Member postings for Nigel Graham 2

Oh thank-you JasonB!

Very generous of you! Though I can't help thinking, "That there Jason's teasing me...!"

I wondered if David George's difficulty was due to Alibre registering the PC, so refusing to work on a second computer - a copyright protection move. I recall seeing similar happen elsewhere.

I think "Uninstall" is like "Delete": it just hides the files - but perhaps when loading from the Internet the receiving computer acknowledges by its own ID or address, so the licence can be locked to the individual computer?

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Jason - I knew Alibre Atom does let you take off elevations from models. So, I think, does TurboCAD.

I'd have to buy Alibre outright as my trial copy had expired, as I found when I tried running further trials it has sent since. It said it was "repairing" what I thought I'd "un-installed" - then, "The licence has expired". Hence my comment above.

It's all still there, complete with desk-top symbol, but not useable.

At least I can already produce "good-enough" 2D drawings with TurboCAD it, though without proper dimensions.

There's also a point I don't think anyone else has mentioned, and that is how you would move the work-piece in a straight line in a controlled manner on a drilling-machine! Without that, the cutter could snatch the work with all sorts of nasty outcomes possible.

A co-ordinate vice may seem the answer, but it is not. Many are quite lightly made, solely for locating the work for drilling holes within quite small limited rectangles; they are not for traversing work against a cutter.

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I have, once and very carefully, committed the cardinal sin though. I had to drill a lot of simple holes on concentric pitch-circles, on a pair of turned discs. So far so good but two had to be joined into an arcuate slot perhaps 15º "round" X 1/2 inch wide, about 3-1/2" radius

However the material was soft PVC 3mm sheet, sandwiched via spacers on a 6" dia rotary table clamped rigidly to the drilling-machine, and slotted by very shallow cuts and gentle feed.

I would not try it in metal, and certainly not by habit. I ought really have chain-drilled and filed the slots as they are simply the rope anchorages in the side-cheeks of a purely-functional winch-drum.

Why not on the milling-machine? I'd not yet put it into service so was limited to the lathe and bench-drill.

Aha! Reading between the lines, I think the pump's designers assumed it would be used as an air-brake compressor, as per prototype, hence the reference to "air tank".

Read "boiler" for that and it makes sense.

These pumps do rely on fine adjustment but from what I have seen, once running properly, they work very well.

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I've not had personal experience of them on miniature engines, but have seen them in action.

At work, I have also seen "full-size" versions driven from compressed-air mains at about 90psi, pumping cold water into pressure-test tanks at up to several-100psi. They slow down a bit at high squash!

I managed to repair one once, but not so much by knowing how they work - I understand they work non-expansively so need a way to switch the valves over very rapidly at the end of the stroke; but not how in detail. Rather, "If it looks wrong, it probably is wrong". It did and was. A screw holding a valve-head on its stem had loosened by a couple of turns. Tightened it, replaced the cover, very gently admitted water and air and away it went, no trouble at all, good even exhaust beats, steadily rising output pressure.

Thank you!

That EW lathe needs refurbishing, but it is probably as old as me and yes, I do have a Bus Pass. My parents bought it for my 18th birthday present, from one of Dad's work colleagues. By Tony Griffith's Lathes web -site, it has all the optional extras except one - the change-wheel guard.

I think the oddest task it's done was screw-cutting a spare, special adaptor for connecting a keg CO2 cartridge to a heat-exchanger forming the core of a warm-air breathing kit owned by a cave rescue organisation. It's used to ward off hypothermia. The thread to be cut was metric but also completely non-standard (a common commercial dodge); the lathe is all-Imperial with an 8tpi lead-screw and change-wheels in 5-tooth steps from 25 to 65 teeth, so calculating the combination for the closest match was entertaining to say the least!

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The concept of soft jaws is nothing new at all but finding ones for a particular, old make of chuck is another matter. Normally chuck jaws are hard, otherwise they would wear rapidly.

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A neat aid for using a drilling-machine as a tapping-guide is a "Sprung Centre". It's simply a rod 2 or 3 inches long that slides smoothly inside a blind hole drilled deep into the end of larger-diameter shank, with a light compression-spring at the base of the hole, between them. The inner rod has a pointed end or a shallow centre-drilled hole to engage the centre-hole or point as the case may be, in the upper end of the tap.

The tap-wrench is on the tap's square as normal, the spring keeps the guide in contact with the tap. In use the outer rod is held in the chuck with the drilling-machine quill locked at appropriate height, the inner rod locates on the tap's upper end, so holding the tap vertical.

You'd probably find a design in one or another of those various books. Make the sliding rod bi-ended: hollow one end, pointed the other, so you can swap it round to suit the particular tap.

Another refinement is a screw and slot or other arrangement to keep the device together when you lift it clear of the tap.

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It is satisfying putting an old machine back into service but be aware that vital spares for what might have once been a very common make, may now be totally unavailable so you'd have to make them.

If it's a lathe with an incomplete change-wheel set you've the added difficulty of finding replacement wheels simply to fill the gaps, because although you can buy stock gears easily enough, you need to know not only the tooth-pitch etc, but also the pressure angle of the originals. I don't know what happens if they are different, but I'd imagine at the least, one set would rapidly wear out the other..

Errr... I assume by "to air tank" it means the pump is for brake air OR vacuum. Your quote suggests air-brakes but let's keep our options open and identify the system.

Similar pumps are sometimes used for boiler feed, too, and I'll come to that possibility.

First then, assuming it's pumping air; what else is plumbed to the air / vacuum reservoir? Does that tank have an air or vacuum gauge - which would tell us immediately - or brake control-valve and train connection?.

In either case, I would expect one air cylinder port on the pump to be open to the air, perhaps with a simple filter if it's an inlet, but anyway probably without a pipe.

The piped connections then are the inlet for the steam driving it; and respectively, the air outlet or inlet to or from the air or vacuum reservoir.

Plus the steam exhaust, possibly piped to the smokebox or just discharged to the ground.

So when you connected the "air tank" pipe to your compressor the poor thing didn't know if was coming or going.

Try linking the "to air tank" to said tank, and the compressed-air to the steam inlet, turn on just enough air for it to run, and observe what happens at that tank. If you've no suitable gauge for the tank, either fitted or available, rig a polythene tube to a jar of water safely below bench-level, and turn on the air very gently. if it blows bubbles it's an air-pump, or compressor. If it draws water up into the hose, it's a vacuum pump - but be careful not to let the water reach the pump (hence the "safely below" precaution).

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Your quote from the drawing suggests a brake pump, but what is its actual purpose on your loco? Is the pump drawing for the entire system, or just as supplied with the pump alone?

If it was connected as a boiler feed-pump it will again have 4 ports, of which 3 will certainly be piped: steam in, water in from tank or tender, water out to boiler check-valve. The 4th is the exhaust, again, either piped to the smokebox or simply discharged below the running-plate - but not so it steam-cleans and rustifys the motion.

And again it will also work only if you connect the air-test supply to the steam inlet!

Fine work there, Saxalby!

What's their thickness capacity? The sample looks to be about 1mm thick.

What's finish on the steel-work? It looks darkened, as if some form of protection, or is the effect just photographic?

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"Irony"? I thought that describes laundry-work quality....

Hugh -

Yes, Plus-gas was in red as well as blue cans. In fact I think I have one of each. Their were about 4 formulae until the one called " A ", in blue cans, replaced all; then in 2014 a new one called "Fast" appeared... in a black tin!

It's not worth struggling with spanners that don't fit properly because they are the wrong sizes.

They will damage the fastenings so making the work even more difficult as well as spoiling it; and they risk slipping off, likely skinning your knuckles on some edge.

And that mill is more valuable than the cost of the spanners, which anyway you may need for future servicing, or to use with clamp sets compatible with what appear to be work-clamping holes in the table.

Put a wanted ad on here, specifying the spanner standards you need. If you're not sure of the standard, include the measured (not approximated by spanner) hexagon sizes across-flats so at least a potential seller can determine suitability.

The fastenings may well be BS Whitworth / Fine - same spanners but staggered in size, and most likely are if neither Metric nor inch-AF (Unified-range) spanners fit properly. The hexagon widths on BSW/F are also not simple binary fractions of inches, unlike the UN series, because they are set by fractional multiples of screw diameter.

Also look out for stockists of replacement fastenings. BSW / BSF fasteners are becoming rarer, but I think there are one or two suppliers advertising in ME and MEW for a start. Some of the suppliers or castings and materials for the larger-scale traction-engines also sell limited ranges of such fasteners.

Do you Plus Gas, as you say, not WD-40 despite its label claims; but leave it plenty of time to penetrate - try over-night for a start.

Note that the link opens the details for the sort of valve common on plumbing systems, and these are very simple but highly restrictive to flow.

I sectioned one recovered from 15mm plumbing, to see if it's possible to make a miniature version, and found the port through the ball is half the pipe bore, so one-quarter cross-sectional area!

The operating spindle has a screwdriver-like tip that engages a shallow slot cut across the ball (verify the orientation before slotting).

The spindle is captive by a shoulder, so the valve is assembled by inserting the spindle from inside, then putting in the far O-ring seating, the ball itself turned to the slot engages, the near O-ring then a special circlip that locks into a groove in the valve wall.

A friend in the plumbing-trade vouched for the restriction they offer, but said full-flow versions are available.

It ought be possible to make full-flow versions for much smaller pipe sizes; though rather fiddly to machine. I'd use a manufactured bronze or stainless-steel ball, but I don't have a ball-turning attachment. Besides, it is likely to be of greater accuracy and sphericity than I'd hope to achieve!

To replace the circlip with something easier I'd be tempted to use a thin push-fitted sleeve trapped by the end-fitting or union, but beware the risk of losing the internal components when disconnecting the fitting.

Alternatively look on the boiler-fittings drawings for almost any miniature steam locomotive or traction-engine. The quarter-turn valves on these are usually plug-cocks, but you should find a design you can adapt to your needs.

The wretched log-in system on this site...]

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A pleasure!

You can use the threaded-end cutters in plain collets as long as it's the shank that's gripped and not the thread.

Lathes are not really milling-machines laying on their backs, and a vertical-slide on the cross-slide is not ever so rigid, so you can only take light cuts at gentle feeds.

The length of the T-nut is more to spread the load than add stability, though it will do that. My smallest lathe is a 2.5" centre-height EW Stringer, and I made not T-nuts as such but T-strips to hold the home-made vice on its vertical slide. These are bars of T-section the length of the slot, with two tapped holes in each.

Yes - that's right- the stud shouldn't ground on the floor of the slot.

Lathe chucks normally have hardened, or at least toughened, jaws; but the "soft jaws" are unhardened so you can modify for special purposes, for example by cutting shallow rebates in their top surfaces to grip thin discs.

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It will be worth as I have done, building up a library of reference books written for model-engineers, on workshop techniques. The "Workshop Practice" series is a good start - I've about 10 of them, each dedicated to a particular machine-tool or metalworking method, selected to suit my own needs. Have a look on TEE Publishing's web-site. As well as mail order they usually have comprehensive stands at the major model-engineering exhibitions.

Note that some reference books appear to be mainly handbooks on making tools and machine-tool accessories, leading to a somewhat unfair reputation of making tools to make tools - but they are still full of valuable information. Harold Hall's books are project-led but in a progressive way, so if you follow them you create genuinely useful tooling as well as gaining experience; without being submerged in cutting-tool theory deeper than strictly necessary to start obtaining decent-quality results .

The older books, by such writers as Stan Bray and L Sparey, are a bit more general and if you own old machine- tool like your Myford, a handbook closer to its era will be more attuned to its capacities and likely to cover the subject of milling in the lathe.

In general as I am not familiar with the Sieg mills, but I'd go with your Option 3.

X and Y travels first, as they are the primary dimensions, but you may as well fit the 3-axis version all at the same time..

The ems-I kit may be like the Machine-DRO one I'm fitting to my VMC mill, and it works independently of the feed method by measuring the table and knee travels. To think the Sieg way I had to read your post carefully a few times and see how it compares to my machine!

Put the Z reader on the head, not quill. Leave the quill read-out in place though: it's there and you may as well keep the option.

Then in use, lock the quill at the top surface, null the Z reading, then use the head travel for depth.

It does depend on the sort of things you are making, but very often the X and Y co-ordinates are the critical ones, the depth or height being less so, within reason.

Still fitting my milling-machine's DRO, once I had the long and cross travels sorted, I am not finding it a disadvantage still using the manual scale for depths, ironically for making the Z-axis bracketry, because there are only a few to measure.

As others say... DON'T. With ANY type of drilling-machine and drill-chuck.

Regarding chain-drilling prior to milling, I would strongly advise filing the worst of the resulting "teeth" down before milling. That's because the milling-cutters will catch on the sharp edges and could cut inaccurately or even shatter. They prefer a smooth, continuous cut you will certainly not achieve on a drilling-machine. And if they shatter I hope you are wearing eye-protection.

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Dunc's paragraphs:

" Drill chucks only support the tool at three points around its periphery. This allows the tool to move sideways to some degree - a lack of rigidity. "

Really? Line not point contact actually, but I don't recognise that lack of rigidity in a good-quality drill-chuck in good condition; used for drilling not milling.

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" If doing this I would purchase the largest Jacobs ball bearing superchuck that would fit the machine. When installing it I would aggressively clean the taper socket and the arbor with clean solvent, and heat the socket and cool the taper before installing. "

Clean the tapers yes, when fitting any chuck on any machine, though I don't know what you mean by "aggressively". It doesn't need degreasing, just any swarf and other particles removing.

Otherwise.... "if doing this..." (Milling) I wouldn't be doing "this".

And shrink-fitting? Not on my machines, you would not!

It's not clear whether you mean the Jacobs taper in the chuck itself, or the spindle taper. If the latter you do not want to shrink-fit anything in there, and anyway, to what temperature would you risk heating such equipment evenly, without harming any part of it?

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Chris -

The threaded ends you refer to are common on most milling-cutters, to fit special chucks such as the Clarkson Autolock. The cutter screws into a collet ground accurately to hold the cutter shank, while the centre-drilled hole in the end of the cutter engages a pip inside the collet-chuck body fractionally before the collet-holder reaches its thread-end, to give axial support. A special ring-spanner is made to fit the flats on the chuck body.

NB: the cutter shank diameter and collet diameter must match. A 1/4" dia shank won't fit a 6mmm collet for example. However, although vice-versa will, you can't expect the collet to grip, and even if forcing it does not break the collet, the cutter could slip or jam and snap.

The collet chuck in turn has a Morse or other standard taper shank to fit a correspondingly tapered lathe or milling-machine spindle, with a draw-bar to hold the chuck back in the spindle. Collet sets of various patterns are available for standard tapers such as those in Myford lathes, and you can use these for holding milling-cutters.

There are two forms of ER collet then, if yours have a draw-bar thread. The ones I know use a dedicated chuck that fits the spindle nose, and holds the collet by a particular assembly / disassembly technique. This allows holding work-pieces that project backwards into the lathe spindle.

Myfords used to sell a neat version of its own, but sadly now they are as common as poultry-dentures and at avian-dentistry prices. I don't know if anyone stocks a copy of them, and if so, what they are like.

Again, the cutter must be the right diameter for the cutter or work-piece.

If you are milling in the lathe you can hold the cutter in the chuck if you must, but not preferably. It will only be as accurate as the chuck, and insecure if the jaws are worn. And being hard it won't do even hardened jaws much good if it slips round. A collet is far better.

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The vertical slide locating-pins. Yes, modify them, not the lathe itself! And yes, the stud holding the vertical slide to the cross-slide will need a T-nut, but a good fit and generous length.

Be Aware that the stud or bolt should NOT pass through the T-nut, as that can load the T-slot shoulders very unfairly, and even break them. That's certainly the advice I have always known, and my clamping-sets' T-nuts all have the lower ends of their threads peened over to prevent it.

A pleasure John! I will see if I do have any photos of how I made the drop-bracket for my Centec mill (which I no longer have). I don't recall photographing the process, so can't promise it - and I've still to find out how to add images here.

An interesting idea, Hopper, that this is a combination machine - a rare but very useful beast, and there were some quite elaborate species of these developed over the years. It does look to me as your second suggestion: the projecting bar is an over-arm, not a shaft.

A gearbox in the column... yes, perfectly feasible, even if giving only two speeds as the handle suggests. This was common practice on horizontal mills.

Is that broken thread, the spindle nose? It's hard to see what happens at the register end, but is the thread actually on the same metal as the spindle or is it some sort of insert? If the only answer will be a new spindle I suggest you do make it as I'd described above - with through-bore and internal taper as well as the thread. The taper will probably have to be a Morse at that size, but it will allow using a range of tooling and collets.

The original builder might have used an existing spindle, perhaps from a scrapped lathe, or a new one sold as a spare for some make of lathe.

" ... from tracing over photos ..."

Via a scanner? I don't know if such software exists, but it could be very useful, being able to translate a scanner file into a CAD one.

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Re-measured and re-drew my bevel-gears this evening. The measuring was a bit of a faff, but I concocted a way using a small angle-plate and the drilling-machine table; and the new drawing is much closer than my preliminary attempt.

I didn't try to draw the teeth, just the overlapped outlines, in different colours for legibility. I could then add the bearing-block, shaft-ends and thrust collar to hold them together. Drawing the assembly upside down synthesised how I'd measured it, replacing the metal surfaces with the axes, so all the co-ordinate values are positive.

I've still to establish how to make the dimensions work, but I now know how to assemble adjoining drawing entities, in 2D anyway!

We all look forwards to it being back in service!

Sorry, I've no photos, but I suggest you look on the Lathes.co web-site, find Denbigh milling-machines and study the Model M horizontal.

I cite these because I own a slightly simpler Denbigh H4 (also in the Denbigh " chapter " so can picture it in mind to explain here what I had in mind.

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I don't know how much you know about horizontal millers, nor quite what I'd not explained fully, so please bear with me if I start from first principles and repeat what's already familiar to you.

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On the Denbigh M photo, the over-arm is the heavy bar projecting forwards from the top of the machine. What I called the drop-bracket is that hefty casting dangling from the over-arm's outer end.

On yours, it is the bar projecting from the vertical-slide, directly above the spindle.

The Denbigh is shown with its arbour, without a cutter, in place, and you can see its outer end runs in a bearing (probably just a bronze bush) in the drop-bracket.

This is analogous to the steady on a lathe, and supports the arbour against the heavy lateral loads imposed by horizontal milling.

The inboard end of the arbour normally has a standard Morse or other taper in the spindle nose, and is pulled in tight by a draw-bar extending back through the hollow spindle. It also means you can use drill-chucks (for drilling only, NOT milling!), boring heads, etc. with similar tapers.

Now, you machine seems to have, or had, a lathe chuck on its spindle, and what we don't know is whether it has a through-hole spindle with taper and draw-bar. If just a lathe chuck, you'd need an arbour with a plain rather than taper shank.

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Now to the nub of what I wrote above. Obviously, the drop-bracket centres need to match the over-arm to spindle centres, so the method I described was to give that.

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On most smaller mills like the Denbigh M or H-series, the over-arm can be slid backwards and forwards through its mounting holes (with its clamps slackened). The Centec has a dove-tailed slide but the principle here is the same. This meant that when I linked the table to the over-arm with the drop-bracket I was making, the over-arm slid back with the table.

On yours, the over-arm is fixed, so you will need to clean it to a good smooth finish and slide the bracket on that.

I would recommend you make the drop-bracket (assuming it's not already there among any bits and pieces that came with the machine) with either of two clamp patterns. The first, common on bench-drill columns, has two scalloped steel bushes on a draw-bolt. The other is the split-type clamp, as on the Denbigh machines.

You need clamp the bottom end of the bracket to the table in such a way you can drill and bore or ream it horizontally for the arbour bush. You could use two angle-plates with a sacrificial steel bar across the gap to support the bracket. Or clamp it on some way in the vice. Either way it all needs to be rigid enough not to spring or rotate under the cutting forces while also transmitting the table movement to the top of the drop-bracket so that can slide without shake along the lubricated over-arm. Ease the clamp just enough to allow it.

I would drill the bulk of the metal out first, before setting up as above.

Effectively this uses the milling-machine as a horizontal borer, but the secret of success is in the drop-bracket moving without springing under full control of the table - along the over-arm on your machine, with the over-arm on my Centec and Denbigh.

Plasma-

Arbor missing? That look like a lathe chuck back-plate on the spindle, suggesting the builder was unable to make a conventional taper-fitted spindle or perhaps used an ex-lathe spindle.

Making a new arbour drop-bracket: I had to do that for a Centec mill. My method:

1. Completed the bracket's over-arm clamp arrangement. (The Centec over-arm is dovetailed but the method is adaptable to any over-arm form.)

2. Drilled the arbour hole just below size.

3. Clamped the embryo bracket to the over-arm and to a pair of angle-plates fitted to the table with plenty of T-bolts, so the hole was comfortably between the angle-plates and aligned with the spindle.

4. With a boring-head in the spindle-nose and the over-arm just slack enough to slide, gently bored the bracket to finished diameter, winding the table inwards to advance the cut along the bore.

I took only very light cuts and very gentle feed as the method does put a somewhat unfair stress on the machine; but it succeeded. I think I wound the handle with one hand while gently pushing the over-arm with the other, to relieve the load.

I have a small Denbigh horizontal mill that needs a new drop-bracket for its single, round-bar over-arm, and will use the same technique.

So I think this a way worth John Milton considering in restoring this machine.

I must admit I've often wondered how close to each other all these programmes are, behind the trade-marks and patented / copyrighted presentation.

That bevel gear is actually very much like the ones I am using.

To make the assembly work I need join them by a central journal that also prevents the axial thrust on one of them from pushing it out of mesh. I have established the most compact arrangement for that.

This particular gear-drive is not too fussy, but I'd like it to be right both for itself, and experience should I wish to make a more critical version in future.

Techniques for drawing gears accurately (irrespective of draughting method) are described in my text-books. Here though I need know only the pairs' relationship and overall dimensions when meshed. I'm not trying to design the wheels themselves.

I could draw the journal isometrically as it's only a rectangular block with a few cylindrical features, all symmetrical; but I need an orthographic drawing for making it.

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To those who say CAD's not for me, I want it for me. I want to be able to use CAD sufficiently to support my model-engineering.

Unfortunately I find the CAD publishers' web-sites are very off-putting by suggesting overwhelming complexity and difficulty. That and the lack of any decent literature on the subject, make me feel like, say, a 'celebrity' pop-singer told you can learn to sing from a Wagnerian opera score!

Blowlamp -

I had that idea from the sites referred to above. The publishers like to show their software's maximum capabilities. Whilst I understand that, I find it a bit off-putting even though I know the artwork is by the publisher's professional designers pushing the software to its limits.

The packaging for my copy of TurboCAD contains a card advertising the agent (Paul Tracey). He used on it, rather more down-to-Earth, 3D images of assemblies for a miniature locomotive: a 4-wheel bogie in plain view with moderate tinting, a luridly rendered pony-truck, and the boiler manifold in wire-frame view. The last is so "busy" it loses details.

Barrie -

CNC cutting or Printing - either way, my point was I took MOI as primarily for CAM files. However, CNC machining or printing is not available to me; and I need primarily orthographic engineering drawings, with isometric views potentially useful but not so important.

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Impressive examples you give though. You designed the aircraft parts in MOI, but I take it BobCAD is essentially the machine-tool programmer building tool-paths etc. around the MOI file?

I like that aid to clarity shown in the second screen-shot, by tinting different parts of a wire-frame assembly. I've found colours particularly valuable in an assembly-drawing when I need pick out individuals of repeated components in crowded elevations. If left in one colour, the drawing starts to resemble well-boiled spaghetti.

Recently I completed some structural-geology diagrams in 3D, using colours to differentiate the strata represented geometrically by extrusions. One looked very odd, as if the bed of rock had been mined out of the hill. Then light dawned: to make that layer white and solid, fill its generating shape with white from the colour-chart, not just leave it empty (" white " on the screen).

The BT Internet service seems to go some way to what Mailwasher does.

I have received a couple of those "stuck in Paris" messages allegedly from genuine people such as fellow club-members, but whilst the criminals might be able to copy the compromised sender's visible address, they can't avoid using their own background source address.

I don't know if other services offer it but BT's e-post page' 'Actions' menu allows you to 'View Source', and whilst most is just unreadable code, the source and any devious routes are visible; as also sometimes are the originating country codes.

I have used this to verify a very convincing message from a friend was false - I compared it with his real address.

An oddity with my computer is that it won't allow e-messages via addresses embedded in web-sites. I have to copy them to the normal e-post function. I don't know if it's an effect of my security software, or if it enhances security.

MOI was totally new to me; but thank you for showing me.

I looked at the links Michael offers. MOI seems really for 3D printing ornamental rather than engineering work. FreeCAD would be the better.

I can use TurboCAD, albeit very basically and roughly but practically; thanks to hundreds of hours of effort.

Indeed I spent this evening starting to design in TurboCAD, a bevel-gearbox for my steam-wagon's brake rigging.

I found the gears, a stock metric pair, on a "come-in-handy-bits" stand at an exhibition. Their actual sizes are not very important. Even an equal pair of bevel wheels isn't easy to measure and draw though! I will need to measure them meshed on improvised stub-axles on an angle-plate and surface-plate; rather like clock-wheel depthing.

The brakes on this thing are right crude, just simple blocks suspended railway-wagon style, and acting directly on the rear wheels' smooth steel tyres. The bevels link the operating-handle's vertical shaft to the horizontal screw-shaft extending to behind the rear axle.

The drawing so far of the two wheels and interposed bearing block, establishes the basic mechanical arrangement. I now need measure the centres, modify the drawing accordingly, then design the box and brake-column around them.

'

BTW I made the differential for the chain-driven, traction-engine pattern, back axle from an old car front-wheel drive unit. I replaced the crown wheel with a machined-out motorcycle sprocket; and annealed the differential wheels themselves for turning, in a wood-burning stove overnight.