Manufacturers have process tolerances and a final functional tolereances. The final functional tolerances on a band saw are such things as blade tracking,radial and axial wheel runnout, wheel balance, table flatness, slot alignment, blade speed, arm deflection under tension, motor power characteristics, overall run vibration, table tilt accuracy, etc...
Good manufacturers check most of these things on every saw. Hitting one out of a thousand would put them out of business in a hurry.
The process tolereances and the philosophy for gettting them are what insures meeting the functional expectations. Or not meeting them in a statistically relevant manner.
All the above, quite likely
Five better than one, but still doesn't result in a statistically relevant sample for a capability study. Better to send the tester to the assembly line and observe the final tests, the number of failures that are set off, and what is done about them.
All true and don't disagree to varying degrees w/ any of the above points.
The point is, of 14 saws in the sample, point estimates for two for alignment of wheels wasn't all that great. Now, whether that is significant functionally is another question not addressed specifically.
Given the two manufacturers whose saws were the two in question, I found that a most interesting observation in as they are two normally considered as "better" than the run-of-the-mill imports.
While a sample size of five is certainly small, the results would certainly be indicative of the variability in the underlying process and would go a long way towards establishing what could be expected by a prospective buyer contemplating a future purchase of one of the subject machines. And, given that few, if any, of us here or in the general readership audience of FWW are going to be able to go and observe the actual operating line quality control data from any of the manufacturers, it would certainly be far more than we know now (or are likely to know in the future).
Again, it revolves around the product review "game" -- much of it is no more than that--guys want to write a story and need something to put into it to make it appear worthwhile...
Yes, I'm aware of that -- he has lots of inside info that the general population don't -- but I have a lot more experience in manufacturing than _he_ may think as well... :)
We were not discussing the general readership audience but the testers/writers representing the various mags. At my place they had an open invitation to come whenever they requested, and often did. However, none spent a week on an assembly line observing units coming off and collecting quality data. Would be an eye opener if that were done on a comparison basis. I would have welcomed it.
And I think that it would be more fun to test a bunch of units in the lab, and quicker to get the results and go to publication.
Back in the late eighties early nineties, I believe it was, FWW did do an article on each of the major manufacturing plants, comparing processes and technology. Somewhere, I have reprints....One manufacturer stood out for technology, cleanliness and impressive process control. "like going on the set of Star Wars", I believe was the quote.
Sadly, that plant is no longer in business, nor, I think, are any of the others that were in the comparison.
While sometimes I would question whether a particular functional judgement was weighted properly in the larger scheme of things, I've found the tester/writers to be very knowledgeable, competent and fair.
My comments had to do with the presentation of a single measurement to the world through the vehicle of a review of a sample of products based on the measurements taken from that sample. Those are the only data available to the person reading that article other than some they might take (if so equipped and inclined to do so) on a similar piece of gear of their own.
In that respect I questioned the validity of the apparent conclusion which can be inferred would be drawn by those readers that the data reported are of value and importance and imply a real difference between the machines themselves that has some bearing on the selection of one over another for a prospective purchase. Otherwise, what is the point of even making the measurement or reporting it other than to have something to write in the article?
I don't doubt either of those although it would undoubtedly have been in the first enlightening and in the second, worthy of discussion and in reporting. I would doubt though, that the invitation would have extended to allowing them to publish those data... :)
Which is what I was driving at. If the vendors would supply the manufacturing tolerances for the measurements the reviewers thought of interest and value and those were published as a reference, _THAT_ would be of real value, far more than an individual number. Lacking that, the best they can do would be the data from the individual machines. And, of course, what that leaves out is context of where is this particular measurement in the overall range of tolerances?
And, of course, there is very little serious evaluation in most reviews at least of what these measurements _really_ mean in a quantitative sense of how the machine actually will perform on a comparative basis. That is where a really knowledgeable reviewer and writer in conjunction with an open and candid manufacturer could provide a real educational service to his audience.
I recall it...it was, as you say very interesting and informative and I, too, grieve that the subject facility is no more... :(
I didn't intend anything I wrote to imply otherwise -- my use of "game" was referring more to the limitations for their reviews owing to the restrictions of format and volume in a publication. There is far more to say than can be fit into the available space and many really useful details are thus never brought out.
Although I'd like to do that, I've been buying tooling from China. Compared to our US suppliers, it is equal or better quality, half the price, half the lead time.
Wait until you want to buy a toaster or other small appliance. The only one I could find not made in China was $225 from England
Not true. You just have to know where to look A friend of mine takes lots and lots of overseas trips, airline field engineer, when in Germany he noted that all the appliances, tools, cars, whathaveyou were actually made in Germany - even things that when sold in the US were made in China. Now that's not to say its ALL made in Germany, but rather it would appear the Germans go out of their way to use German made goods. Hell I'll do that - arrange to buy German goods and have them shipped over here. It's not like I buy all the much anyway. I'll gladly buy Chinese made goods when they stop poisoning us and when they pay their employees comparable salaries and benefits. Japan is a good example of that - Japan used to equal crap, now its equal or better to many good and services. It took years of training, rethinking their business models, and demonstrating those successes to the consumers here in America to accomplish that turnaround. No reason why China can't do the same. But for now I'd rather support my fellow American whenever possible, if not, then my next door neighbors Canada and Mexico.
Every few days there is a bandsaw thread and we always talk about the same few brands (Laguna, Grizzly, Jet, Craftsman, Harbor Freight). You don't even have to ask here. Either search the archives (Google is your friend) or just wait a few days.
Big bucks are on Laguna. Grizzly is for serious hobbyists. Jet is for occasional users. Craftsman is for habitual losers (hey ... it rhymed). And Harbor Freight is for the likes of me, big ambitions and dinky wallet.
See the followup where I corrected my quoting context...perhaps that helps, I don't know???
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I don't think we much disagree at all, fundamentally, but seem to be having a communication problem (hopefully not deliberately)...
I'll try again...
The "they" in the above paragraph did indeed refer to testing but was intended generically to include an individual test/tester and/or a sponsoring publisher such as FWW. I don't care specifically who does the test and as I replied in the followup, even if it were vendor-supplied data that would be fine for supplying the population data currently missing.
That being given though, the point of any testing and reporting isn't for the benefit of the tester but the readership of the resulting test report for whom it is at least one if not the primary basis for selection of or at least a winnowing down of one particular machine for purchase. So, the overall target of my comments was intended towards providing more meaningful data for the general readership, yes, and that is why I said I, at least, was directing comments from the readership audience pov.
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For a lot of these measurements reported, no, I don't (and certainly don't believe the general audience for which such reviews might be of real value do either). Whether the reviewer does have some knowledge turns out to be immaterial for the most part because I've never seen that knowledge or information presented in any review that I can recall. Some of them are probably not even measurements that are part of the manufacturer's QA/QC checks, either. That may be because they're derived measurements controlled by others or because they could be considered as immaterial.
Really basic measurements such as runout on a tablesaw arbor flange are pretty clear. The offset in the guide bar on a bandsaw in mils so that it isn't perfectly straight and therefore might require a tweak of a fixed guide block type of blade guides when switching from thin stock to a heavy cut isn't nearly so obvious as to how much is too much. Sure, it makes sense that "less is better" but it certainly isn't directly clear that the worst of a reported value is actually enough to make a real problem in the shop.
The other difficulty in the reports that I was attempting to address is that if the sample measurement for machine A is 1 mil worse than the same measurement for machine B, does that imply that if another unit A and B were purchased and measured that the same differential would be present or would A even still be worse than B for this pairing of test machines? Certainly the way test reviews are written and presented there is no basis for judging anything else but you have done enough QA/QC testing to know that isn't necessarily so. In fact, the population mean of the two machines could be the same or even A better than B instead of what the single sample result indicates. If so, the poor reader who concludes that B is the better buy in conjunction w/ the author's "Best Buy" label just might have made the wrong decision if swayed by the reported numbers. So, I'm simply saying it is an incomplete service imo to not have context such as that provided in reviews but recognize that to do so raises the scope of reviews to a level beyond what would be practical for general circulation magazines. Hence the "game".
It doesn't imply I think anybody is rigging anything, incompetent, nor underhanded in any way. They're simply operating under a set of conditions that aren't optimal to answering some questions in a rigorous manner. As you have pointed out, vendors have such data and some of that data would be of real value and lots more of interest (if of little actual practical value) to at least the more astute and interested in the general readership. You also noted at least one manufacturer made such information available if requested, but didn't contradict my conjecture that such data would not have been allowed to be published which is certainly understandable for competitive reasons if no other. I suspect not all vendors were so open to potential reviewers for such data even then, particularly if they were aware the same reviewer was visiting other vendors. With the present competitive environment I can only imagine such pressures weigh even more heavily upon them to maintain such data closely held proprietary information.
One other thought struck how to perhaps explain the pov I was trying to get over. I consider the test/tester/publisher as an entity to be a surrogate for the reader who would like to do what they're doing but has to rely on them for that service in a practical manner. Ergo, from that point of view, yes, the "they" does indirectly refer to the readers...
Well that's too bad, maybe you should study up a little, or better yet, use your machines to get some practical experience.
(and certainly
Then there is probably no basis for continuing this discussion. I believe the vast majority do. I base my conclusion on talking with literally thousands of end user woodworkers at shows and directly resolving issues as quality manager for a number of years. And your belief is based on...
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