|Nir Somthing||25/09/2020 13:11:12|
|23 forum posts|
I have recently bought a Sieg SX2.7 and wanted to share with you my experience, when I checked the alignment of the table relative to the head I found deviations in the order of 0.1mm, checking the alignments relative to the chuck I found out that the right side is of by 0.2 mm the left side is off by 0.12 and the left to right is of by 0.4 mm. There was also paint problems and rust and bent back cover. and the table was flat to only 0.05 mm. I talked to the seller and he agreed to replace the mill for me for free. I was happy for a while until I got it and realized the same story in a different version! This time the head was moving to the left by 0.2mm when it was locked and when I closed the gib all the way down it changed to 0.1 mm which is still a mess and the head couldn’t move all the way up. I also found that the head is tilting back while the spindle is also tilting the same amount - meaning that if I fix the tils of the spindle my head will be at an angle of 0.25mm over 15 cm. This time one corner of the top-back cover was sheared apart and they simply apply post paint in a brutal manner to cover it up. Bottom Line - based on this to machines it seems that they assemble the mill and that’s it. You must align it yourself. -The problem is that you cannot! apart from the gibs and the base of the column there is no way to adjust anything! the only way to fix it is by taking it apart and paying for someone to machine it for you bottom-up. which will cost the same amount as the machine does... If someone can tell me if the Sieg SX3 is more accurate I will love to hear that, and if someone has any suggestions please do tell I am very frustrated and I need a machine which is at least 0.05mm accurate. Thank You.
|Bill Phinn||25/09/2020 16:36:33|
|367 forum posts|
In order to get the help you want from this forum, you're going to need to go into far more detail about what you're measuring and how you're measuring it. Photos will be necessary, and you will only be able to post these once your post count has reached a certain minimum.
A number of things you say are puzzling, only one example of which is the following contradiction:
"the table was flat to only 0.05mm"
"I need a machine which is at least 0.05mm accurate".
|Ketan Swali||25/09/2020 16:42:43|
|1296 forum posts|
Welcome to the forum Nir. Where are you from?... just asking as I am sure that it is not a machine supplied by ARC.
The issues you raise are of concern. However, before you explore comments and advice which may follow from various forum contributors, could I ask about your engineering background and knowledge of checking machines? Did you use the machine as received, or, did you strip it apart and re-assemble it?. How did you lift and place the machine in its final place of operation? There are several methods of measuring alignment - good and bad. Checking alignment is a subject which most people - new to the hobby have less experience with, and I do say this with the greatest of respect. Most people will speculate. This is not something which I would/could discuss at length, because it is difficult to be sure without sight of the specific machine.
How old is your machine and what is the serial number (you will find it on the bed of the Y axis, near the front). Is your machine the standard length table or the longer 'L' version?. There will be variation from one end to the other. the longer the table, the more the variation, but it is normally addressed by use of shim/s under the work piece being machined - if the workpiece being machined is long (I will keep away from getting into a debate on this point - as there are too many variable factors involved), based on how the variations are measured, combined with expectations over the length of the table. There was a batch of SX3.5 machines which had a paint issue, which has now been rectified. However, I am unaware of such an issue with the SX2.7.
I am surprised to read that a corner of the top-back cover on the second machine had 'sheared apart'. Could you show some pictures of this?.
It is true that most Chinese factories will touch up paintwork where it may have come off, be it SIEG or any other. With reference to alignment, ALL Chinese machines in this price range are first assembled, and then checked and adjusted for alignment. Possibly not the best practice, but that is the way it is.
Once the machine leaves the factory, temperature, handling, mis-handling can effect alignment too. In your case, I would suggest that you employ the services of a machine tool fitter to adjust and align this or any other machines you may be considering, be they SIEG or otherwise.
The SX2.7s and SX3s are very popular sellers for ARC in the U.K. and Europe. Most customers are happy with them, and our general advice has been to use them as they come out of the box, making slight adjustments for anything which may have become loose for example. Only consider 'major' adjustments if they have the knowledge, once the machine has settled into their working environment. This is possibly different from advice you may get from some others, but that is our view on the subject. In the U.S. these machines are sold 3x more than in the U.K., even after the Trump tariff, and usually, the users there invest in a pack of shims to deal with their specific needs. With a few Friday afternoon exceptions, these machines are great for most hobby users.
Before anyone says anything, in our opinion, these machines are fit for general use as supplied. Yes there will be some Friday afternoon assemblies, which most good sellers will replace or refund, but if one is expecting a toolroom spec., or a machine which is adjusted or prepared by a toolroom fitter at the installation end, they they should consider alternatives or budget for the extras, depending on their own knowledge and experience. In this respect, some Youtube knowledge is great and some is poor.
Finally, if you are considering an SX3, the assembly teams which assemble the SX2.7s are the same as the teams which assemble the SX3s. So, I hope that in some way that answers your question about the SX3, to a certain extent, excluding other peoples opinion. No doubt Paul Lousak from Australia will come along shortly to tell you how happy/disappointed he was with his SX3 which he used outside/beyond the limitations of the SX3.
Ketan at ARC.
|1709 forum posts|
You make some very valid points re test readings etc but without knowledge of the posters experience/qualification you question his method of testing and assembly expertise, better to find out more about the person before questioning his ability IMO.
18868 forum posts
Emgee, I thought Ketan got that question out of the way early on.
"The issues you raise are of concern. However, before you explore comments and advice which may follow from various forum contributors, could I ask about your engineering background and knowledge of checking machines?"
Like Bill I find some of the "errors" hard to follow
"checking the alignments relative to the chuck I found out that the right side is of by 0.2 mm the left side is off by 0.12 and the left to right is of by 0.4 mm."
If right is reading +0.2 and Left reading + 0.12 then one would expect the total difference to be 0.08 not 0.4
Edited By JasonB on 25/09/2020 18:25:43
|Pete White||25/09/2020 19:50:10|
|108 forum posts|
Nir, ..................as an aside welcome to the forum, .................sorry to hear of your problems.
|Nir Somthing||25/09/2020 20:10:07|
|23 forum posts|
First of all I want to say that I am very impressed by the responses, I thought this post will never get any feedback, Thank you for your time, it is very nice of you all.
Regarding my background, I am Material Engineer, however I am deep in Mechanical Engineering since basically ever.
My experience is very little with mills however I did see hundreds of videos online by now, and I have a press drill which I added to it a x-y table and a DRO, not for the sack of milling but for accurate positioning of holes. That said, when I contacted the supplier I mentioned that my press drill has a play of around 0.5mm when I center holes (the play is in the quill not the table), and he said that I can be sure this mill (Sieg SX2.7) will be in the range of hundreds (~0.01mm).
So I decided to buy it. Here, in Israel it costed me 3,000 USD! Two times the price one will pay in Germany, USA or Canada!
I must mention that for the first mill that I got I didn’t touch the gibs and only cleaned the machine properly according to a series of videos on YouTube by Frank Hoose. I didn’t see any play, so I didn’t bother – definitely a mistake. However, when testing I always locked all the axis not in use.
At first, I used a centering Indicator to measure the table normality relative to the spindle, however the Supplier gave me a number of a co-worker who is a Mechanical Engineer and he said that this is not a valid test. So according to him (and videos seen on YouTube) I built a rigid angle made from a rod of 10mm diameter of SS304 and 20mm aluminum block that I connected to the spindle and measured the end of the table. The radius was 35cm and I measured the right side to deviate by 0.2 mm and the left side to deviate by 0.12 mm the left to right deviation was 0.42mm! When I used parallel to measure the flatness of the table it was across the y axis about 0.04mm, I could see light going through easily. When compared to my old x-y table this looked terrible to me... I also measured the table height relative to the head which was around 0.1 mm on top of that I had paint that fell of at some places and rust on bolts and the overall experience was not good. So the seller gave me the option to get a replacement. – It is unfortunate that at this time I didn’t thought to adjust the gibs.
When I got the new mill, this time I reassembled the gibs and tighten them properly (first only in x and y than also in z). I used the centering indicator that I was told is not a good indication and it was spot on! 0.01mm deviation over 20cm.
And when I used my right-angle tool that I have built I measured 0.12mm on the right side, 0.16mm on the left and 0.09mm right to left. That made me think – “great” I can shim the column and it will be perfect!. Then I measured the table relative to the head not the spindle. I got 0.09 mm change on the right, 0.13 mm on the left and 0.03mm right to left. So again, only need to adjust the column. BUT – in the first measurement, the higher side of the table was the one close to me, on the second measurement the higher side was the side next to the column! At this point I knew I don’t have a problem on my x axis only on my y axis but then I found out:
|Nir Somthing||25/09/2020 20:10:28|
|23 forum posts|
I saw that when I tighten the head the dials move all over the place, so I measured its movement, and the head moved to the left by 0.2 mm when locked. So I tighten the gib all the way down the movement only changed to 0.1mm which is still not good compared to 0.05mm in x and y axis. I then moved the head up and at some point the head got stuck! After some inspection I could see that first the head is not centered it is pushed to the left, and second that the milling done on the column bed is uneven. And in essence, the bed has a trapezoidal shape. So I either lock the gib all the way in and lose ~7cm of the top of the column or release it and have a play of ~0.15mm when locking. So at this point I thought maybe it doesn’t matter if I lock it all the time but again I was wrong! I took a machinist right angle tool and attached it to the table. And marked every 3 cm the height, then I measured the movement of the head relative to the table, I found out that when I don’t lock the head I move 0.1 mm in one direction, when I tighten it I move in the other direction by 0.16mm and that is over 15cm.
So, from the last measurements I realized that my readings are changing relative to the height of the head, that is why I got a spot-on measurement with the centering dial and not with the tool I made. (The height with the centering dial is probably the same height for which they adjusted the gib since it is tight at the top and loose at the bottom).
Regarding one of the comments, the second mill cover at the back was sheared at the top as if it got hammered and sheared open, and they simply someone took a brush and painted on top of it (the brush was full of sand or something of the sort&hellip
So now I have the feeling I should ask to get the first mill again and check it properly this time. Since it didn’t have a play in the z axis (for what I remember). And maybe if I tighten the gibs this time the measurements will be different.
In any case we are allowed to have a mass of 150 kg per square meter in an apartment, mining that if I want to go for the SX3 I will need to use some sort of a bar to level the weight. And as you said Ketan Swali, there is no reason to think that this one will get a different treatment…
What I am thinking of is offering the seller a fair price to take it to a leveler and adjust it for me. Sins I already spent so much on the mill and dedicated accessories (6,000 USD total).
Regarding the comment by Bill Phinn, for me a 0.02mm was obvious two weeks ago. Now after all this measurements, If I get 0.05mm I will be very happy. And I mean 0.05 mm in general so this errors add up and in the end a real 0.1 mm will be good enough. Regarding the table accuracy, we learned how it is made in one of the courses I took, and the method allows one to reach accuracy of around 2 microns! My x-y table from USA costed me less than the shipping price (~150USD for the table) and it is flat on. You will not see any light going through nor you will be ably to insert a shim of size 0.02mm underneath a parallel in any orientation. Not so, with both mills, the table is bent in both cases like a banana at the middle it is lower by 0.04 mm in the first mill that they sent me and 0.05 mm in the second. And my parallels are only 120 mm not 160 mm across. (They are 100% accurate).
Thank You for your time reading all of it, Any advice, comment is welcome
|Nir Somthing||26/09/2020 06:17:27|
|23 forum posts|
When I say right side, I mean to say deviation of the right side of the table - that is the y axis
When I say right-left I mean to say deviation of the table from right to left – that is the x axis
I am sorry in advance if I describe things in a somewhat non-conventional manner.
18868 forum posts
Nir, as mentioned by Ketan it would help to see some photos of how you are testing the machine then those answering will be better informed to offer help. There is nor restriction on how many posts you need to make to add photos either hosted elsewhere or added as described here.
As has been said the machines are checked at the factory and meet whatever spec is required. The fact that both your machines showed signs of physical damage which could go deeper than just paintwork or bent outer covers could have happened in the shipping container or even by whatever courier was used to deliver them. The second one having been repainted would be less likely to blame on the courier though possible you were sent a replacement that was already a customer return. This damage may well be the cause of some of your readings.
You have not replied if you took the machines apart to get them into position as this again will affect the column position. On both the SX2.7 and X3 that I have here I took them apart to lift onto the bench and reset the tram as I put them back together, both have a feeler gauge shim in place to get the tram I was happy with. Neither machine have had the full strip down and rebuild like some Youtubers show, just broken down into a couple of parts to make lighter and then put back together.
As you have found on a machine in this price bracket there will be slight errors between the travel of the head and the travel of the quill but I have not found much needed to get these to levels that are acceptable to me beyond simple gib adjustment. This video shows the readings I get off the SX2.7, Tram within 0.01mm over 140mm diameter, Head movement 0.015mm over 50mm and quill 0.04mm over 50mm ( it's full range of travel) all within your 0.05mm though you do not give a length over which you need that accuracy so a bit meaningless as a stand alone number. I don't have any 100% true parallels ( does anyone? )but I'll have a measure for table flatness and report back later but the tram readings suggest it is flat to within 0.01mm
I don't know what use you intend to put the machine to that requires your desired level of accuracy but a look through this album or this playlist will show what I have done on my Sieg machines. If you really do need more accuracy then I would suggest you need to up your budget to more than a Sieg machine and your suggested same cost again for blueprinting it. so somewhere starting at $10,000USD.
Also as requested if you can let Ketan know the serial number Sieg are able to trace each machine back to who assembled and signed it off and they will also be able to trace others in the batch to see if there have been similar problems such as a batch of warped tables.
Edited By JasonB on 26/09/2020 07:30:22
|Nir Somthing||26/09/2020 08:16:56|
|23 forum posts|
I didn’t took the machine apart, I check it still in its box, I added some wood blocks underneath to reduce the movement of the mill, I am sure it will change when I pace it on a proper table, but I don’t buy the claim that it will change completely, it will move probably but no more than a few hundreds (~0.02 mm). I only cleaned it truly and removed the gibs, cleaned them, applied little engine oil to them by hand and locked it until I had proper resistance on the handles. Which gave about 0.05mm movement in the x and y. But as I mentioned, I have the real problem in the z axis, as I described earlier.
When I said 100% true, I meant that I didn’t made the parallels myself, I bought them, and they are supposed to be within a 0.01mm accuracy.
My intension is to have the ability to make two part with a few holes at certain location, and not worry that the holes will be aligned, I am tired of making bigger holes to account for deviation of my old press drill. I have no idea what I will do with it in the future but milling accurate parts could help me a lot. For my work real 0.1 mm will be perfect but over ~50cm. Error adds up as you already know, and I expected this machine to be a lot more accurate.
The serial number on the first mill I got was 90415 and the one on the new mill is 90414.
Since everyone seem to not trust my measurements, I have an idea, I can ask the seller to check the first machine that I already returned, by a professional, it will cost me around 200 USD. And if he confirms that the machine is inaccurate, we know the problem is with the machine. If he confirms otherwise, we know that I am the problem, and I can ask him to return the machine to me – but then I will be sure I got a good mill.
As for your videos, I did the same tests, except that I used the chuck since the ER collet that I ordered a month ago is still on its way… And buying it here is not an option.
I am afraid from the rust since I know that it may shorten the life of the circuitry.
The paint is just cosmetics – but it indicates the “quality assurance”
Note I have a different panel and a feed lock handle.
|Neil Wyatt||26/09/2020 09:38:50|
18232 forum posts
I haven't gt involved as between Jason and Ketan there is little they don't know about these machines, if anything.
What I would add, by way of background, is that more than once we have had posters who have got very flummoxed about the accuracy of their machines when the underlying cause has been something quite simple: examples include poorly adjusted spindle bearings, loose gibs and not appreciating that a relatively light machine will inevitably flex when the table is moved fully from one side to the other.
It's helpful to see and understand exactly how a test is carried out because there are many variables involved.
You mention adjusting the gibs ' Which gave about 0.05mm movement in the x and y.' Assuming that is 'play' measured somewhere it sounds excessive, and that much side to side movement would be enough to allow the able to shift or tilt out of being square to the column. Without seeing how you made that measurement, it's not really possible to understand if this is an issue or not.
I'm not trying to criticise, just to explain some of the hazards of trying to understand such measurement at a distance. Very often, ten minutes spent with the machine could replace hours of headscratching on line!
|Nir Somthing||26/09/2020 10:35:43|
|23 forum posts|
Ok, since I made the videos for the first mill and they are no longer relevant I will make new videos one by one for the new mill, not neseserly in the proper order, since I already know the main proble.
Neil regarding your comment, you are absolutly right, and if I knew it when I did my tests on the first mill I may have seen completly diffrent results. However in the tests I do now I took care of such problems. You can not lock a gib all the way in otherwise you apply to much force on the handwheel. As I mentioned the gib in the z axis is all the way in and I still have a play at the bottom and I cannot go all the way up, in the video I just made you can see the dial move about its center when I am at the top becuae I apply force on the handwheels, and when I am at the bottom, the needle is stationary. Pleas see the following table of my test results and the following video (I made the test twice, test deviation is 0.005 mm).
I will try and make all the rest of the videos today
6322 forum posts
Welcome to the forum Nir.
Apologies of course if you know what you're doing, but the suspicion the measurement are untrustworthy is based on experience. As taking accurate measurements is a skill in itself, it's not unknown for newcomers to buy a mill, micrometer and DTI and immediately confuse themselves and the forum by measuring all the wrong things badly.
Another mistake is to strip the machine down, give it a good clean, and then do a poor job of reassembling it.
These machines are what they are - hobby machines, built down to a price. My experience is the design is sound, but assembly is done quickly and inspection is high-level only. All my machines have needed minor fettling, apart from my milling machine which was fine out of the box.
There's a hint big resellers and those who build relationships in China get better machines than those who buy them by the container full. I suspect factory and customer rejects are sometimes sold on by non-specialist internet traders, which is why I prefer to deal with an established UK business. The machines certainly aren't race tuned by master-craftsmen, but you can do that yourself.
Occasionally dud machines are sold in the UK by reputable suppliers, and the fix is to replace them or get money back.
You may have a dud, but may I suggest you start by using the machine to cut metal rather than assume it's no good based on measurements? In my experience, cutting metal reveals problems in a way measurement and inspection don't. If the machine cuts metal successfully, all measurements are irrelevant! And the forum is much better at explaining photos of bad cuts than it is at decoding showers of numbers, especially when some of them appear contradictory.
Measurements are vital after bad cutting is detected. They pin down problems and quantify what needs to be done. But one step at a time. For example, I'd rather test tram (head lean) in the first instance by flattening a test piece. Any error will become visible on the test plate, is easily measured, and it may not matter. If the tram is too wrong, measure and reset it with a DTI on a rotating boom.
Trained men assess machine tools by measurement but it's much harder to do correctly than it looks! I recommend beginners avoid precision measuring for this purpose at first. Until skills have been developed precision measuring done wrongly can be grossly misleading.
It's unfortunate these machines are expensive in Israel, presumably due to import costs. We can be sure the extra money paid by Nir didn't find it's way back to the factory, or get spent anywhere in the supply chain on improving the tool!
There's no hope of getting tool-room quality from an off-the-shelf Far Eastern Hobby Mill. For that expect to pay about six to ten times as much for a mill from the Industrial range.
If Nir was in the UK and really requires the best, I'd suggest exploring the second-hand market for a high-end machine in good condition. But finding one and exporting it to Israel sounds like a lot of expensive bother, especially if it too needs repairs. So, I'd see what the Seig does to metal. Provided it isn't a dud this class of mill is certainly capable of good results, but it may need fettling.
Fingers crossed this works out OK for Nir,
|Nir Somthing||26/09/2020 10:49:07|
|23 forum posts|
|Nir Somthing||26/09/2020 11:18:16|
|23 forum posts|
I will never dream of disassembling a new mill, as I said I only disassembled the gibs cleaned them added little engine oil by hand and then locked them in place such that I have decent movement of the table.
My worries is that since me head moves at an angle, every time I change a tool I will have to change the hight, that is since an edge finder and a center drill and a normal drill all have different heights and my quill can only move 70mm.
I cannot buy a good old mill and renew it. I live in a apartment in a building, here you can only have a load of 150 kg/meter – so only a Sieg SX2.7, maybe SX3…
Your argument of cutting metal is interesting, however I can only do it tomorrow since it makes a lot of noise and to day is “shabbat”… Anyway I didn't fully understand you when you said:
Again thank you all for your help, I really do appreciate it!
|525 forum posts|
It would be interesting to see how vertical that square is to the bed. Not a good way to measure anything. Is the square actually square? Taking the measurements in a ? drill chuck are dubious at best. All the answers regarding quality measurement seem to apply here.
|Dave Halford||26/09/2020 12:02:18|
|921 forum posts|
Drill chucks tend to have quite a wobble and add their own random error when you turn it or re chuck something.
Do not use any milling cutters on that without a proper cutter holder
|Ketan Swali||26/09/2020 12:08:11|
|1296 forum posts|
I have forwarded your serial numbers to the factory, and suggested that they check their build logs for these two machines, and also check which of the two dealers in Israel they have supplied the machines to, and enter into a conversation with them, if it is felt necessary by all concerned.
As far as I am concerned, the rust and paint touch up you have highlighted is not a big deal. Some people may disagree. Regarding the inaccuracies to which you refer, this is really a matter for you to take up with your supplier. To build up a case to present to your supplier by directing him to this thread to refer to every ones opinion is speculative and wrong. What you really need is an experienced machine tool fitter in your country to assist you to make the necessary adjustments as he feels appropriate, to meet your specific requirements. This is different to your suggestion to get a professional to check out the machine at the dealer for USD200. In my opinion, if you are paying for it, it may be better for you to discuss the matter with your supplier to get an experienced machine tool fitter to assist you, with mutual agreement between the two of you. Although, I am still uncertain if the fitter or anyone else will be able to solve your problems. It may also pay you to do a milling coarse of some description.
There are too many variables in this conversation, to include the human element. It would be wrong of me to speculate, especially as it is a machine sold by a different dealer in a different country. I believe that the dealer would need to be given a chance to deal with your concerns directly. If you would have purchased the machine in the U.K. from ARC, looking at the variables involved, I would have just taken the machine back and directed you to consider purchase from elsewhere. This would not in any way deny your concerns. It would only recognise that it would take too long for ARC to deal with the concerns you have raised - be they right or wrong. There are people on this forum who are aware that this is ARCs company policy, as we simply cannot afford to get into an endless discussion on so many variable issues - regardless of there being so many issues/perceived issues or otherwise. Mind you, in the old days, for $3,000.00 we would have done a full overhaul - preparation service and even polished the machine for you at this price, which is nearly double what we sell at. (Before anyone asks, ARC stopped offering the preparation service about five or six years ago.).
ARC currently sells this machine at around USD1750 inc.U.K. tax. Our profit margins on SIEG machines are very low. So, from your perspective, I can understand your expectation for the price you have paid, but at the same time, I have no idea of what your dealer paid SIEG for the machines, nor do I have knowledge of Israeli import duties, taxes and overheads, so again, it would be wrong for me to make statements of what your dealer should do for you in your particular case.
Ketan at ARC
|Nir Somthing||26/09/2020 12:43:05|
|23 forum posts|
Ketan Swali, My Dealer offered to replace or take it as you mentioned and he is on my side, I came to this forum to find more professional view on the matter. And take the best option, thank you for your detailed post.
Oldiron & Dave Halford, as I mentioned I ordered a ER collet more than a month ago and it still didn't came. However Your claim regarding this specific test is not accurate. It doesn't matter if the check deviated, I move the head and lock the chuck and quill so there is no movement of the dial relative to the head. The right angle is new from iGAGING and it is supposed to have squareness of 0.0003" and straightness of 0.0006".
Here is another video to describe this mills problem:
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