Optimum products?

[gerry maddenParticipant @gerrymadden53711]

Apologies, were we talking only about bench drills ? The original thread was about Optimum products in general which includes mills lathes etc

[gerry maddenParticipant @gerrymadden53711]

Posted by Ian B. on 19/10/2020 15:47:09:

……It is really a basic prerequisite of any machine that stiffness is a much needed criteria. That comes from mass in the bed casting……

Regards

Ian.

Edited By Ian B. on 19/10/2020 15:48:57

Ian B's comment above is correct but I would add that how/where that metal is placed is equally important. Good machine manufacturers should have the benefit FEA these days and should be able look at the structural stiffness of their designs and identify deflection 'hotspots'. This should allow them to move the metal to where its most effective and create a more efficient structure for no extra money.

More and more machines come with geometric inspection documents for flatness, straightness etc. We like this don't we ?!" It really wouldn't be a significant jump for the makers to put a mandrill in the spindle and do a two or three load~deflection checks too. In fact, they wouldn't need to do this to every machine they assemble. Its not going to change unless the structure changes. So a measurement of the prototype would be fine.

Gerry

[Bill PudneyParticipant @billpudney37759]

In 1964 when I was at tech school in the early stages of my apprenticeship, one of the lecturers was talking about basic machine design. On of the things he said remains with me today, "….there are three criteria for good machine design…..RIGIDITY, RIGIDITY and RIGIDITY". Try saying it three times, quickly.

Another thing, talking about the myth of European car manufacture.  I once knew a Senior Engineer (i.e. an ENGINEER not a technician), who said "If you want a new car and you don't buy a Subaru, Toyota, Honda or a Mazda, you are either bonkers, or you just want an ego extension"

cheers

Bill

Edited By Bill Pudney on 20/10/2020 01:47:26

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Bill Pudney on 20/10/2020 01:41:49:

In 1964 when I was at tech school in the early stages of my apprenticeship, one of the lecturers was talking about basic machine design. On of the things he said remains with me today, "….there are three criteria for good machine design…..RIGIDITY, RIGIDITY and RIGIDITY". Try saying it three times, quickly.

[…]

.

Although, in practical reality, the more relevant word might be STIFFNESS

Please see my posts here: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=107544&p=2

MichaelG.

.

Edit: …  noting [of course] that, in some circumstances, the difference between RIGID and VERY STIFF might be considered negligible.

Edited By Michael Gilligan on 20/10/2020 08:25:11

[LathejackParticipant @lathejack]

As well as Optimum there was also another Chinese/German brand called Quantum. The Optimum and Quantum hobby lathes that I looked at some years ago were good but didn't appear to be particularly better in terms of the machining and fit of parts. The equivalent Chinese machines from the main UK branded suppliers are just as good, allowing for the odd lemon of course, which you can get from any brand of Chinese made hobby machine tool. A Chinese made SwissTec 10X22 lathe I also examined was certainly not any higher quality.

I can recall a conversation I had several years ago with a UK supplier of Chinese lathes and mills. He told me that on one of his visits to the factory in China he asked the owner if he could have his own inspector there, the factory owner put his arm around him and replied " Of course, you can have as many of your own inspectors here as you like, but we will corrupt them"

 

 

Edited By Lathejack on 20/10/2020 21:55:28

Edited By Lathejack on 20/10/2020 21:56:10

[Bill PudneyParticipant @billpudney37759]

MichaelG wrote "Although, in practical reality, the more relevant word might be STIFFNESS

Please see my posts here: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=107544&p=2

MichaelG.

Edit: … noting [of course] that, in some circumstances, the difference between RIGID and VERY STIFF might be considered negligible."

Thanks for that MichaelG. I was aware of the small difference between Rigidity and Stiffness, but as I was quoting it seemed reasonable to quote accurately.

cheers

bp

[Tony Pratt 1Participant @tonypratt1]

I had a Super 7 for 45 plus years, lovely m/c but 'limited' now with my son. Now got a Warco 290v [is that a Weiss?], cost £3300, it's build quality is as rough as a Badgers a**e but it is such a capable m/c, I threw the crappy gear train away & fitted an electronic lead screw, what a bonus!

The new Myford super 7 ['British engineering at its best'] is the wrong side of £10 k without tooling, I hope for that price it really is made in Britain?

The choice is yours dear reader, but if I was looking right now the Boxfords look value for money.

Tony

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ian B. on 21/10/2020 07:57:55:

[…]

… how many of the posters here have ACTUALLY had experience of Weiss products and various badged and liveried versions and have actually bought and used them?

All Chinese product has its problems and horror stories. I know horror stories from long standing fellow hobbyists about the much vaunted and very overpriced Myford product.

I have never owned any Myford product, never intend to do so. And this is the first comment I have made about them because I have no personal direct experience.

.

I am outwith that set Ian, and have therefore made no comment about the actual machines

I have merely responded other posters’ comments about technical assessment and design.

I do however, wonder how you can justify suddenly declaring Myfords to be ‘very overpriced’

[ ‘though I would consider any further discussion of that point as inappropriate to this thread ]

MichaelG.

[Alan AmbroseParticipant @alanambrose45980]

Well, before we get too deep into, brand wars

Thanks everyone for your thoughts & knowledge. The info re which factories / what happens in China etc are interesting. The discussion helped my understanding and changed my mind about a few things. Given I have a little mill that has been CNCed, my leaning atm is to buy a smallish lathe to get to get to grips with and then convert to CNC and then buy a bigger lathe and miil as manual machines. Yeah probably Warco and/or Optimum.

Alan

[VicParticipant @vic]

I read a short piece some time ago by a guy who worked in China, that they like to save money whenever possible and will not replace measuring equipment like temperature probes etc as often as they should. As a result basic materials like steel and iron may not be up to specification. Obviously if the material is for critical engine components etc then hopefully it will be properly tested before too many components are made from it. I somehow doubt this happens for things like hobby machines though.

[Neil WyattModerator @neilwyatt]

Posted by Ian B. on 21/10/2020 08:04:07:

Oh and I notice from an earlier post I wa not quite definitive in my comparisons. Hence:

Chester Conquest 14" between centres weight 42 kilos.

Warco/Weiss WM180 12" between centres weight 63 kilos

Colchester Bantam 20" between centres weight 499kilos

(Latter partially stripped for moving house twice).

Hope that clarifies the stark reality and differences.

Regards

Ian.

Deflection of a beam varies as the third power with length.

Taking the ratio of centre distance to the power of 3 to overall weight makes the differences much less dramatic:

65:27:16

OK that's a crude measure, but a first approximation it's reasonable – especially as I haven't made any reduction for centre height. Note also that these machines are not intended to perform the same duties (and also that a large part of the weight in the colchester is in its stand).

Edited By Neil Wyatt on 21/10/2020 18:32:20

[Alan AmbroseParticipant @alanambrose45980]

Nice Just for grins, I've been calculating cost/Kg of various lathes & mills I'm getting numbers generally between 10 & 20 £/Kg.

Maybe cost / specific stiffness next (never mind the quality)?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Alan Ambrose on 22/10/2020 13:26:17:

Nice Just for grins, I've been calculating cost/Kg of various lathes & mills I'm getting numbers generally between 10 & 20 £/Kg.

Maybe cost / specific stiffness next (never mind the quality)?

.

Today’s scrap value for Iron is about nine pence per Kg

… so now you can work our what manufacture and distribution are worth, and guess the profit margins

I would like to think that the skilled labour and/or high precision machining centres represent a significant portion of the purchase price … but who knows ?

MichaelG.

[Dave WoottonParticipant @davewootton]

I didn't really want to get involved in any arguments, but, as a long time user of Colchester and similar industrial sized lathes, both at home and at work, I thought I would add just a few comments based on experience of using a Warco GH1322 lathe in an industrial setting over a period of over five years. probably 15-25 hours a week on all manner of work, most of which would equate in model terms to that involved in a large scale traction engine.

I reacted in horror when told that I was to be put in a satellite workshop newly equipped and on turning up found a Warco lathe and Bridgeportish clone mill. Despite my protestations I found after a couple of weeks I liked both machines, they were capable, accurate and rigid. Lots of screwcutting, press fits, intermittent cuts on fairly lumpy castings and fabrications the Warco coped with it all. the three jaw chuck was as accurate as any and was still good when the place closed down in April. So despite not being as well finished as some, it did the job under difficult conditions, always someone asking how soon can we have…..

Not wanting to start any rows but I did want to point out that these imported machines, may be lighter built and not as well finished, in my experience of this machine it actually did the job, which in industry is what matters.

I worked at a firm in the early 1980's that took my war finish big old Holbrook lathe and replaced it with a new Colchester Triumph, The Colchester could never achieve the finish of the Holbrook, I missed that lathe terribly.

I think I'm reasonably unbiased I've got a Bantam 2000 at home.

I'll go and put me tin hat on!

Dave

Edited By Dave Wootton on 22/10/2020 17:20:08

Edited By Dave Wootton on 22/10/2020 17:20:42

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