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Quality Problems With the Sieg sx2.7

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JasonB26/09/2020 13:17:14
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Drill chuck is fine for that test, I get about 0.01mm when locking the head sideways but nothing measurable front to back. My head winds up with what I feel is a good compromise between too loose or too tight to turn without excess effort. resistance, you do need to use top and bottom screws when adjusting the tapered gib. Has not caused me any problems assembling engines and I use tight clearance holes for example M3 clearance will be drilled 3mm for general use, if I want it a bit tighter 2.9mm is still OK with commercial cap head screws.

I had a check of the flatnessof the table on my Sx2.7, a 0.0015" ( 0.04mm) was the thinnest feeler gauge that I had used with a 152mm long parallel. It would not go under.

Nir Somthing26/09/2020 14:15:17
23 forum posts
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The following measurement I did maybe 10 time, I locked the right angle tool that I made to the chuck and after each measurement I removed the tool and attached it again in a slightly different direction, to make sure my readings have nothing to do with the chuck, the video shows just one test. But the results are the average and the deviation is within 0.006 mm (not 0.002 mm).

I may add that not all measurements are terrible but they add up and in the end I can have serious deviations... What's the point of having an accurate DRO to within 0.01mm (mins seppoesd to be 0.001mm) If every time I change the height of the head my last coordinates changes?

https://youtu.be/pLJrq6BVlao

measure 3.jpg

Nir Somthing26/09/2020 18:09:22
23 forum posts
16 photos

The last measure I can think of is of the height of the table relative to the head. The results in the x direction make no sense, it is probably because of the weight of the table itself, but since it is only 0.03 mm on all four measurements I consider it great, I will probably won't use the entire table length anyway....

The results in the y direction are indicating that I should shim the column at the base to get better alignment, but the problem is that if I do that the spindle will not be align even more, note that the high side of the table is the low side when measured via the spindle.

https://youtu.be/GqFT1BLS4JA


Measure 4.jpg

Bottom line, and thank you for bearing with me all the way:

I can leave it this way and ignore the fact that I have a play in the head of 0.2 mm which I can not fix since the gib will not go any further and if it did I will lose even more travel of the head (at the top) and I will have to live with the fact that the quill is not parallel to the head.

or

I can pay and have the previous mill checked by a professional since I didn't touch the gibs at the time, and I probably should have. So than I have a certificate of the accuracy of the machine and a peace of mind. I would really like to have an "experienced machine tool fitter" as Ketan Swali suggested, but I am not sure if there is one in Israel - I need to check it. One way or another, if he / she are unable to do some serious machining they will not help. Proper tooling and methods may indicate that my tests are not accurate however doubtedly, but adjusting the machine only by hand is something I can do myself and the real problem with the sieg SX2.7 is that you can only adjust the column base - and that's it! (Gibs don't count if you know what you are doing they don't "adjust" anything just reduce the play)

Lastly I would like to know, what you consider as accurate? does 0.1 mm in the z direction over 120 mm counts Good/fair/terrible(My opinion? What about other parameters?


Thank You Very Much for your time! Hope this will help others too in the future!
Nir

Nir Somthing26/09/2020 18:10:55
23 forum posts
16 photos

The red lines indicate the measurement in the x axis that where in the range of 0.03 mm***

Vic26/09/2020 18:55:16
2613 forum posts
20 photos

I wouldn’t be happy with the damage to the cover. There’s also signs of rust and other badly prepared paintwork. If Sieg really have sent that out of the factory like that they don’t deserve the business. I do wonder however if this machine has been damaged in transit and been tarted up (badly) by the dealer or someone else? Perhaps you’re not the first owner. It would be interesting to know the date of manufacture. This doesn’t necessarily effect the standard to which it’s been manufactured, maybe they’re all like this. I can’t comment on your methodology except to say using a square in one of your setups wouldn’t be my first choice. I wonder what other dealers of similar machines think of your findings and what they’d be prepared to do about it? Good luck with the machine whatever you decide to do but be aware there are plenty of folks out there that have “fettled’ these type of machines to improve them. Looking on the net should give you some idea if you decide on that route.

Dave Halford26/09/2020 19:05:17
938 forum posts
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I can leave it this way and ignore the fact that I have a play in the head of 0.2 mm which I can not fix since the gib will not go any further and if it did I will lose even more travel of the head (at the top) and I will have to live with the fact that the quill is not parallel to the head.

If this was an old style gib with screws every 50mm to adjust the play, then being tight at one end would imply the wrong adjustment and would possibly tilt the head.

Don't wedge gibs require equal adjustment at each end?

Nir Somthing27/09/2020 15:00:48
23 forum posts
16 photos

Ok, So I noticed from the previous results of the head movement (that I shared here), that the maximum deviation is in the middle of the column. So I thought maybe I will adjust the gib at that height and see what the results will be. I found out that even if I take the gib all the way down such that the counter screw only holds by one turn (obviously if I will lock it tight I will damage it’s thread) that the head still move by 0.27 mm (it was 0.275mm before) and that now I cannot move the head all the way up by 10 cm, in the picture you can also see the cover shear that I talked about covered in paint. I found someone else here in this forum that also talked about this problem, Piotr, luckily I can still get (hopefully) service from my dealer.

Adjusting Gib again.jpg

Dave Halford, the old style gib is somewhat flexible compared to the new style, however it’s purpose is the same. there is not much of a different between them, so long as all the parts are properly machined. As I see it, and please tell me if I am wrong, the gib’s only job is to lower the play between the column (bed) and the head (saddle?) of the mill and the more you tight it up the harder it will become to move the head and the wear of all parts involved will increase. In my case since the column (bed) has a trapezoidal shape (wider in the top, thinner in the bottom) both styles will not have helped. The way you adjust the new style (if you want to tighten it up) is by releasing the bolt at the top half a turn, then releasing the bolt at the bottom half a turn, and then locking the top bolt against the bottom one full turn. If there was only on bolt at the top then when the head was moved upwards the gib will have tighten itself while moving downwards and the head would not move.

I also decided to share with you a few more pictures from the first mill I got, so that others may take it into account before buying. The shipping Is by the sea, so obviously high humidity and a lot of salt, you can see in the picture the rust on the box metal strips, and there was no silica gel bag inside. So no wonder the paint peeled off and the screws got rusted, it will probably affect the electronics in the long run.

First mill.jpg

Vic, thank you, I totally agree, which method would you have used? I learned it from the internet… About the mill, it is 100% Sieg fault. The dealer ordered 12 machines (There is a sticker on the box) and when he shipped me the first mill it was after waiting for it to arrive, so it was sent to me directly from the harbor not from his store, and the number embedded on the base was 90415 and after he sent me a replacement, the mill was stamp with the number 90414, so there is no chance he did it. I think that, as SillyOldDuffer mentioned, Sieg don’t put the machines for Quality Assurance (even if I have a triangle piece of paper that says so) when a dealer orders a full container. Maybe they are counting on the name of the brand? Or maybe they haven’t renewed the manufacturing line after producing 100k machines? I have no idea, but I am truly disappointed. I can tell however that the new mill was painted twice, it is very hard to see depending on your monitor, but they have repainted the front with a slightly different tone, the camera doesn't catch it but the eye certainly does…

Repainted.jpg

Thank You,

Nir

Nir Somthing27/09/2020 15:08:24
23 forum posts
16 photos

*** I forgot to mention that:


https://youtu.be/EIcVFVVNnHM


It’s only a cosmetic, the inside runout is 0.01mm , but when I first saw this, my heart fell off

ChrisB27/09/2020 15:43:10
548 forum posts
192 photos

Hi Nir, rather than worrying too much and loosing time checking the machine, it would be more helpful if you squared up a piece of material and then measured the work piece. This will help you better understand the problem with your mill and to what extent it is. I saw your video up above where you appear to be measuring the mill head tram, with that extension arm swinging from edge to edge of the table you will never get a reliable reading.

Steviegtr27/09/2020 18:43:55
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1509 forum posts
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Nir i have stayed quiet on this one. But one comment if i may. I have an old UK made Tom Senior vertical mill. When i was tramming the head, i tried various methods. Using a Jacobs chuck with a swing rod just like you have done. It was miles out. I then used another quality Albrecht hand tighten chuck. Both were a long way out. I ended up using a 22mm MT2 Facemill arbor of chinese origin, but with a DTI was found to be very accurate. I then bolted this to the swing bar. My bed is 720mm long so quite a range from end to end. With this & very careful use of a rubber mallet got the Tram pretty much perfect. I think it was Jason B who told me that using a chuck is not going to be accurate.

I also had problems with a precision square set. There were 4 different sizes in a lovely wooden box, bought new. Not one of the squares is accurate. Luckily someone recently gave me an old Rabone Chesterman steel set square, which is ancient but very accurate.

With all your other problems i do sympathise with you & hope with some effort you may get the Mill as you would like it to be. It sounds like where you are in the world that machinery is very expensive.

Regards. Steve.

Tony Pratt 128/09/2020 08:26:33
1234 forum posts
5 photos

Steve, if you understand tramming you will realise it doesn't matter how the swing rod is held [chuck/collet etc.etc] as long as the set up is rigid & the DTI used is repeatable the results will be reliable.

Tony

ChrisB28/09/2020 08:48:49
548 forum posts
192 photos
Posted by Tony Pratt 1 on 28/09/2020 08:26:33:

Steve, if you understand tramming you will realise it doesn't matter how the swing rod is held [chuck/collet etc.etc] as long as the set up is rigid & the DTI used is repeatable the results will be reliable.

Tony

A chuck's radial runout should not make any difference in the tram readings, but if there's any angular runout (wobble) in the chuck jaws you will get errors, especially when using a swing rod the size the OP is using. He should measure over a shorter range imo. That rod's length is amplifying any misalignment the head may have. I would be much more realistic is he faces and squares off a piece of material and then measure it. Most probably the OP will find it is within his precision expectations.

I had similar issues with my WM18 when I first bought it, but soon found out that it's useless chasing decimals without taking some cuts to reference with.

Michael Gilligan28/09/2020 08:52:48
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Posted by Tony Pratt 1 on 28/09/2020 08:26:33:

Steve, if you understand tramming you will realise it doesn't matter how the swing rod is held [chuck/collet etc.etc] as long as the set up is rigid & the DTI used is repeatable the results will be reliable.

Tony

.

That should start an interesting discussion angel

MichaelG.

.

Edit: and I see it already has

Edited By Michael Gilligan on 28/09/2020 08:54:08

Tony Pratt 128/09/2020 09:59:32
1234 forum posts
5 photos

Chris, I totally disagree, whatever holding method is used will present the DTI probe in the same relative position to the table as long as the set up is rigid, furthermore you are better off using a longer arm to amplify the head error so when you get it 'close enough' at that large radius it will be completely acceptable at say face mill diameters of 50/60/70 mm. If you use a block to check squareness you are then possibly introducing a vice error.

Tony

Emgee28/09/2020 10:17:36
1724 forum posts
232 photos

ChrisB stated: A chuck's radial runout should not make any difference in the tram readings, but if there's any angular runout (wobble) in the chuck jaws you will get errors, especially when using a swing rod the size the OP is using.

I agree with this so if there is any runout measured with a DTI it needs to be established if it is radial or angular, if radial then using the longer bar will magnify any tramming error.

If angular rotate the chuck so the high/low points are aligned in the Y axis and set the bar along the X axis, this will allow some readings to be taken that will give an idea to the amount of lean over of the head/spindle.

Emgee

Michael Gilligan28/09/2020 10:20:47
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16389 forum posts
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Posted by Tony Pratt 1 on 28/09/2020 09:59:32:

Chris, I totally disagree, whatever holding method is used will present the DTI probe in the same relative position to the table as long as the set up is rigid […]

.

Sorry, Tony ...

It’s simple trigonometry : If there is an angular error between the ‘output axis’ of the chuck and the axis of the machine spindle, then your trammel beam will act like a swash plate and the DTI will rise and fall.

MichaelG.

.

Edit: Swash Plate animation: https://youtu.be/z-wA9Tx8930

Edited By Michael Gilligan on 28/09/2020 10:23:21

Tony Pratt 128/09/2020 10:35:58
1234 forum posts
5 photos

Nothing to do with trigonometry, say the DTI is at 0 degreees on the LH side of the table, you then rotate the spindle 180 degrees to the RH side of the table the DTI will be in the same space in both positions, the chuck/collet or whatever is only really connecting the DTI to the spindle bearings in a rigid set up. Difficult to explain in words which make sense?

Tony

Vic28/09/2020 10:51:26
2613 forum posts
20 photos

Like others I tram my mill by holding a bar with a dial gauge mounted on it in a chuck.* I’m not sure though how I’d actually check a machine but as others have said using a square on the table as pictured earlier isn’t a method I’d trust. I’d probably use a mandrel directly in the quill and take measurements from that somehow.

* When I asked an old time served machinist how to do it he said it could be done with just a bent rod and a couple of fag papers. I actually did it that way at first and it seemed to work fine judging by the results!

ChrisB28/09/2020 13:15:49
548 forum posts
192 photos
Posted by Tony Pratt 1 on 28/09/2020 10:35:58:

Nothing to do with trigonometry, say the DTI is at 0 degreees on the LH side of the table, you then rotate the spindle 180 degrees to the RH side of the table the DTI will be in the same space in both positions, the chuck/collet or whatever is only really connecting the DTI to the spindle bearings in a rigid set up. Difficult to explain in words which make sense?

Tony

You're actually right Tony, after thinking about it, it's true any runout will not have any effect as long as the spindle is running true in it's bearings. As you correctly pointed out, with the mill head and spindle perfectly trammed, if the chuck jaws had to have ''x'' amount of radial runout on the LH side of the table, turning it through 180deg to the RH side of the table the runoit will remain the same.

Still, I believe a longer arm will be more unhelpful rather than helpful. I swing the dti at the max depth of the table rather than the length. Why? because I do not need to chase microns. Measuring at the edge of the table will be next to impossible to align the head from my limited experience with this type of mill head. A small tap one way and you're out, another tap the other way and you're out again.

I reason that I will never need to swing a cutter diameter larger than the depth of the table, so if at this diameter the table is flat, that will be enough for me.

editing spelling

Edited By ChrisB on 28/09/2020 13:38:02

Tony Pratt 128/09/2020 13:29:01
1234 forum posts
5 photos

Chris B, thanks I thought I was right but as you might have imagined I did think it through again. As you say using a long 'arm' is a bit tricky but that's the way I do it, each to their own.

Tony

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