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: Vertex (V4?) Rotary Table|
I've got a Vertex rotary table. I think it's a V4 model. I've only ever used it to make incremental cuts (e.g. bolt circles) which is, admittedly, very easy using the main degree scale of the table and has been totally successful.
Apart from the main 360° scale on the table I have 120 divisions behind the hand wheel (two hours?) and then six divisions on the inner scale (tenths of one minute?). So...wind on 0-19° on the main scale...then what...?
Also, could I ask, what is the pin/lever about an inch long that screws into the second scale ring for? All I can see that moving it ever does is reverse the direction of the table when you turn the handle (if you hold said lever it over!)
Sorry to be so basic. But guidance would be much appreciated and, as always, thanks in advance.
Best wishes and keep safe.
|Thread: Gear Cutting|
Thanks again. I can take it forward now using the formulae, reading list and practical advice.
Tim, don't go out in the snow. Not yet anyway.
Again, many, many thanks for all the information and the trouble so many people have gone to to explain this.
I have come to the conclusion that gear cutters are not the way to go in this instance!
To Michael G, I would say, with the help of the forum and the internet I had 'worked a lot of it out for myself' but some of us are too daft to clinch the deal!
Thus, I'm still not clear as to which set of eight I might need for a particular task - an 0.5 module, 0.6 or what.
Putting the question brutally simply - which one for a gear train on a Showman's locomotive and which for the escapement on my half-hunter pocket watch. 0.8 for the traction engine, 0.5 or less for the watch I guess.
That said....I think the way to go on the Simms coupling is as suggested by 'old mart' - use a rotary table (in my case the dividing head) to measure the divisions and cut the teeth with a small ball mill and finish the angular tips with a file, Dremel or even a very small radiusing tool.
Can't thank you enough.
Many thanks for all of that and for the encouragement.
As Lieutenant Columbo might say: 'There's still one thing bothering me'.
The tool supplier I use is RC Machines in Luxembourg who do indeed have eight piece cutter sets, just as we said. They are marked 20°, again as we said and then they have different number ranges to indicate the number of teeth each can cut. Understood.
Then there is a 'module' number. I now understand the 'module' to indicate the coarseness of the tooth; thus a low module should give a fine tooth, a high number a coarse one. However, the 'RC' cutters have numbers such as 0.5, 0.6, 0.8 etcetera.
So, following Jason B's most helpful advice of taking a Number 3 cutter from the eight piece set to achieve my Simms vernier gears, what module would I be looking for?
And, if I do other gears for different things in the future, do I need to keep buying additional eight piece sets of different modules (at 130-160 Euros a throw!)
Clarification would be, again, much appreciated.
Seasons greetings and best wishes for peace and health from rural France.
I have treated myself to a dividing head (not a Christmas present!) This may be a bit ambitious on my part as I'm not sure my skill levels will enable me to master it. But I'd like to.
As far as I can determine from images on the internet, it's a clone of a Brown and Sharpe O Model Semi-Universal. It's probably Chinese judging by the incomprehensibly garbled manual, although it doesn't state it's parentage either on it or the box. That said, and I'm loathe to admit this, it seems rather beautifully made.
The prime purpose of buying it, is I wanted to make Simms vernier couplings for the magneto drive on my Austin Seven projects and this is where I would. appreciate some help. I'd like to do other work in the future.
As I understand it, one buys sets of gear cutters each one of which is suitable for a gear with a specific range of teeth. Say, for the sake of the argument, any number between 36 and 48. The next cutter would then take you from 49 teeth to 60 and so on.
But how do you establlsh the angle between the teeth? I think I'm talking about diametrical pitch (?). There seems to be a value in degrees on the cutters - for example 20°. Is that it?
So would the way forward, along the 'Simms road', be to count the teeth on the gear (19) measure the angle between them (?) and choose a cutter that includes 19 in its range and is of the appropriate angle?
I have a Machinery's Handbook and basic instruments such as grinding gauge, protractor, combination set, calipers etcetera.
As always very many thanks in advance for any comments and advice with renewed good wishes.
|Thread: Steering side tube|
Many thanks all - that's exactly what I wanted to know. There's no brazing or welding involved but it's useful to be reminded that there needs to be enough wall thickness to create the correct I/D but, very importantly, leave enough metal for the seating that takes the pad, shims and spring behind the ball connection on the drop arm and steering lever respectively.
Thank you again. Best. Martyn.
I want to make a steering side tube (drag link if you're American) for a vintage Austin Seven. Could someone tell me the grade of steel tube that would be safe for this purpose?
I know....look for an old one on the 'net'. But living permanently in France, as Brexit cometh, this is an increasingly unattractive option as I strive towards engineering self-sufficiency!
Thanks in advance and if it's not premature - seasons(?) greetings.
|Thread: Shear Tool|
Not long ago (26/8/20) I asked for some advice on obtaining a high quality finish on some Austin Seven track rod pins I was machining. The consensus was that I should be making the last pass(es) with a 'shear tool'. In my ignorance I had never encountered a 'shear tool' and I don't think you can buy them.
Anyhow, I sent for a blank and watched Tubal Cain (American not old British) on the internet who happens to deal with making one. I thus ground up something that approximated to Tubal's although not nearly as neat. Tried it on a piece of scrap aluminium and worked like a dream on the finish and even produced swarf like maiden's hair! Picture attached (hopefully)
Thought you'd like to know and receive renewed thanks.
|Thread: Horizontal Milling Attachments|
Thanks for the additions. I can certainly work something out on this basis but accept 'attachments' are definitely 'out'.
Thanks again everybody.
As always, many thanks for the observations and guidance. I think you have helped me avoid wasting much money.
I suspected the attachment offered by Chronos is only suitable for Bridgeports or Bridgeport clones. Even then I can't see how the dovetail support would fit onto the Bridgeports I have seen. The GTS item might go onto a Warco, although the taper is an issue. And there again, who would risk that weight of unsupported 'gubbins' hanging off the Warco spindle? Furthermore, as we all know, rigidity is 'all' in milling, and as has been pointed out, none of these set-ups, especially the GTS one, is going to be very rigid.
I don't think I can afford a horizontal mill or have sufficient work for one; neither do I really have the space.
However, I already have a three-slot rotary table that will configure vertically as well as horizontally, plus a dedicated three-jaw, self-centring chuck for it. If I bought another four slot rotary table (superior to the three) that came with indexing plates, I think I could contrive set-ups that would do everything I was hoping for with the horizontal 'attachment'. Yes?
Thanks again for all the valuable guidance.
I'm considering investing(?!) in a horizontal milling attachment for my machine. This is a very expensive piece of kit in my terms and I wonder if experienced machinists would advise going ahead; or otherwise.
I'm running a Warco Economy. I fancy the horizontal device from Chronos (almost certainly a Vertex) because it has a support for the outer end of the arbor, although I can't, for the life of me, see from the photograph on their on-line catalogue how that would fit to the Warco.
Also, I'm looking at one (more expensive and definitely another Vertex) from Gate Tool Services that has no outer end support. That worries me although it seems it would fit my machine.
Important factor...I want to use the attachment just for more convenient use of my slit saws on some jobs and for some light gear shaping - for example bronze vernier couplings for magnetos.
Any views, experiences, however damning, would help me greatly;
Very many thanks in advance.
|Thread: French model Engineers|
Not a modeliste, but build vintage Austin Sevens from boxes of bits in what used to be Picardie, now Hauts de France. Lathe and mill a bit in a very modest sort of way to make small parts for them. Like others here find vintage engineering outfits hard to find but buy materials and tools from the most excellent company RC Machines in Luxembourg who will deal in English and have no silly automated credit card insistence.
I'm in Gueschart which no one's ever heard of, nor can find on the map. But it does exist and lies between Auxi-le-Chateau et Crecy-en-Ponthieu, or, if you prefer Abbeville et Hesdin!
4, Place de l'Eglise, 80150 GUESCHART (don't you just love succinct French addresses), website email@example.com
Best and many thanks for the opportunity to reveal this.
|Thread: Quality Finish|
Many thanks again for all the good advice.
I didn't know about shear tools which seem essential to the process.
Strangely enough, Tubal Cain has a whole video on making them and I'm now studying this.
Many thanks all. HSS, fast, light, lubricant, stone. Got it.
I wonder if the experts could give me some advice on obtaining a high quality finish on a part.
I'm making track rod ends for a vintage Austin Seven. As many, many of you will know; on an Austin Seven a fork on the end of the track rod clenches a steel pin by means of the ubiquitous cotter pin, then the steering arm/track rod arm has a bronze bush to pivot on said pin.
I'm using EN16T at diameter +/- 9.5mm and for mechanical rather than purely cosmetic reasons I'd like to achieve as near to a glass-like finish as I can. Recently I used some steel described as 'polished' from my supplier here in continental Europe (the excellent RC Machines in Luxembourg) but found the tool tended to tear the surface and leave it rough how ever sharp the insert or light the cut. I don't want that to happen again.
I won't be tryng to harden the pin in any way - the mileage doesn't warrant it.
Any advice and many thanks in advance. Keep well.
|Thread: drillling bronze|
Like Philip, I've had trouble drilling bronze which I do when I make bushes. I have to confess that I have found that blunting the drill lips is of absolutely no help whatsoever! Maybe I do it wrong. As I understand it, what are termed the 'lips' are the parts of the tip that look like hooks and you are supposed to take the 'points' off said 'hooks'. I've bought and spoiled drills doing this and got no where.
That said, I find a brand new (or very sharp) unmolested drill will cut bronze as if it were cheese; no problem.
Just my experience.
|Thread: Wot No Teeth?|
In the end I began by setting the flywheel vertically on the milling machine and, using a slitting saw (4" x 1" x 1/32), I undercut the teeth at the root in tangential increments. This is a laborious process as there are 80 teeth and the saw would only span 5 or 6 teeth at a time.
The tedium was relieved somewhat by the fact that, as we know, Bendix pinions of the pre-engagement era, are brutal devices. They bash their way into the ring gear usually in about the same place each time. In my case this meant that over about a third of the circumference of the flywheel the Bendix had destroyed around threequarters of the width of the tooth and I figured that could be removed by means other than the tangential cut process.
Having treated the teeth from the root end I chucked (three jaw self centring front fixing) the flywheel. horizontally on a rotary table. I then repeated the previous process but at the bottom side of the tooth. This isn't quite so tedious as I calculated I only needed a cut about 2mm deep on an undamaged tooth to reach the first cut. The theory was to end up with an 'L' shaped incision that 'voila' would part the teeth from the flywheel. This time I used a 1/16" thick slitting saw but the diameter was the same so I could still only treat 5 or 6 teeth at a time. I used 18° increments on the rotary table. There was no clever math about that, I just guessed that was the most I could rotate each time if the two cuts were to meet.
Naturally, the two cuts didn't meet! But I found it relatively easy to break away the teeth in short sections with a cold chisel after joining the slitting saw cuts with an ordinary hack saw.
I have a strong aversion to, and fear of, angle grinders but I used my Makita to take off the remains of the teeth that had been virtually destroyed by the brutality of the Bendix. I then gritted my teeth and used the grinder again to restore some degree of roundness to the denuded wheel.
Next I put the fmywheel in the lathe held on the tooth side in a four jaw independent chuck. This is the only side that has a decent boss on which to grip. I supported the opposite side on a rotating tube centre fitted to the tailstock. One has to work from the 'backside' of the job and I used left hand and right hand cutting tools to clean up and 'round-up' the wheel where the teeth had been. I got to 0.02mm run out on a dial indicator
The photos show the toothless wheel and the set-up on the lathe. The good news, apart from the wheel, looking 'half-decent' is that it has lost about 9 oz from its original 12 pounds.
The bad news is that I cut slightly too deeply on the tooth sides with the slitting saw leaving visible saw cuts around the periphery of the flywheel. You could revove these by continuing to machine away the area where the teeth had been, and although this would lighten the flywheel further, it might impinge on the bolt holes forthe clutch cover (see photo). Also I'm wary of heavily lightened flywheels as I've known them burst with nasty consequences!
Thanks again to everyone who suggested and advised. It really set me on a successful track.
Edited By JasonB on 09/02/2020 16:23:09
|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.
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