Member postings for martyn nutland

Hello All. This is never going to win any prizes at any engineering shows anywhere.

But, it is my interpretation of the Birmal fan pedestal that company made in the thousands for the magneto-fired Austin Seven. The point is, I made it with the advice and guidance of members of this forum, and it fits and works perfectly.

For the benefit of the armchair experts and 'tyre-kickers' I do know that you can now buy them for 12 quid, which is about a third of what it cost me to make mine (who cares?).

Yes, and I do know these would not have been machined at the works. They would have been Birmal castings costing ha'pennies!

Onwards and upwards,

Martyn

Edited By martyn nutland on 14/02/2016 16:17:10

Michael

Very interesting point this.

Perhaps the real answer is: Does it matter?

You open with a familiar adage. Perhaps another is also apposite. To travel hopefully is better than to arrive!

I wouldn't and couldn't ever build a model anything. I do modest vintage car builds. Whether I will ever finish one is entirely for God to decide and I'm not worried by his conclusion. The satisfaction and pleasure in in the work itself.

So full steam ahead?

Martyn

Hello Roger

This is a very common situation amongst Austin Seven restorers (my own enthusiasm).

As Michael says a picture of the part might help, but as Clive intimates, heat is the one essential ingredient.

Depending upon what you are trying to do and its structure (which is why a photo might help) you may be able to make an extractor that will pull or push the bearing out. But even then, with old or fragile aluminium you need to heat things up. This, for example, is how one can remove Austin Seven main bearings from the aluminium crankcase.

Alternatively, if you can access the bearing with a brass drift - i.e. if it is not against a flange or lip - you may be able to knock it out. But again, heat is essential. Don't bash it cold. Old-fashioned brass stair rod may be suitable for the drift.

Try to heat the part to around 80°C and aim for generalized heat not local. A domestic oven is ideal for the purpose. In the Austin Seven context their steel hubs will give up their steel bearings quite readily when heated and you will probably be surprised how aluminum, once expanded by heat, will let go a steel bearing.

Good luck, just don't bash it cold!

Martyn

Or you could all use the one invented by Frenchman Pierre Vernier in the 17th Century. Much more satisfying.

Martyn

Okay.

Job abandoned.

Can we please leave it there now?

Martyn

Please don't let's get unpleasant about this.

I did take everything in the spirit it was intended including being told, rather unflatteringly, I was 'clearly new to the game' and should read a book! (I've been studying and referring to Sparey's The Amateur Slave (sic) for at least 10 years along with many others including Hall and Using the Small Lathe, and will continue to do so.)

The problem, as far as I can see, was the revolving centre. I was generously given it by a retired professional engineer who never claimed it was perfect. However, which I didn't realize, it was worn out and I will buy a new one. As I said earlier, when I supported with a brand new (because it's not something you use everyday) revolving scroll chuck in the tailstock my problems were largely solved.

The collet, the arbor and the clamping nut were virtually new and clean, as I pride myself on keeping my tools that way.

It was a mistake to work the compound and not the carriage, but I was addressing a space and logistics issue. When I did use the carriage, and was thus able to engage automatic feed, the finish was transformed. Any taper or lack of parallelism that is there now (and we are not looking for tenths of thous here - to loosely quote Brown & Sharpe in Instructions for Young Engineers: 'don't spend hours agonizing over a dimension that's not critical' is down, I feel to the configuration. I.e don't work shank to shank, which means a pass of around 100mm with cut off allowances on a diameter of less than 8mm, but work head to head so the pass is half that and much less likely to deflect the work.

I'm happy. So let's not be saying people are infantile!

Martyn (with a 'y'

PS Liked the photo of the double-waisted bolts. Need one like that for the radius rod anchorage. Wonder how it's done?!

Thanks for the further comments.

I think the problem was deflection, caused, as Eric said, by the revolving centre. I changed this for a brand new scroll type self-centring tailstock chuck, gripping on what will form the bolt head and on the third bolt of the batch had no discernible 'taper' and a mirror finish.

But a further lesson is in planning the job. On the first three I got two shanks end to end and that is clearly going to exacerbate any deflection. When I do the remainder, I will arrange the bar(s) so the bolts are machined head to head thus minimizing the length of thin section exposed to the tool.

Thanks again for the advice. A happy outcome for once in life!

Martyn

Many, many thanks for all of that.

Extrapolating - I think it is deflection is the problem. The revolving centre I'm using is second hand, old and 'grumbly'.

The bar may not have been straight and I didn't check and should have.

The machine is relatively new and I have been very careful with it so the compound and tailstock ought to be within acceptable limits.

It would be better to use the carriage, I agree. The handle for the compound is close to the tailstock and awkward to turn and thus to deliver an even cut. Am now using the carriage on automatic feed. Much better.

I have now lightly cleaned the bar and 'miced' it and am repeating that measurement periodically as I reduce the diameter and if there is any discrepancy taking a pass on the previous setting and that seems to have eliminated any taper and the finish is very good.

The bolts are for the Austin and I take the point about big end bolt breakage. In fact, the exercise is about that very point. I have the old bolts and I could put them back and they probably wouldn't ever break. After all, whoever dreamed of renewing big end bolts in 'the old days'. However, I'm thinking new bolts from new steel of the correct spec are a few percentage points less likely to 'let go' than an old one.

Thanks again for the guidance everyone.

Martyn

Although this was recoverable by a bit of contrivance I would appreciate the experts' observations on what was wrong so as to improve my technique.

Dave

Broadly true. And not wishing to prolong a peripheral thread.

But you can't re-use an Amazon box without it screaming 'suspicious' as the act of opening a virgin, and genuine one (if you forgive the analogy!), largely destroys them. Plus the French post office wouldn't accept a re-used packet of this type and neither should the UK authority, and that is an inbuilt safeguard in itself.

What I'm suggesting is ways we might avoid photographing things, everyone making claims - an interminable process - and all the hassle.

Martyn

Martyn

I don't know if this is of any relevance, and it's certainly not going to be of any comfort to Clive, but as the man said: 'the world is in a terrible state of "chassus".'

I live in rural France, which is hardly Outer Mongolia, but I have recently had a delivery of tools 'lost in the post', a package of metal severely delayed and my wife has had clothes and books fail to show up - all from the UK.

More sinister, for some years now, practically everything that arrives both here and at my wife's flat in Paris has been interfered with. This is often so carelessly and savagely done that the contents are damaged. For example a very expensive review copy of a motoring book had had a knife or spike pushed through the Jiffy bag until the slip case was torn, an almost as expensive boxed set of Shakespeare DVDs similarly, while another DVD was torn from its padded envelope altogether. If any of these items had been bought as presents, they would have been 'ungivable'.

Why does this vandalism in what should be a secure service occur? I don't know. No doubt the postal authorities would tell you - particularly now, here in France - that it's for security reasons. But a book from Amazon in a purpose-designed envelope, overprinted with the company name is unlikely to be packed with drugs or explosives. In my more cynical moments (frequent) I suspect such items are being 'checked' not for drugs, explosives, contraband or weaponry but to see if they contain anything worth stealing - and sometimes they do which is why they never arrive.

This leaves model engineers - especially overseas - in a very difficult situation. We can get a friend to receive the goods in the UK and bring it to us personally. Not very practical for most people. My feeling is that we should prevail upon our suppliers to always use a courier and, we the customer, should be prepared to stump up the cost. I know that even the international household names can be iffy, and I've had some dodgy service from UPS. On the other hand, excellent experience with DHL. Royal Mail...oh dear.

Is this the way to go?

A peaceful and safe 2016 to you all and I hope you get your post.

Martyn

From Paris, good wishes everyone.

Here's hoping 2016 is better than 2015 on all fronts.

A peaceful, safe and healthy future to you all.

Martyn

A bit like the man with a sore back who encounters a doctor at a Christmas party and says: 'it's not for myself I ask...'; it's not for myself I ask this question!

But my friend Gerard has just bought a Holbrook lathe. These vintage machine tools appeal to him and he already has a Melhuish under restoration. He would like to know the age of the Holbrook (picture attached) and, if possible, the model. Can anyone help?

Mornin' All

Denouement?

Have just run Super B lathe expirementally with Chester fixed steady and a piece of approximately 10 inch long EN24T in a 16mm collet chuck. No machined surface for the fingers for this purpose.

Everything rock solid, no movement on steady, no movement on 'work', no loosening, no heat, no perceptible run out. Kept lathe going for about four minutes with no change.

What I've done is position the fingers first so they bear squarely on the work and initially tightened them up. Located the fixed gyb (operator side of the lathe) hard against the bed, then I've slewed the gyb on the far side at an angle to the bed, wedged it with a piece of packing and tightened that up hard. Then finally tightened the fingers up hard. I also have a packing piece between the foot of the steady and centre of the bed which eliminates any axial rock.

Not elegant, but it's working.

Martyn

I think I'm grasping this. Go for solid. Turn a 'journal' on which the steady fingers can bear. Etcetera.

However, I got the Chester contraption solid(ish) tonight with much packing. I know that was against the advice, but 'no-way' was it going to firm up without.

Now I can see, without even taking a measurement, it's twisted and has been from 'new', or from the time Chester used it and then sold it to me as 'new'.

I think I'll be alright now if I get a decent steady. I rather fancy Neil's from Machine Mart and intend to investigate if it actually does fit a Super B.

Thanks to everyone. Have learnt a lot.

Martyn (Merry Kissmuss)

Hello Martin with an 'i'

I never supposed that steadies were anything to do with centering work.

I thought they were to resist the deflection of long thin work under the pressure of the cutting tool; either, in the case of a fixed steady, while one performed an operation on a relatively short section of the work, or, in the case of a travelling steady, if one was transversing a much longer section with the tool.

What I didn't know was that you needed to machine an accurate bearing surface (a journal, if you like) on which the steady could bear. I assumed that if you bought a piece of bar from the likes of Noggin End or Mallard or whoever, its diameter and parallelism would be within sufficient limits of accuracy for you to attach the steady and turn whatever was needed.

Thanks for that enlightenment.

Martyn with a 'y'.

Good advice. I'll try these solutions. I think the Chester design is probably a 'dud' now I know things should be 'rock solid'.

Thanks again.

Martyn

No Jason, I think Nigel means your steady is not 'up to the job'.

My steady should be 'up to the job' because, as I was at pains to explain, I bought it from Chester as it was specifically for the Super B machine.

Now I have to make a confession that I honestly, honestly did not think was relevant when I started this thread; but perhaps it is. I had a big row with Chester at the time over these items. They took ages to arrive and when they did they were very battered and had clearly been used (maybe abused) although I paid list price.

I took this up with Chester, who I don't like as a supplier, and they said the steadies were in the state they were because they had been on the shelf for years. This was clearly a load of b-----ks. They had been using them at an exhibition, which explained the delay in despatch and they were in fact 'second hand'.

This needn't have been said, but as everyone seems to have steadies that are as steady as a rock, I feel I must be totally honest.

Martyn

No...as Andrew says, or in my case, just hex drive cap screws for the three fingers and one, on the leg on one side, through the gyb

So, as I see it, on the Chester (aka Chinese) design(!), you pull the one leg of the steady as tight as you can against the underside of the bed, then tighten the threaded gyn on the other side (with or without packing, but normally with, as otherwise it is extremely floppy) via the cap screw and an Allen key. Result, in my experience, overall floppy!

As I also see it, all Neil's lock nuts would achieve is to lock the floppy set-up.

Maybe I'm missing something.

Martyn

Jason

That's true. One reason I bought the Super B was the clearance bed to spindle. Enough to turn an Austin Seven flywheel!

And Andrew.

That's one 'helluva' steady. Not like you get from Chester! So we must go for 'rock'.

Understood.

Thank you.

Martyn