Member postings for mgnbuk

MZ-adorer mgnbuk

Guilty as charged, Niels !

Though I did actually sell one last year (an ES150/1 ) that I finally admitted to myself would never get rebuilt by me. That means that I only have 5 at the moment - and a couple of those may be getting moved along to someone more likely to put them back on the road than I am. I did have a Trabant at one point & got it running without too much difficulty after it had been stood outside for many years, but at the time didn't have the time sort it's many structural body issues - the non-corroding Duroplast panels were only the outer cosmetic panels - so that found a new home as well.

The return of "modified" 2T engines has been mooted before & seemed to hold great promise at the time - remember the Orbital engine ?

Two stroke motorcycles are actually still available today - see KTM motocrossers And until fairly recently Aprilia (Piaggio Group now ) were working on a direct injected small two stroke for scooters, but that seems to have gone quiet.

Nigel B

Edited By mgnbuk on 30/06/2023 14:43:47

Post reunification, aftermarket catalyic converters were made for Trabants. IIRC they had a working life of around 50,000 Km

The ground, graduated, section of the dial on mine is 37.0 mm diameter, the knurled section is 38.35 diameter.

Overall height (excluding the small boss ) is 13.6 mm, with the ground, graduated, section being 11 mm wide. I can't get in to measure the boss height without removing the handle - IIRC the dial is screwed down to set the leadscrew end float & is locked in position with the handle. As luck would have it, the two flats on the small boss have fallen either side of the handle, so the measurable part of the boss is inaccessible. I could get this dimension later if you really wanted it.

HTH

Nigel B.

I fitted one of those in place of the standard ML7 style Mazak dial on a Myford vertical slide & it works fine.

I probably bought it from the original Myford works spares counter, but the item pictured looks to be the same (or very similar) to the one I have.

I will have a look in the garage later on & post the diameter.

Nigel B.

Space available - something like the footprint of a washing machine,

Be aware that milling machine needs more space around it to function - uinlike a lathe the area needed is larger than the basic footprint of the machine as the table is moved throughout its working envelope. You will only get a small machine "working space" in the 600mm or so width of a typical washing machine.

Nigel B.

Thanks for looking that up Gary,

But your noted pin difference for the 5641 doesn't agree with the device datasheet (manufacturer LightKey) I downloaded from Alldatasheets, which shows pin 10 as Segment F and pin 12 as common cathode for digit 1 - same as the 5461 datasheet (manufacturer Taiwan Oasis Enterprise Co. ).

The 5461 datasheet just has pin-outs & dimensions - no electrical or other performance data like the the 5641 sheet to be able to compare such data.

I had thought initially I had ordered the wrong parts, but the supplier has not sent what was shown on the listing so the onus is on him to sort things out. I won't be fitting the others unless I can be comprehensively convinced that they are directly interchangeable.

Thanks for your assistance,

Nigel B

Shortly after starting to use a Jingce brand DRO on my mill, one of the X axis display segments failed. The DRO is still usable, but on the "10s" digit the top horizontal segment does not light, so 7 cant be differentiated from 1 without nudging the axis to see how the digit changes.

I dismantled the DRO to get the LED module part number (5461AG ) and ordered some from Ebay but, on arrival, find that the supplier has sent 5641AG modules, not the 5461AG ordered. I have queried this with the supplier and, while awaiting a reply, have downloaded the datasheets for both part number displays. I can't determine the difference between the two items from the data I have been able to find.

I don't want to fit the "wrong" module and risk causing damage, but would rather like to know the difference between the two modules that, as far as I can see, share similar characteristics. Could anyone explain, please ?

Nigel B

That style of turret is usually designed to suit a particular height of tool - inserted tools should be accurately made to put the insert on the correct height so the tools just required clamping into the turret to be on centre.. The only time shims are usually used iis if, say, a 12mm tool is used in a machine designed for 16mm tooling, where a 4 mm shim would be required. The manual should state what size tooling the turret is designed for, and using this size tool should put it on centre.

When the turret is initially fitted onto the machine, it should be adusted so that a standard tool is correctly on centre, but a bump (i.e running into the chuck) can easily knock the tool disc out of alignment. You can check for this with a dial gauge running against the tool bottom seating faceon the tool disc - this should be parallel to the X axis motion. If the disc has moved, it will show a taper . The rear vertical face should also be parallel to the X axis motion - the whole turret body can be displaced in a bump

You would have consult the machine documentation for how to remedy this. On the industrial machines I used to work with, the disc was usually positioned with a Hirth coupling, located with taper pins. A bump would rotate the halves of the coupling, damaging the pins & causing the disc misalignment. The cure in this case was a strip down, remove the damaged pins & stone the flat surfaces to remove any burrs. The halves of the coupling had a "master" taper pin hole that re-aligned the coupling halves correctly. With this in place, the location pin holes were re-reamed, new pins fitted and, most importantly, the "Master" pin removed before re-assembly.

I don't know how the Boxfrod turret postions, but I doubt it will have a Hirth coupling - for cost reasons if nothing else. Given it is intended for educational use it would be reasonable to assume that collisions would occur & have have a straight forward means to sort out any misalignment - the four central screws could, for example, just be a friction clamp that allows the disc to slip easily & re-alignment as easy as loosening them, clocking the tool seating face parallel with the X axis motion & re-tightening.

I would havce expected the drill / boring bar bores to be out in this case, though. If they are truly on centre (clock the bores with the X axis in the X zero position) that would suggest it is your tool holders that are not accuarte enough WRT to tip height from the tool shank base.

Nigel B.

How fit are you ?

Manual surface grinders are a good workout, particularly on larger parts.

Nigel B.

When you learned to drive, Dave, did you jump straight into a Formula 1 car having done a few laps on a Scalextric track?

As Jason said, learning the basics of turning on a lathe that you drive with your hands teaches many things that are advantageous later on should the trainee move on to CNC machines. As part of the CNC retrofits / rebuilds where I used to work I had to run a 2-3 day training course for the operators. In part this was to force the machine into production & allowed us to find any aspects of software, set-up etc. that had not been addressed - like a final de-bugging before leaving site. With experienced operators this was an easy 2-3 days for me, but often the victim was a manual machinist who the machine buyer wanted training up on CNC. Some were older and, on occasions, quite worried at the outset. But a bit of time spent on the basics usually brought the realisation that they were basically doing the same job they were familar with in a different way - rather than approaching a job as a series of seperate operations they were defining the operations as a series of events & programming the machine to complete them in the required order. They knew workholding, tool setups, feeds, speeds etc - it just required a bit of a mind set change to write the operations down & program them into the control.

I can only recall one chap who didn't make the grade, and he was "let go" after a couple of months. Not because he couldn't grasp the concepts or operation of the control - it was because he couldn't get to grips with using a 4 jaw manual chuck ! It is rare to find a vertical borer with a power chuck - most have a manual 4 jaw arrangement or face plate. This otherwise experienced CNC turner had only used power chucks and just couldn't set the parts up with the 4 jaw - maybe more time spent on a manual lathe earlier in his carreer would have helped here ?

Last place I worked before escaping still used a Harrison 330VS lathe for some batch jobs, as it was quicker and easier than setting up one of the 7 CNC lathes. Manual lathes are not obsolete in industry.

And never miss an opportunity to get a dig in at Myfords !

Nigel B.

AMT Machine Tools would probably be in a position to regrind and definitely in a position to mill the beds in house, when I last saw them they were reassembling a Webster and Bennett VBL which had just had the columns come back from being reground.

There is a lot more money in a W & B rebuild to be able to absord the regrinding costs + the cost of a new replacement is much higher than the rebuild cost. A new CNC VTL will start around £350K and up - a rebuild from around half that.

I have to say I am a bit perplexed. You are all entitled to your opinions but personally I would like to see my taxes spent on British products.

And we wonder why all our industry has disappeared. 🙄

I quite agree.

Unfortunately, in this case, it is simply no longer possible and has not been for quite a while - there are no UK manufacturers of manual lathes to compete with the Far Eastern products. They stopped producing here because they could not compete on a less-than-level playing field.

Nigel B.

There's a good number of machine tool reconditioners out there, and the boxford beds are so small that it would fit the capabilities of many larger grinding shops, without needing to go to someone with a dedicated bed-grinder.

I spent 27 years working for a CNC machine tool retrofit / rebuilding company, so do have a bit of prior experience of bed reginders, Jelly. I don't share your optimism regarding finding a company with the machinery, experience or inclination to regrind a Boxford bed for an economical price. The companies my former employer used to use have long gone now. While a Myford can be reground with any surface grinder of sufficient capacity, machining 6 angled faces + 1 flat on a Boxford is a bit more involved - a lot of setting up time at commercial rates. Being soft the Boxford bed could be milled or planed (if you could find anyone with a planer these days ), but still a lot of setup. Then there is the labour to strip and rebuild the machine + replace any other worn or damaged parts & possibly repaint - I would guesstimate be that a reasonable Boxford rebuild would be at least twice the price of buying a Chinese replacement machine like the gearhead Warco.

Not certain about the current incarnation of DS&G, but in the care of the previous owner of the name there was little more than a place-holding website. That company was in Halifax, though, and I note the current incarnation are in Preston. Their website doesn't give much away about any in-house machining capabilities.

Nigel B.

Nigel B.

I suppose it is all down to risk asessment, let them wind up the wick or let them change gear while the machine is running in which case the variable speed may cause less damage.

Relatively easy to frustrate a careless / malicious speed change on the Warco GH600 gearhead machine - set the required speed then remove the handle from the speed change dial. It may be still possible to rotate the dial without the lever in place but, given it is detented, I suspect it would take two hands to do so.

Not so easy on a variable speed machine. The inverter equipped machines (WM Warco 280V IIRC) may work if the speed were preset & a cover fixed over the potentiomer, as the inverter should ramp the spindle up & down from standstill. But the "brushless motor" setups seem to require the pot to be used to stop the spindle before pressing the off button & start from the zero pot setting when starting (these drives don't seem have acceleration ramps & require the ramping to be done from the pot ? ) - so access to the pot required at all times ? Obviously damage to headstock gears isn't an issue here, but the pot is easily accessible to be easily "tweaked" by, say, another pupil while the machine was in use.

I would guess that bed wear would be a issue with a well used '60s Boxford. The Boxford bed top formation (all vees and flats + vertical edges) were gang milled in one operation originally. In the early '80s Boxford did re-machine worn beds but those days are long gone (along with the machines that used to do the job) , so I would guess that machining out bed wear would be a costly excercise now.

Nigel B.

How do you currently handle such things as setting the spindle speed on the Boxfords, Tristan ?

I would have thought that letting 14 year olds loose on the workings of the machines (belt / back gear changes) would be frowned upon in educational circles (though I could be wrong ! ). Boxford underdrive machines are great here, as the rotating bits are in the base behind a lockable door, allowing the teacher / technician to pre-set the speed so that the pupil just has the start / stop buttons to control. The hobby size variable speed machines would possibly be problematic here - speed near instantly changeable from minimum to maximum with a 270 dgree twist of an easily accesible potentiometer on the headstock.

Screwcutting is another area where the hobby machines are generally more akin the the Boxford CUD (changewheels to set for each pitch), with few having a gearbox like the AUD. The industrial trainer lathes which have screwcutting gearboxes are larger, more powerful machines than the Boxford - not sure I would like to put an inexperienced 14 year old on one of those for their first turning experience.

Having had a look around at what is currently available (for my benefit as much as yours - I am mulling over a change ATM) one machine rather stands out - Warco's geared head GH600 lathe, currently on offer for £2860. This includes a stand, 3 & 4 jaw chucks, faceplate, machine light, fixed & travelling steadies, covered leadscrew, start/stop operation via a handle on the saddle + more. 12 speed geared headstock and screwcutting gearbox that cuts a wide range of metric & Imperial theads with just one changewheel change to go between the two , it is a bit larger than the Boxford but not as large as the industrial trainer machines & has similar capabilities to an AUD.

You could probably get 4 for your budget to replace all the Boxfords and have change.

Nigel B.

Such a compact "800W" motor, yet no cooling provision - do they use the headstock casting as a heatsink ?

Could you confirm how many wires are contained in the cable from the motor. What passes for an electrical diagram in the EU Vevor "manual" only shows 2 wires to the motor, but I would guess 3 or 4 (3 phase motor with maybe an eath direct to the stator).

Nigel B.

I’ve found the electronic chargers won’t charge a flat battery .

Ditto.

They seem to need to "see" at least 10.5v from a 12v battery to start charging. I have managed to get charging started by connecting another, good, battery in parallel with the flat one to raise the voltage that the charger sees to a point at which charging starts. The parallel good battery can then be disconnected. Whether or not a battery that has discharged below 10.5v will be of much use subsequently is another matter.

The Aldi / Lidl chargers work well - while they work. I have had a couple fail - one in warranty that was replaced & one just out of warranty that wasn't. The Accumate charger I bought 25 years ago is still working fine.

Nigel B.

I assume the Myford Super 7 Connoisseur suggestion is a joke? Good lathes in the hands of a considerate machinist, but surely too delicate for trainees. Myfords were never popular in schools, who generally bought more robust kit.

I guess the school that bought my Super 7 initially (and the other two that the dealer I bought it from had from the same source) didn't know what they were doing then, Dave. Myford brochures also suggest that they saw education as part of their target audience - but what did they know ?. I assume that you have not used one from your comments.

Tristran has not said which specific model of Boxford he is looking to replace, the target audience (age or capability) or what he wants the machines to do. More detailed info would help narrow down the choices offered.

600 Group is mentioned above. Their manual machines are made in the Far East (Taiwan at the time of the last discussion I had with one of their reps) & the last quote I saw (from a YouTube video from a chap who was suffering various woes with an ex-industrial M300 & got a quote from 600 to replace it with a new one late last year) was around £15K + Vat.

Nigel B.

Thread heading says "recall" - text says "rejected at border" i.e the products with inadequate documentation didn't get in to the UK.

How is what is described a "recall" ? Are there any other links stating that Vevor heaters that did make it in to the UK are being recalled due to safety concerns (other than iffy instructions ) ? I am aware that Vevor have had to "recall" at least one product due to safety issues (300 Bar air rifle compressors where the earth cable was not actually connected to the metalwork of the machine). In this case Vevor didn't actually "recall" the item (i.e have it returned to them to be destroyed) but just refunded anyone who had bought the item & told them to destroy it. Of the reports I read from those affected, non destroyed the item after getting the refund - when checked most did have the earth wire correctly connected & on those few that were not the owners chose to rectify the error and carried on using them.

Nigel B.

(not a Vevor customer)

Ajax are long established importer, though the current company are different management to the original company. Their "Trainer" lathe looks like a generic Asian lathe, most likely Taiwanese. I would expect good backup from them. The "Trainer" lathe looks a lot bigger / more powerful / more capable machine than a Boxford - more Harrison M250 / 300 -ish.

Another industrially biased company are Excel Machine Tools - another long established importer. Their manual machines are Optimum brand - made in China for a German company who apparently oversee quality. Similar machines to Warco / Chester / Amadeal etc.

Another company who advertise in ME is Aries Duct Fix who sell Cormak branded machines. As far as I know, Cormak are a Polish company, though the machines are most likely Chinese in origin.

You will struggle to find a manual machine not made in China or Taiwan these days.

Nigel B.

Direct Drive Motor: The mini metal lathe machine adopts a direct drive motor, no belt drive, and no need to replace the belt. 800W brushless motor that provides more power and avoids the need for brush replacements, saving time and effort.

The EU Vevor site has a link to "manual" for this machine which has a cursory wiring diagram that shows only 2 wires to the motor. No parts list in the manual. Photos of the leadscrew gearing end of the headtstock show no belt or other mechanical input shaft., but there isn't a whole lot of room in a mini lathe headstock (particularly with a large bore spinlde that this machine appears to have) to build in a motor of any kind. The lowest speed of 150 rpm is less than the old geared head DC motor machines & I wonder how much power it has at this speed.

I would agree with the "send it back" route as being best option. Doesn't look like this is a straightforward headstock to start diving into. This must be a very recent development - not seen anyone else offering this configuraton yet. This arrangement would be a lot more difficult to rig up an alternative drive to when the built-in motor or drive fails, so if suitable spares are not available from the supplier (and Vevor are just "box shifters" ) then the machine is potentially totally dead.

Interesting that this has appeared just a few days after such spinlde drives were mooted on another thread !

Nigel B.

ps. That gib strip looks a bit grim.