Member postings for Marcus Bowman

If it was me, I would use a polished, uncoated single-flute carbide cutter with an aggressive geometry designed specifically for machining aluminium. If possible, I would avoid using long small diameter cutters,

Speeds and feeds are pretty important. Spindle speed shold be basded on around 100metres/minute, so a 3mm cutter should be turning at somewhere around 10,000rpm. I'm guessing you are not running your spindle at that speed. A 10mm cutter should spin at around 3000rpm, which is achievable on many small mills, so that's a good go-to size for starters. Won't work for tight corners, of course, but ,as JasonB says, you may be able to deal with those by drilling, or by machining separately.

Rough out, leaving 0.2mm to finish. Climb cut the finishing cut. High speed, but a slower linear feed may help.

I have had decent results with a long series 2 flute cutter on 50mm deep finishing cuts, but it was a 10mm cutter, not a 3mm matchstick. Roughing at 3000rpm, and up to 500mm/min, taking cuts of 15, 15 and 20mm down the face, finisihing with a single climb cut pass at full depth, 3000rpm and 120mm/min. Material was grade 6082 (HE30).

Marcus

I have sheets of aluminium 1050 and it is officially specified as soft, with poor machinability (see: http://www.aalco.co.uk/datasheets/?gId=1). The 1050A is grade 'O' which is the softest, and I also have grade 'H' which is tempered. You do need to be quite careful when specifying which grade you need when you buy it. Grade O is easy to bend and shape, while grade H14 has a bit more stiffness. 1050 is lovely stuff, but only for forming, bending, etc.

At the risk of offering a counsel of perfection, I would punch holes in sheet up to about 2mm and would not normally attempt to drill it. I consider 3mm and over to be plate. The Q-Cut cutters work ok on the thin sheet, but they need to be sharp. They do, however, produce a nice curve into the hole, on one side of the sheet. At a pinch, you can use woodworking techniques, and I have seen, and tried, some simple techniques like using a woodworking gouge or chisel to punch a hole, then using a shaped fibre or plastic punch to finish the edges with a flare. It may seem like butchery, but produces lovely finished work. I have a Metalman 'corking tool' which is a chisel-style punch with various heads for that kind of job, and its a handy tool.

Bosch produce sheet metal hole saws with very fine teeth, and those may work on 1050, but they are expensive.

I also use some of the 6000 grade bars, plate and flats (6082, 6060, etc) and cast tooling plate. 6032 was formerly called HE30 and it machines quite well. The cast tooling plate is a joy. I would not use a standard milling cutter, though. In my opinion, the only cutter you should use is one produced with a geometry specifically to suit aluminium --- carbide with a single tooth and very aggressive angles. Accupro (sold by MSC Industrial) work very well indeed, but are very expensive. The finish is like chrome, even when machining dry. Use a high spindle speed and feed rate. Lathe tools are the same - you really must use a polished carbide, uncoated tipped tool for good results.

Its a lovely metal to work with, though.

Marcus

Is there a grub screw hiding in the groove of the pulley? My MF4 has grub screws as well as tapered keys in both pulleys. I'm not convinced its a tapered bush. I think it is a parallel shaft.

Meddings would tell you.

Great drills. I have had mine since 1975 and use it a lot.

Marcus

Once upon a time, MEW or ME published a table showing equivalences across W, BSF and Metric bolt heads, Sadly, I can't recall the issue.

Marcus

I use a couple of Vertex K4 vices, bought from Chronos, I think. They have worked well for me. Jaws are plain, with no grooves. I use sets of parallels almost every time I use the vices, so I'd recommend those, if you don't already have them. I don't see them on Chronos ay more, but Warco do them. I also see vee jaws for sale on Chronos, for the K4.

I took off the swivelling bases and fixed each vice to a plate of 16mm steel which has through holes to suit my tee slot spacing.

Marcus

Is there room to make a short adapter?

Marcus

If you are worried, part off with by parting the major (continuous) diameter section of the bar, with the edge of the tool just at the intersection of the continuous section and the milled section. Any clean up or bringing to final finished width can be done using a 4 jaw chuck.

Marcus

Can you post some photos in an album?

Marcus

I seem to remember that an individual is allowed to make a single instance of a patented device, for personal use or study, but not for resale. Patents are, as you say, Michael, public documents.

Marcus

Oh Dear! I bought and paid for a paper copy some time ago. However; I can confirm this is a jolly useful publication. I must say I prefer reading the paper copy in bed, rather than the electronic copy. The paper copy does a soft landing on the floor when I fall asleep...

Marcus

I have used AbTec for several wheels for surface grinding and for tool & cutter grinding, in recent times, and have had a happy experience.

www.abtec4abrasives.com

Marcus

Although 8 and 12mm bars are useful, I made an additional larger diameter bar with an HSS tip for finishing cuts on larger bores. It's 25mm diameter and much more rigid than the smaller bars. Although the tip is an inserted bar of HSS, it is fine for 2 or 3 fine finishing passes (all of the same depth of cut). It is a bit of a chore having to remove the 4-way toolpost and mount the big bar, but I have found it pays dividends. One of these days, I will make a similar bar which takes a polished tip insert. As you probably know, those polished inserts are available with different tip radii, and the slightly larger radii are ideal for smooth finishing cuts.

I have bought nice inserts and bars, and other tooling, from www.shop-apt.co.uk (with whom I have no connection).

Marcus

LBSC's magazine articles did that, of course. His subsequent books did the same thing for individual designs. In modern times, the equivalent is the ARM1G design, the book for which is shown here: http://www.g1mra.com/shop/

and its predecessors (Project and Dee), although ARM1G is designed to accomplish just what you describe, including lots of parts which can be bought from trade sources, such as frames, complete cylinder assemblies etc, so that the entry level can be tailored to an individual's pocket, capabilities and resources.

There is a case for 3D modelling of LBSC's designs, as a project in its own right.

There is another case for updating those designs, by converting sympathetically to metric dimensions (which would get my vote) to make them accessible for younger or newer builders (say under 70), and/or by updating the designs comprehensively to modern standards and practices, including modifications in the light of previous builders' experiences.

There is also a case for preserving the 'words and music' of text and drawings from the magazine articles. Those preserve an important aspect of his success, which is the 'can do' spirit. I agree with earlier comments about LBSC's intentions, and his ability to describe how to do the job with limited resources. It would not, however, be my approach now, as I think that although it may (and I do say 'may' lead to success, there is a danger that it fosters an attitude which rather devalues the depth of understanding and sheer skill which can be developed by deliberately pushing oneself to develop the appropriate workshop resources and associated skills to do the job in a more precise, and often more effective, way. This is, if you like, the difference between the approaches of LBSC and G. H. Thomas [I will stop here, as I notice a hobby horse preparing to gallop]. This is important, though, as it impinges on the discussion of whether to simply preserve the LBSC designs in their original state, or whether to comprehensively update them.

Drawings re-drawn by the magazine staff would be M.E. copyright, of course, as would the page layouts, but the words and original illustrations and drawings belong to LBSC's estate. Which takes us full circle, I think...

Marcus

RPM = cutting speed (metres/min) / circumference (metres)

Aluminium has by far the highest recommended cutting speed of all the common materials in our workshops, at 75 to 105 metres/min for HSS tools and 900 to 2200 metres/min with an uncoated polished insert.

At the lower end, on a 50mm diameter bore, that translates to 500 - 668rpm for HSS and 5732 - 14102rpm for a tipped tool. Two limiting factors have already been mentioned: lathe top speed and chuck rating.

So; run the lathe at top speed, but expect the carriage feed rate to be slow. The tipped tool rpm are well outside the Myford/Boxford/mini-lathe speeds, but that will not prevent the tips working reasonably well. I certainly would not be inclined to attempt this job with HSS tools, but opinions (and results) vary. I machine aluminium frequently on the lathe and the mill and have found the tipped tools or polished carbide cutters ground with cutting angles specifically designed for aluminium to be the answer to the clogging and sticking problem. Flood coolant helps too, of course, if you can stand the mess. WD40 stinks too much for me. Carnauba wax works too, but is too laborious to apply, and too expensive. Neat cutting oil works, as does water-soluble cutting oil. Application by toothbrush is too much effort, on a time-consuming job like this.

Some manual lathes (Hardinge, for example) can run at 5000rpm, and suitably rated chucks are available at a price.

The smaller diameter stages of drilling and initial boring will work best at correspondingly higher rpm.

In the end, we do what we can with what we have, and a 50mm hole is perfectly achievable without too much difficulty (except, as previously noted, for the copious swarf).

Despite the higher recommended speeds, I would simply use top speed and be content with the chrome-like finish on the final finishing cuts. Wondrous to behold.

Two other points:

The work needs to be gripped in such a way that there is clearance behind the work for the cutter to pass through without hitting chuck or faceplate, at maximum cut diameter.

The boring bar for the final stages needs to be stiff and/or of large diameter, to prevent 'ringing', and to provide sufficient rigidity for the finishing cuts. It depends on the finish you need on the job.

Marcus

I have recently done much the same thing, for several workpieces. In aluminium, machining speeds are so high this is not a terribly lengthy job using large drills then a boring bar, compared to the same thing (also recently undertaken) in steel.

I mounted my AL in the chuck, drilled to 19mm, then used a toolpost-mounted boring bar and power carriage feed.

I used a tipped tool with an insert designed for AL (mirror polished, and with an aggressive rake). You have little chance without that, as an HSS tool will clog in seconds, especially at higher speeds without a lubricant. Using the insert, I machined the work dry, although flood coolant would be better. Coolant will also help prevent HSS tools clogging, but not for long.

I also changed the speeds as the diameter of the bore increased, to stay within the efficient cutting speed range.

The grade of AL also makes a huge difference. I used 6082 (HE30). 7000 grades are even better, but much more expensive.

Interesting points, raising different issues.

Firstly. although I like the idea of open source plans available in an editable format, the CAD platform would have to be open source, to allow anyone to edit or alter the plans. There are several possibilities, but there is a somewhat larger question. The nature of open source suggests that a user could make changes and re-post the plans. That might be useful for allowing the correction of universally accepted errors or making necessary modifications. But that leads to two questions: who is to say those errors and/or modifications are necessary (because the plans would then deviate from the original); and who then controls availability of the new open source plans?

One solution is to use a platform such as GIT, where changes are tracked, and it is clear which versions are which, and, especially, which is the current version.

Controlling the addition of modifications and 'enhancements' becomes important as plans are changed and morph into something else, over time. Take 'Pansy' for example. Doug Hewson's version is more accurate and up-to-date, incorporating much more modern approaches, so if I was to make a Pansy, I would choose Doug's drawings. But would it then be fair to call that LBSC's PANSY? It's not a straightforward question. I would not want to use any of the LBSC boilers, because they really need to be brought up to date to comply with current legislation and safety requirements. But does changing the boiler make those designs non-LBSC? We need some person or group to control this aspect.

I might draw the distinction between the developmental course of Mach3 and LinuxCNC, for example. Mach3 was originally updated and amended by its creator. When it was sold on, modifications and bug corrections stopped, as the new owners focussed on Mach4 development. They control development, so that was their choice.

LinuxCNC, on the other hand, is open source, and undergoes active development, with new versions available from a central repository. The development is driven by user suggestion and by the willingness of users to contribute to that development. Older versions remain available.

A mechanism of some sort is required to manage any changes. It could either be the original draughtsman, or a user-driven group. What would not be good would be the model where development was frozen once the initial drawings had been released.

As to the format of the plans; this could either be an agreed open source CAD package, or simply the DXF files. The difference is that having the CAD package available to everyone would allow anyone to edit the plans and perhaps incorporate their own mods, for their person use. The DXF files would be the most useful for the person who simply wanted to take and use the plans. DXF may allow some modifications within some packages, but would certainly allow the CAM stage to take place, to prepare G code files for manufacture by CNC.

PDF files would allow non-CNC manufacture, just like existing paper plans. The benefit of PDF files is that printing could take place at any size or scale. Larger format plans can be printed by may local print/copy shops.

JPEG files are not quite as useful, if the print size is to be made larger, as definition suffers when the file is enlarged beyond the native size. PDF, on the other hand, scales well.

Marcus

I assume you know of LBSC's book 'Shop, Shed and Road'? It contains some photos of some of his designs. It does not contain build instructions for any complete locos, but it does deal with his standard fittings and approach to design and construction, including: injectors, pumps, gauges, whistles, safety valves, releif valves and snifting valves, motion work, lubricators, North-Eastern compounds and Mini-steam engines.

First published in 1929, the version I have is the 1969 version edited by the late Martin Evans.

There is also the book 'MONA: A simple 0-6-2 tank engine' by LBSC. That has drawings and build instructions for MONA in 3&1/2 and 1&1/4 inch versions.

The Gauge 1 Model Railway Association members are familiar with LBSC's gauge 1 designs

www.g1mra.com

You may also be interested in the copyright position stated here:

http://www.john-tom.com/html/LBSCEngines.html

What would be of tremendous interest to me would be new sets of drawings, updated to reflect modern safety standards (boilers etc), and dimensioned primarily in metric units. If you want the designs to live on, that's the way to go, IMHO.

Your CAD approach is the right one, I think, especially as it would allow easy transfer of the drawings from CAD to CAM and CNC with little effort.

Marcus

Excellent idea.

Marcus

Copyright for literary persists for 70 years after the death of the author. I remember attending a conference in 1995 at which this issue was raised, at the time when the Alice in Wonderland books were about to go out of copyright. Aspects of the 1995 Act were somewhat controversial, but the basic rule is that for literary works copyright continues to exist for 70 years after the death of the author.

Marcus

Ah, Whistons. Sorely missed. I still have lots of the little bundles which were supplied wrapped in old newspaper...

The "assorted BA screws" still come in handy. There must have been a thousand in the bag. And the very odd sizes of silver steel wire and small rod. I could go on, but my specs are misting up with nostalgia...

Marcus