Just installed a super 7

[grahammarchParticipant @grahammarch]

Hi all finally got my new to me Myford super 7 home and installed and levelled up, please forgive some stupid questions but really interested in machining but never used a lathe before but will hopefully learn a lot and become confident using it

my only concern at the moment is it’s an imperial lathe and have been brought up metric and would like to convert it, how difficult will it be, I understand I need to convert the dials to metric but the gearbox I want a metric conversion and when I look I see 2 types Norton metric gearbox and normal metric conversion can someone enlighten me if I have a Norton type gearbox or not, the gearbox serial number is QC148391 sorry for the stupid questions but on a steep learning curve here

some pics below what do you guys think

[bernard towersParticipant @bernardtowers37738]

I think the g/box conv is a metric conv set behind the lefthand cover and an overlay on the chart. for the rest of the lathe its feedscrew and dial changes. not sure about the tailstock. why not go DRO?

[Martin of WickParticipant @martinofwick]

you will need to convert the dials AND the leadscrew/feedscrews AND the feednuts for a proper conversion. Plus conversion pre-gear set for the gearbox and presumably a new overlay chart unless you are able to memorise all the combinations.

Simply not worth the cost. All you need to do is remember the magic number 25.4 and learn to think imperial. That way you will find the true path to enlightenment.

[KEITH BEAUMONTParticipant @keithbeaumont45476]

Looks a nice piece of kit.  Dont mess about changing dials, look at the kit DRO for that lathe from M-DRO.You can then change from Imperial to Metric at he touch of a buttom.

Keith.

[Charles LamontParticipant @charleslamont71117]

The gearbox in the middle of your middle photo is the Norton gearbox. It just means the generic type. The leadscrew – the long one at the front – is 1/8″ pitch, and metric pitch ones are not available so there is no metric gearbox . A metric conversion kit for the Myford gearbox involves different gears to be put inside the changewheel guard on the left hand end of the machine. This alters the gear ratio between the lathe spindle and input shaft of the gearbox to ‘fool’ it into cutting metric pitches.

Do you have an idea of the kind of thing you want to make? Bear in mind most existing designs are in imperial.

And a first safety rule: never, ever, leave a chuck key in the chuck.

 

[Wink HackmanParticipant @winkhackman25989]

As others have said, don’t bother changing dials, just spend the money on a DRO kit. You’ll never look at the dials again.

[Roderick JenkinsParticipant @roderickjenkins93242]

+2 for the DRO. I have just fitted one to my S7.

The addition of 33 and 34 tooth change gears will allow you to cut most of the usual metric fastening pitches using the Norton box.  You will find that there has been much discussion of this fix on the forum in past times.

Rod

[John HaineParticipant @johnhaine32865]

As Charles says, there isn’t a true metric z axis leadscrew made for the S7.  You can change the dials and screws and nuts on the crosslide and topside, but still have to live with an imperial leadscrew.  I see you have a PXF which makes the screw and nut even more expensive.  If you want a fully metric lathe the best approach would be to fit DROs as Keith  suggests.  And perhaps an electronic leadscrew to solve threading.  I have a Super 7 which is CNC converted.  If youri machine has a single phase motor I strongly recommend fitting 3 phase and a vfd, it transformed my machine especially on the high speed range.

[HopperParticipant @hopper]

How much screwcutting are you going to do? Probably the 33 and 34 tooth metric conversion gears will do all you need in that area, keeping the original leadscrew.

To “properly” convert the cross and topslides to metric, you really should get metric feedscrews and nut to to with the metric dials. Otherwise, you end up with dials with odd partial numbers of divisions that become a bit unmanageable when trying to use more than one revolution of the dial. As suggested, DRO might be a tidier, even cheaper, solution.

[SillyOldDufferModerator @sillyoldduffer]

Welcome Graham!

Can you explain what type of work you intend doing?  If your workshop celebrates the past, learning Imperial and leaving the lathe alone may be the right answer!  It’s because many model steam locos are built from traditional Imperial plans and converting them to metric is error prone hard work; easier to do the job the old-fashioned way!   Likewise, repairing and restoring legacy machinery is easier with Imperial tooling.   Otherwise living in North America favours Imperial, though it’s fading there too.

I do experimental work, where the Imperial system is a hissing and an abomination.   As supporting metric in my workshop is a priority, I wouldn’t buy an Imperial Myford, because I would have to waste time and money converting it.

In practice, metric lathes can do most imperial work, and vice-versa.  Just slowly!   When cutting to length or diameter, do the maths (1″ is 25.4mm”), or ignore the dials and measure with a caliper or micrometer.  Best of all, a DRO measures accurately in both systems and reduces the risk of backlash errors.

The main exception is screw-cutting, which, again depending on the work, may not matter much.   It’s because small-threads are almost invariably cut on the lathe with taps and dies, not with a single-point tool or insert.   When taps and dies are used, they impose their system, and the lathe’s lead-screw, gearbox, or change-gears are irrelevant.    Single-point screw-cutting is wheeled out for threading large diameter,  maybe once in a blue moon.   A threading gearbox saves time, but they only pay if a lot of different threads have to be  cut quickly.  Could be a gear-cutting gearbox is an expensive accessory, another complicated part to go wrong, when change-gears might do most jobs just as well.      So Graham, what threads do you expect to cut?   If the answer is lots of different metric, have a look at Myford’s website, search for conversion kit, and then ring them for advice.   If the answer is occasional threading, ask here about 63 and 127 toothed gears.

How much of a PITA doing metric work on an imperial lathe is, or vice versa, depends on volume and complexity.  The pain is anything between barely noticeable and unacceptable.

Not unusual for beginners to be unclear about what they intend doing!  I was.  Model Engineering is a broad-church, everything from tiny watchmaking to full-size repair.   My advice to Graham is to put his metric worry on the back burner for the time being, and start by learning to drive the lathe.   Does it work properly?   Problem with second-hand is condition;  is Graham’s machine ‘as-new’,  or is it badly worn, with damaged or missing parts?   Best way to find out it to use it – nothing identifies problems faster than cutting metal.  Doesn’t matter at this stage if the lathe is imperial or metric – they cut in exactly the same way.   Learning to drive a lathe requires the owner to select a few projects, and what he chooses often points to the future.   Spend six months learning, and then decide about converting the lathe.

Other newcomers might learn a lesson from this.  Although Myford’s have a well-deserved reputation that doesn’t mean a particular model will meet your needs!   Many older British lathes were made at a time when great-grandad failed to comprehend the world was going metric.  They were wrong.  Imperial is slowly disappearing, for example I don’t believe fractional inch steel plate, once a standard stock item, is made anywhere now.  In 2024, metric dominates, making it likely that a newcomer to the hobby might accidentally buy an awkward to them Imperial only lathe.    Far Eastern and later British lathes do better;  lathe designs after about 1955 tend to major in one system, whilst also providing reasonable support for the other.   My metric WM280 happily cuts 21 Imperial threads.

Dave

[noel shelleyParticipant @noelshelley55608]

As Martin has said the magic number to remember is 25.4 The number of mm in an inch ! or for all but high precision work 40thou to a mm. A calculator by the machine will give exact sizes if needed. I have had a S7 for 50 odd years and work in both metric and imperial systems on an imperial machine, it’s not a problem. A DRO would be the easy way out, and probably cheaper than conversion. The gearbox conversion using the Myford kit is expensive and how often will you cut metric threads Only when you have an excess of money would I buy a 3 Ph /VFD conversion. Enjoy your new toy and don’t get carried away with needing to buy the best gear, you have a good machine in the myford. Tool steel/HSS will do most of what you will do, Carbide tips are fine but may easily chip,leave parting off for the time being and just get the feel of the machine and enjoy. Good Luck. Noel.

[JasonBModerator @jasonb]

You don’t really even need to remember 25.4.

Just open your digital callipers to the metric size you want and zero them. Now all you need to is measure the length or diameter of the part and the callipers will show you how many thousanths of a banana need to come off, just dial in that amount on the handwheels.

It’s worked for me for years

As has 1mm = 40thou which will get you close enough on a lot of small work.

If I were buying a lathe now I would go for a metric one a sthat is 99% of what I now work in, when I got my WM280 14yrs ago I had not fully seen the light so have to put up with imperial. This has not stopped me doing a lot of metric work.

If it is models you want to make then there are a reasonable number of metric designs out there with more being added all the time

[Ches Green UKParticipant @chesgreenuk]

On the subject of micrometers, mine are all non-digital Imperial. My Verniers, DROs etc are all digital and switchable between metric and Imperial.

I mostly make one or two Stuart/PM Research models per year.

I think it is time to upgrade my mics (0-1″ max) to digital, not least because digital is much easier and quicker to read.

Any thoughts on a supplier with reasonable prices? eg RDG do a couple of 25mm ones…  https://www.rdgtools.co.uk/acatalog/Digital-Micrometers-.html  from about £70 – £100.

Or are 2nd hand digital ones off eBay, say, a more ‘cost effective’ solution? I suspect, because of the internal electronics, those might not prove as problem free as mechanical ones though.

Thanks, Ches.

[JasonBModerator @jasonb]

Ches, I thought the same a few years ago and got digital Mitutoyo mic and cheaper depth one but just don’t like the feel so they sit in a draw unused. Though I find I don’t use a mic very much just digi callipers do for my model making needs with the traditional mic only getting used maybe once or twice per engine.

[bernard towersParticipant @bernardtowers37738]

On a part that is less than 13mm dia why would you use a digital cal when a 0 to 1/2 or 0 to 12 mic fits in the space easier or even 0 to 25.

[Ches Green UKParticipant @chesgreenuk]

Jason, thanks.

Firstly, apologies to Graham for slightly hijacking his thread, but ‘measuring’ is a big part of modelling/maching.

Yes, the digital mics do look a bit unwieldy, certainly compared to the mechanical ones which I can operate with one hand.

I haven’t got in to the habit of using a Vernier as a universal measuring tool … I still find the 1″ mechanical mic just easier to handle. But maybe a bit of brain-reprogramming is required.

OK, off to have a think about this.

Thanks again, Ches.

[JasonBModerator @jasonb]

Bernard. That is another disadvantage of the digi Mics over vernier, they are bigger

Not found getting a 150mm digi calliper in to measure diameters on the lathe a problem be ther 13mm or 130mm maybe I have more room on the 280 than a Myford and there is no rear toolpost to get in the way on my machine. Even the 300mm callipers  are easy enough to use when the work is over 150mm dia

Yes that is why the mic sometime gets used particularly on the mill as it saves having to move the table away to the side to get access for measuring. I do have a small Digi calliper but not seen small digi mics so would have to do the conversion on a calculator and then use the mic

[Ches Green UKParticipant @chesgreenuk]

Useful comparison pic.

That short digital Vernier is something that never crossed my mind…hmm.

Ches

[grahammarchParticipant @grahammarch]

Hi rod the pitch threads I would in interested in doing would be 1mm and 1.25mm threads would it require me just to change a couple of change wheels

[Roderick JenkinsParticipant @roderickjenkins93242]

 

A relevant thread(!) Here

https://www.model-engineer.co.uk/forums/topic/thread-cutting-2/#post-204892

There is a typo free table in my galleries.  I can’t  work out how to paste from a gallery into a thread on my tablet.🙄

 

Rod

[Neil LickfoldParticipant @neillickfold44316]

I have the 33 34 gears and the other set as well. I use what ever makes the most accurate thread pitch in  theory. I made a 8mm with a 0.5mm pitch thread and used the imperial 0-100 count dial with it. Made the nut with a M8X0.5 tap. The best part with it, what ever you measure on mic, you take off the dial. The down side is a lot of handle winding. I also have an M8X1mm pitch screw and nut as well. Is 1/2 the amount of winding and each division is 0.02mm on diameter. When using the cross slide for milling, the 1mm pitch nut and screw is very handy. Like when pitching out conrod centres etc.

My lathe has the metric leadscrew handle and is rounded on the count to 3.18mm, but is actually 3.175mm per rev. Until I got the glass scale Z axis and a DRO, I always treated each turn as 3.175mm and would work out the distances by so many turns plus the final wheel count. Eg, 20mm bore depth was 20/3.175 = 6.299212598 turns. Then .2992×3.175 is 0.9499 so 0.95 on the handle. So 6T+0.95 was the length. Check with a depth mic or what ever you use to measure with.

Thread cutting is not really difficult once you get your head around the whole process. There are many great books out there too, as well as some great threads on this site with many tips etc. I have a friend who has had a lathe for 30 years, and only last year did he for the first time need to cut a thread. All else has been done with taps and dies which can be bought for quite reasonable prices these days and in HSS.

A very useful attachment to make or buy, is a die holder and a tap holder. These have a pin that fits the MT2 of the tail stock, that can have a hole inside the parallel pin that protrudes.  Then make a series of die holders to hold the dies you get and make a tap holder or an adapter to hold drill cuck for the tap. The pin will guide the tap or die as it runs down the part. On my holders, I added a thick piece of plastic tube and then glued it to the steel. It has some longitudinal ribs to grip with the fingers. That way I can let it go when it gets to the end of the threaded area when the die gets there, or the tap. I don’t like the ones with the lever bar incase something jams etc.

I do like the convenience of the DRO setup I have installed, but was not cheap. I put the readout on the front under the apron and got a Sino micro scale, that with some fiddling and making of a mount etc managed to get it to work. As it is slightly shorter than the full travel of the lathe and I do not use it’s full travel. It is set so that the carriage can travel to the headstock stop. The cross slide I installed a magnetic strip one. But does require access to a mill or another machine to cut the recess slot for it. I am happy with the magnetic cross slide option installed.

The reason for the under carriage front mount dro, was so that I could could still have the use of the taper turning attachment. Although I have not yet used it since the installation, I do have a pending project that will be utilising it , that I have not done yet.

Have fun making parts and enjoy the hobby of turning.

[Howard LewisParticipant @howardlewis46836]

+1 for Sliding Die and Tap holders. (Buy a 2MT blank arbor, the actual Die Holders, and drill chuck from Arc Euro, and then insert a bar into the blank arbor). Make bodies to carry the Die Holders, and the drill chuck.

They need to be a fairly slack sliding fit on the bar, (say 0.005″ clearance) so that the Dies, or Taps can self centre on the workpiece.

(Include a radial tapping to take an anti rotation bar, which can bear against the Cross Slide or the  toolpost).

These activities will give you practice, so that you gain confidence, and familiarity with the machine. You will also have a couple of tools which will be used in the future.

Using Dies or Taps under power may mean that the speed is too fast, even using Back Gear. If this is the case, make a Mandrel Handle, so that the spindle can be rotated by hand.  This will have the advantage when working upto a shoulder, or in a blind hole that you can feel when you reach the end, and stop.

Under power, you could suffer the calamities of hitting the end and stripping the thread that you have just cut, or even worse, breaking the Tap on the work!

If you want, I can provide pictures of a Mandrel Handle, and advice on how to make one.

Howard

[HopperParticipant @hopper]

Yes, mandrel handle is brilliant for tapping and die-ing in the lathe. Makes it sooooo much easier.

I use taps and dies always for any threads 1/2″ and under.

Very rarely do I ever need to do actual screwcutting. Once a year maybe, making heavy duty pullers for motorcycle engine disassembly and the like, or one time years ago making new half nuts for the old Drummond lathe. But on those rare occasions, it is darn handy to have.

[JasonBModerator @jasonb]

If running under power is is safer to not use any form of handle or key to prevent rotation. Simply grip in your hand an when the cutter bottoms out or you reach the point where you want the thread to stop let it spin – No risk of a crash and nothing spinning round to hit your hand. As for speed I usually run a lot faster than a Myfor’s backgear. Often run in reverse to back the die off the work but may not be a good idea on a Myford.

Both shop bought holders as I’d rather be making models than tools

[Neil LickfoldParticipant @neillickfold44316]

Jason, Yes I power the tap and Die on my Myford like your video shows. I Stop at the end, manually unwind the 1st turn, and then power in reverse with no issues. I have a plastic sleeve from thick plastic pipe glued to the holders and have scallop slots for the hands to hold. I try not to have things that can catch a sleeve etc as well. So have smooth rounded edges too. So far with this setup have never broken a tap or die . I have broken a tap when being lazy and power tapping with the chuck. That was another story and a lesson in using a hand tap and expecting it to being able to evacuate the swarf in a blind hole. I solved that with buying spiral fluted machine taps.

Making tooling, is a great way for beginners to make mistakes on things that are not really important and to pick up the skills on the way at the same time.

One of the more difficult things to adjust to, is using a file in the left hand control to file without an arm or hand over the rotating chuck. Easy if you are naturally left handed. It’s about safety around machine tools.

The best part is the fun of making something. Anything and learning. Even after 45 years of using a lathe, there are still things to learn from someone.

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