Myford ML7 questions

[Will ScrivenParticipant @willscriven26906]

Evening, I’m new to this forum and struggling to find answers to my questions.

I have been able to obtain a Myford ML7 from around 1965. From reading the forum it sounds like the best tools to order would be 8mm square shank and shim them up 3/8” does this sound correct?? I only have the original tool clamp

The lathe did not come with a Dewhurst forward and reverse switch so i have not been able to run it yet. Everything is free when moving the gears so I’m fairly sure it will run correctly. Does anyone have a suggestion for a cheap replacement switch, with forward and reverse (I read on here somewhere reverse is useful for metric thread cutting??) is there a need to include an NVR?

What is the taper in the tail stock?? I think its MT1 but not sure. It came with an MT2 drill chuck which looks way too big for the tails stock but might come good for a future wood lathe I have my eye on.

I’m sure there’s more questions I’m forgetting but that’s a start anyway, thanks in advance.

[Will ScrivenParticipant @willscriven26906]

[Simon CollierParticipant @simoncollier74340]

Lots of Myford cult members on here but for starters, head and tail stock are 2 MT. I got a Dewhurst type switch online from USA and a friend kindly wired it in for me. Before that the previous original owner just turned it on and off at the power point. Try the forum search box and you will finds heaps on Ml 7s.

and welcome to the forum!

[Brian WoodParticipant @brianwood45127]

Hello Will, welcome to the forum.

You will get answers to pretty much all your questions, I will pass on the Forward/Reverse motor switching, there are many others who will advise you better than I

Do though please include No Volt Release in the wiring, it is an important safety issue preventing accidents in the event of a machine tool coming back to life unexpectedly after a power failure

I can confirm the tailstock barrel is bored for 2 Morse taper

Happy days with your new acqiisition.

Regards Brian

[roy entwistleParticipant @royentwistle24699]

Will Please note that a Dewhurst switch is only for forward and reverse not for stopping and starting. Both tapers are No 2 morse

Roy

[HopperParticipant @hopper]

I would not worry about the forward reverse switch at this stage. As a beginner you will be while before you are turning metric threads. Even then it is often best done with a simple hand crank on the other end of the lathe spindle. Just get the motor wired up to run forwards and some kind of basic switch. NVR is nice if you want industrial standard WSH but absolutely not necessary in the home workshop. My old Drummond ran 40 years in my Dad's shed with nothing but the switch on the wall outlet. No severed digits. No burned out contacts. No dramas. But might be best to get a cheap online on/off motor switch or NVR if you fancy it and wire it in. You can upgrade to a reversing switch later. Forget Dewhursts. Overpriced and mostly clapped out. Plenty of cheaper modern alternatives on t'internet.

You should get the book The Amateur's Lathe by LH Sparey and also Ian Bradley's book The Myford 7 Series Manual. Also the original Myford manual is all over the net in free PDF format. Sparey's book is the best I have come across. Starts with the Myford basics and goes right through it all, including setitng up motor and switches etc and screwcutting etc.

Yes 8mm or 5/16" or even 6mm-1/4" tool bits on a bit of packing works just fine. Sparey's book is the best I have seen for grinding your own instructions for beginners. I've been using 10mm carbide insert tooling on my ML7 too and it works rather well. Had to machine a bit off the bottom of the 4-way toolpost to drop the 10mm down to the Myford's original 3/8" level. But if you just have the plain clamp that won't be a problem.

Edited By Hopper on 20/08/2020 09:50:37

[john fletcher 1Participant @johnfletcher1]

Hello Will, a proper motor starter in my opinion is essential for your own personal safety as Brian above says. Regarding the Forward & Reverse Switch, a double pole double throw change over switch (NO centre OFF) is all you need, wired such that you have to select motor direction of rotation then press the GREEN button on the motor starter. Let the motor starter do the work. Should you move the toggle of the DPDT switch, the motor will continue to run in the same direction until you stop it via the RED stop button. But next time you press the GREEN button the motor will run in the alternative DOR, DON'T DO IT. The a 5 amp DPDT switch is adequate but get a 10 as I think it will be more easily work with and little difference in price. If you send me a PM with your email address I'll send you a wiring diagram. Regarding cutting metric threads as you say leave the clasp nut engaged and reverse the motor. .John

[SillyOldDufferModerator @sillyoldduffer]

Hi Will,

Q. sounds like the best tools to order would be 8mm square shank and shim them up 3/8” does this sound correct??

A. That will work. The important requirement is to get the cutting point of the tool on the centre line of the spinning job. If the cutting edge is too high, even slightly, it will rub rather than cut – disaster. The cutting edge is more tolerant of being, but too low makes dig-ins likely. Biggest tool that will sit on the centre line is good because they are more rigid, but it's often handy to go smaller to get into tight spaces etc. An ML7 owner should be able to confirm if a 10mm tool would fit the 3/8" holder; I suspect it will be a shade too high.

Q. Reversing?

A. I always cut threads in reverse but my lathe has a bolt-on chuck. Myford lathes feature a screw-on chuck which can undo when the lathe is run in reverse. With metric threads, the Threading Dial Indicator probably won't indicate correctly, so the easiest way of of keeping spindle and lead-screw aligned is to leave the half-nuts engaged and reverse the lathe out. However, you may find not many threads are lathe cut on your machine. Taps and dies are faster and easier for most sizes, so my lathe gets used for big threads and specials rather than standard sizes. So, unlike an NVR/Emergency Stop, a reverse switch need not be a priority. You might consider wiring the lathe in forward only as a first step: likely >95% of jobs don't require reverse. Another possibility is thread-cutting with a hand-crank in the spindle rather than under power: hand-cranking provides excellent control, it's just slow if lots of threads are needed in a hurry.

When the time comes to reverse the motor I wouldn't recommend using an original Dewhurst switch unless period chic is the goal! Plenty of alternatives: try searching for 'Motor Reversing Switch' on ebay or Amazon. Not having bought one, I can't recommend a particular model, like this example. I expect others can! (What sort of motor do you have? It may make a difference. )

Dave

 

Edited By SillyOldDuffer on 20/08/2020 10:29:01

[GeorgineerParticipant @georgineer]

I use an ordinary "intermediate" light switch, which does the job splendidly. The one I use is by MK, £6.28 at Screwfix, plus a back box to mount it on.

It's rated 10 AX, so it handles inductive loads up to 10 amps – ideal for this application, especially since you shouldn't be switching it while the motor is running.

George B.

[steamdaveParticipant @steamdave]

Will

You would do well to subscribe to the Myford group on .io There you will find a wealth of knowledge.

Not saying that there is a dearth of knowledge here, mind you!

https://groups.io/g/myfordlathes

Dave
The Emerald Isle

[Matt Homer 1Participant @matthomer1]

Myford ML 7 mystery part ?

does anyone know what this is….came with a load of bits when recently aquried a 1956 Myford ML7

looks like some sort of indexing device but cant see anything in old catalogues for Myford parts.

thanks

Matt

[BufferParticipant @buffer]

What do you mean about the Dewhurst Switch not for stopping and starting? I have been doing that for nearly 20 years, I have no other switch except the one on the wall socket. It works fine. Have I missed something?

[SteviegtrParticipant @steviegtr]

As said by others do not put any load on the chuck in reverse. I suspect you would not & that you want reverse to leave the leadscrew engaged & revers back to the begining of the thread which a lot do. I have a nearly new Dewhurst switch & stop start station all wired up for the Myford super 7. Also the 3/4 hp single phase motor. I did advertise on here a long while back. Not sold. Also have the wiring diagram somewhere that came with the lathe. I guess i could split from the motor & save the motor for future projects.

Not sure where you are in the country. I am in Leeds. P.M if interested. Will not put a price on here as not sure of rules.

Steve.

Edited By Steviegtr on 25/08/2020 00:19:19

[Will ScrivenParticipant @willscriven26906]

Evening gents, thanks for all the info.

I Have been checking what I have and it would seem the motor is a normand electrical DC shunt motor. What would I need in place to convert from 240v to the correct DC for this motor? I was also given in the deal an ‘English Electrical company’ motor but this only has a home made stand which I’m not sure can be attached to the motor bed on the lathe. If more info is needed I can provide pictures of the motor plates. Thanks for any help you can give.

[SteviegtrParticipant @steviegtr]

You would probably need to show pics of the motor plate. Could be any voltage. they were never fitted to the Myford lathe. The origonal one would have been A.C. 240volt. either 1/2 hp or 3/4 hp. Odd 1hp ones around. It would have the capacitor on the side of the motor case.

Steve.

[HopperParticipant @hopper]

Posted by Buffer on 24/08/2020 19:00:53:

What do you mean about the Dewhurst Switch not for stopping and starting? I have been doing that for nearly 20 years, I have no other switch except the one on the wall socket. It works fine. Have I missed something?

 

 

Just wait another 20 years. You'll be regretting your folly then when the Dewhurst contacts burn out.

Modern practice popular among today's more WHS-concerned model engineer types is to fit a NVR switch upstream as the main on/off unit and save the contacts on the now ageing Dewhursts that are starting to burn out from age. Most of them are over 40 years old by now.

 

Edited By Hopper on 28/08/2020 05:35:20

Edited By Hopper on 28/08/2020 05:36:24

[Will ScrivenParticipant @willscriven26906]

Info from neco dc shunt motor

Frame :5

H.P: 0.5

Torque:

Volts: 180A 220F

PH:

HZ: DC

Amps: 3.0

RPM: 3000

Rating: Cont 1 NSF

Type: SHUNT

info for the EEC

H.P 1/3

RPM: 1425

VOlts: 220/240

Amps: 2.8

Cycles: 50

Rating: Cont

Type: LF02/26

all help greatly received

[Author]

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