Myford ML7 accuracy

[Former MemberParticipant @formermember1325364342]

[Former MemberParticipant @formermember1325364342]

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[not done it yetParticipant @notdoneityet]

Accuracy, precision, or reproducibility? They may not be the same.

I would expect that maybe a Cowell lathe might be more pertinent for jewellery making uses. Smaller, very good, british and available new.

I use a Raglan 5” and would not consider swapping it for a myford – but that is my own personal opinion.

Accurate work can be accomplished on many ‘quite worn’ machines – but that requires a good deal of input from the operator in order to achieve those redults.

[Tony Pratt 1Participant @tonypratt1]

What do you mean by 'accurate enough' & we come round as always to new far eastern manufactured lathes vs pre loved possibly worn out domestic manufactured items. The better condition domestic jobs are in some cases serious money.

Tony

[John HaineParticipant @johnhaine32865]

New Myford lathes cost silly money, as do used ones (worn or not), and you could find it difficult to decide if a used one is in good condition or not. I am a Myford S7 owner, from new, and though it's a decent lathe I wouldn't buy another one. I certainly wouldn't buy a used one.

Cowells are very nice, British, accurate, but hideously expensive.

From the US, Taig lathes are nice but quirky. Sold in the UK by Peatol. There is also the Sherline range, not sure who the current stockist is, but owners seem to be very satisfied. Both these are quite small so that may limit you. (Actually UK Sherline stockist is Millhill.)

Accuracy has at least as much to do with the operator as the machine. In your place I would consider buying a new far eastern machine from a reputable stockist who can provide backup – I have had nothing but excellent service from Arc Eurotrade. They have a range of lathes of different sizes and can provide good advice.

**LINK**

[Mike PooleParticipant @mikepoole82104]

The newest ML7 is going to be 40 years old as is was superseded by the ML7R which is a non power crossfeed Super 7 with no clutch and the ML7 crosslide, a few other details were deleted to make the ML7R slightly more budget friendly. All the parts for the Super 7 can be retrofitted to make a 7R into a non power crossfeed Super 7. When buying a Myford condition is everything so view the machine preferably with someone who is very familiar with the machine, a bit like buying a secondhand car really. There is no real reason why a ML7 will not be as accurate as a Super 7. The Super 7 had a lot of refinements and a high speed headstock and better tailstock. The top speed of the Super 7 and ML7R is about 2400rpm whereas the ML7 is not recommended to exceed 1000rpm. There will be people who have pushed their ML7 much higher and report no harm. If you damage the white metal bearings then as they are obsolete you are faced with an expensive upgrade to bronze bearings and a new spindle or trying to make new white metal bearings. The supply of the spindle upgrade seems a bit erratic and may not be currently available. I would not dismiss imported machines as they have improved greatly since the days when they often did fall short of a well built machine. Japan had a shakey start with quality but they bought into how to improve and then became the leaders. It’s a fact of life that quality will cost money but the Chinese will build you whatever you are willing to pay for so a truly bargain price will almost certainly not be the best made machine, however a bit more money seems to get better built and better specified equipment. If you buy a new machine the check what is included in the price, you may have to pay extra for steadies chucks and tool post etc. which may be included in some deals.

Mike

[JohnFParticipant @johnf59703]

Cal, I think the question you need to answer is what tolerance do you want or need to work too ?

+/- 0.0005" +/- 0.001" +/- 0.010" or ????

The next question is your budget ?

Then decide what size of work you want to do, I see several of the small machines mentioned which are fine if your work is very small but you are of course limited to their capacity whereas a larger machine will give you more scope

Hope this helps

John

[Chris CrewParticipant @chriscrew66644]

I cannot add much of value to the comments already made, they are all relevant IMO. But for my twopennorth, if you go for a myford forget all about an ML7 and go for either a pre-cherished ML7R or Super 7. Be prepared to pay several thousand pounds from a reputable dealer or even the new myford itself and get as many accessories included in the package as you can because if you buy a basic machine you will end up paying as much again to make it anywhere near useable. Myford accessories are rising in price almost daily.

[Former MemberParticipant @formermember1325364342]

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[SillyOldDufferModerator @sillyoldduffer]

'Lathe for Jewellery Making' changes the requirement somewhat. The purpose implies a small lathe like a Sherline, Taig/Peatol or Cowells. All these are available new. The Cowells is an attractive machine but calls for deep pockets;

In comparison to these small lathes, Myfords are relatively clunky – general purpose, small workshop machines. Certainly not out of the question for jewellery, but a bit clumsy for persistent fine work.

In my opinion the main problem with Myfords is they are overpriced. Chaps rush to pay premium prices for them, even in poor condition. Many Myfords have been lightly used and well maintained by careful owners. Plenty of others have been thrashed beyond economic repair. High prices attract dodgy refurbishers, who periodically cause forum fun when their vile paint jobs and obvious crocks pop up on the web. Best to see second-hand lathes cut metal before buying: remember that a famous brand name on a good looking lathe might be a complete wreck. Being old and British doesn't guarantee reliability – look at the state I'm in!

On the other hand, even well-worn lathes will do acceptable work in skilled hands. This is particularly true of short travel work where a worn bed and wonky chuck don't matter much.

Not sure where the idea Chinese lathes only last a couple of years comes from. Not my experience.

Dave

[Former MemberParticipant @formermember1325364342]

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[Mick B1Participant @mickb1]

Posted by SillyOldDuffer on 13/09/2021 15:09:48:

….

Not sure where the idea Chinese lathes only last a couple of years comes from. Not my experience.

Dave

C'mon, we all know where it comes from – seller greed playing to buyer prejudice.

Not my experience either, from my 6+ year old Chinese lathe.

+1 on your other comments. Cowells are certainly impressive little machines.

[Anthony KnightsParticipant @anthonyknights16741]

I have had my Chinese lathe for 12 years and have only had one major problem when I blew the control PCB thanks to my own stupidity. This happened about 6 months after I got it and has worked fine ever since I replaced the PCB.

[Gordon BullardParticipant @gordonbullard35804]

Hi Cal

with my ml7 I can turn down accurately

to 0.0005 thou by swivelling the cross slide tool holder etc.

But for very accurate work such as making injectors I use a Toyo lathe using collets. Lathes .co.uk give information on this lathe. They do not come up very often but well worth the wait

[Tony Pratt 1Participant @tonypratt1]

Posted by Gordon Bullard on 13/09/2021 19:23:08:

Hi Cal

with my ml7 I can turn down accurately

to 0.0005 thou by swivelling the cross slide tool holder etc.

But for very accurate work such as making injectors I use a Toyo lathe using collets. Lathes .co.uk give information on this lathe. They do not come up very often but well worth the wait

Realistically .005” is very good for any lathe, not sure what you mean by ‘very accurate work’?

Tony

[JasonBModerator @jasonb]

You don't say what far eastern CNC machines you have found lacking? A cheap 3040 I could understand giving problems but the hobby CNC I have now would sell for over £10,000 and gives 0.01mm to 0.02mm accuracy. I can also hot these sort of sizes on my imported lathe that I've had for over 10 years and my manual mill for almost 15yrs. A Myford in good condition will do similar.

You are likely to take more than 0.02mm off a part when you start polishing it.

[Former MemberParticipant @formermember1325364342]

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[Robert ButlerParticipant @robertbutler92161]

What a pleasant change the OP has taken on board the information provided by Forum members in the spirit it was intended and offered thanks for help.

Robert Butler

[CalumParticipant @calumgalleitch87969]

Cal, it's probably worth saying that cheap Chinese made specialist equipment and cheap Chinese made lathes are not quite the same quality of thing. A lathe is fundamentally a machine that can make machines, and as such it can be altered, updated, improved, in a way that (say) a polishing tumbler or a ring engraver can't. You can with a little effort acquire a very bad Chinese lathe, though these days you'd have to make an effort to do so, but it would be capable of improvement in a way the ring engraver isn't. Many are based on the same fundamental design and they've been making them for thirty odd years.

That said, I think I'd agree about a Taig or Cowells: we often say "you can make small parts on a big lathe", but the truth is it can be a pain and there's an ideal machine size for a given part. Those lathes will be far better machines than the smallest/cheapest Chinese lathes.

[Pete.Participant @pete-2]

Lots of great used British machines available, Harrison, Colchester etc, a Myford would come pretty low down on my list, from the get go it was an amateur hobby machine not in the same class as small industrial machines.

overpriced, every Myford I see around 2k to 2.5k I'd value at about 1k to 1.3k, they seem about 50% overpriced in my opinion.

screw on chucks, wouldn't choose one of those again if I could help it.

warco sell a mini lathe for £545 delivered, get something cheap that's easy to sell, use it for 18 months and immerse yourself in what's available while you learn, then you'll have a good idea what you want long term.

maybe you won't want anything more.

[Mike PooleParticipant @mikepoole82104]

The electronic drive is the component of an imported lathe that is likely to have a limited life, some electronic components do not have an unlimited life, capacitors in particular degrade especially some of the ones fitted to electronic drives which have a tough life and are not the most stable type of capacitor. At some point the electronics will fail and need replacement or upgrading. A good few years of service should have passed before any trouble could be encountered so it is not an immediate worry but one day it will happen. It is near certain that a modern lathe will have had a few replacement drives in 50 years time but a solution will always be available.

Mike

[John HaineParticipant @johnhaine32865]

I agree with Mike, the component of the small Chinese lathes most complained about is the drive electronics. I think there is a lot of evidence that these are not well engineered which makes them prone to early failure, probably due to overload. There was a rumour that they were sensitive to "power surges", but that doesn't square with the millions of electronic devices with always-on power supplies that carry on year after year without problems. When it does go you can fit a cheap one off eBay or a proper US or British made one from KB or Sprint (or just wait for an equally flaky replacement part!). By the way these DC drives don't have electrolytics smoothing high voltage like VFDs do, the component that goes is I think usually the output triac. The KB one I have on my CNC mill must be at least 20 years old and though I've managed to blow the fuse it has never let me down.

Apart from the drive there isn't much can go wrong with a lathe if it's treated with respect, whether "cheap Chinese" or British. They will get worn with use though.

VFDs rectify the mains and store a high voltage, ~400V, on a big electrolytic capacitor. These can go especially if they have been left discharged for a long time – if this happens "reforming" is recommended. People suggest that if you have a VFD it is best to just leave it switched on (obviously not running) to keep the caps charged, for long life.

Don't think a used Myford will necessarily have a more reliable drive! Lots of posts here from people with single phase induction motors that have failed due to the start or run capacitor going. Getting at the motor on an ML7 / S7 is a nightmare unless the lathe is free-standing well away from a wall. If you have to remove the motor then good luck getting the pulley off… And if it needs a new belt you have to dismantle the headstock – what a stupid design. (Or fit a link belt.) Also in my experience the S7 vibrates a lot at high speed, I think because the spindle is inherently unbalanced. In fact I find the highest speed range unusable. Basically the Myford 7 range was originally designed for low speeds up to maybe 800 rpm, for jewellery type work you probably want to run without vibration up to 2000. The S7 at least has a rolling bearing at the back of the spindle but still has a cone bearing at the front.

The OP's comments about CNC and finding the limits of the machine after a short period are actually based on a British designed and built machine from Ooznest. This is basically a gantry router – actually it looks to me like quite a nice machine but will always be limited when cutting harder metals. Jason mentions his X3-based machine but that's a very different animal, a "proper" column-type milling machine. Compared to the WorkBee it can manage much harder materials and is probably (much) more accurate but have a considerably smaller work area. When it comes to small, low cost CNC milling machines of reasonable quality these are thin on the ground. Here is where a used British machine might be a good bet, such as a Denford Novamill (which I have) or a Triac. Still pricey second-hand.

So I would recommend the best approach is to buy an imported lathe from a reputable supplier (such as Arc), one slightly bigger than you think you need. Look after it, don't over-stress the drive, be prepared to replace the electronics with something better when and if it blows. If you do feel patriotic then think of a Boxford rather than Myford – better machines to start with and less fashionable so cheaper.

[Former MemberParticipant @formermember1325364342]

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[John HaineParticipant @johnhaine32865]

Yes, well most electromechanical parts are made in the Far East these days, and none the worse for that generally.

[Anonymous]

Posted by John Haine on 14/09/2021 10:03:37:

……..not well engineered which makes them prone to early failure, probably due to overload….

Quite so, hence my assertion that anyone can design power electronics that will work. But it takes a higher level of skill to design for overload and fault conditions without letting out the magic smoke, and it costs more.

Andrew

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