Warco Super - Major Vario inaccuracy

Hello Adrian.

I have sent PM if that will help,

Anna

Edited By JasonB on 20/02/2019 14:35:56

Not really sure how that would help Anna, as there are a lot of people on here that offered help, and surely they would like to know what the problem was.

Regards

Hello Fmes.

Please see my post page4 "quality issues with sieg sx2.7"

this perhaps will explain.

Regards Anna

"

Ahhh, haven't got a Sieg, so didn't bother reading the thread, does make it awkward when people cross posts.

FWIW I bought my Super Major (standard) with DRO in 2001, and its fine.

Maybe like the Rover V8 engine the same tooling was used throughout the entire production run and might be getting a little tired.

would still really like to know what the problem with roberts machine was - or was just mis measurement??

Regards

p.s. we borrowed a Sieg Mill from Ketan a couple of years back for evaluation, and everyone here including the apprentices thought it was the nuts of the mutt.

Edited By FMES on 21/02/2019 14:10:48

Hello FMES.

In my own mind and from what I deduced I am almost certain it was bad machining, but I could be wrong.

Cannot resist this one, were you or are you a Rover fan. In my wealthier days many moons ago I had first an SD1 2.6 followed by the SD1 SE 3.5 V8 loved them both but particularly the 2.6 straight 6. I still drive a 16 year old Rover 75 Connie ES 2 litre KV6 fabulous car and engine despite the naysayers

Regards

Anna

Latest on my warco super major vario

the machine by my company’s maintenance department using there test equipment and the results are and the main column is 5 minutes of angle out

does not sound much but over 300mm that’s .012 mm

warco are coming to fix it Monday

i guess they are going to unbolt the column and shim it, not happy about that but short on options

The numbers don't stack up?

Andrew

Thanks for the update, Robert

Did they also check the parallelism of the quill to the column ?

MichaelG.

Yes they did

it’s definitely the column is out

I make it 17 thou. But how do you measure 5 minutes error or is it a back calculation from a measurement of distance?

Agreed, also lack of column squareness would not account for the error originally reported, which was measured by traversing the Y movement.

They don't! Different from what Bob first said, and inconsistent with each other. 0.012mm over 300mm means the mill is good, 5 minutes (which I make about 0.4mm over 300mm) is bad. As Bazyle points out, the numbers are almost certainly back calculations, themselves error prone, not actual measurements.

I don't think the confusion should be blamed on Bob, far from it. My forum record includes several miscalculations and measurement blunders, so I know how easy it is to get this stuff in a muddle! Rather it underlines the difficulty of making precision measurements and expressing them meaningfully.

Make an interesting MEW article perhaps: when error matters to accuracy (quite often it doesn't); how to take trustworthy measurements; and how to interpret the results. I don't think I could write it, I've read a few textbooks, but applying the theory is a whole different skill set.

Glad to hear Warco on the case, and I hope Bob ends up with a machine that does what he needs.

Dave

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Whilst it would be very helpful if Robert would clarify exactly what measurements were taken, and how: I can see no reason to make that "almost certainly" assumption.

It is surely not unreasonable to think that direct angular measurements may have been taken.

MichaelG.

Edited By Michael Gilligan on 22/02/2019 09:36:18

We seem to be getting a lot of these threads recently.

I'm concerned that some people jump in with both feet with conclusions/condemnation before we know full details.

A quick google will show Tormachs and Bridgeports being shimmed to correct similar errors so neither the issue nor the cure is unique to far-eastern imports.

I think we should not speculate further until Robert confirms the outcome of Warco's visit.

Neil

That's hardly a surprise. The original posts are often incomplete and confused as to what is being measured, with incorrect conclusions reached. And then people jump in without necessarily having read the previous posts.

If I've understood this thread correctly the original measurement implied that the top of the table (in Y) wasn't parallel to the guiding ways. Now we're told that the column isn't square, presumably to the table top? The column not being square won't affect the parallelism issue or measurement, and shimming it won't cure the problem, if that's what it is.

There seems to be a trend, in response to any problem, to immediately suggest the most complex, and least likely, solution. For instance if anyone posts about poor finish or other issues when turning on a lathe, it won't be long before it is stated that the headstock bearings need changing.

I've never touched the column on my Tormach, although I did shim the base when mounting the mill on my home made stand to correct for some small tram errors. The Tormach is a far-eastern import. It'd be interesting to see how you'd shim the column on a Bridgeport given that the column and base are an integral casting. Saw it in half to start with?

Andrew

Postscript: Why don't the smileys display correctly in the pulldown?

It might be as well to live in ignorance unless the work produced reflects the the errors in the construction of the machine. Taking measurements has to be done with a full understanding of the limitations of the measuring equipment and what you are measuring. In my electrical world it was part of our training to understand that meters and scopes etc. affect the circuits they are applied to, much of the time the effects need not be a problem but being aware of their existence and selecting suitable equipment was necessary. Stefan Goteswinter does a nice demo of how flexible a dial gauge mounting is by setting up a measurement and then inverting the whole setup, I suppose the result is not surprising if you think about it but it is quite a dramatic demo.

Mike

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I was wondering that, too ...

MichaelG.

Maybe - so much depends on what the individual knows and his instruments!

I guessed 0.012mm to be a calculation because the very best I could measure is about ±0.01mm, 0.002mm is a step too far for me. (0.00007874016 inches is less than the famous tenth many aspire to and never achieve.) Likewise 5 minutes of angle is only 0.08333°, which I would be hard put to measure directly. So I conjecture both numbers come from an opposite over adjacent calculation based on DRO & DTI numbers.

I have a precision bubble that could easily detect a 5 minute slope, but it's not calibrated. Though I wouldn't do it that way, I understand how a bubble could be used to check a mill was trammed correctly but not how to measure the actual angles between table and head.

Even measuring distance, I recall there's a problem calculating with trigonometry in that the tangents of small angles are all close to zero, making the sums iffy as well.

tan(0.005) = 0.000087266
tan(0.01) = 0.000174533
tan(0.02) = 0.000349066

How would you take an accurate angular measurement in a workshop? Something like a baby theodolite perhaps? I love this forum, the more I learn the more I find I don't know, or have misunderstood!

Ta,

Dave

Edited By SillyOldDuffer on 22/02/2019 13:47:29

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Given that Robert was calling-in the experts from work : I would have hoped that they could detect angles of about 20 seconds using a clinometer ... or considerably better than that with an autocollimator.

'though the small size of the mill might preclude convenient use of an autocollimator.

MichaelG.

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The Hilger Watts TA1 instructions include quite a good discussion:

https://www.chipmaker.ru/search/?q=hilger%20watts

... Vintage stuff.

Edited By Michael Gilligan on 22/02/2019 14:27:12