springs would be to a colour between dark straw and purple/blue. On this chart - 260°C to 290°C would be my target.

https://www.westyorkssteel.com/technical-information/steel-heat-treatment/tempering-temperatures/

https://www.westyorkssteel.com/technical-information/steel-heat-treatment/tempering-temperatures/

Chris of http://www.clickspringprojects.com/ http://www.clickspringprojects.com/ shows how (for appearances) he blues his clock parts.

Hope this all helps.

Regards,

Sam

Edited By Sam Stones on 13/05/2018 22:44:08

Dave,

While it won't restore the TiN, stick the cutter back in the mill and take some (similar) cuts off a piece of mild steel.

Add a drop or two of turpentine (or similar) at the same time.

Good luck,

Sam

Edited By Sam Stones on 30/04/2018 20:16:54

Would time run backwards if you applied a vacuum to the ‘air spring?

Metal 'stamping and forming' in miniature?

While designing and building a 'bundle' of quite small prototypes, it was necessary to make about 300 stainless steel electrodes 7x7mm square by 1mm thick. First thoughts were to just chop up some 1mm stainless sheet and machine them as blanks.

Attaching stainless (suture) wire for electrical (and other) purposes presented a few difficulties, as did securing the electrodes in place. Then I discovered a process that would allow me to profile them from much thinner material, SS 0.07mm shim to be exact.

As you can see here ...

the electrodes could feature tabs as a means of attachment together with a (rather crude) means of attaching the wire.

The block in the picture, now more of a desktop novelty is 25x20mm. The stack height of about 300 shims measures 35mm. Gauge steel pieces 1.5mm thick riveted through the length provided support hold the sandwich together.

Held tightly in this sandwich arrangement produced clean blanks with no need for deburring.

Although the wire EDM process was developed in the 60’s, it was about 1990 at a company somewhere south east of Melbourne when these particular electrodes were ‘burned’. Clearly from the literature and links, significant advances have taken place since then.

The process might prove useful to Model Engineers!?

Sam