Seig Sx2.7 Milling Machine

[salindroth]

I have had the LMS 5500 mill (2.7) since about Sept/2016. It's my first mill and I've been pretty happy with it on alluminum but it a little small for cutting steel very well. I've run a 3" face mill just fine on alluminum but it chatters on steel. I guess I've outgrown it so I ordered the 9x49 G0796 from Grizzly which is on backorder till at least February. I may end up selling the small one at some point but it's not a bad machine and I really like Frank Hoose's videos on it, that's what made me buy it. It's really too small for tapping over 1/4" holes also.

I’ve gotten good results with CR if I go easy, but, yes, I usually use aluminum or delrin for my projects. I’ll be interested to hear about the G0796 once you get going with it.

 

[harrzack]

These smaller machines can do pretty much anything - if you take the time. Lighter cuts, depths, correct speeds will win out - again if you go slowly. When slow is "too slow" then you move up - next thing you'll have a Bridgeport in your shop! !

 

[lcrepairs]

These smaller machines can do pretty much anything - if you take the time. Lighter cuts, depths, correct speeds will win out - again if you go slowly. When slow is "too slow" then you move up - next thing you'll have a Bridgeport in your shop! !

I understand your point but I have found that there just isn't enough Ridgity for some jobs like facing large surfaces on steel type materials with these little Girly Mills like the one I currently have.

 

[DDS]

The SX 2.7 looks like a good choice if you are concerned about size and weight, but there are things about this machine that need to be answered first.

1) This machine does not have a closed square column like the Mini Mills, it has an open "C" section channel design which is not the best design for rigidity. Trying to get a value on the stiffness of the column is apparently not possible. In facing operations this machine may not be much stiffer than the Mini Mill, and IMO may be the reason Seig classified this machine as a "2" instead of a "3" - everything else looks really solid.

2) One parameter on the 2.7 has remained an enigma for me. That being the distance from the table surface to the bottom of the spindle in the full up position. Seig's web site gives this dim = 14 9/16" (370mm) but both LMS and Grizzly sell machines with the dim = 12 3/16". I suspect the difference may simply be how much the R8 spindle portrudes below the head casting, compared to the MT3 spindle, but trying to get that verified has been harder than it should be. 12 3/16" "head space" is not very much for a 1 horse power machine. And I suspect Seig has kept the column height as short as possible for concerns about ridigity - but that is only speculation.
LMS 's machine has a head travel = 11.25" while Grizzly's machine has only 8 5/8" head travel. They both have table to spindle dim's = 12 3/16" and both have R8 spindles. Why would these travels be different? This would suggest Seig is making different machines for different distributors - that they are all not the same. Send seig an email asking about these things and you will get 1 reply directing you back to your local seller, and there after no replys at all. The sellers in the USA are LMS and Grizzly and they haven't a clue about these things.

3) I can't help but notice the parameters of these Sx2.7's seem so close to being really good, that I remain interested in them. My experience with my Seig Mini Mill which is 16 years old has been nothing but positive. I broke my plastic gears for the first time last month and fixed the problem in one week by buying an entire assembled head casting with new gears for $140. Everything else has been just fine. I might add here, that years ago I removed the head travel limiting screw on my Mini Mill which resulted in a full 13" head space. This is one reason I am concerned about buying a SX2.7 replacement for my S2 which would have even less head space. I might also add that the SX2.7 looks like it could easily have the head space increased by simply inserting a riser block between the column foot and the base. LMS actually offers this option for the new Seig Mini Mills. Also it looks like a easy job of modifying the SX2.7 column by replacing the sheet metal cover with a bolted on heavy steel plate, making the column a closed rectangle rather than a open "C" section. It appears that the only thing under that sheet metal cover are wires they could easily be reroute out the back through a hole

4) In summary the SX2.7 looks like a real winner but only with some modifications and only with some good technical information which is almost impossible to obtain. I hesitate in buying one and finding out the hard way.

If anybody has any answers about these things please reply

 

[salindroth]

The SX 2.7 looks like a good choice if you are concerned about size and weight, but there are things about this machine that need to be answered first.

1) This machine does not have a closed square column like the Mini Mills, it has an open "C" section channel design which is not the best design for rigidity.

True enough m, but the LMS 2.7 is far more rigid than an S2. I mostly work with aluminum, but cuts of .035”(+) are fine. I seldom went beyond .020” on the S2 and even then thought I was pushing things.

2) One parameter on the 2.7 has remained an enigma for me. That being the distance from the table surface to the bottom of the spindle in the full up position...

I’ve not had any problems with vertical headroom compared to the S2, but YMMV. The big difference is cranking the head up and down. You will fatigue quickly unless you use a power driver of some kind to turn the crank for you.

3) I can't help but notice the parameters of these Sx2.7's seem so close to being really good, that I remain interested in them...

I’ve really enjoyed the S2.7 from LMS. Here are my grumbles:

- tramming the head was easy (and frequently required) on the S2. It’s a bigger deal on the S2.7. In fact I think I’d need a hoist of some kind to lift the column off the base for shimming. It’s not far out of tram, but I wish it were easier to “dial it in.”

- I’m not completely happy with the finishes I get when side milling. I imagined that I got better finishes with the S2, but it turns out the results are comparable, especially if I lock down the head and table on the S2.7.

- I was able to reduce spindle runout to < 0.0005” on the S2 when I upgraded the spindle bearing. The runout on the S2.7 is just over 0.001” and I think this contributes to the problem with side milling finishes. Again, I haven’t had the gumption to deal with it because the head is so much heavier than an S2.

Overall, the benefits of greater rigidity and the tapping feature on the LMS 2.7 have outweighed what for me are very small compromises. Like the S2, you learn how to get accurate results with the tool at hand. I’ve been able to take the on projects that would have been awkward if it not impossible on the S2. And the ability to take beefier cuts in aluminum has been a big win for me.






Sent from my iPhone using Tapatalk

 

[DDS]

Salindroth, one question I would like to ask is about the method of taking slack out of the "X" and "Y" table movements. With my old mini mill, in order to accomplish this I must tighten (4) 5mm set screws against a filler bar that pushes against the table ways. The pitch on a 5mm thread is about 1/32" meaning it is almost impossible to control the clearance to levels of about .001" which is a must for a smooth cut (even closer). Furthermore when I finally get the clearance set properly, and try to lock the set screws in position by tightening lock nuts, it changes the clearance and makes the job a tedious trial and error operation. The reason you cannot lock the set screws without screwing up what you just set is the slop in the threads of the screws and nuts and the imprecise painted surfaces the lock nuts push against. My solution for years has been to simply apply weak (old) thread locker on the set screws and leave the lock nuts loose. But this method only lasts for a short time, and I am constantly adjusting the set screws. I noticed on the 2.7 it looks like the table clearence adjustment is accomplished by a single set screw pushing on a long tapered dowl that runs the full lenght of the table, which could be a solution to this problem. But Is it in fact?

 

[salindroth]

...I noticed on the 2.7 it looks like the table clearence adjustment is accomplished by a single set screw pushing on a long tapered dowl that runs the full lenght of the table, which could be a solution to this problem. But Is it in fact?

Yes, that is correct. (And in my earlier message I meant to say "X2" and "SX2"...)

 

[lewiss66]

Hi DDS,
I know It's a bit old but I ask.
Did you finally decide to buy the SX2.7 ?
Thanks

 

[Niros]

Hello,

I have recently bought the mini mill SX2.7L (My first mill) after looking at Frank's video on you tube, however I think that I have gotten a rotten apple.
After doing some tests I measured (relative to the spindle) a deviation along Y axis on the right side of the table of 0.2 mm and on the left side 0.12 mm and the right to left error is 0.4 mm! (Table length 700 mm)
Relative to the head, measuring on one spot and moving the table in the x and y directions, there is also a deviation of the same order which I don't get since as I understand it, if the table is tilted to 5 degrees and the table is moving along its plane I should be able to read constant height - no matter the angle, so does this means that the table itself is moving relative its own axis!?.
The table is also not flat, I can see light clearly when using a precision square ruler, but my feeler gauge smallest shim is only 0.05 mm and it doesn't fit by force, I will guess 0.04 mm is the flatness of my table in the y axis (length 160 mm)...
The only part that is accurate is the run out of the spindle of 0.01 mm.
The seller offered me to replace the mill by a new one from a closed box, however he mentioned that I will realize that it may behave in the same way, and that in such a case I will not be able to complain again.
Please tell me based on your experience, should I take the offer or try and level what I have? (There are other troubling factors, like back cover a little bent on top, corrosion on 3 bolts and paint removed at 3 different places).
I can shim the head along one axis but not on two (at the same time) this is way over my league...
What is a precision that is counted to be "good" and what will be considered "terrible"?

Thank You Very Much!
Nir

 

[higgite]

Have you adjusted the gibs?

Tom