Quality issues with a SIEG SX2.7 mini mill

But all those Ha'porths add up.

All ways and surfaces to be hand scraped, add in heavier gears, higher quality circuit boards, another 50kg of iron and it WILL go on the price.

More expensive mills are out there like Ceriani and Webaco which are said to have a better build quality and demand a higher price but demand is far smaller. Even with the reasonably priced far eastern machines from our suppliers there are plenty of examples of hobbysts wanting to go direct to China to save a few quid more on machines that may very well be built to even lower standards.

Apart from John Mac's comment I have still not heard anyone suggest what is Acceptable accuracy for a hobby machine in these price brackets, anyone care to put their neck on the line. John Mac' suggested an accuracey of one handwheel devision in which case that slot at 0.01mm off was well withing the 0.02mm dial divisions, just because someone may stick a 1micron res DRO on there machine they should not expect it to suddenly work to 1 micron.

Is a person working with surface ground finishes and measuring with slip gauges just expecting too much from a Hobby machine in this price bracket?

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Ok. Dave. S.O.D.

Tell me where do I buy the Precision Mathews equivalent 9/35 mill, which is made in Taiwan, here in the Uk. As far as I can see nobody is importing Taiwanese machines. Which would be a good half way house in terms of quality

I have a similar lathe to you which is now ok with some work. My super major mill however, which is Chinese garbage which cost me over £3500 with dro was money down the drain. the Test sheet was work of fiction.( and it had nothing to do with the distorting casting red herrings etc.) If I just wanted to put a few electronic components in a box a drilling machine would do.

A recent poster has just paid £3650 for the vario super major which was clearly badly machined and not fit for purpose, for the most part all his posting got for his query, was criticism of his measuring technique, most unfair. I would be quite upset with the response he got. He deserves better.

Anna

Anna when questioned as to which of two measurement methods the poster had used he replied to using one method yet showed photos of the other method. Without seeking clarrification of how the results were obtained how else could people offer their views on what his machine was like?

The reason people buy Chinese is they are 'value for money' and - for many purposes - 'fit for purpose'. Has anyone ever proved by turning a mild steel rod to size that a Super 7 produces more accurate results than a mini-lathe? No. The Super 7 might do the job faster, but with a little care a mini-lathe will produce an identical result. For many people that's plenty "good enough".

Dave

I bought a second hand Clarke CL500M, which to many is the lowest of the low in the mini lathe world, and dont regret a minute of it, I manage to make parts for my stationary engines to the required tolerances required. I've had to tinker to make the lathe how I want it but working on machine tools is what I did in my working life, it cuts threads albeit a little fast and can produce a good finish when needed. I go to exhibitions and look at nice shiny new lathes and think can that do any better than my lathe at home.

Martin P

Anna, you might try XYZ Machine Tools their manual mills come out of Taiwan and also have the original makers "M" cast into them which can also bee seen on the PM machines though I think they start with the 9x42 table size.

Chris, with the production of hobby machines there is always a compromise between cost and quality. To build a machine of high quality inevitably means a high cost to the customer, as I explained, to reduce costs the main castings are designed using the least amount of volume of cast iron that will achieve the physical envelope required, this means that the castings once machined are nowhere near as stable as those of commercial quality machines. The designer has worked to his brief to design for production within the cost envelope, this means that in all probability the castings will relieve internal stresses once they are machined, this is not to say that there is anything wrong with design or manufacture this is an expected consequence of minimalist designs. The equipment manufacturer would be aware of the consequences of this process and would, in so far as costs allow, build the machine and where possible adjust the components to minimise the errors. It is rarely possible with these hobby machines to produce a unit with zero errors, this means that machines in this price range may well have errors. Whether those errors render the product to be not of merchantable quality is dependent on the use to which it is being put, if the end user requires a machine capable of consistently holding very tight tolerances then a hobby machine is not the way forward they would require a commercial quality machine. Hobby machines are built to a strict cost and are offered as hobby machines not precision machine tools. We all obviously want the best machine for our hard earned cash but we must remember there is always a compromise of quality over cost and in choosing a hobby machine we have chosen cost over quality, I am sure that the overwhelming majority of hobby machines sold are deemed of merchantable quality, they are what they are and built to different standards than expensive commercial machines, we as the end users have to accept that they will not be the same quality as their expensive counterparts. Dave W

Hello Jason

Thank you for xyz machine tool pointer

Regards

Anna

Well thank goodness for Chinese hobby machines is what I say, without them I wouldnt have been able to make a start, I dont have the money or the space for anything bigger or better.

Yes they have their faults and limitations and even as a beginner I have come to recognise and accept that. I have done a few mods and upgrades on both the lathe and the mill in an attempt to improve them but straight out of the box they worked and worked well. I think they are great value for money and you cant expect a Rolls Royce for the price of a mini.

The question of how accurate hobby machines need to be, well mine have produced all the parts I,ve needed so far with some down to quite tight tolerances so I could argue that my mill and lathe are accurate enough.

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Problem is that a milling machine is usually a once-in-a-lifetime purchase. So a bad experience does not alter future behaviour. The buyer was never likely to buy a second mill anyway.

Although imported machinery is cheap it still needs quite a lot of hard earned money to buy it. Expecting Aciera or Schaublin quality at Asian prices is unrealistic. When you sit back and think what you get for what you have paid you are not doing to badly. As you have bought cheap you are going to have to put in some effort or money to reach your expectations of precision. When you have fettled the unfeasably cheap machine to an acceptable level you will be quids in compared to buying a top quality machine. As we are obsessed with the lowest price it is unreasonable to expect the highest quality, it would be interesting to see how the price rises if the specification was improved, I suspect the Asian suppliers could provide very good value for money but at the end of the day quality does cost money.

Mike

Not at all Hopper. I originally bought an SX2P, which I subsequently sold to Ron Laden. He, as I before him, realised it's limitations, but within those limits is able to produce perfectly adequate machined parts, as he as reported up thread. I have latterly purchased an SX2.7 which does all I want of it to perfectly acceptable tolerances. There does seem to be more than a hint of people wanting a Bridgeport for buttons, which is of course impossible, the simple answer is if your unhappy with what's on offer, be prepared to spend a lot more, or conversely if you think that £1200 or so is going to buy you a high precision tool room machine, don't be unduly surprised if it doesn't deliver. At the end of the day the skill of the operator is always going to be more important anyway.

Martin

All Credit to you Piotr for starting this conversation.....

And to all the other contributors too. Reading between the lines there is clearly an undercurrent of dissatisfaction, The comments have be based on actual user experiences not just rhetoric, and better still no flaming or invective. Genuine concerns explained clearly and politely. Democracy at work.
I rather hope some of the suppliers are also watching, If I was one oth them I would be thinking how I could improve matters before the weight of public opinion started impacting on sales.

Regards
john

Interesting conclusion, I've just been back through the thread and taking those that have actually said they have chinese nachines i get those against 3 (Piotr, Peter Shaw,Anna) those happey with their s 4 (Martin Shaw, Martin P, SOD, Ron) and you know which way I feel about my X3

have the original makers "M" mark cast into them

I was told that the "M" mark signified that the casting was Meehanite, not a maker's mark.

XYZ import (or have imported - they have been doing so for a while) Bridgeport type machines from at least two different makers - when looking for a manual on their website to order spares for our XYZ KRV2000 there were two makers of turret mills to choose from. The KRV is made by "King Rich" IIRC. Decent machine, but a bit big for my garage.

Nigel B

If you are going to use jacking screws then there was little point in flattening the mounting plate as the jacks will adjust out any errors on what the mill is stood on.

Unless the base of the casting is as flat as the plate then as soon as you bolt it down to the plate which ever is more flexible will move.

FWIW the SX2.7 I have here just sits on a length of laminate kitchen worktop on some old draw units and my X3 sits on the provided adjustable feet. The KX-3 I have just got has similar adjustable feet which I will be using. My personal thinking is that they are not bolted down when assembled and "adjusted" as far as I know.

Michael your thoughts would seem reasonable and are why I said that someone working with ground surfaces and gauge blocks to make tooling would probably be expecting too much when you think that a half decent grinder should be able to work to 0.002mm

Edited By JasonB on 21/02/2019 11:16:32

Are not model engineers FITTERS too. Bore a hole and machine shaft to fit, mill a slot and machine slide to fit. If you want make 100 off with guarantee interchangeability then you would need high end machine. i have made lots of model engines from wobblers to internal combustion and traction engine too, and not ever really check the accuracy of my Chinese mill or lathe, but all my models work. Get some pleasure from your machines

I don't know what reputation this chap enjoys among members of this forum, but I found this YouTube video about tramming a column-type mill very illuminating and it offers perspective of what we might expect from our affordable equipment. Stephan Gotteswinter

As Andrew Johnston and probably others, accuracy depends on what you are trying to achieve. I was a machine tool designer for most of my working life. The accuracy required by any machine and fixtures. most usually there where more than one machining station and hence multiple work holding fixtures, was required to be a percentage of the produced component drawing tolerance. For those who like reading look up Sigma tolerance analysis. Machines were built with spacers and setting blocks to enable tweaking of position. Here of course I am talking of one off special machines.

European and USA designed standard machines were/are built using special machines in some cases to achieve part tolerances which when built into the final assembly achieve their standard tolerances. These machines in most cases where heavy cast iron floor mounted machines, built like the proverbial house. Over the last thirty years the CNC machines have largely took over where multiple hand operated machines stood, but these are still heavy duty machines. All these machines are built with the ability to achieve a final accuracy check, which may require a part to be re-machined or reset to achieve this.

Our hobby machines, I use a Sieg SC3 lathe and a SX2P which I bought three years ago, new. Both machines have been partially stripped for one reason or another more than once, and some improvements (as far as I am concerned) made in that time. But other than checking tailstock alignment, I haven't bothered with any other accuracy checks. Once you start chasing microns as a hobby machinist you would be better to walk away and find another hobby, you will never be satisfied. The drawings from LSBC or whoever have no tolerances, so if two bits fit together and look about right then that is it, What ever we produce is a kit of parts which with varying degrees of hand fitting may produce a finished working assembly. Alright in the past model engineers probably got a few of the more accurate parts produced on the side at work but they also had less accurate machines with no DRO, but any of these where probably time served indentured engineers. Work with what you have and strive to achieve the fits required by thoughtful processes.

Would I have done anything with this SX2.7, probably. If surface finishes are poor between two sliding faces then I would try to improve it. But if column squareness creates a problem on a machined part then is it the right machine process. Could the part be processed some other way to achieve a better end result.

If anybody wants to start up a UK manufacturing facility for designing and building hobby size machines then I am sure Ketan would support them so long as prices where compatible with our purses.