Myford ML7

[MattF]

Do you think I, as a beginner, could still benefit from Sparey's books?

Absolutely. You'll find gems of information in any books you have on the subject. Age of the book(s) is irrelevant, as the main principles remain the same.

 

[Rannsachair]

I like Spareys books and I am not a model maker.

I also have

I learned to use a lathe/ mill when I was an Engineering student, used lathes at work occasionally over the years for simple tasks and bought a Myford 6 or so years ago and found reference books invaluable, even just as a reminder.

 

[RichardM]

Sparey "the Amateurs Lathe", dated as you would expect, but well worth buying for the information.

 

[25.4_mechanic]

Yesterday we finally got around to putting the Myford on elevation blocks to better align and adjust it.

It took me some time to decide whether to keep the blocks that were delivered to me or send them back - in the end I decided to overlook the flaws in the finish.
Besides, my older son has a lot of exams to take at the moment, so he doesn't have much time for his father's whims.

Of course, we wanted to prevent oil from running past the M16 adjustment elements into the base cabinet.
To do this, I had bought O-rings - in order for them not to break right away, we had to work on some burrs a bit.

We still have the chip tray with four 10 mm holes and our heavy steel plate with M8 threads in it between the machine and the base cabinet.

The raising/adjusting blocks, for their part, also have M8 threads for the standard stud bolts in addition to the M16 internal threads for the adjusting elements.
This makes sense when there is only the base cabinet underneath.

In our case, however, this led to the fact that - when we screwed our own, newly cut-to-length stud bolts (190mm, stainless steel) through the blocks into the steel plate - it became completely random whether the two superimposed M8 threads started at the same time.

This in turn caused the blocks to tilt - we had anticipated this problem and now had to decide which female M8 threads to dispense with.

Since the heavy steel plate is the actual stable anchor of the machine and very important, we decided to drill out the M8 threads from the blocks to 10mm through holes.

We screwed the stud bolts so far into the steel plate and through it that there was enough thread sticking out inside the base cabinet to be able to connect everything to it later. We then tested the correct fit of the blocks.

Since we didn't want any oil to run under the blocks into the base cabinet either, we also closed off this path before the actual assembly.

The fact that we only had to put the blocks on after smearing them with silicone because of the drilled out threads made this step much easier.

The small Myford is up and running again, now the adjustment and calibration can begin in earnest.

Georg Schlesinger sends his regards.

Have a nice evening all,

Carsten

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[JMS1972]

I wish I'd used something to seal my blocks with. Still the drip of oil stops the cupboard contents going rusty.

 

[25.4_mechanic]

Still the drip of oil stops the cupboard contents going rusty.

That's what I always say when I spill something oily.

Tell me, did they talk about Dr. Georg Schlesinger in your studies, as far as I know he is still relevant today?

Carsten

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[RichardM]

On the subject of books download yourself a copy of the Presto Counsellor if you haven't got a copy already.

Downloads - Presto International UK Limited

Presto International UK Limited is a UK based leading supplier of Drilling, Countersinks, Reaming, Milling, Threading tools and so much more, visit our website to discover our history and more.

www.presto-tools.co.uk

 

[25.4_mechanic]

Presto Counsellor

Great! What a lot to know Thank you!

Carsten

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[prepman]

That's what I always say when I spill something oily.

Tell me, did they talk about Dr. Georg Schlesinger in your studies, as far as I know he is still relevant today?

Carsten

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I don't know if you ever intend to use a suds pump? But did notice you don't have drain hole in the tray. Easier to fit now than in the future?

 

[25.4_mechanic]

I don't know if you ever intend to use a suds pump? But did notice you don't have drain hole in the tray. Easier to fit now than in the future?

Active recirculating cooling is currently not in the planning stage, but the tray was nevertheless necessary, if only because of the total-loss lubrication of the two main spindle bearings.

The amount of oil that remains to be absorbed after the chips have been vacuumed out is still within the range of what the blue workshop tissues are capable of absorbing - this should be even more successful now that the machine has been raised.

The tray has become so luxuriously large that it should be quite easy to install a drain at a later date - if, say, there is a milling machine with a built-in circulation pump to the right of it ...

Thank you for thinking of this!

Have a wonderful sunday all,

Carsten

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[25.4_mechanic]

Good evening everyone,

since I can't get consistent results with my attempts to get the little Myford straight and true, I clamped a new, purchased, certified, ground 1/2" bar of silver steel and measured it just behind the jaw chuck:

Turned by hand, I already get a runout error of up to and over 1.5 tenths here ....
With the hand wobbled on the rod it is easily more than that ...

Thereupon I have the front, the chuck first lying bearing shell removed to see underneath - this I had not done earlier, because the screws were so tight that I did not get them open with the T-handle Allen keys, since I now also have normal angled Allen wrenches I could now push a tube over it and got them open.

I think that in the fact that they were so tight is already an indication that the previous owner was also not satisfied with the concentricity ....

On the shaft we could see these marks, but not feel any unevenness (what non-radial marks can be seen, we caused when feeling, that is just oil).

The bearing shells correspond in their image approximately to the shaft, here you can feel a very slight braking when you run your finger over it, but this seems to be a property of the material, not the traces ....

The shims don't look original to me, anyway they are quite different from what you get offered on the Myford site today.

I'll have to take a closer look at them again, so far my perception is: homemade steel shims with brass applications from lying together in the past ...

The shims are front <- 0,407 0,398 -> / rear <- 0,406 0,404 ->

What's the process going forward? What do I do next?

Many thanks in advance,

Carsten

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[brightspark]

the bearings just need shimming up so the shaft turns freely without any chatter or movement you can make your own shims out of coca cola tins or buy various thicknesses of shim stock till you get it right. i just did mine on a spare lathe im rebuilding . its simple to do . the bearings wont make your lathe spindle run out and it wont help having your test bar set in the chuck

 

[25.4_mechanic]

the bearings just need shimming up so the shaft turns freely without any chatter or movement you can make your own shims out of coca cola tins or buy various thicknesses of shim stock till you get it right. i just did mine on a spare lathe im rebuilding . its simple to do

Thank you very much!

Do I understand correctly: you agree that the shaft needs to be guided tighter, so shims need to be thinner?
Other possible reasons are ruled out?
The chuck itself can not produce this error?

To make the shims then myself does not scare me, I just want to go in the right direction ...

Carsten

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[Seadog]

Make some shims that are thicker than you think you'll need, and of a parallel thickness. Acquire some Plastigage and, from that, work out the thickness that you think you'll need. It may take two or three attempts.

 

[brightspark]

i cut some strips of a set of feeler gauges and inserted till i got it rite then measured with a micrometer and made the proper ones up

 

[25.4_mechanic]

Plastigage

Thanks!

I know how to work with that - is there a spec for right range bearing clearance at that position?

Carsten

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[brightspark]

Thank you very much!

Do I understand correctly: you agree that the shaft needs to be guided tighter, so shims need to be thinner?
Other possible reasons are ruled out?
The chuck itself can not produce this error?

To make the shims then myself does not scare me, I just want to go in the right direction ...

Carsten

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the chuck can produce the error 3 jaws are never accurate and a 4 jaw has to have the bar clocked up to be accurate

 

[RichardM]

Did you try measuring runout taking the chuck off the spindle and checking against the spindle Morse taper?

 

[JMS1972]

the chuck can produce the error

I agree that's 6 thou run out at the chuck. I've seen worse on a three jaw chuck.

Unless the mandrel is moving a huge amount you shouldn't need to change the shims.

If you take the chuck off what is the runout on the mandrel?

 

[25.4_mechanic]

the chuck can produce the error 3 jaws are never accurate

I had previously understood that only the repeatability of the three-jaw chuck was so poor, not the clamping accuracy per se.

Can I assume that I am reasonably correct with a centering four-jaw chuck?


Carsten

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