bertiedog

The Grindturn is a flat top lathe bed, with V under edges, the Gib strips are at the back, with two bolts bearing on them, and should be removed , de-burred, polished and checked to be straight, and replaced, adjusting the bolts till they lock and then back off. A small project would be to replace the steel gib strips with phosphor bronze strip duplicates, easily made from the original dimensions. It makes the movement very, very, smooth. After adjusting, the whole main slide should be free to move at the chuck end, but may be stiff at the other less used end, it is best to set it for the usual area of operation, near the chuck. As long as the back lash in the leadscrew is not wildly loose, forget it, and work against the play! It is never good practice to rely on the screw for measurement and estimated movement anyway, measure it if vital. Later on a new split nut can be machined up in the lathe as a project. An actual worn lead screw might make precision screw making difficult, but not for average users! As it is a flat top lathe bed check no deep marks etc are showing anywhere, and if there are and they have burred edges simply file away with a fine file the depression in the mark matters not a jot, but raised burrs cause jams and tightness. No amount of gentle fine filing and scraping would ruin the lathe bed!! The other thing to check is the main bearing, probably bronze with a hardened shaft, simply back off the adjusting nuts, remove the main shaft, clean everything , lube, and re-assemble, and adjust to get the tightest fit where it will still turn. If the bronze is scored badly, (the lathe may have been near grinding dust etc, ), then a replacement must be made, but you may be able to do it on the adjusted lathe, or get another owner to make it in glacial cast bronze or Colphos. It is unusual for the centre mandrill to score or bend, and most remain usable. Once cleaned and adjusted, check for accuracy, 1/2inch ground steel rod in the chuck, basic checks for straightness, etc, and you will have an accurate lathe. Chucks are totally replaceable, but older ones remain surprisingly accurate, and can have the jaws ground in situ to bring back accuracy, a Dremel motor tool can make a toolpost grinder for such work, with cheap diamond burrs to do the re-grinding. The whole lathe should be the equal or exceed the Sieg Mini Lathe in accuracy, it is not the lathe itself, but the way the older lathes are used that makes them accurate... you have a nice basis for the whole home workshop in this lathe.

Full details on the Grindturn,(later by Haighton), of Shrewsbury on Lathes (UK) site http://www.lathes.co...hton/index.html Nice small lathes and totally usable these days, it can be serviced and should be accurate. The www.Lathes.co.uk site is the best reference on the net about lathes and milling machines. Stephen

Once you have got the lathe you will find uses for it!!!! buffers, buffer shanks, funnels, domes, handrail knobs, wheels, whistles, smokebox doors, fittings, milling chassis from solid, frame spacers, making nuts and bolts, washers, and rivets...the list is endless, and mainly from scrap materials if you try hard to find and save them. There are lots of websites for steam engine models, and related projects, and lathe projects in general. All the milling and drilling on this brass bogie for a GWR railcar is done on my MD65 milling machine. I do use a bigger lathe, it is a Warco 1324, but all lathe work on this could be done on a Sieg or equivalent lathe like a Taig, Toyo, Hobbymat or Unimat. The mills used are solid carbide burr sided mills 3mm diameter, very wear proof!!.. they fit in the collet chuck. Stephen.

With reference to the Sieg mini lathe............ Arc Euro also offer the tailstock lock modification, new steel gears if needed, and roller bearings as an option for the headstock. All are nice, but not absolutely required to get things running and could be retro changed later on. ................................................................................................................... With reference to the MD65 it does in fact take all chucks easily, there is a drawbar to fit the back of the morse tapers to lock safely, the only issue is some no 1 morse tapers are hard to drill and tap, and need heating red hot to soften first. This converts it properly to a vertical light mill and drill machine. For proper holding of mills the nose takes adaptors for standard small end mill holders, easily modified in the lathe. The three set screws lock it in place on the register, no problems in mounting at all. The collet chuck is a standard type and very expensive, and still made. It fits via an adaptor plate, easily made if you want on the lathe. I bought one whilst the East Germans were still importing them. Also made are FE made direct morse fitting pull collets in metric sizes, and these take drills or light mills and burrs. The only restriction Prazi placed on the mill is fly cutting, they do no recommend it, due to out of balance and vibration with the geared head version. It will work with fly cutters for gears as long as the work is brass, and the cuts light. Stephen.

Try http://video.google.com/videoplay?docid=1439064267545192193# To see a CNC Bridgeport miller in action machining as a CNC Lathe !!! Stephen.

I would agree about a lathe being more useful, but any decent vertical miller with a horizontal option makes a perfectly capable lathe for larger items, the faceplate fits the shaft, and the tooling fits on to the table, with power feeds etc available. A Cincinnati 10 inch mill will tackle lathe work happily, allowing two foot diameter turning, and of course can go smaller. Even a Bridgeport vertical can handle work held on the spindle, with the tool on the machine table, very flexible in what they will do. Mentioning this works does not mean I recommend it, it is just worth knowing it can be done, the MD 65 vertical mill can do 12 inch diameter wheels for instance, but needs a special speed reduction system added. Also the flanged wheel on a miller would be easy, just put the blank on a rotary table........it allows any round shape to be milled out, this is the way CNC is often used to form rounds. Stephen.

If starting from scratch now, then the Sieg 7x10 miniature Chinese made lathe is good value. It has been around a fair time, in a thousand assorted retail names, as well as Sieg, and comes in a 7x12 variation as well. A new 7x16 also exists on the US market and should be here soon. The very latest versions come with brushless motors as well. Plenty appear on Ebay in the US, not so much over here. There are clubs, blogs, and whole websites devoted to this small Mini Lathe, fitting it out, using it to max capacity, and beyond, and curing some minor niggles with the design, like the tailstock locking clamp, there is none, only a locking nut. In the UK, Warco, Axminster and Chester do them, also Clarkes list them, there may be other suppliers. They come with lots of accessories and can take lots more, either bought in, or made on the lathe itself. It can do milling as well, (horizontal), and has stepless electronic speed control of a DC motor. Full metric or imperial screwcutting as you can change the whole leadscrew in moments to give accurate cutting. The spare one costs extra, but under £30 from most suppliers. Again do not expect to screw cut BA threads they are oddball T.P.I. despite being based on metric dimensions, use taps and dies. It comes with a full changewheel set. Regrettably there is no European or UK equivalent, except Myford, and the cost is very much higher, although a S/hand Myford would give good value. The current Unimats for instance are Sieg made anyway, as are the new Hobbymat. Some copies of the Seig are made in Taiwan, it seems from mainland Shanghai produced parts.

Worth it for the BFE milling attachment.......with free lathe! Reserve not met, so presume a responsible price.........

Tracy Tools, on the net, I have dealt with them for 30 years, good prices and service, and they know what they are selling. There are also Chronos and Maidstone model engineering and Reeves and many other suppliers. The MD65 takes standard small lathe tools and can easily be modified to take better tool posts and interchangeable types. At first you may want to use modern carbide insert types to save tool grinding, but get a simple grinder and you can make HSS tools in the workshop. Make sure the jib strips and adjustments are 100%, no slack, and the accuracy of the lathe is very good indeed. Spares are available, although I believe the German production stopped several years ago. They are basically a metric lathe, and cannot cut a wide range of imperial sizes for threads, but most would be done with taps and dies anyway, especially for BA threads, where all lathes have difficulty matching the odd turns per inch. They have fine surface cutting feeds and all common metric threads available in the gear set. A slow speed extra belt drive was once made by the then English importer, Essar, but the components can be easily made on the machine if you want extra low speeds for cast iron turning. The extra belt turns a layshaft at the back with an extra large pulley, and then a new belt back to the lathe. The rest of the lathe is standard tapers and fittings, and there is a collet chuck made, expensive but very accurate indeed. All standard chucks fit or can be adapted to fit the back plates. The tailstock is standard morse taper, and takes all normal small chucks and tailstock tools. Like all these smaller single phase lathes it cannot take a speed controller to slow the motor, wrong type of AC motor, do not try them, the motor will not start!! Early MD65 have s switched start with a gyro start, or later versions have a capacitor start. If it is an early model, a modern capacitor can be added to give a smoother and quieter start. One word of warning on all MD65 lathes is not to overdo tightening the tool post the bolts that retain the tools in place, the whole top slide is somewhat thin to get clearance under the lathes centreline and in consequence is weak, and if the bolts retaining the tools are over tight, it warps the top slide. The effect is not permanent, does no damage, but throws out the jib strip adjustment, appearing to jam things when the tool retaining bolts are very tight. Just be careful, make sure the retaining bolts are tight enough for safety, but then adjust the cross slide jib strips at that point to ease things, a balance point will be found, and as long as big spanners are not used!...things should remain in adjustment. I still have one of these lathes in daily use, and they are very accurate and pleasant to use, it's only limit is size, and even large 5inch gauge live steam engines could easily be built on them, bar perhaps the large size wheels, without adding the slow speed devices to get them to run at 60 RPM or less. For model railway use it can do all the work, including milling, and there is a vertical milling attachment once made for these that turn up S/hand. The attachment could also be converted to a full milling machine with the addition on a milling table. These are still made in Germany, but are now extremely expensive. The whole machine was designed to be used in East German schools and colleges, heavily subsidised by the State, which expected a good standard machine which could be exported as well. The makers were independent, even under the East German systems, and continued after unification, but costs have driven them to cut the design back or use FE production now. Stephen.

The zinc chromate primers are really designed for treatment of Aluminium, before anodisation became more common to stop corrosion of aluminium parts in aircraft. It also inhibits steel and works to an extent on brass. Acid etch primers are different, they attack the surface deliberately and neutralise as they dry, leaving a passivated surface that stops rust, and again will work with brass. Copper, the main component of brass is naturally corrosion resistant, developing the green copper oxide which stabilises the surface. But Brass has zinc added and that reduces the oxide but makes the surface resistant to paint etc. Tin and other metal are added as well, including lead, which make brass too "slippery" to class as easy to paint. It makes up by being easy to colour, or plate etc, but the surface has to be abraded to get paint to really stick. The simplest safe way at home is to dip in Vinegar, 10% spirit if available, (or buy acetic acid powder), it is safe and will not ruin the brass if left overnight in the solution. It cleans the meal and etches it mildly. Citric acid powder, (lemon juice), will also work in a strong solution. By strong solution I mean here as much powder as will dissolve in warm water, a saturated solution, this is mild compared to Nitric, but keep it away from eyes and skin, and clothes. As mentioned before do not use stronger acids without good reason, they are very nasty indeed. The Etching mix I use is a traditional formula, and will send shudders down the back of a Health and Safety Officer, you have been warned!!

The German to English Google translations are often thrown by German grammar, reversal of descriptions, but the Google seems fine with Italian to English, more logical grammar! But it can be thrown with German to English translations of Youtube titles, not aided by the love of nonsense titles on 1920/30's German dance band and jazz music......Such as "Aunt Paula sits in bed eating tomatoes"....yes..... that's the correct title to a 1929 hit recording !! http://www.youtube.com/watch?v=-CB59pJ13x0 Google has a good stab at the translation, but Hans Albers comedy hit record "Mein Gorilla hat 'ne Villa im Zoo" stumps it.. the lyrics should be ( don't ask why!!!) approx as below!!!!(enter "Hans Albers" on Youtube to hear the famous recording!!) or click on link below. My Gorilla Has a villa in the zoo My Gorilla Satisfied and happy lives He knows no politics And it is his greatest happiness The itch to wife And each of bothers him For the very indignant Villa Full spitting contempt My Gorilla Has a villa in the zoo My Gorilla Well, the boy is so Mrs. gorilla still holds the If he wants to kiss her views Yes if he wants then Villa My Gorilla Has a villa in the zoo Mrs. gorilla still holds the When he wants to kiss her views If he wants then Villa My Gorilla Has a villa in the zoo

The forgotten fact about etching primers is that they are meant for steel, not brass, but do work in a way on brass, as the acid does affect the zinc content, but ordinary primers are just as good on clean etched brass, and the key is etched, etched in a bath of acid to finally clean and erode the surface. Citric acid, or strong acetic acid is all right and safe, do not use strong hydrochloric, it attacks the brass far to much, removing zinc. Weaker sulphuric acid, (less than battery type), is OK, but handle with care. (Drain cleaner is sulphuric acid based and easy to buy). Simple domestic cleaners are a bit suspect as they contain oils and scents etc, and may clean loo's but also leave deposits. Cloudy ammonia can be used to clean brass, leaves no deposit.(must be rinsed though). Vim powder with a toothbrush is as good as brass for painting needs, flushed with hot water, and then washed in thinners, and then primed.(Ajax, Vim, Barkeeper's, all work the same.) If you want to, and it's at your risk, a mix of nitric acid , hydrochloric acid , and sulphuric acid, neutralised with caustic soda,(BPC) and then mixed with Soft Soap(BPC), is the very best etchant and cleaner for brass. The mix is made fresh for each use, and immersion of the brass is done into warm solution, and it takes seconds to impart a textured etched surface that looks as if it has been micro bead blasted and it glitters as well. It is the treatment clockmakers use to use for frames to get a perfect finish. If you do not understand acids, forget it, it is a toxic noxious liquid to make..........I use it myself though as I worked with it making instruments in brass. Stephen.

For non Italian readers, (mine is slow and unsure!), if you have the Google browser, Chrome, it automatically offers a very good translation of the Italian text, press the button offered at the top and it instantly displays the whole thing in English, occasionally fails on technical terms , but tries very hard!!! It detects foreign languages automatically, except on some pages where a mix exists, and it only detects fully foreign pages. Works well on You tube pages as well. Some security software tries to stop the translation button appearing, I have no trouble , but others report this. Stephen.

There's a bit about Rossi in the article about Polks and the efforts to get Rossi to change from toy making to scale locos especially for the US hobby market, which influence also brought about the move to HO European models after 1950. Early course scale Rivarossi branded items are very rare in the UK, the early US HO items are far more common. No imports were allowed from Italy till 1951 anyway, same as Germany, due to the war, but often items like these were available to US troops serving in the UK, and got sold on. Early Japanese models also turned up here via US servicemen, at a time when nobody would touch Japanese goods on principle, let alone an import ban. The first Japanese made items in the UK in the 1950's were cheap cameras and even cheaper tin plate toys, which hardly gave an inkling of what was to come from the Far East........ Stephen.

I trust you noticed I did not mention DCC, where the back EMF of coreless is dealt with by the Chip Circuit, (on suitable chips). I was commenting on a PWM circuit delivering 12 volts PWM, a very different beast, which without clamping the back EMF, causes the arcing, and heating, that harms the commutators on coreless types. Now.... a couple of more general points, back to the circuits being discussed, In an ordinary motor the iron core damps the effect as it operates, and coreless means that, no iron core, so adding the bigger and finer coils they are efficient generators as well. The lack of a core also means heat builds up faster in coreless under high load, and PWM DC makes this worse. PWM DC will work at high frequency with coreless if some protection is added to the circuit, and even at low frequency if fully clamped to remove the back EMF. As mentioned before the Pentroller takes advantage of the back EMF, turning it from a problem into a feedback signal to modify the speed against load. DCC can do this as well, and requires the Cv to be matched to the motor in the same way the Pentroller requires it to be used with matched motor types. The general purpose circuits here for DC do not need such a sophisticated approach, but also fall short of the Pentroller or the DCC control on offer from the model trade. Bear in mind that one chip can cost more than a complete home produced DC controller, and cannot match a computer DCC system costing many hundreds of pounds, which many people cannot possibly afford. Personally I am not anti DCC I have a home made NMRA compatible controller that does the lot for the few chipped locos I have. Stephen

Useful collection, "The Throttle" looks interesting, as everything is adjustable. The ones based on the IC regulators are good, but up rate the regulators!, not worth saving a few pence. The Scaler is interesting as it adds onto other controllers, scaling can be applied to most designs easily, switch in or out, it just spreads out the area the controller acts over. The only nuisance of these US based circuits are the relays, they specify "Radio Shack" and these types are not easy to source here, you may have to find substitutes if you want the hand held units, although a cased unit can use direct switching reverse instead. Stephen.

Yes, the timing of the pulses is down to the 555's, the bursts would have ripple, but it does not matter with motor control. In effect the 5000uf isolates the pulse circuit from the motor supply effects.

As I said all PWM can make noise, and it depends on the mechanism, a stiffer, tighter tolerance motor will be all right, but a Lima pancake will rattle like loose teeth. Coreless motors should work, but the coils generate a lot of back emf at a higher than applied voltage and can have arcing troubles on PWM across the brushes. Better motors have potted windings, coated with resin, and these are OK, but cheaper motors do not, and the looser windings vibrate just like a loudspeaker. Can motors are generally quieter on PWM signals, the casing quietens it, whilst open frame are worse, and flat pancake the very worse. With the simple 555 circuit, you can dampen the action with caps on the output transistors, or the feed to the base, this will distort the square wave but reduce the noise, but also lessen the control at crawl speeds. Stephen.

Quick check, it is the power during each cycle for the 555 timers, without C2 they would shut down. The pictures separates the simple PWM parts from the output transistors which varies the fixed max to zero each cycle as defined by the 555 oscillators. Stephen

I would have to check the whole circuit's action , but as the power transistor takes the applied voltage from supply to near zero on each cycle, the lowering of voltage would make the 555's inoperative, but with the 5000uf it effectively un-couples the oscillators from the effects of the PWM output, as they can draw power from C2 on each cycle. The top of each variable width square wave would have a ripple from the rectification, but it has no detrimental effect in practice, a perfect square wave is not needed, just the mean result. Stephen.

The copy of the circuit is from the book, I know I re-drew it several times, and I do remember a modification, but I have not got the notes either my own or from the Bambini book. I am pretty sure it worked though from the book, I used one for ages. Anyway I am not using it again, the IC regulated PWM one from Shortliner's reference is far superior, especially as it is pretty fool proof on shorts etc., the regulator will shut down. Stephen.

The circuit from WW has not been published here so far, so I think that you are referring to the dual 555 PWM circuit, (totally un-related to the WW one). The 5000uf is simply smoothing in there, it is high, but decouples any ripples as far as I can see. The circuit was by Penfold in Bambini books. I have used the circuit several times and it works very well.

And a quick point...... often over looked .....is the type that progressively reduce the Pulses as the DC level increase only do this in the upper range by definition, ......do you always run your locos at top speeds???? If you have a vast layout with long drags, then a plain DC controller is frankly much better, no complexity at all, apart from possibly feedback. Maybe the very best would have all these modes switchable !!!! but the most useful for most layouts is crawler speeds, (without too much noise). Stephen.

The WW version makes the reference to the patent type unnecessary, as the patent one has curiosities in it , and for actual ease of building a proven published one will be better, even an older design, all components are available, or better alternatives made to substitute, like power transistors that used to cost pounds and now cost pence!! For instance virtually any older circuit with the 2N3055 as output can have TWO in parallel to halve the heat, the plastic versions are so cheap now!! Stephen.

It sounds like the WW controller was PWM, with an increasing level of DC as the speed increases, this is the typical way they operate. This type uses the load to assess the current supplied, just like a regulator chip. Only a full PWM with dormant parts of the waveform can check the back EMF to use as feedback control, although I have seen circuits set to function with a core DC level as well. This is the PWM circuit based on 555 timers, not as sophisticated as the one Shortliner introduced, no momentum setting, although it could be added.