New Member – looking for a Myford Super 7 (I think!!)

[HopperParticipant @hopper]

Geez, look at all the hoary old chestnuts coming out of the woodwork (not to mention the mixed metaphors!)

Yes Dewhurst switches can get wear on the contacts after about 50 years of being used to switch the lathe on and off instead of using a separate push button stop/start switch as seen the above pic. But like everything else on the lathe, the Dewhurst switch is infinitely rebuildable. Info on that here https://misterlinnsworkshop.wordpress.com/2014/03/08/dewhursts-big-switch/

Non-leaking oil guns to use on the Myford oil nipples are available from Wanner (expensive!!) and more reasonably from Pressparts.co.uk or you can just do what I did for many years and use an oil can with a pointy brass nozzle on the end of the spout. You just push it into the hole in the nipple and squirt.

In all my years (almost 60) of using Drummond, Myford and Hercus (Southbend clone) lathes with screw-on chucks, I have never had one stuck. But I do keep a lick of anti-seize on the threads and keep the threads clean. If you do get a tight one, I think the S7 has a spindle lock that should be used while undoing the chuck with a length of wood through the chuck jaws as a lever. DO NOT use the back gear to lock the spindle to undo a stuck chuck, unless you want to pay for two new gears when the tooth under load breaks off.

It is fine to run the Myford in reverse on the return run (only) when cutting metric threads. I do it all the time. RPM is low and there is no cutting force on the return so the chuck does not unscrew itself. But, as SOD says, do not attempt screwcutting away from the chuck with the spindle running in reverse as seen at YouTube university (Joe Pye etc). You might get away with it, but not for long. One way around it might be to use a tailstock centre to prevent the chuck unscrewing and moving the job to the right, but might put unnecessary stress on the tailstock etc.

Other than that, the lathe in your pic sure looks nice. As Jason says, if the mechanics are as nice as the fresh paintjob, it will be good. But you would need to inspect and preferably measure the bed for wear to really tell.

Generally it looks pretty good. Handwheels and levers don’t show signs of massive wear, if they are the originals. It looks like the stop/start switch is a new addition, which is a good thing to have, as mentioned.

It does look like the lathe is freshly painted and the handwheels as noted look pristine, but unable to tell if they are originals or new ‘uns. Well worn examples start to lose the nickel/chrome plating around the rim and handle where acid sweat from hands etch into them, combined with friction. But the stand looks like it has not been painted. I would ask the seller what is the story there.

Another telltale sign of high mileage on these lathes is look at the condition of the V-belt pulleys on the lathe spindle and countershaft. They are made of Mazak, a softish aluminium/zinc diecast alloy. If the lathe has had a lot of use, the V belt wears the sides of the V grooves in the pulley, leaving a noticeable step where the bottom of the belt sits, about 3/4 of the way down the groove. If there is a millimetre or more step there, the lathe has done a lot of work over the years. You can buy new pulleys, but if the bed has a commensurate amount of wear on it, you could be up for an expensive regrind job.

It looks like the lathe in the pic has the long cross slide with rear toolpost, very nice to have.

Does it have the four jaw chuck and faceplate with it? These are pretty much essential items and not cheap to buy as extras. Plus a fixed steady is almost mandatory on a Myford. Because of the small hole down the middle of the lathe spindle, the fixed steady receives regular use when turning longer jobs of over about 1/2″ diameter that can not be shoved up the centre of the spindle as on larger or newer lathes.

Let us know how you get on with it and don’t hesitate to ask any questions you have. Plenty of us Myford know-it-alls on here!

[JA]

On JA Said:

…
Myfords have their failings but owners accept them and keep quiet.

 

Which is why I posted the list!

Surely Model Engineers need to know what’s good and bad about their equipment?  Is it really a good thing for flatline to have to find out  the hard way that trying to get a stuck chuck off can break a Myford?   And why shouldn’t the world know that the life of a Dewhurst switch is reduced by abusing it?  Especially as the abuse is easily avoided.

One of the best things about Far Eastern kit is that pride of ownership isn’t a factor.   There’s no need for me to accept and keep quiet about my warty equipment!  In comparison, feels like some Myford owners feel the need to protect the brand against any and all valid negative comment.

Being economical with the truth would improve my engineering reputation no end, but I’d rather be fully open because it gives others the chance to learn from my mistakes.

In engineering, I believe honesty is the best policy.  Maybe I’m wrong, and there’s huge demand for engineering reference books full of misleading data designed to support wishful thinking.

Dave

 

 

[JasonBModerator @jasonb]

As Hopper says the Dewhurst switch should be OK if used as intended which is to select the direction BEFORE starting the lathe and AFTER stopping it. I’m expect Dave’s Warco would start smoking if he flicked between fwd/rev without stopping the lathe first, I’m sure mine would.

There have been a few methods published over the years to retain the screw on chucks should you what to do things like threading away from a shoulder at a reasonable speed. They are also quicker to change than a 3 stud import so advantages as well as possible disadvantages

Never could get all the oil into the oil points on my Warco either but a bit of rag soon sorts that out. The rest will drip out the bottom over time anyway

[JAParticipant @ja]

Dave

Your list of Myford failings does not include any of mine: The cross slide platform is not very stiff (sometimes mounting items such as a cylinder to be bored needs some thought), the tailstock is inclined to get in the way of the top slide, the motor usually fitted (single phase induction motor) has a finite life, replacing the drive belt to the headstock spindle is a very major exercise. There is more.

I never had any motor problems on my old S7. WHEN SAFE the clutch should be used and the motor left running. My present Myford has an inverter with a three phase motor. The smooth starting is great compared with the old single phase motor.

JA

Flatline – One other thing, if possible do not place the lathe flat against a wall. Sooner or later you will want to get to the back of the lathe (fitting a taper turning attachment is one example). I have made that mistake.

[mgnbukParticipant @mgnbuk]

Another telltale sign of high mileage on these lathes is look at the condition of the V-belt pulleys on the lathe spindle and countershaft. They are made of Mazak

Not on a Super 7, Hopper.

Both headstock multi-vee + the clutch pulleys are cast iron & the motor pulley (on my machine at least) appears to have been turned from solid. And the “long cross slide” is a standard S7 part as well – most areas of the S7 were “upgraded” from the ML7. The cross slide isn’t that rigid, though, due to the mounting & clamping arrangement for the compoud slide – overtightening the two clamp screws causes the cross slide casting to bend. Both my current machine + another I had bought to get the QC gearbox both had cross slides bent at the same position, fortunately not so much that couldn’t be ground out.

Although the S7 has the spindle lock pin that engages the rear of the spindle multi-vee pulley, ultimately it is the Woodruff key in the bull gear that takes the strain of removing a stuck chuck – cheaper & easier to change a key than repair or replace a damaged gear, though.

All the Dewhurst switch detractors seem to have missed that the Super 7 has a spindle clutch, so the motor does not have to be switched off every time to stop the spindle. Like JA, my machine has a 3 phase motor & an inverter (used as a static 240V 3 phase source) & it doesn’t get turned off for in process measuring, tool swaps etc. Always off & switched off at the mains if the chuck key comes out, though.

I oil mine with a normal pump action oil can with a piece of PVC fuel pipe that is a snug fit over the oil nipples  pressed onto the end spout. If you get the Myford Tecalamit pump oil gun, these can be made less leaky by putting a folded over piece of cotton cloth (like an old sheet or table cloth) between the gun & the nipple.

Super 7s are versatile machines that are very nice to use – hope the OP enjoys his.

Nigel B.

[Howard LewisParticipant @howardlewis46836]

It looks as if you have done really well. A good choice.

As said, use the No Volt Release switch to stop and start, selecting Forward or Reverse, while the motor is stationary, before restarting with the NVR.

If you have a chuck that is stuck, do NOT fall prey to the tempataion to lock things by just engaging Back Gear (Unless you like replacing gears that have lost a few teeth).

There are less damaging ways of freeing stuck chucks

Prevention; never screw on under power. Spinning on by hand can be more than tight enough.

Set to lowest lowest speed, tighten belt.

Don’t hit the Chuck Key. They tend to break!

Grip a poece of large (1/2″ A/F mimimum) hexagon bar in the chuck, if a 3 jaw.

Use a close fitting socket, and fit a long handle/tommy bar. Hit, hard, with a mallet, at the outer end.

Alternatively, put a substantial piece of wood across the jaws, and smack the end hard, with a mallet.

Hope fully after one or two jolts, the chuck will unscrew.

Yoiu are set for years of pleasure!

Howard

[JAParticipant @ja]

Myford suggested, with a length of wood or aluminium across the jaws of the chuck to stop it rotating and using the lowest speed and in back gear, easing the drive belt backwards by hand.

No nasty shock loads, no surprises, no electricity.

JA

[flatlineParticipant @flatline]

The Super-‘7’ came with a selection of tools & accessories, the majority of which are shown in the photo.
Also a thick file of hand-written notes, drawings, diagrams, photos & the original(?) + more modern Myford manuals for the lathe & the quick-change gearbox. Also a contemporary Myford brochure from back-in-the-day.

The previous owner sadly passed away a few years ago – he was an enthusiastic restorer of motorcycles & I believe a few examples went to a motorcycle museum after he passed.
It has been quite humbling leafing through this history of his time with the machine – I hope to carry on the story with some decent work of my own, as I too am a keen motorcycle enthusiast.

Many thanks to everyone for their positive contributions… 😎🇬🇧👍

[JAParticipant @ja]

You have done well!

Replace the ice cream/spread boxes with somethings more substantial. They get very brittle with time.

Also, you cannot have too many quick change tool holders.

JA

[SillyOldDuffer]

On SillyOldDuffer Said:

 

On SillyOldDuffer Said:

And why shouldn’t the world know that the life of a Dewhurst switch is reduced by abusing it?  Especially as the abuse is easily avoided.

 

 

 

It says something about Myfords when a switch that needs rebuilding after about 50 years is considered a weak point!

[JA]

On JA Said:

Myford suggested, with a length of wood or aluminium across the jaws of the chuck to stop it rotating and using the lowest speed and in back gear, easing the drive belt backwards by hand.

No nasty shock loads, no surprises, no electricity.

JA

I believe, from memory, one recommended practice is to have a block of hardwood between the rear jaw of the chuck and the rear bed way, then spin the lathe spindle backwards either by pulling on the belts or by a quick blip of power and let the chuck jaw smack into the wooden block and jar the chuck loose. Desperate measures under power but better than using the back gear to lock it!

[flatline]

On flatline Said:

The Super-‘7’ came with a selection of tools & accessories, the majority of which are shown in the photo.
Also a thick file of hand-written notes, drawings, diagrams, photos & the original(?) + more modern Myford manuals for the lathe & the quick-change gearbox. Also a contemporary Myford brochure from back-in-the-day.

The previous owner sadly passed away a few years ago – he was an enthusiastic restorer of motorcycles & I believe a few examples went to a motorcycle museum after he passed.
It has been quite humbling leafing through this history of his time with the machine – I hope to carry on the story with some decent work of my own, as I too am a keen motorcycle enthusiast.

Many thanks to everyone for their positive contributions… 😎🇬🇧👍

Wow! Looks like you got the motherlode of accessories with it. Well done! And it sounds like the old gent took pride in his gear and looked after it so you should have a good set-up. Most of the accessories look barely used, so most likely the lathe is in the same condition. Like most of us motorcycle restorers, he probably only used the lathe on occasion as needed to make the odd part or two. Well done!

[Hopper]

On Hopper Said:

On SillyOldDuffer Said:

 

On SillyOldDuffer Said:

And why shouldn’t the world know that the life of a Dewhurst switch is reduced by abusing it?  Especially as the abuse is easily avoided.

 

 

 

It says something about Myfords when a switch that needs rebuilding after about 50 years is considered a weak point!

Who, apart from Hopper, believes that abused Myford Pattern Dewhurst’s last 50 years?

I see it this way.  Switch lifetimes are expressed in number of operations, not elapsed time.   A lightly used Myford Dewhurst, say on a 1950 machine that’s only abused 10 times a week, will clock up a mere 38480 operation in 74 years, so there’s a good chance it won’t be wrecked.    Same machine abused 10 times a day will clock up 269360 operations, and the switch will be hurt.

The problem lies in the design of the switch.   When the contacts open with power applied, there will be a spark through which current  passes as an extremely hot arc, which lasts until the contact gap grows big enough to snuff out the arc.   It is the arc that damages the contacts, causing severe wear.

When a switch is designed to make and break power, special attention is paid to minimising the arc.   For example, the contacts of a domestic light switch are spring-loaded, so their contacts open and close very rapidly.  In addition to spring-loading, beefier power switches add extra copper to destroy arcs by cooling them quickly,  and others blow the arc out with compressed air or operate in a vacuum.   The contact materials are chosen to resist arc damage, Tungsten, Rhodium, Platinum and such.  All a bit pricey.

The Myford Dewhurst has none of these features because it’s a plain reversing switch.   What’s supposed to happen is the motor is turned on and off with the main power switch, and the Dewhurst contacts only moved when the power off.   Done that way the Dewhurst doesn’t experience any arcing at all, and should last donkeys years.  The Myford Dewhurst is a sensible answer, provided the operator plays ball.  Trouble is that too many owners don’t read the manual.

I’m pretty sure Dewhurst switch problems are mentioned in my early 1960’s ME magazines, and the issue is common knowledge today.   Part of the problem I suspect is the chunky good looks of the switch.  It lives in a hefty case and is operated with a whacking great ball-ended lever:

Looks as if should be able to switch megawatts forever, but the reality it’s not, and was never intended too.   Though a rather old-fashioned drum switch, I’d I’d say it’s fine, provided previous owners haven’t beaten it up.   The innards of the Dewhurst are one of the first things I’d inspect after buying a Myford.   All smiles if it’s been looked after, but all too many will be more-or-less damaged.

Abusing the electrics is a common problem on Far Eastern lathes too!

Dave

[Michael GilliganParticipant @michaelgilligan61133]

You make a good ‘electrical’ point, Dave … but there is also an Ergonomic issue, of Dewhurst’s making.

The Central OFF position is an open invitation to abuse the switch !

MichaelG.

[SillyOldDuffer]

On SillyOldDuffer Said:

On Hopper Said:

On SillyOldDuffer Said:

 

On SillyOldDuffer Said:

And why shouldn’t the world know that the life of a Dewhurst switch is reduced by abusing it?  Especially as the abuse is easily avoided.

 

 

 

It says something about Myfords when a switch that needs rebuilding after about 50 years is considered a weak point!

Who, apart from Hopper, believes that abused Myford Pattern Dewhurst’s last 50 years?

 

Based on my own observation of the number of Dewhursts from the 1950s to 70s still in (ab)use on Myfords today. Unbelievably, the 1970s were 50 years ago! How, I don’t know.

I spent yesterday riding a 1977 Harley that I bought brand new. How can that be? And people have been telling me since 1977 that they are unreliable. I’m still waiting for the first time for it to break down. I guess I will have to wait until it is old and worn out (like me!).

 

[Martin of WickParticipant @martinofwick]

Uugh…..!  it is only a switch at the end of the day. The Dewhurst is what it is… a just a cheap and nasty rotary mechanical reversing switch. I care not whether it arcs and burns the contacts, vapourises, or grows wings and flies away. It is used as the principle operating control,  stop, run and occasionally reverse, all the time. For all I know, it has likely been used this way from the day my 7 rolled off the production line in 1948.

If it keeps working and does what I want, great. If not, it is simply replaced with a modern cheap and nasty Chinese Q60 equivalent  for a tenner from one of the usual online market places.

[Bantam BillParticipant @bantambill]

I had a super 7 with all the accessories and it was a lovely machine but then I brought a Myford 254+ and the difference was amazing like chalk and cheese. 254’s can be had for much the same price as a well sorted super 7.

[Mark RandParticipant @markrand96270]

As a point of contrast. The 1952 Hardinge HLV that I rebuilt from a basket case and now use, has a switch which is very similar to the Dewhurst switched as used on Myford and other machines, but more poles (three phase, two speed motor). It is used for turning the motor on and off and for changing from high to low speed as a natural part of the machine’s operation.

Its contacts were severely eroded, but still worked, when I got it. Making new contacts was a trivial exercise, though.

The Dewhurst switch was designed for and is quite happy with switching the motor’s load. That’s why most machines didn’t have any other switch…

[Howard LewisParticipant @howardlewis46836]

As an aside, my ML7, bought in 1979 had been well mused, and was heavily coated in sawdust.

The Dewhurst switch never caused me any trouble during bthe 24 years that owned it, and there was no ON/OFF switch upstream of it, so it received all the abuse that ia, and previous owner(s) gave it.

Reprephensably, I did manage to crack the Cross Slide, (But contacts withe the Toolroom produced a replace,emnt in steel)

Frustration with the 2MT headstock bore, and impending retirement caused me to seek a replacement.

A new, well equipped, Super 7 Sigma, which was what I yearned for, would have cost me four times what I paid for a larger Taiwanese machine, with PCF (unavailable of the S7 S) and importer fitted VFD.

BUT, horses for courses, NO machine is perfect (I have made some mods to the 12-24)

If the machine does what you want, to your required level of accuracy, you do well, and can be happy.

The OP looks to have done very well.  Long may they be able to enjoy using the machine.

Howard

[HopperParticipant @hopper]

Use of the fixed steady will solve most problems created by the small spindle bore on the dreaded Myford. I use mine a lot and consider it an essential accessory that no Myford should be without if you want to work on anything bigger than a small model etc.

I regularly use my fixed steady to machine parts on the end of a length of 2″ diameter bar etc and then part it off, so I dont end up with all sorts of useless noggin ends where the bar was cut off to length of the job plus inch and a bit to grip it in the chuck. I find machining using the fixed steady as easy and chatter-free as when using the tailstock centre etc. No particular dramas.

The only limitation is machining the far end of long large-diameter jobs over about 22″ length, such as motorcycle fork tubes. The bed is not long enough to move the carriage down to the far end to machine it. But the need has arisen so rarely over the years I would not count it a major problem. Plenty of mates with 13″x30″ Chinese lathes that can accommodate it up the spindle ‘ole.

 

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