The Home Machinist!

My X3 is a bit "iffy" in the head/column junction. The head doesn't lock into the same position consistently, depending on how much torque is applied to the lock handle. You might want to check yours in that area. Without consistency there, attempts to super-accurately tram the mill would be futile.

One of these days, I'll strip the head and gib apart to chase the problem down but right now I'm making decent parts and having too much fun with it.

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"Accuracy is the sum total of your compensating mistakes."

Bolsterman,
I think before you go any further you should thoroughly investigate the gib situation that Harold mentioned in his last post. I have a Grizzly/SX3, which I think has exactly the same gib setup on the head/column interface. I had the same problems you're experiencing and finally tracked it down to the gib strip itself being rough and uneven. I lapped it smooth/even/level on a granite plate with wet/dry paper and lots of elbow grease. When I finally got it smooth/level/even, I'd removed so much metal that the taper allowed the lower end of the gib strip to project below the head when properly adjusted, but it had solved the problem. I have since obtained a new gib strip from grizzly. It came as a totally blank tapered gib strip, but was very straight and even. I had to machine the adjustment teeth on the top end, drill the oil port and mill-out the slot that serves as kind of a half-ass oil reservoir. After I did that, I lapped out the 'chinese-finish' on both front and back. I'm very happy with the results. I would also like to mention that adjusting this gib is nothing like adjusting the gibs on the x or y axis, or gibs on a lathe. The weight and lever-arm of the head puts a lot of pressure on the head/column interface (and gib), giving you a false feeling that the gib is properly adjusted, when in reality it's not snug enough.

First of all, thank you for your invaluable advice. You guys are my lifeline!



Indeed. I would be pleased if I could keep the machine itself square within .001 over 5" and would settle for .002. As far as projects are concerned, I'm hoping I can hold .003 on small items (think 5" or less) and would grudgingly settle for .005. I have snugged the gibs until I feel binding and then let them off a scootch, which was my prof's recommendation, although I could tighten them up a bit more. While I did remove the X and Y gibs and stone them a little, I did not remove the Z gib for inspection.

I think I understand your advice about method sequence now (I misunderstood it the first time you gave it!) but just to make sure: First you get the column square left/right by using the indicator running vertically against an angle plate. You use the Z-axis crank only (not the quill feed) to move the head up and down. THEN you perform the sweep method referencing against the table, and rotate the head as needed to get that as good as possible. When it comes to correcting front/back, if the chin is dripping, I'd need to place a little shim under the bottom two bolts holding the head to the column, right?



I've noticed that my head shifts position between .002 and .003 when tightened (with the "chin" coming up, obviously), and the amount you tighten it does make a difference! I've wondered how to deal with this when Z-axis movement is necessary to make the cut. With testing so far, it seems it'll cut up to .003 deeper if the head isn't locked. Well, you can't lock it when you need to plunge a cut, so...here's maybe an .003 I'll just have to live with.



That sounds like an excellent lead, and what you say makes sense. I have not separated the head from the column yet, and it sounds like I should at least pull the gib and get it nice and flat. Do you have to pull the head to do that or does the gib just lift out?

I have been corresponding with Grizzly who on several occasions have said "Send it back" and am still leaning that direction. I'll keep you abreast in the next update. Thanks again for all the help, B.

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A Bona Fide Soggy Bottom Boy

I hope you realize that some of that will depend on your level of proficiency. Running machine tools with precision requires some very careful steps, consistent clamping, consistent locking of devices. It gets down to almost everything making a difference. It's something you'll come to understand as you become familiar with your given machine----so do be a little patient at first. And please remember that it's easy to make chips, but not so easy to make good parts. It comes with experience.


Judging from your comments, below, that may be part of your problem. You should not experience excessive movement when locking a slide. Depending on the nature of the lock (BP, for example, always moves a little), you shouldn't see more than a thou, and less is very desirable.


That you misunderstood it isn't as important as the information you now understand, so you can see the significance of what I said.



That's correct, but when you're running the head up and down, determining the attitude side to side, it will be wise to do the same with the indicator touching the face of your angle plate (square) while it's facing the column. There's no guarantee that your spindle housing is bored parallel to the ways. It would be useful to you to know if the column is proper in both directions. Once you have the column properly aligned, then the reading you get from your spindle will be indicative of the quill as it relates to the column. You have adjustment for side to side, so that's a non-issue. If you find you are out front to back when the column is erect, you're going to have to make some decisions about how much error you can live with. That's assuming that there is no mounting surface between the head and column ways. If there is, the surfaces can be altered to correct parallelism.
Definitely you should investigate the gib, and how tight it is. Make sure it is bearing full length. When properly adjusted, you should see little movement when tightening.

Harold

Bolsterman,
In regards to your question about gib removal, "Do you have to pull the head to do that or does the gib just lift out?".
No, you don't have to pull the head, but the gib doesn't easily slide out. First, remove the head locking lever/screw completely, don't just loosen it. Then, turn the upper gib adjustment screw counter-clockwise until it is very tight. Now turn the lower gib adjustment screw clockwise. The gib should move slightly upward. If it does, continue alternating between first turning the upper screw counter-clockwise, then the lower screw clockwise to push the gib up. If the gib doesn't move at all, the weight of the head is jamming it tightly in the dovetail groove and you'll have to 'unload' the head by placing a piece of 2x4 or something between the table and the spindle and take the weight off the head by moving the quill down. Once you've moved the gib up a bit, the taper will loosen it even more and it'll come out easier. The upper gib screw is a double-headed bolt the mates with 'teeth' cut into the gib, so when you turn it counter-clockwise it pulls the gib up, but initially it will need help with a push from the lower screw.
When you replace and adjust the gib, remember, there's no gib screws like on the saddle, to keep the gib from sliding back and forth, so the gib must be tightly locked between the upper and lower adjustment screws. If it's not, because of the taper, the gib will move up when you lower the head, loosening itself, and move down when you raise the head, becoming overly tight.

Bolsterman,
Arc Eurotrade in Europe is one of the more reputable vendors of the X3 mill. When you pruchase and X3 from them, you have two choices. The first is about the same as Grizzly. They open the crate, do a visual inspection for damage, close the crate and send the mill to you. The second choice, they will 'prepare' the mill. Tear it down completely, clean all parts, inspect and correct any deficiencies, lubricate and adjust it correctly, then pack it back up and ship it to you. This adds 250 UK pounds to the price (about 500 of your dollars).
The reason I mention this to you is that you expressed an intent to possibly tear into the head. Arc Eurotrade is benevolent enough to make the detailed, pictorial laden X3 preparation guide available as a free download. I'd recommend you get this if your going to do much teardown.
http://www.arceurotrade.co.uk/projects/ ... 0Guide.pdf
If you do, pay special attention to the section about the upper bearing journal on the spindle being oversize, making adjustment of the spindle preload difficult/impossible. This seems to still be a problem occasionally on some of the X3's and definitely can have an effect on the accuracy of the machine.

I’m baaaaack! You haven’t heard from me in awhile because I returned my previous X3 and got a replacement. Here’s what’s new:

If you have been following the story so far, you know I was measuring plumb on the column the wrong way (with a sweep bar, which can hide bad plumb by compensating with a head tilt, as explained above by Harold_V).

That insight was invaluable to me. So I took the shim out of the base of my previous X3, put the reference pins back in, basically to “start all over from factory setup,” and found the column was leaning to the right about .012 over 5”, as measured with a precision angle block on the table and a dial test indicator run across its face in the Z axis. This means, that over 15” of headstock travel, the column was out of plumb (leaning right) about .036! If you do a quick calculation based on how much correction you get for the width of shim under the column bolts, you get a multiplier of about 1.5 (provided you are checking based on 5” of z travel)--that number should be handy for some other X3 owner out there. [EDIT: That multiplier is waaay off for my new machine...stay tuned, I'll post it when I figure it out.] In other words, if you measure out of plumb .012 over 5” of Z travel, your shim under the column bolts needs to be around .018. I just could not live with that much shim, it offended me. Plus, the table was .003 overall (Griz specifications say it should be within .002), but the most difficult part was that .001 dip or trough running diagonally across the table, which just happened to be in the area needed to tram the mill. So my indicator sweep measurements were always suspect. When you are sweeping an indicator with only a 3” radius (the table is about 6” deep), .001 can get you thinking you’ve got problems, when you may not.

So I built a crate, packed it up, loaded it into my pickup. Learning a lot about how to lift the little beast; have a look at this photo, it’s my best lift yet, pretty much straight up and down. The trick is to have the lift point as far to the rear as possible, then to have straps going horizontally around the machine to keep the vertical lift straps in place.

Sent it back to Grizzly via FedEx…Grizzly was very cheerful during the whole process, paid for return shipping. They never gave me a minute of grief, they were very willing to replace…they were actually encouraging it. I have read that Grizzly sells “mediocre machines with excellent customer service” and I would say that description was accurate of my experience with them. About 10 days later I had a new mill. They even sprung for the additional payment of a lift gate and pallet jack, and I got it set down in my garage directly under the lift point. I opened it up and found the left front mounting bolt had fallen out, just as had the previous shipment. But, no apparent damage from flopping around, as the box must have only been lifted and lowered vertically.

The new mill, manufactured just 6 months later (It’s a 7/09 machine) has a number of interesting cosmetic differences. The hand wheels are much higher quality, no longer are there globs of melted metal on them. The Hi Lo gear changer got knurled rather than fluted. A heftier Z-axis lock. Looks like they have mounted the electronics differently in the column, which is now perforated with louvers to increase airflow. But the most welcome change, for me, are the measurements below.

The table is really flat, not deviating noticeably from .000 until you get to within an inch of the L & R edges of the table, at which point both L and R rise about .001. No dip in the table anywhere. Thank goodness!

Placing the angle plate on the table and raising and lowering a DTI against its face, to check for L/R lean of the column, showed I’m somewhere around .002 to .003 out over 5”. Leaning right as before, but under a quarter as much. Using my 1.5x calculation, that means I’m looking at adding a .004 shim under the right column bolts. I can live with that. [EDIT: as mentioned above, that multiplier isn't working for my new machine. The shim will actually be considerably less in size, I'm guessing .002, will update below.]

So far, I’m happy with my gamble of sending it back and getting another. Still have to go through the lubrication and break-in processes. I’ll spare you the details on that unless something interesting happens.

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A Bona Fide Soggy Bottom Boy

Here is the "how to lift" photo I promised above. This is the old machine that got returned. If you are new to lifting your X3, study this photo. My best lift yet.

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A Bona Fide Soggy Bottom Boy

I think you made a wise decision to return the old one.

Harold

Very glad that you now got a X3 that seemed to come excellent out of the box!

MD

I'm watching this with some interest because I'm seriously considering getting an SX3.

I know that there are differences, but I expect that there are enough similarities that I can apply a lot of what I've learned here (including your rigging and moving experiences).

I'm a bit curious about whether you've found any downside to setting up your shop in the garage (as opposed to in a more environmentally-controlled area such as a basement) and dealing with any effects of temperature and humidity extremes on the repeatability of adjustments made to the mill, possible rust issues, and the like...

I live about 2 miles from the beach in Southern California. Basements are very rare, not how homes are built here. Temperature extremes aren't a worry as they may be for you, but moist air is a concern. Haven't had the mill long enough to have troubles, but the recent heavy rains made the top of my table saw go a little darker shade of brown. However a tablesaw has to be kept clean of oil, whereas the mill is doused in Vactra and also Mobile 30W, the one that was at the top of the "rust preventive" winners in a recent test. If I lived back east, and had a dry basement, that's where I'd put it!

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A Bona Fide Soggy Bottom Boy