Satisfaction.....

Little wonder:

:-)

Ha, ha well done Tom, just shows what a bored and tired mind is capable of, or not as the case may be! Still a messy machine covered in butter is better than having these inaccurate machines "breeding" everywhere. I'm sure there must be a law against the procreation of the inadequate.

Regards

Less bored of Wales

Boxford and South Bend both succumbed to such a law.

Regards Not enjoying an English summer.

Some real data at last - thanks. Numbers are interesting not only for what they say, but also for what they don't. The Schaublin may only have guaranteed that figure, but the production processes to maintain that spec means that most examples would have been be far better, some perhaps by an order of magnitude. The Boxford specs were quite a bit lower to start with, even if some got very good reports on a good day. If you look at the way the Boxford headstock is bolted down, for example, variations in the tightness of either of the two clamp bolts could add up to a tenth or more variation at test bar end. And, as John inferred in another post, 5 years hard work down the line and the Boxford might be quite a bit less accurate than it's original inspection figures and would need regular checking and setup to maintain accuracy.

The sort of thing i'm trying to find out as well. I realise that this stuff is pretty irrelevant and tedious for those working in the business everyday, but I like to get skilled up and do a bit of research, so I know what i'm dealing with and why. It adds to the knowledge base and is a good defense against getting saddled with a lemon. So, I guess the enquiry still is: what makes a good precision lathe ?.

Also been trying to find a copy of the Schlesinger Limits book, but the only one I could find so far was on a booksite at 100 ukp, which i've blinked at for now. The northerner in me says I should be able to find it for 10 if I look hard enough :-)...

Chris

What is it Tom ?, someone stolen your long wellies ? :-)...

Chris

You really are quite anti brit aren't you ?. Tell me, what did nz ever produce, other than sheep and butter ?.

Overall, i'm very, very disappointed :-j. Here you are with one of the reputedly finest lathes that money could buy, (Well, 50 years ago anyway) and you seem incapable of telling us anything about it, other than it's weight. If I had a machine like that, I would be all over it, how it worked, design features and weaknesses, original spec and what state it's in now.

What do you actually use it for, other than for decoration ? :-)...

Chris

One other probably tedious and irrelevant factoid: The Cromwell lathe co claimed that if two random beds were put back to back, the variation in flatness between the two would be 1/10th or less over the whole length.

Quite impressive for a 50 year old machine and most likely pre optical inspection methods as well...

Chris

Chris

I'm struggling to know how to help, you asked for some figures on what makes a precision lathe and I've quoted DIN8605 for toolroom lathes and figures from Schaublin (albeit for mounted work runout) which I believe very few would argue are makers of fine precision lathes. You are correct in saying that most of their machines would be better than that but it gives an idea of the range of possibilities and what they are actually prepared to guarantee. I also have failed to find a free copy of the Schlesinger Limits on line and unfortunately no longer have access to one but I doubt that Shaublin would be claiming their machines were outside of them.

If you are actually looking for figures from our own lathes or those of the lucky few people who can afford the "real deal" then it becomes difficult as most home workshops are not equipped to measure accurately to those levels. I have a couple of very fine Starret DTIs and cannot measure any (unloaded) runout on the spindle registers of any of my 4 lathes (Boxford, Warco 2 Myfords), but that doesn't mean that I would claim that they are all perfect, just better than I can measure. Obviously, any bearing requires clearance to operate so if you load the spindle you will get some movement. In fact, the older of the Myfords gave me a chatter problem for a while and I took the spindle into our metrology lab for them to measure. Their figures over the length of the spindle were within a couple of microns and they actually mentioned when I picked it up that they were impressed with how straight and true the spindle was.

As several have alluded to before, if you can really measure, for a quality lathe, 2 tenths on the spindle register surface that is a fair bit and requires a little investigation. In my experience it will either be the obvious, bearings, or some out of round caused by a clod polishing out the odd mark caused by chuck fitting over the years; maybe even a bent spindle. From my Aerospace experience shafts that are straight initially may not be so 25 years later even without any damage. To be honest I would be much more interested in any runout on the internal taper than the outer surface which is prone to minor damage.

The real "precision" in turning is provided by the guy operating the handles, as you quite rightly said before superb work can come from the most unlikely machines if the "craftsman" using it is worth that title. I'm no expert in helping you to avoid a lemon but after 25 years of lathe buying I would be put off by any lathe spindle that showed repeatable .0002" runout on the spindle register unless I could see the reason for it. Having said that I did buy a well used Taiwanese lathe that had a runout problem, that was cured by replacing the bearings with reasonable quality ones (not the most expensive) and ensuring the bearing seats and tracks were spotless prior to assembly. Again, after this, I could not measure any unloaded runout. If you really want to see what is available these days have a look here:

Also have a look here for a more traditional toolroom lathe:

You will see that they quote 0.000025" for the maximum spindle runout (TIR) and as I said you would be lucky to find anyone who can measure that at home.

One last "rule of thumb" before I shut up is that your machine should operate within about 1/3rd of the total limit for the work you require to do with it, so if you want to turn repeatedly to within 0.0002" the machine needs to position within 0.00007". As far as I know this is not specified anywhere but it was what we used to define required machine accuracy for specific tasks in a non climate controlled environment. It does show why "precision" can be just a little expensive and I am astounded at the levels of accuracy we can now buy for a few hundred pounds.

Regards

Keith

Like women and good wine eh ?. Get better with age :-)

Typical tolerances / limits on the Boxford spec sheet show eccentricity and runout, 4/10th's. Axis parallel to bed, 0.001 per foot. Cross slide orthogonality, 0.002 across full slide range. Axis of centers parallel with bed, 0.002. Looks like typical inspection figures were about half these values.

Not the best, but there again, they never claimed to be. Perhaps the figures you're thinking of indicate how much machines have improved in

50 odd years...

Chris

Keith, don't worry and without disrespect to others, there's more usefull data in those two posts than the rest of the thread put together. Have just printed out for future reference. Again, many thanks for the input.

I guess the idea is to build the big picture - There's a lot this kit around and prices seem to bear no relation to true value or quality. For example, there was a late Smart & Brown Model A, 3 and 4 jaw chucks and faceplate, full set of 40 collets and original manual on Ebay recently. Hardly a mark on the paint and the vendor said no wear and that it was ex Marconi toolroom. The only iffy thing was half assed conversion to single phase electrics, but it made 570.00. A few days later a perfectly bog standard looking Boxford A went for over 700. As you say, you need to be carefull and the plain bearings might be a problem, but was sorely tempted by that machine.

I wonder if interest in machine tools becomes an obsession if you are careless. If so, let's hope there's a cure :-)...

Chris

You don't need to be careless - it just creeps up on you, and there is no known cure! I had estimated 26 tons for 'capital machines' (ie discrete chunks of machinery) for my house move, but to that I now have to add approximately 30 pallets stacked up to 6 foot high where possible. It's estimated it'll take a hi-ab equipped flat bed with a clear 20 foot of bed 5 or 6 days to shift it all. Moving the house contents is a doddle by comparison, though actually costing about the same !

Stop NOW while you can - say NO !

AWEM

Chris, I've often contemplated the same anomaly which is repeated constantly, IMHO the cause is a mix of factors which seem to be important to the "new" home workshop collector. Size and Weight is important as most either don't have sufficient room to accommodate large lathes or can't handle the weight. This of course works inversely, the larger, heavier machines being the cheapest. An aligned factor is the capability/size/weight ratio and here your S&B scores very poorly, while a superb machine it is incredibly heavy and large for its relatively small capacity. Many of the new import lathes have greater capacity (on paper) and they can be lifted by one man. Another factor I see as relevant is the costs of parts and accessories (often missing) and of course their availability. Here the likes of Myford and Boxford score very well as they are everywhere and have been for

50 years and the new imports do well as they are so cheap. Cosmetics also seem to play a part and people fail to look beyond the paint and a little oil to see the actual mechanical state of the machine; often on the larger heavier machines that were designed for 24/7 working they can be superb even after 30 years use. As you have highlighted the 3 phase electrics still have a huge negative impact, not really understandable with the VFDs etc that are available today. Lastly, I suggest versatility is important for many, while in pure turning ability the S&B will outperform the Boxford easily, with a few additions (long Tee slotted cross slide etc.) they can be used successfully for a bit of milling. I may be a little biased as I own one but the Boxford AUD still seems to be a bit of a bargain, a good one is definitely a fine British product capable of hard work with a reasonable capacity. At the same time it takes up less room than a typical Super 7 particularly if stood against a wall. Spares are plentiful and cheap but of course it suffers the problem of all secondhand items, you have to choose wisely as there are plenty about that are worn out.

One thing that I find interesting is that although still terrific value compared with smaller more popular machines the larger toolroom equipment is actually slowly becoming relatively more expensive as more home engineers realize the potential of a "real" quality lathe. Some 20 years ago I stupidly turned down an S&B A in superb condition, fully equipped and straight from an MOD establishment where it had decorated the corner of a prototype workshop, the price being asked =A3150?? Exactly the same issues can be seen with milling machines. Although I went for a Bridgeport I would have had a much better machine for less money if I had been brave enough to go for an Ajax or similar. I suppose we live and learn.

I'm sorry to say that once "research" has reached an advanced state it is already too late for any cure to be effective, the obsession can grow in a number of ways. Some collect on size (bigger the better), some on numbers (more the better) and some (look in the mirror here) chase accuracy of two tenths of the hair on a gnats a** or preferably better. Of course, as you will see on here, many unfortunate souls are stricken with all three variations....................

Regards

Keith

LOL. I would hazard a guess that I seen more of Britain than you have, hold a UK passport amongst others and have a greater appreciation of things British than yourself. However I'm not enamoured with those who tend to disparage anything that wasn't designed with the aid of a computer or consign anything made over 50 years ago as something that was created by some black art, that includes myself, btw.

Tell me, what did nz ever produce, other than sheep and butter ?. >

New Zealanders, give it some thought.

Excuse me? I can't remember anyone requesting details nor can I remember quoting my lathe's weight. I suggest you pay more attention to facts rather than your opinions. If proffered at this point in time, taking your present disparaging attitude, any details proffered, would like casting pearls before swine. >

Yeah, but you're one out of the box, aren't you Chris? Some of us are shy, modest and unassuming, that's the New Zealand way.

Well, being as I'm a New Zealander: Spinning wool, spit roasting the odd hogget, driving the milking plant, churning butter and ensuring that the cheese rounds have a reasonable degree of symmetry. Most importantly, it winds the ss tubing for the beer coolers. Really necessary in OUR summers, beer coolers, otherwise the beer just plain evaporates.:-( I mean to say, what else would you possibly use it for?

Tom

LOL, just as well Braille had been invented by then.

Tom

Britten motorcycles. Built in a garage by a genius (John Britten) in Christchurch with a home made casting furnace, and beat the best in the world. THen of course there was Bert Munro who took alterations to a 1920 Indian to another level.... Then of course the computer you are using relies on chips made in machines by Buckley Systems (who also made a motorcycle - a 500cc GP bike). A few kiwis play aroudn with boats as well. And we have the largest dairy factory in the world - which makes butter and cheese. Geoff

Rugby players?

Mark Rand (in Rugby :-) RTFM

You obviously know me better than I do myself, but one of the reasons for getting the workshop a bit more together is to provide a foil for the more cerebral work. Every man should work with his hands and keep interests and skills as broad as possible, especially with age. "If you don't use it" applies to what's between the ears as well.

Sorry, but if you give someone a hard time, you must expect the same in return, especially from a 60's mentality bod with a past living in Gods Own County :-).

Someone else mentioned rugby team, which would be the first thing on my list as well, even if i take little interest, but the next thing would be the help we had in WW1I and no, i'm not old enough to remember it, but am old enough to remember the immediate aftermath. 3 score years in May in fact, but still have a passion (if that's the right word) for any thing to do with engineering. To put the record straight, the initial involvement with this thread was one of enquiry. If you work in any discipline for any length of time and you love your work, you can't help but develop critical facilities and i'm sorry, it's not good enough for someone just to tell me that something is better. If it is, it should be possible to at least describe what is better about it. In the case of a machine tool, it should also be measurable, or in a spec somewhere, describe ergonomics, establish a baseline, whatever. The interest was essentially: "what was special about the high end machines of the time", and perhaps more interesting to me, what design techniques were used to bring this about ?.

The comments about "throwing metal at it" might have been a bit tongue in cheek, but engineers of that generation should understand. What I was implying was that the world of design was very different in the 40's and

50's. They had far fewer time saving design tools and had to rely a lot more on highly skilled labour, experience and good judgement to get results. That's not denigrating them (just the opposite in fact) and doesn't mean to say that they did no math, just that process was different. Aviation is a bit of a special case, in that they were one of the first industries to adopt computers for stress and strain calculations, so not typical. I may be wrong, but this is very different from modern practice, where everything is worked out to the minutest detail before even cutting any metal or whatever. Although my work involves computing, (well, quite a lot in fact) it's still engineering to me and i'm dismayed by just how much has been lost in terms of the old skills. It's perhaps why I'm really only interested in the older, non automated machines for my own workshop. Preferably uk built, though there are a few european and us machines that look interesting as well.

To anyone who might think that experience and previous knowledge isn't important, what do you think happens when you sit a grad fresh out of engineering school at a cad station, no experience and tell him to design a lathe ?. Reinvent the wheel, ad nauseum, that's what, and is effectively what's happening in a lot of industries now.

Right, you start off from a position of assumed superiority, judgmental, carping criticism, already made up your mind etc. Just the sort of thing that's red rag to my generation. You really can't expect anything other than quid pro quo in return. Really Tom, if you are anything like as old as i am, you have to guard against the "hardening of the attitudes".and continually re-examine your assumptions. Hardening is a naturall process that comes from seeing too much of life, but it can be cured :-).

Ok, and some of us are brash, outspoken and clumsy from time to time. Are we done with this now ?.

Let's lighten up a bit and bury the hatchet. Then we can get back to talking about something more interesting, like machine tools, for example :-)...

Chris

Cutting the crap:

To put it succinctly you took exception to the following which I posted:

"I really think your idea of fitting them to a Boxford is a bit OTT."

"Them" being tapered roller bearings to fitted to both cross-slide and top slide spindles, instead of the usual convention of 3 piece ball thrusts.

So using "standard off the shelf bearings" and the SKF manual as a reference, The following data is for the range of bearings that are of a size that could be used in the application. For any particular inside diameter, only the bearing with the smallest outside dimension is listed:

d = inside diameter D = outside diameter H = assembled height C = dynamic basic load rating Co = static basic load rating T = assembled height (cup & cone)

Thrust ball bearings (metric) Single direction:

d D H C Co Designation

10 24 9 8710 6800 51100 12 26 9 9040 10000 51101 15 28 9 9360 11200 51102 17 30 9 9750 12200 51103

Taper roller bearings (metric) single row:

d D T C Co Designation

15 42 14.25 21200 12700 30302 17 40 13.25 17900 11000 30303

Before you start bleating about metric vs imperial bearings, just remember that cost has been your whinge throughout and metric bearings are akin to your persona.

As for being OTT, I stand my ground or metal, something you won't have when you go to do your alteration. Then you'll be bleating about the paucity of cast iron those old engineers specified for their various castings.

40-42 mm OD LOL Of course you won't get it, being a Pom, it's only Brits who have a sense of humour in your neck of the woods.

Tom

Explain. Or have the tablets run out again?

Mark Rand RTFM