Here is a list of all the postings martyn nutland has made in our forums. Click on a thread name to jump to the thread.
|Thread: Apologies for raising this again|
Many thanks all. I will have a go and report back.
The question as to 'why bother' is sensible. It's just that, although it will be out of sight, it looks and is a mess and offends the eye.
I apologise to everyone for revisiting this but I'm having a lot of difficulty trying to remove chronically bashed up ring gear teeth from an Austin Seven flywheel. To be clear, these are teeth, milled directly onto the flywheel (not shrunk on ring gear) and not on the clutch cover, and I do not want to cut them away with a view to fitting new ring gear. The flywheel will go on a vehicle that will always be started on the handle or with a push. Thus, in a sense, this is a cosmetic exercise.
I am very adverse to putting the flywheel on the lathe because although my Chester Super B has plenty of swing, I'm afraid that the tool running over dozens of teeth is going to hammer the machine to pieces. Even if I did resort to attempting this on the lathe I can't see any realistic way of holding the piece securely. There's no boss worth speaking of that a chuck could get a grip on and fixing the thing to a face plate is going to cause the clamps to obstruct the cut. A mandrel through the centre hole might be a possibility, but I'm not sure one could get it tight enough to resist the pressure of the cutting.,
Is this an idea....there are two blind 1/2" BSF holes on the face of the flywheel (to attach a puller). Could I drill the holes all the way through and use them to bolt the 'wheel to a face plate?
The plan to date has been to mill the teeth off with a roughing mill or slot drill. To that end I've tried to do a set up on the mill with a rotary table and its dedicated three jaw self-centring chuck. I've adapted an Austin Seven flywheel puller (mentioned above) to try and grip the job. (Cross-piece of puller bolted tightly across the flywheel and the forcing bolt gripped in the chuck on top of the rotary table. However, when the job is tight it's horrendously out of true axially and side to side and when it's true it's loose in the chuck. NBG.
Could I...get rid of the rotary table/chuck set-up but retain the bolted on cross-piece and lock that in a milling vice mounted on its rotating base on the mill table. Then, rotate the vice under the cutter in increments?
Sorry to 'go on' about this. It's becoming a 'give up for good' moment.
Many many thanks in advance for any views/suggestions.
Bonne 2020 to one and all.
|Thread: Opening a Port|
Again, very many thanks for all the advice and practical guidance. This accords with everything I have read and studied on the subject of enlarging/profiling ports and I will be printing this off and keeping it close as I work. Congratulations to everyone who has already made such a splendid job of the procedure and, above all, thank you for sharing the expertise with me.
Many thanks everyone.
Especial thanks to Grindstone Cowboy. You seem to understand exactly what I want.
By the way Brian...I'm not into 'messing' with pre-War components. That is normally anethema to me. I'm just using conventional (pre-War if you like) engineering methods to try to improve an extremely poor aspiration system as thousands of Austin Seven Special builders have done since pre-War days!
Thanks again everyone. Bonne année from warm and sunny Paris.
A Peaceful and Healthy 2020 to All
A very simple question...I need to enlarge the inlet ports on my Austin Seven exhaust manifold. It's cast iron of course. Would you recommend doing this with an end mill, slot drill or with a stone (perhaps even with a Dremel attachment).
Many thanks in advance.
|Thread: Bronze bushing|
Many thanks everyone.
Yes...they were Oilite originally. I bought the Oilite replacements from the site Colin mentions of whom I am also a satisfied customer. But on this occasion the bushes were a mile too big. I baulked at making a tapered mandrel to hold them to try to turn them down largely because I'm not good with tapers. Hence I decided to make new ones.
Yes also...they were Imperial originally, but I always work in metric because I find it 100(!) times easier and logical.
Finally, the 'Oilite' bushes I got from the supplier had a lubrication hole halfway along! Struck me as a bit odd as there's no provision on the back plate for an oil/grease nipple and my understanding was Oilite bearings were permanently pre-lubricated?
Thanks again and a tres bonne weekend from la belle France!
I'm needing to make bronze bushing for the brake camshafts on my Austin Seven project. For those not familiar, the bush carries the stem of the shaft through the brake backplate from the brake actuating cam itself to the operating lever.
The bushing needs to be about 26mm long, 13-ish mm O/D for a push fit in the back plate with a bore of 11mm.
I've got the stock set up in the lathe with a 10.5mm drill in the tailstock drill chuck. (The plan is to reamer to 11mm when the axle is attached to the chassis).
However, the drill is making painfully slow headway and repeatedly snatching in the bore.
I think this is because I haven't 'backed-off' or blunted the lips on the drill (didn't want to spoil a drill!). Would that be the likely cause of the problem?
As always many thanks in advance for a view/advice.
|Thread: RENAULT DAUPHINE|
Remember them well, and a school mate who was very miffed if anyone raised the issue of instability.
Think it was a myth. As someone says, you had to accustom yourself to the characteristic of the car in those days, and the Dauphine layout was helping to break new ground, particularly in the UK.
Rust? Everything rusted to billy-o then, even R-Rs and cars like the Vauxhall Viva and Hillman Avengers were catastrophies.
Suspect the disparagers of the Dauphine may be displaying a touch of Europhobia....lot of it about.
Martyn in Paris
|Thread: Automotive starter ring (ring gear)|
Very many thanks everyone. That helps.
I wonder if anyone could advise on this?
I have an Austin Seven flywheel from which I want to remove the ring gear. This is the early type where the teeth were milled(?) onto the solid. I.e. not the type where you heat a gear ring and shrink it onto the flywheel.
Most people would probably do this on the lathe and I have sufficient swing to do that. However I am worried such a heavy interrupted cut will bash the hell out of the lathe headstock.
I'm thinking a gentler approach would be to mount the flywheel on a rotary table and cut down just behind the teeth with an end mill or slot drill.
Is this a sound tactic?
Thanks in advance for any help. Martyn
PS Not an angle grinder please! They terrify me.
|Thread: Tab Washers|
Good advice and tips I shall employ.
Does anyone make tab washers in their workshop, and know an easy way to do so that's not like taking a steam hammer, the size of Big Geordie, to crack a very small walnut? I know your going to say: ' tab washers cost buttons, so why bother'. True; but my supplier makes them from far too hard a steel and when they are close behind a nut and tight against a ball race (my context) they are nigh on impossible to bend neatly without damaging the nut and/or bearing.
Soften them by heating. Yes? But to what colour and quench?
Or, could you do it like this? The Big Geordie and nut method! The principal difficulty as I see it is the internal tab. What if you took a piece of aluminium bar, turned to the desired outside diameter of the washer and bored to the inside diameter less the width of the tab. Now set up the workpiece on a rotary table and mill round with an endmill for, say, 350° of the bore - or any circumference that left the appropriate tab width. Could you now slice off as many washers as required, as thinly as practicable, with a slitting saw and grind them down to an appropriate, bendable thickness.
|Thread: Milling that slot|
A few weeks ago forum correspondents were good enough to advise me on milling a slot in a round bar and I thought it would be an appreciative gesture if I let you know the denouement.
We explored a number of possible causes for difficulty. Unknown specification of the metal - I was using a surplus Austin Seven gearbox shaft; lack of centricity and/or rigidity of the workpiece, suitability of, and working procedures in using the slot drills I was 'hell-bent' on employing, and so on.
So, I threw away the bit of A7 gearbox and ordered virgin, free-machining steel from that most excellent supplier, R C Machines in Luxembourg. I took the precaution of buying both 15mm and 20mm diameter lengths as the finished part was barely 14mm in diameter and break out either side when machining was an issue, particularly if I let the tool deviate to one side or t'other.
To that end I trammed the vice to within 0.02/0.05 mm parallelism which, in spite of watching numerous 'how to You Tubes' from the great and the good, is about the best I can manage. I also decided to use about half the 300mm long bar although the finished part needed to be no more than 30mm long, the thinking being it would give me plenty of material to 'hold on to'.
To do so I set up twin precision ground V-blocks held as far apart as practicable in the vice jaws. I found the jaws would only grip one block. This could be because there is slop in the newish Vertex vice, although none is perceptible, or the identical V blocks (Chester) aren't in reality .
I have to confess to not taking the advice on centring, largely because I didn't really understand. I guess I could have touched on one side of the bar with an edge finder, done the math, touched from the other side, calculated again and divided, but given my level of competency and the back-lash on the Warco I stuck with my dangly inverted V gadget, that I do happen to like, in the mill spindle. But I did double check with the old machinists' trick of touching down with a centre drill on a steel rule placed across the circumference and eye-balling it for levelness.
I then drilled into the top of the bar at each end to seat the clamp of each V block and I overcame the fact that one was not gripped by the vice by building up with parallels a step block pressed across the end of the recalcitrant block. I also packed with spacers the gap in the vice jaws between the V-blocks.
I found I could get away with an 8mm wide (as opposed to 9mm) slot, so I amended the 'spec' accordingly. I felt the rigidity and centricity(?) I now had was the 'answer to a maiden's prayer' so applied the previous technique. Drill holes on the ends of the required length; cut through with an end mill and widen accordingly. M-I-S-T-A-K-E! Worse mess than before.
Thus I decided to 'bite the bullet' and experiment with a brand new 8mm slot drill. In a test slot on the material I found the slot drill would plunge 0.75mm static then
happily slot at that depth over a test length (12-ish mm -18/20 required). 'Perfick'!
Try it for real. Problem. Slot drill is pushing the bar along the V blocks. This problem was identified in the forum when I was holding with a collet block in the vice. Paper stuck to the ground surfaces was suggested. Because I didn't want to disturb the workpiece I didn't do that but instead pressed step blocks against both ends of it. Slot drill now plunges and advances with no problem and makes a perfect slot on the axis of the bar. I finished to diameter with an interrupted cut on the lathe. I ran the mill at 360 rpm and plunged the slot drill by 0.5mm increments.
Delighted with the result so thanks again.
10 avenue de la Porte de Ménilmontant
|Thread: Cut a slot in round stock|
Thanks everybody, I think we can make progress here!
Rigidity, rigidity, rigidity is a good axiom I feel.
Maybe turn down the centre of the stock shy of diameter first. Clamp the collet block vertically certainly, but with a long piece of stock there's also the opportunity to hold the other end rigidly.
Not working to the finished diameter would strengthen the sides of the slot during the cutting process and once it was done an interrupted cut on the lathe would take it down to size before finally cutting off the part at each end.
Take the point about the material. That's the trouble with non-virginal material isn't it? You don't know the composition. I'll buy new steel.
I'll forget slot drills. Cut a flat with an end mill I think. Use twist drills at each extremity then gently take out the balance with end mills of increasing size.
I appreciated the drawing. That's not quite it. The bar, 27mm long at the finish remains intact at 14mm diameter. The slot - 9mm wide x 19mm long - goes through it. Thus you can't take out a complete portion as in the drawing but are leaving about 2.5mm on each side which is what makes it tricky. The slot needs to be straight, consistent and in the middle so as not to weaken one side or the other. Nice artwork though!
Thanks again everybody
Firstly, many, many thanks for all the comments and help.
For clarification, at the risk of being boring, what I'm trying to make is a pivot to sit between the forks of a vintage Austin Seven brake lever. The slot is necessary to accommodate a rod that links the brake pedal to the lever without putting any sideways load on the connection (rod).
To make the pivot I'm using a surplus Austin Seven gearbox mainshaft which is a nice bit of 'stuff' and because the gears would have been keyed to it, is not in itself hard. Its about eight inches long and 19 mm in diameter. and I turned it down to 14mm which is the only really critical dimension (hole in fork).
I am holding it in a collet block with an ER32 collet in a Vertex 4 inch vice on a Warco Economy mill. I have about 35 mm protruding out of the collet and for the later/heavier cuts I supported the overhanging end in a vee-block. Prior to that the collet block tended to tilt downwards.
Thus, I think overall rigidity is an issue.
I centred the spindle over the stock with one of those simple 'swinging vee' gadgets, scribed a line along the axis; centre drilled at both ends 4mm + 4.5 mm from the true end and from the intended cut off point (27 mm overall). Four millimetres because that's how much solid metal I want to insert on each side of the fork and 4.5mm because that is half the diameter of the width I want the slot. The rod is the diameter of a 5/16 BSF thread. (7.9mm)
I drilled on the centre drill indents at 6mm, 8 mm, 8.5 and 9 mm. When I now say mess I mean the 9 mm wandered off and chewed the sides where there's not much lee-way (as you point out) - 2.5mm. That's why I corrected with an 8 and 8.5 and why I think rigidity is an issue.
I tried to take out the remaining metal between the two holes with an 8mm slot drill and that was a mess too. In fact it wouldn't do it! Stalled the mill. Resorted to a file.
This is another bit I don't understand! I know that the difference between a slot drill and an end mill is that , because of the way the teeth on a slot drill are formed, they can 'plunge' whereas end mills' capacity to 'plunge' is minimal. Yet, my slot drills have a marked reluctance to 'plunge. Do you....drill a hole first, insert the slot drill part way - say for the sake of argument - to a depth of 2mm, then advance it the length of the slot - say 20 mm, come back, go down another 2mm and advance and so on until you are at depth or do you advance (plunge) the slot drill the full depth, as you might a conventional drill, then advance it along the slot cutting all the way in one go?
Good news is, the pivot piece, rough and unsatisfactory from a machining point of view though it is, works like a dream.
Can anyone advise me how to do this accurately? Fourth attempt coming up! I need a through slot 19mm X 9mm in 14 mm mild steel bar 27mm long.
Have tried a slot drill which just made a mess. Tried enlarging holes I thought to be accurately placed on the axis then cutting out the 'bridge' with a slot drill. Latter made a further mess and although I did get the slot I wanted by filing it was dangerously over to one side to the extent the part is unusable.
Guidance much appreciated, and many thanks, as always, in advance.
|Thread: 1935 Austin Seven Ruby ARQ|
I know it's very 'bad form' to 'muscle in' on someone's thread with a topic that has absolutely nothing to do with the subject under discussion, so I'm not going to. Thus could Ol Baillie e-mail me on email@example.com or firstname.lastname@example.org so I can ask him something about Austin Seven Rubies!
All the best. Martyn Nutland
|Thread: Rotary Table Scales|
I wonder if someone who is familiar with rotary tables could explain to me how to read/operate the degree scales.
I have a 150mm diameter Vertex model. It has a 360° scale around the table and a randomly (I presume) placed pointer on the fixed base.
Working in from the hand wheel, there is a knurled ring that looks separate from the hand wheel but won't rotate without it. Integral with the knurled ring there is a scaled cylinder - rather like the markings on a lathe. But these are engraved 0 - then 15 divisions on - 30 - then another 15 division on - 1, and so on until you pass 3 and come back to zero after a full revolution of the hand wheel. Thus, I assume each of the 15 divisions between 0 and 30 represents two minutes and the 1 represents 60 minutes or one degree of table movement or four degrees per revolution of the hand wheel i.e. a ratio of 90:1 in terms of wheel to table revolutions.
After the aforementioned knurled ring and cylinder there's another stepped cylinder that turns independently of the outer one. This is engraved, at random as far as I can see, with a scale 60 0 60, with three divisions to the left of the zero and three to the right. I assume these are seconds of one minute of one degree. Protruding vertically from the after part of this cylinder is a short lever that engages or disengages the worm drive to the table so you can turn the latter by hand, if so wished, without turning the hand wheel. A thumb screw on the body of the machine locks the worm in engagement.
By way of example of my frustration: If I want a bolt circle of three, what I would do is twirl the hand wheel until the pointer on the fixed base registers with zero on the annular ring on the bottom of the table. Then, twirl again to 120, do the business, twirl another 120 (240 on the scale) and so on. But this strikes me as very unsophisticated and negates the point of all the gubbins behind the hand wheel. So, anybody, how do you set it up to do, for the sake of argument, a segment of 60° 12' 30"?
Thanks in advance for any guidance. Martyn
|Thread: Edge Finder|
Nobody's writing anybody off. All I said was, there are not many books available that deal specifically with milling. And there aren't. Plenty on lathering.
As regards You Tube and videos, a bit of common sense will enable you to quickly identify the bozos.
For nearly an hour of first class, professional, instruction try Erik Vaaler 'Essential Milling Skills: Working With A Milling Machine Part One' and take it from there. Or refer to any of Tubal Cain's very many videos that involve milling.
I think Neil hits the rivet precisely on the head when he asks: 'what sort of project do you want to see in a book' - like Harold Hall's?
And the answer is, surely, none at all.
What a beginner wants to be told is how exactly the mill works, how to set it up and fit the tools, and above all, how to use it all safely. Little of which is contained in Hall's book.
If you understand the above, potentially, you can make anything from a T-nut to a precision boring head.
There are excellent videos on You Tube that show you precisely how to use a mill safely, what it can do and how you can set it up and maintain it to perfection. As usual most are American! But I would humbly suggest carefully selected You Tube 'films' are the way to go.
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