Myford ML7

[25.4_mechanic]

That just means you MAY need another motor. No big deal it's the easiest thing to fix on a lathe.

Installing a new motor would really not be a problem - but it also means that I can't see and hear the machine working. I find that much worse.

Get some photos in good lighting. A good front-on pic showing it nd to end and close up of the slides and bedway, and all the loose bits like chucks. The condition will soon become apparent.

Will ask him about it, let's see what he does. But I won't be able to catch play in the spindle bearings, radial runout and noise that way.

Take a little 3ph inverter with you?

I even have a full-blown generator with 3x400V~ ... unfortunately much further away in northern Germany at my second location.

But

Or maybe just threaten to do that and see what he says...

this is a brilliant idea! Will do it, let's see.

 

[25.4_mechanic]

It doesn't sound unreasonable that new owners would have three phase disconnected,

yes, it does. No one in their right mind disconnects their rotary current.
Those who don't have it want it!

Almost every household here is on three-phase anyway, you don't need an extra meter for that. We have virtually only three-phase meters in the country.

There are very few houses that get their electric power via roof stands, to which only two "wires" run - this supply is almost extinct, even in the countryside.

And it can't be the case with this house, because there was already three-phase current there. Something like this will not be dismantled just because you think you don't need it.

It is safe to say that most properties today are supplied with at least 3x400V/32A, many even with 63A.

Carsten

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[Maker]

Fair enough, I know it's more common in Germany than it is here but still assumed it was somewhat unusual. Do you get three phase domestic appliances over there then?

 

[dobbslc]

My Rangemaster oven is 3 phase but comes with a set of links to make it single phase.

 

[25.4_mechanic]

OK. Where to start? In Fig. 35 above, the gear labelled 4 is the same one you have identified higher up as 45t. In Fig. 35, you can see the 25t gear behind the smaller gear that is labelled 4. The gear labelled 4 can be removed from the holder it has in common with the 25t one behind it. You are correct that it is always called 'driver' in all the tables.

The three diagrams to the right of Fig. 35. are showing:

(1) A driver 2 (call it A) with an idler gear 7 and a leadscrew gear 4 (call it B). So the gear ratio in (1) is A/B. What is labelled 2 in diagram 1 is labelled 4 in Fig 35. For homework, work out what pitch would be cut if A=40 and B=127.

(2) The way the diagram is numbered is not great. The same driver- not labelled, so we can stick with (A) - drives what is labelled as 3 (let's call it B). B is fixed to gear 5 (call it C). C drives an idler (8) which drives the leadscrew (not labelled, call it D). So the gear ratio is A/B x C/D. Gear 1 is a spacer, behind gear 8 and does not mesh with anything.

(3) This is the same set-up as Fig. 35. Starting at the top, we can go A, B, C, D (D is labelled 3). 2 is behind 3 and we can call it E. The gear on the leadscrew is F. So the overall ratio is A/B x C/D x E/F.

Notice with all three set ups the relative position of the gears with respect to the body of the lathe. In 1 and 3, the leadscrew gear is tight to the body of the machine. In 2, it has moved to the left and has a spacer to its right.

46t is NOT used for 0.45mm. That is just a poorly scanned diagram. You can prove this to yourself if you look at the gears for 0.9mm and 1.8mm. The three pitches are multiples of each other so the gears used have to bear the same relationships to each other. Alternatively, if the 46t was needed for 0.45mm pitch, it would also be needed for 0.9mm and 1.8mm.

I don't think I claimed anything else.

Only with the one metric thread I was probably wrong, I had only looked for the appearance of 46t in the tables and when I found it at this point I was satisfied with it without checking this for plausibility.

I assumed I could trust the instructions from your link.

Before that, when I talked about not being sure about a gear in the photo, I meant that the quality of the picture was not enough for me to be sure of my tooth count.
Indicated by a ? behind the number.

It was a visual problem, not a comprehension problem.


Carsten

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[25.4_mechanic]

Fair enough, I know it's more common in Germany than it is here but still assumed it was somewhat unusual. Do you get three phase domestic appliances over there then?

My toaster is not, as well as refrigerator or washing machines in the private household, all the light (of course) - but the stove tops have 3x230V/16A, as well as the so-called night storage heating, which simplifies the planning for the producers and has only disadvantages for the user.

A normal house distribution splits after the three-phase meter and it is up to the executing electrician to divide the three phases sensibly among the consumers in the house or to supply the consumers that need three phases also in the correct direction of rotation with it.

It is then nomal in the basement / utility room / garage directly CEE sockets for at least 3x400V/16A to lay, many stationary handicraft machines need that.

Carsten

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[25.4_mechanic]

My Rangemaster oven is 3 phase but comes with a set of links to make it single phase.

Using the oven this way then has one of two possible consequences:
1) less power;
2) if the same power, then three times the current flows through that one line - with again two possible consequences;
2a) stronger heating of the line up to finally fire danger;
2b) the above is made safer again with thicker lines, but costs more.

Carsten

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[dobbslc]

Options 2 and 2b is what we get here!
I have a 10mm cable feeding it on a 32A MCB (it should be a 40A one) as that's all I had when I fitted the new consumer unit
Its fine, its designed to be run like this.

 

[25.4_mechanic]

I have a 10mm cable feeding it on a 32A MCB (it should be a 40A one) as that's all I had when I fitted the new consumer unit
Its fine, its designed to be run like this.

Completely knocking down an existing infrastructure is enormously difficult and also very expensive.

The lucky one is the one for whom the better solution was introduced early (this does not always have to be the one for whom progress began earlier).
After that, the obstacles become greater and greater.

The advantages are obvious, of course
- the part of the power that comes from the voltage does not need large wire cross-sections, the current causes the heat and P = U * I;
- Three-phase current makes all components behind it cheaper, since only 120° pass between two voltage maxima instead of 360°, which is why motors operated in this way also run more smoothly;
- we get even further into optimization by increasing the frequency, because less iron is needed in components like transformers, very good to see in aircraft construction, where every gram counts, a lot is done with 400Hz instead of 50/60Hz (but that's no model for our households of course).

Where I need power I install 5x2,5mm² (L3/N/PE) NYM-J cable.

Carsten


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[Wozzaaah]

Posts moved from general lathe discussion as this warrants one of it's own.

 

[25.4_mechanic]

Take a little 3ph inverter with you?

Or maybe just threaten to do that and see what he says...

I have done that.
The reaction shows that my mistrust was unfounded:
He took it upon himself to lay a temporary three-phase connection from the house distribution to the machine and the machine can be tried out.

If you do buy it, a useful book is this one: https://www.amazon.co.uk/Myford-Lathe-Manual-ML7-R-Super/dp/0852427751/

I have ordered this one: Greiner Walter, R: Myford Series 7 Manual: ML7, ML7-R, Super 7 - it is available in Germany.
Thanks for the advice.

Look on the internet archive for 'Screwcutting in the lathe' by Martin Cleeve.

Got it. Thanks!

Carsten

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[25.4_mechanic]

I would not fret too much about the parts it is made of. What you have is an improvement over standard. The later dials were resettable, whereas the earlier ones were not.

The ml7 I sold with a 3 phase motor and inverter did this beautifully, just flick the switch - it slowed, stopped, reversed - would have been nice to cut a thread with it. I guess, if you were creative, you could put a momentary switch on the bed - auto reverse at the end of the cut...

So is this a step I should definitely do at the viewing that should work smoothly?
Will keep an eye out for it.

Any other important tests beyond those to be completed on any lathe?

Today is viewing and maybe purchase

Carsten

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[Pete.]

TBH if it's the lathe in the pics in the first post I would not worry at all about the condition. That machine has done no work at all. The edges of the bedway up near the chuck are nice and square, there isn't swarf-rash all over everything and the pulleys look like they have no wear at all.

I'd say that was one of thebetter examples of ML7 you would find.

 

[25.4_mechanic]

I'd say that was one of thebetter examples of ML7 you would find.

Yes, it's exactly the machine from the pictures in the first post

and I'm delighted to read your words, because I'm just coming home after a 600km ride, exhausted but happy with this very machine.

(pics to follow later)

Carsten


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[25.4_mechanic]

Keep an eye out for a 12t/25t double gear.

Just ordered one on ebay.co.uk! Thanks!
Just to get used to the prices. (Couldn't I have been bitten by this bug a year earlier? Then it would have been half the price ...).

To change the suject completly ... is there anyone from Northern Ireland reading this?

Question about the eBay offers: Obviously I would like to purchase accessories such as a vertcal body for milling work.

When searching for something like this, many offers from India inevitably catch the eye. That makes sense when you think about it.
Is there a basic "hands off" advice here or is it the general "it depends"?

I remember a watch spare part I couldn't get anywhere else and so ordered it from India: it arrived, was original, correct and good, only unfortunately it took several months to get to me ... That's less what you want.
Of course I can not know if it was the seller or this is the rule with goods shipments from India?!??

Question about the vertical slide: which one do you want? Is it at all advantageous to be able to adjust the part in all axes? Don't you get too much unrest in the workpiece with the swivel version without having a real advantage?

Thank you!

Carsten

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[brightspark]

the fixed is more robust and will do 99 percent of what u want it for

 

[25.4_mechanic]

the fixed is more robust and will do 99 percent of what u want it for

Many thanks for the information.
I had a suspicion in this direction, but the fact that the answer would be so clear makes it easy.

What about the origin of the parts?
Or are there dealers/sellers to avoid or look for?

Carsten

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[Pete.]

They come up quite often but really the milling slide is quite limited. If there's any backlash in your cross slide screw it often makes for a miserable experience.

 

[25.4_mechanic]

If there's any backlash in your cross slide screw it often makes for a miserable experience.

What is my conclusion then?
- invest a lot in the adjustment of my cross slide;
- look for a vertical milling add-on (probably hopeless or unaffordable);
- increase the care and at the same time lower the expectation;
- just forget it.

Thanks!

Carsten

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[Pete.]

The slides come up from time to time usually about £70 for a fixed one. If you plan your cutting and use gib locks you can make them work but only for light cutting. You need a lot of patience.

The lathe slide is just not really rigid enough to stop the part moving about when milling. If it moves enough to make the cutter dig in it all goes wrong with a bang.