Stringer EW lathe

[V8EngParticipant @v8eng]

Hi Alan.

I will post the advert later this week, when I have access to home equipment again.

Terry, yes it seems we are doing pretty well on prices these days.

 

Edited By V8Eng on 17/12/2012 18:14:55

[alan smith 6Participant @alansmith6]

Michael,

Would it be possible for you to scan and post the article by JJ Constable in 2790 " A self acting fine feed for thr lathe.

David Clark1. Do you have a scanned copy of this ME?

Alan

[alan smith 6Participant @alansmith6]

V8Eng,

The post by IanT said that he did not know who had posted the details of the EW lathe. Surprise surprise it was me.

You are very welcome to go into my photo albums and look at the copies of the catalogue from 1953.

I hope that you will find this interesting.

Alan

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Hi Alan ,

Michael,

Would it be possible for you to scan and post the article by JJ Constable in 2790 " A self acting fine feed for thr lathe.

I'll do that during tomorrow .

Regards ,

Michael Williams .

[alan smith 6Participant @alansmith6]

Thank you Michael,

Alan

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Alan ,

Upload system is in one of its bad moods again and keeps aborting and then locking up mid transmission . Could you let me have your Email address for me to send copies direct ??

MikeW

[IanTParticipant @iant]

Hi EW'ers,

I've sent you 'select few' copies of the JJ Constable EW Slow Feed article, as I've finally had the time to dig it out myself and read it. You will be pleased to hear that "the lathe maker's claims are fully justified" in Mr Constables opinion, something I think we would all be happy to agree with.

Happy EW'ing!

IanT

[IanTParticipant @iant]

Whilst I'm here….work on my hand pump is progressing well.

Having managed to drill the first valve body off centre – I was a lot more careful the second time around. I'm sure my approach is not new – but it might be useful to some so I'll just run through the essentials.

My new bit of brass (fished from the 'scrap' bin) had a raised 'rim' at one end. My initial thought was to turn this down to the main diameter but on thinking about it, I decided it might have some use. I therefore chucked it (as level as I could with a little packing) in the 4 jaw – and turned down a 'flat' on the raised part of the first side – just enough to bring it level with the main body. I then turned the part over, hoping to use the 'flat' to help hold the body steady (as it had appeared to "roll" slightly the first time). No, I don't know how or why either – but it did!

I then did the same again on the second side but this time went 2 thou futher in to make a very slight flat on the whole body. If you look at the photo you will see that the flat is wider at one end, suggesting that the part moved up slightly during this process. Fortunately this didn't matter too much, although obviuosly the thinner the flat the better.

I then unscrewed the 4 jaw and marked the flat the required distance from the end and then using my trusty optical centre punch, placed a punch 'mark' in the middle of the flat/scribed mark.

Returning the chuck to the EW it was then very simple to make sure the part was bang on centre using two MT1 centres as shown above. It only needed a few slight tweeks to get it centred to 1 or 2 thou – more than good enough for my needs. I then drilled out to 8mm and bored the blind hole to final size but mostly to get the hole's bottom flat. All went well this time.

So the clear morale is that with a bit more care and thought, you can get a much better result!

It also leads to much more Happiness (as opposed to much more Annoyance, as per the first time around!)

IanT

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Alan ,

Bit confused by your private message and :

—- I've sent you 'select few' copies of the JJ Constable EW Slow Feed article, as I've finally had the time to dig it out myself and read it. You will be pleased to hear —–.

Don't mind either way but are my copies still needed ???

MW .

[alan smith 6Participant @alansmith6]

Michael,

Sorry for any confusion, as I couldn`t enlarge the copies sent by IanT, I would be grateful if you could send me your copies so that I can see the article full size,

I offered to send you copies of the drawings of my EW designs in case you had bought an EW.

Alan

[alan smith 6Participant @alansmith6]

V8Eng,

Thank you for adding a copy of the EW advert to your photo album. This offer of an industrial machine poses more questions than answers!

I`m sure that some of the other EWers are gagging to see this advert, would it be possible to post it onto the thread?

Best wishes,

Alan

[V8EngParticipant @v8eng]

All you EW fans.

Here is an advert from 11th June 1953 issue of ME, hope it makes interesting reading.

[V8EngParticipant @v8eng]

Sorry about the missing image in my previous post, hopefully I got it right this time!

 

Edited By V8Eng on 24/12/2012 18:44:56

[alan smith 6Participant @alansmith6]

V8Eng and EWers,

Looking at the description of the industrial version of the EW as seen in the advert that V8Eng kindly posted, the only difference between this version and the standard version is that the spindle or mandrel is chromed and the slides are longer than standard, how long it doesn`t say!

Chroming of bearing diameters is a normal repair method for worn bearing diameters. What happens is that the worn areas are turned down to minus 25 thou and then hard chromed to build up the bearing diameter to about plus 10 thou and then the diameters are ground back to the nominal diameter. This is a very effective solution.

When I stripped down my EW I found that the front spindle bearing was minus two tenths of a thou .0002". The diameter of the rear spindle bearing and the spindle pulley bearing diameters were absolutely nominal. This is a pretty good result for a cheap lathe but means, because of the front bearing wear, that the spindle material is probably not that hard.

Chroming the standard spindle would be a way of increasing the durability of the spindle.

For a serious lathe using cast iron plain bearings I would expect the spindle to be case hardened and ground to size.

I`m considering having my EW spindle chromed and re ground at a later date and if anyone else is considering this action, please remember that this is specialist work so that you will have to seek out the appropriate specialist.

I will be making patterns for casting longer slides with tee slots and will keep you all advised.

Alan

[alan smith 6Participant @alansmith6]

Ewers and bookmarkers,

The JJ Constable EW Slow Feed and Clutch

Just a bit of preamble before we cut to the chase; We have considered slow feeds for the EW designed by Martin Cleeve, Exactus, the unfinished design by Alan Smith6 and now JJ Constable who will be known as JJC.

All of these designs contain faults and it`s up to the reader to mix and match or modify them to suit their own particular needs. One problem is that the drawings and explanations provided by the articles leave something to be desired and JJC`s article is no exception.

It`s one thing to cobble up a design that works for you but would not satisfy the standards of accepted machine design and another to publish the design in a popular magazine where unsuspecting amateurs read and copy this design. I`m writing this in the hope that I can help the non engineer EWers to see the pitfalls of the design.

Now at first glance the JJC design is quite clever and has avoided the problems that Martin Cleeve imposed on us with his slow speed gearbox. JJC starts his article by explaining that he is a beginner and has no engineering background. The detail drawings seem to have been drawn professionally, perhaps by a female tracer who has used “UNO” stencils and Indian ink to complete them.

If we look at Fig 1 “the handle extension” and then at Fig 3, which shows the handle extension in position on the lathe, one can see that the configuration shown in Fig 3 is not possible, probably due to the tracer misreading JJC`s sketches.

In Fig 13 the gear train shown is diagrammatic only and does not show clearly both the lead screw in situ and the banjo extension.

If we look at the gear train by itself; JJC has designed it for this particular ratio only and if the ratio were to be changed, then the Banjo Extension (Fig. 5) would have to be modified or re manufactured to suit the new gear centres. Better to use the variable banjo suggested by Alan Smith6, thus any suitable gear ratio can be used without modification to the banjo. Also, the lead screw driving gear will be adjacent to the lead screw support trunnion on the lathe.

Looking at JJC`s clutch configuration, I`m all in favour of not cutting the lead screw to achieve the clutch design. Unfortunately I cannot see exactly how the clutch is actuated. There is a clue shown in Fig.9 where the dog clutch has a groove machined into the diameter; probably for a glut, actuated by a lever, which is not shown in the drawings or mentioned in the text. To have a lever in the position necessary to actuate the clutch would compromise the possibility of fitting a gear cover to the lathe.

The worst aspect of the design is the method of connecting the Extension Piece (Fig 10) to the lead screw which is achieved by means of a 0BA screw! This extension piece should at least be spigotted onto the lead screw to ensure that it runs concentric with it. I don`t consider the two pins on the dog clutch as being adequate to do this.

This clutch design could be reconstituted to be quite a nice one and I will certainly be having a closer look at it.

Those of you that have not been involved in design work professionally, please note that a design is based on ideas and it`s the norm to collect all the best ideas at that moment in time and incorporate them into one design. That`s the way the world has progressed.

Alan

[Sub MandrelParticipant @submandrel]

As the Chilean red suffuses into my veins this New Year's eve I am tempted to contribute on a subject beyond my competence. What happened? the words have gone all lopsided?

I made a leadscrew clutch for my mini lathe – irelevant? Perhaps? But I did it by a very simple expedient – the banjo in this case has an arctuate (good eh?) slot which permits it to be adjusted for different gears. I added a bellevile washer and an extended nut so that it can be set so the gear can be moved in or out of mesh and stay that way. I also added a simple arrangement so that a lever (which protrudes through a slot in the gearbox) can move the gears in and out of mesh, just by moving the banjo. A cunning (i.e. too complicated to describe in a state of partial; inebriation) arrangement means the lever can adopt one of three different positions to allow for different gear sizes. Result? A simple clutch that works for both fine feed and gear cutting BUT it does not keep the gear engagement like Gray's masterpieces as you can engage the gears at any relative position.

That said it does make it very easy to securely engage or disengage the gear train without any spanner wangling and probably could apply to any banjo-style gearbox.

Neil.

[alan smith 6Participant @alansmith6]

Neil,

When the euphoria brought on by the alchoholic cordial has subsided, please do give us a clue as to how you achieved your modifications by posting photos sketches etc. So that we can plainly see what benefits your ideas can bring to our humble characterful, pre-Chinese lathe.

Alan

[Sub MandrelParticipant @submandrel]

To my surprise there are a few pics in my albums:

The lver just pivots the banjo up and down on the end of the leadscrew bush.

You may just make out two of three countersunk screws that hold the device to the banjo.

The lines on the left hand part show positions where the handle can be screwed in to an outer ring and engage with the inner 'hat' shaped part.

You can see the tiny extended nut that adjusts the grip poking out below the change wheels.

The body filler is just to stop a bush made from hex material rotating in the bore. A kindly chap sent me some surplus plastic chnge wheels when he converted to metal ones so I have a proper one their now.

Neil

[alan smith 6Participant @alansmith6]

Neil,

It can`t get simpler than that!

In my last but one post I mentioned that a design may work for you although it doesn`t necessarily satisfy the standards of accepted machine design, and I think that this is such a case.

I`m interested to find out whether your idea will work with the EW and at this moment cannot see too many problems, except that the poor old gears may protest when engaging the drive at top speed. Perhaps the answer is to engage the gears when the spindle is at rest and, of course, the gears may be disengaged at speed with little or no protest.

I was in my garage in Oslo today, tidying up ready for reassembling my EW which I will do in the next couple of days, thankfully the outside temperature was only about minus two degrees C. I will carry out a test on your idea and also try to find a solution to the friction in my clutch design, as well as figuring out a practical improvement to the JJC clutch design.

Well it gets me away from Norwegian TV.

Alan

[Sub MandrelParticipant @submandrel]

At the very least it provides a way of stopping the leadscrew reliably without having to use a spanner or reach round the back to play with the tumbler reverse. It really is no different from putting the tumbler in neutral, but it is so much quicker and easier. It also speeds up changing the gear train a little.

I keep meaning to make a super-fine feed banjo with another 80:20 gear pair, to get ~1 thou per revolution.

Neil

[alan smith 6Participant @alansmith6]

I will also be looking into a finer feed for the EW which at the moment is about 6 thou per rev of the spindle but with a 1 thou per rev of the spindle it will be excruciating waiting for a feed to finish if in the lowest backgear ratio. Have a look at my photo albums which will give you an insight into the EW lathe configuration.

Alan

[AndyfParticipant @andyf]

I'm a bit late on parade here, and may be missing something, but am a little surprised by Alan's comment that "I`m all in favour of not cutting the lead screw to achieve the clutch design."

A dog clutch on the leadscrew has been in use on the similarly sized Cowells lathe for 40 years or so, and my Perris (which became the Cowells) has the same arrangement. It uses the heads of small Allen screws (described in Mr Perris's build instructions as "specially prepared" and about 4BA, I think) engaged in slots in a sliding bobbin to transmit the drive, a task which they have been successfully accomplishing on my lathe for going on half a century.

The first section of a two-part article by Tony Jeffree appears in MEW No. 198, describing fitting a dog clutch to his Cowells. It looks as though it might work on the EW too, if an additional plummer block is provided for the leadscrew.

This is a long thread, and if I have missed some vital point, please just ignore this post.

Andy

[alan smith 6Participant @alansmith6]

Andy and EWers

You are quite right. To use the politically incorrect saying "There`s more than one way to skin a cat" describes the situation.

Yes it`s a long thread and yes the Cowell can be easily converted to a dog clutch. It`s my fault that I proposed a design based on Martin Cleeves articles for a dog clutch for the EW. There`s no convenient place to fit an intermediate trunnion on the bed casting if the lead screw is split as in Martin`s design. I`ve cobbled up a prototype of my design and you can see this if you look at my photos. My intention is to split the lead screw but eliminate the extra trunnion but the design, as it stands, is not performing to my complete satisfaction and needs tweaking.

Recent archaeological digs have unearthed JJ Comptons design for a dog clutch which I looked at and found some possibilities in that we could eliminate the split in the lead screw by positioning the dog clutch at the headstock end of the leadscrew.

At the same time Stub Mandrel came up with a suggestion that warrants investigation so that now we have several lines of investigation to follow.

I will post a sketch soon.

Alan

[AndyfParticipant @andyf]

Yes, Alan, I see from your albums that, even if the bed casting were milled out to provide a seat for another leadscrew bearing block, there would be little room left between that block and the existing bearing at that end to accommodate not only the sliding bobbin for the clutch but also two collars to prevent axial movement of each part of the leadscrew.

Andy

PS Just to create a few more ripples in the pond, I see that the EW seems to have a solid leadscrew nut. So did my Perris, and moving the saddle any distance either by hand cranking or with the power feed was tedious because the pitch is 1mm (50 turns to shift the saddle two inches). The solid nut was bolted on under the front end of the saddle, so I replaced it with a little apron carrying a single half nut. No apron handwheel, but with the half nut disengaged the saddle can be pushed quite easily along the bed . I don't know why Cowells don't do the same; after all, they charge enough for their machines.

[alan smith 6Participant @alansmith6]

Andy and EWers,

When I started out on the EW designs my self imposed limit was that no modifications were be made to the lathe castings and any other changes would have to be re- instateable.

I had my first EW lathe at the tender age of 14 and had it for many years before selling it on and now in my dotage have another two EW`s. It`s a pleasure for me now, using my older head with over 60 years of industrial experience, which unfortunately comes with an older body, to create the modifications that I lacked the know how to do all those years ago.

You mention the half nut solution which was also proposed by Exactus in an article in the ME in the fifties and discussed earlier in the thread. I have some bound volumes of an engineering magazine "The Amateur Mechanic" published around the end of the 19th century and it`s incredible how many things that we consider as modern design are depicted within those pages.

I would personally forego the half nut solution for the EW as one would then require a screwcutting dial to cut threads which is not required with a solid lead screw nut and a clutch that engages in the same position every time. I have found that the EW leadscrew is very easy to operate and one can twirl the handle five times per second, that is approx one inch per 1.5 seconds, so that when screwcutting, the best operating technique is to disengage the clutch and rewind using the handwheel.

Alan

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