Myford Ml7 Technical Drawings

[JasonBModerator @jasonb]

Just set your CAD to duel dimensions and if they are not happy with that they can do one their own

Though even then you will get the debate between fractions or decimals of inches and the sub pedantry of how many decimal places😈

[Nick Clarke 3Participant @nickclarke3]

Mixed dimensioning might be the way to go as the current Myford site lists cross slide screws as 3/8” x 2mm pitch!

[bernard towersParticipant @bernardtowers37738]

Surely that’s for te metric version?

[bernard towers]

On bernard towers Said:

Surely that’s for te metric version?

… and surely that demonstrates the point !

The 3/8” is a native description of the spec. and is being used appropriately.

MichaelG.

[David George 1Participant @davidgeorge1]

Hi I have over time drawn many parts for the M Type Drummond / Myford lathe and if I was to put them on offer to download them to here would it over load the web site and would anyone be interested in them. I have downloaded most of them on to the  https://groups.io/g/drummondlathe web site so they are available there.

David

[Nick Clarke 3]

On Nick Clarke 3 Said:

Mixed dimensioning might be the way to go as the current Myford site lists cross slide screws as 3/8” x 2mm pitch!

Typical Myford cost saving when making feedscrew for their metric models.

Uses the same barstock and feeders as their 3/8 x 10tpi imperial screws. Just change the rollers on the thread rolling machine and carry on. And use the same collets to grip the screw while machining the spigot and thread for the handle.

[egaParticipant @ega]

I think I remember seeing that Myfords had difficulty in sourcing the large-head BSF cap screws securing the ML7 saddle to the apron and resorted to using a metric equivalent (the large head was needed to accommodate lateral adjustment of the fit).

Perhaps someone with a late lathe can confirm?

[Howard LewisParticipant @howardlewis46836]

Perhaps the moral is unless ABSOLUTELY necessary, do not mix systems on one machine, using wherever possible the same as the original.

Mixing threads can be result in damage. I found a Perkins S6 marine, (Originally built using BSW and BSF nthreads) where the exhaust outlet had beed damaged by someone forcing a Metric srud into an Imperial hole. With an engine at least 60 years old, spares were going gomg to be like hens teeth.

Fortunately, the situation was recoverable, in this case.

Wherever, stick to one system, and need the calculator less!

Howard

P S

I cannot envisage RDG being too keen to supply drawings so that Myford users can manufacture their own spares, rather than buying from RDG!

Some manufacturers deliberately make parts non standard to keep the aftermarket captive for as long as possible

[John Haine]

On John Haine Said:

I suspect that Myford might like an accurate and detailed CAD model!  I wonder what state the “original” drawings are in?
Edited By John Haine on 16/09/2023 10:36:15

I was making a mounting plate for a Z axis digital scale to fit my S7 where the taper turning attachment fits, so I called RDG tools to get the mounting hole centre dimensions and they told me that they did not purchase the manufacturing drawings along with with the Myford name.

So somebody still has the drawings and is hanging onto them.

 

[vintagengineerParticipant @vintagengineer]

Does anyone know the dimensions of the worm wheel for the thread dial?

[vintagengineer]

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vintagengineer

Said:

Does anyone know the dimensions of the worm wheel for the thread dial?

From distant memory (Caveat emptor!):

It’s not a worm wheel.  It’s a simple straight cut gear cut at an angle to match the leadscrew thread helix angle, ie pitch vs circumfence right triangle. (Myford cost saving)

If you have a universal mill where you can angle the table and gear a dividing head to the table feed, you could make a proper helical gear for line contact rather than point contact, but it absolutely is not necessary.

Gear is 16 tooth, circular pitch of  125″ to match the screw. Doesn’t even need to be involute curves as each tooth is merely a place holder, not delivering any power. Either an Acme 29 degree profile cutter to match the screw thread, or the nearest size involute gear cutter from either imperial or metric set would work for this purpose.

Material is brass so it doesn’t wear the unhardened lead screw. (Not phosphor bronze etc!)

I’ll measure the diameter of mine next time out in the shop. But you can work it out from the CP on various online gear calculators and charts.

[vintagengineer]

On vintagengineer Said:

Does anyone know the dimensions of the worm wheel for the thread dial?

See reply above. A 125″ circular pitch gear may be a little expensive in material. 0.125″ (1/8″) CP would work better.

The point that it is just a place-holder/counting wheel is important in establishing an appropriate level of precision for the item.

Please double check the hand of any gear (before) you cut. At worst, you will have to cut a second one of the opposite hand.

Calculator here:

https://evolventdesign.com/pages/pitch-calculator

1/8″ CP (25.13 DP) is quite close to 1 MOD (25.4 DP).

For what it does, a 3D printed version, even 5-off to give you spares if ever one should wear out would seem a practical way forward.

[alecsParticipant @alecs]

LOL. Ooopsies. Yes decimal point was left off the .125″ circular pitch. Here’s a couple of extras for next time……..

[alecsParticipant @alecs]

FWIW the gear on my ML7 measures .710″ diameter by .375″ thick.

(All decimal points present and accounted for!)

[vintagengineerParticipant @vintagengineer]

Thank you

[alecsParticipant @alecs]

One piece of belated advice, if making your own thread indicator dial, make the rotating dial way bigger than the tiny, hard to read standard Myford item.

My previous lathe had a homemade thread indicator by a previous owner. The dial was a good inch or more diameter, vs Myford,’s tiny half inch, or maybe 5/8″ . The bigger dial is soooo much easier to use as it is much clearer when the marks are lined up properly. I curse the puny Myford dial with its puny marks every time I use it and swear once again to make a bigger dial for it.

The indicator on my old lathe was very similar to the design in Ian Bradley’s book The Amateur’s Workshop, which has the large dial.

[bernard towersParticipant @bernardtowers37738]

Mr Meeks Dog clutch comes to mind

[alecs]

On alecs Said:

…it is much clearer when the marks are lined up properly

The standard Myford dial has 8 divisions. The gear wheel at the bottom has 16 teeth.

The mark does not need to be a hair’s width from the fiducial line in order for it to engage properly.

The nearest possible place for another (incorrect) engagement is half the gap between the divisions. Even on a small dial, that is easily distinguished.

[DC31k]

<li class=”bsp-quote-title”>On DC31k Said:

On alecs Said:

…it is much clearer when the marks are lined up properly

The standard Myford dial has 8 divisions. The gear wheel at the bottom has 16 teeth.

The mark does not need to be a hair’s width from the fiducial line in order for it to engage properly.

The nearest possible place for another (incorrect) engagement is half the gap between the divisions. Even on a small dial, that is easily distinguished.

Not for me it ain’t. I find the small Myford dial less user-friendly than the full-sized dials on every other lathe i have ever used. Maybe simply because bigger is easier to see for us half blind folks.

[duncan webster 1Participant @duncanwebster1]

Why does everything have to be so argumentative, surely it’s a matter of opinion. Obviously a bigger dial is clearer, but I’ve taken ME since the late 1960s and cannot recall anyone describing fitting a bigger dial to a Myford, so the current one can’t be a widespread problem. No doubt some GoogleMeister will prove me wrong!

[alecs]

 

On alecs Said:

…The indicator on my old lathe was very similar to the design in Ian Bradley’s book The Amateur’s Workshop, which has the large dial.

Thanks for the reference to this old classic. At p 181 he gives an accessible explanation of the way the indicator works; GHT is also good on this.

 

[ega]

On ega Said:

 

On alecs Said:

…The indicator on my old lathe was very similar to the design in Ian Bradley’s book The Amateur’s Workshop, which has the large dial.

Thanks for the reference to this old classic. At p 181 he gives an accessible explanation of the way the indicator works; GHT is also good on this.

 

You’re welcome. Yes those old books are a treasure trove of trade craft.

[howardb]

On howardb Said:

On John Haine Said:

I suspect that Myford might like an accurate and detailed CAD model!  I wonder what state the “original” drawings are in?
Edited By John Haine on 16/09/2023 10:36:15

I was making a mounting plate for a Z axis digital scale to fit my S7 where the taper turning attachment fits, so I called RDG tools to get the mounting hole centre dimensions and they told me that they did not purchase the manufacturing drawings along with with the Myford name.

So somebody still has the drawings and is hanging onto them.

 

I find it difficult to believe that they didn’t acquire the working drawings, if so how are they producing new parts/spares or machines either in-house or out sourced ?  There is a series of videos not produced by Myford or RDG https://www.youtube.com/playlist?list=PLDV_TkPc48RF1Szel4GHk9MLSW9Qs1CrE showing the setup in Mytholmroyd

Maybe as Howard says they just don’t want to offer the drawings to the public ?

John

[JohnF]

On JohnF Said

I find it difficult to believe that they didn’t acquire the working drawings, if so how are they producing new parts/spares or machines either in-house or out sourced ?

Perhaps they discovered that rare creature – an engineer – who measured an existing sample.

It’s like the people who come on here asking for the manual for a 1920’s lathe that only has 3 moving parts anyway. Not enough people nowadays have grown up making Meccano models from just the picture.

[BazyleParticipant @bazyle]

Re dial size. A bit of cardboard and blob of Bluetack and you have the largest dial that will fit in seconds.

[Author]

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