A Small Mill: My Sieg X3 Saga

Discussion on all milling machines vertical & horizontal, including but not limited to Bridgeports, Hardinge, South Bend, Clausing, Van Norman, including imports.

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Harold_V
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Post by Harold_V »

I'm inclined to think that you are experiencing chip welding, loading the flutes so chips can't exit the hole you're drilling. That often binds the drill in the hole.

A move to kerosene instead of WD-40 may yield better results. Dark cutting oil has sulfur in its composition and is not recommended for machining aluminum.

Harold
Jack772
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Post by Jack772 »

All this about this mill/drill has really helped me to get everything in tune.
Thanks agan,
Jacj
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DICKEYBIRD
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Post by DICKEYBIRD »

Bolsterman wrote:Putting a 3/8 drill through 2" of aluminum with a marginally sharp bit had the machine bogging down and faulting before I figured out I was using the wrong drilling lubricant. Once I got a heavier oil down the hole, all was well.
Huh? I just made an emergency plumbing repair clamp out of some 1 1/2" 2024 aluminum I had lying around and used a 3/8" bit as the pilot hole for the 7/8" bit and punched them both right through with nary a whimper.
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Plumbing Clamp.jpg
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Bolsterman
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Post by Bolsterman »

FWIW, my machine shop professor diagnosed the problem as my using a high helix bit for a deep hole.

[EDIT] HOWEVER, I've noticed there are recently a number of complaints of X3s bogging down during drilling, and faulting, in the Yahoo X3 forum, so maybe there's more to it than just a high helix drill bit.
Last edited by Bolsterman on Fri Apr 16, 2010 11:45 pm, edited 1 time in total.
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Bolsterman
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Re: A Small Mill: My Sieg X3 Saga

Post by Bolsterman »

Back at it.

I've happily used the machine for several small projects, but it's time to get back to getting the machine in better shape. I could use some advice at this point. Here are my issues:

(1) Ever since I got the column within .001 for left/right, I have ignored the fore/aft measurements, just wasn't up to it. Wanted to get some work done. However tonight I screwed up my courage and measured, using a precision angle plate and a DTI on a 'dogleg', as you can see in the photo. (The orange oiled plywood frame in the background is the beginnings of a tool board.)

Image

I found that I'm somewhere between .002 and .003 out of plumb, over 5", with the column leaning forward. (Then, just for ducks, sweeping the table with the indicator shows I'm between .003 and .004 in the "nod" attitude, meaning that...what...the head is drooping somewhat, that the Z gib isn't tight, or something.) OK, .002 to .003 isn't too bad, but if I wanted to add a little shim to the front two bolts, how would I do that? The shims would probably be sub .0015, which is the thinnest I have. Any clever ideas of a very thin shim I could try? I've heard of plastic shims. Should I be trying seran wrap? (I've experimented a little with differentially tightening the four column bolts, I think my prof called that "torque tramming" or something but haven't been able to get it to work. I'm at about 30 ft lbs all the way around at this point.)

Secondly, how would I make/insert shims for the front two bolts? Would they be "half shims" under just the front bolts, as I've attempted to illustrate below? Is that OK to do? I've heard that cast iron cracks if not fully supported, but I can't imagine a .001 shim causing trouble...but I don't know. Any additional shims would be in addition to the .002 shim that's already under the right two bolts.

Image

(2) My second issue, is that when I turn the z axis downward, the head doesn't come down smoothly. It jumps in about .006 or .007 increments! What's up with that?

(3) Third issue is, the head seems to be fairly noisy. While the gearing inside the head is well oiled, maybe I have the wrong oil? Or should I be using grease in there?

Thanks for you input, ... Bolster.

PS: Nice upgrades to this forum, thanks to those who put in the effort to upgrade it! Mods, if you wish to move this thread to the new Mill section, go for it. Or leave here. Doesn't matter to me.
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Harold_V
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Re: A Small Mill: My Sieg X3 Saga

Post by Harold_V »

Bolsterman wrote:Secondly, how would I make/insert shims for the front two bolts? Would they be "half shims" under just the front bolts, as I've attempted to illustrate below? Is that OK to do? I've heard that cast iron cracks if not fully supported, but I can't imagine a .001 shim causing trouble...but I don't know. Any additional shims would be in addition to the .002 shim that's already under the right two bolts.
You are on the right track with your shimming concept.
If you are concerned about breakage-----once you have the prescribed amount of shimming in place, assuming you have room, insert a shim that bears on the casting, between the two bolts on each side. With the bolts snugged up, slide the shim towards the tight side until it won't move any more, then torque the bolts to the prescribed tightness. That should lend enough support to discourage any cracking.
(2) My second issue, is that when I turn the z axis downward, the head doesn't come down smoothly. It jumps in about .006 or .007 increments! What's up with that?
That's a sign that you have the gib slightly too tight, or that the ways lack proper lubrication. If you are using way oil, I suggest you back off the gib ever so slightly. The head should settle of its own weight, and keep up with the screw.
(3) Third issue is, the head seems to be fairly noisy. While the gearing inside the head is well oiled, maybe I have the wrong oil? Or should I be using grease in there?
It's hard to say if the noise you hear is proper or not. I expect the gears are spur type. They are known to be noisy.

I would suggest you open up the gear box and inspect the gears to insure that they are not showing an unusual wear pattern. Also, check to see if you find fine metal particles in the bottom. Look for signs of metal flaking off if you do. Gear teeth should be smooth and shiny. If they are rough, good chance they are breaking down.

Harold
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Re: A Small Mill: My Sieg X3 Saga

Post by stovebolt »

Bolsterman, I bought one of the HF clearance X3s, just after I ordered it I found your thread, thanks for posting. I too had to shim the right side, I forget how much but it's close to what you did. I've used a fly cutter a few times, it seems to be close enough. Raising and lowering the head wasn't a smooth operation so I added a counterweight and worked on the Z gib, my Z gib strip was bowed, a few minutes with a some sandpaper an a surface plate fixed that. While I don't know if it is entirely necessary I made a gib strip lock. ( click on for larger image)
Image

My head was noisy too, whether the noise level is in the normal range for an X3 ? how can one tell unless you have access to a couple of other X3s. I live across the river in AZ , weather condition, HOT ! , during the summer I work early in the morning and late at night so I did a belt drive conversion to reduce the noise, it made a big difference. For you still using gears, I don't think using that top oiler is a good idea, the oil passage comes out right on top of the drive gear, it seems to me it will just throw the oil all over the place including the motor drive belt, I would recommend grease, also it seemed to me the noise did diminish some the more I used it.
I posted some pics of some of my mods on the Yahoo X series group under Jim's X3 mods,

http://groups.yahoo.com/group/X_Series_ ... 8/pic/list

or

http://profile.imageshack.us/user/stovebolt

I've been home machining for a few years but I still consider myself a rookie and as I said the X3 is new to me too so I'm not saying I really know what I'm doing :mrgreen: .
Last edited by stovebolt on Sun Apr 18, 2010 5:30 pm, edited 1 time in total.
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GlennW
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Re: A Small Mill: My Sieg X3 Saga

Post by GlennW »

Bolsterman wrote: The shims would probably be sub .0015, which is the thinnest I have. Any clever ideas of a very thin shim I could try?
Use differential shimming.

If you use a .002" in the rear and a .0015" in the front, you have changed it .0005".
Glenn

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Bolsterman
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Re: A Small Mill: My Sieg X3 Saga

Post by Bolsterman »

@ HV, you were right. A half turn ccw and the head now lowers smoothly (yes, lubed with Vactra 2). Thanks. I really need to take off the head and look at that gib. Have been putting that off, but I've read from enough users who say it's a problem area, I dare not ignore it too long.

@ Stove: That has to be one of the nicest spindle locks I've ever seen on an X3. Nice work. FYI this is my second X3 and it's a bit noisier than the first. Need to try grease in the head and see what happens. Will report. (Just across the AZ border? Quartzsite? Former stomping grounds o' mine!)

@GW: Good tip. The left side has no shim but a good trick for future use.
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Re: A Small Mill: My Sieg X3 Saga

Post by stovebolt »

The spindle lock was one of the first things I did, not that the wrench supplied would be easy to use, but it was a ½" too wide any way. I have both R8 and ER collets, the lock really comes in handy with the ERs, after loosening the nut you can keep enough pressure on the spindle too keep the lock engaged so you can hold the cutter while you pop the collet loose.

I'm up in Havasu.

Jim
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Re: A Small Mill: My Sieg X3 Saga

Post by Bolster »

Months later, I finally got around to removing the Z gib, having frequently heard it's a source of problems. Lower the head onto a supporting piece of wood, then unscrew the Z gib screw, and out it comes. Shocking, what a strange looking piece of metal to find in a precision machine, looks like shrapnel. Lots of small grinds on one face (not precision scraping, but grinding with an angle grinder in a cross-hatch pattern) making me think the roughness of the surface is intentional...perhaps to hold oil? ...decrease friction by reducing mating surface? ...or just plain shoddy workmanship? Having read many recommendations to flatten the Z gib on the X3, I give it a sanding on plate glass. I didn't try to remove all the imperfections, or even most of them; I'm just going for SOME smooth areas on all four sides of the gib. Here's the point at which I stopped, gives you an idea what it looked like when I started.

Preliminary, but this seems to have resolved two issues: (1) the head doesn't move as much anymore upon tightening the Z axis lock, less than .001. (2) You can get the gib pretty snug and not have the herky-jerky lowering issues I was having earlier.

Even with this modest sanding, the gib now rides lower than it did previously.

Image

More tramming...a check of the machine indicates it's not falling out of tram, that's good.

With a 5" angle plate sitting behind the quill, I check column's forward-back lean. Run a DTI mounted in the quill up and down the angle's face. Out of plumb by .001-.002 over 5", still a slight lean right. (Difference based on which face of the angle I use!)

With a 5" angle plate sitting to the left of the quill, I check column's left-right lean. Run a DTI mounted in the quill up and down the angle's face. Out of plumb by .001-.002 over 5" again, column slightly leaning forward.

Previous to pulling the gib, putting the DTI in a "dogleg" and sweeping the table in a 6" circle gave me an out-of-tram reading as large as .004 at about the 4:30-o-clock position on the table, indicating both nod and rotation of the head, that's just not good enough. So I pull one of the two registration pins on the head, loosen the four 8mm bolts, and tap the head with a dead blow in the direction it needs to go (counterclockwise). The one remaining registration pin won't let it go too far. And, since the sweep tells me the head is nodding a bit, I try differential torque when tightening back up. Two top bolts get 30 ft/lbs, bottom two get 15 ft/lbs. (I'm not convinced differential torque does anything, really.)

A 6" sweep of the table yields .002 off if the head is locked and .003 if not; the error is now at the front of the table (6pm position) so my tapping the head counterclockwise worked. Remember there's an addition of errors here; the column is leaning forward a little AND the head is nodding a little.

Fortunately the quill seems to pull down pretty straight, I don't see that it's adding any error that's not there already. Running the DTI along the vise jaw gives me .0005 over 4 inches.

I'm thinking that's about the limits of what I can reasonably do with this machine; it's really hard to do finer adjustments, because even the thinnest shims will probably overcorrect at this point. If I were to pursue perfection it would mean finding sub .001 shim stock. I have heard of very thin plastic shim stock, I should probably look into that.

Questions:

(1) Next time I pull the column from the base I'm really tempted to go after the mating surface on the base with fine sandpaper wrapped onto a piece of flat glass, putting a bit more pressure toward the back of the mating surface, and a few more swipes on the left side, to get the column to lean a bit more back and left slightly. When I mention this to my machining buddies they scream at me not to do this, they say I'll ruin the machine; the only appropriate method is to scrape (which I guess takes training).

(2) I'm at a loss regarding how you would get rid of the last bit of nod that seems to be a head-to-column issue. Perhaps I have to just live with it...if this were your machine, would you?

(3) Given that I seem to be mostly < .002 in my tram measurements (the worst being the 6" sweep of the table if the head's not locked, <.003), do you think I've taken this to its logical conclusion...do I live with it? The reason I'm asking is that my machinist prof made us tram the mills at the school to .005 with about a 8" radius sweep bar, and mine's a 3" radius. I have a sneaking suspicion my prof would not consider the mill correctly trammed yet.

Thanks to all for the advice to date. Hope others find this helpful.
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Re: A Small Mill: My Sieg X3 Saga

Post by Harold_V »

If you have access to other equipment, you can make a proper setup and skim cut the base, correcting the error you report. It can be accomplished on a lathe, assuming there is a method to hold the part. It can also be accomplished on a surface grinder---or even a mill. You may be able to narrow the error to less than a thou.

Accomplishing this task would require that the shims be removed, and a determination made of the existing error. That error would be corrected in making the setup, then a re-inspection performed to determine any final corrections that may be required. I suspect that the amount that needs to be removed would be difficult to accomplish by hand work unless you chose to scrape.

Scraping is the method that is generally applied, but it can be accomplished by other means. It is important that you understand that machines like the Bridgeport mill are NOT scraped, contrary to popular opinion. They are ground, then flaked (supposedly for oil retention). Hardly the same thing.

On the subject of the pattern you discussed on the gib----I am of the opinion it is a scraped pattern, just coarse. It has that appearance, but I could be wrong. I am looking at a picture, not the gib.

Scraping does not yield a well defined pattern, but tends to be random, much like your gib. Flaking, by contrast, generally has a relatively consistent pattern, often well defined by the person doing the flaking. Each person has his own way of accomplishing the task.

In regards to comments from others, that you would "ruin the machine" by attempting to correct the inherent error---it's pretty simple. If the interface of the two components requires shimming (and it does), what can you possibly do to "ruin" the machine? If your mission is accomplished, you end up with properly mating surfaces. If not, you end up with surfaces that require shimming. Seems to me that's where you are now.

Something to consider. All you know right now is that you have error, and that you have shimmed previously. That does not define where the error is to be found. You may have a mounting surface on the base that is distorted. That needs to be determined, as well as the condition of the mating piece.

How much you torque the screws shouldn't make a difference. If it does, the machine isn't likely very rigid in use and will be troublesome. The ideal situation is for the two surfaces to mate properly, at which time increasing torque will not make a difference. I'd encourage you to improve the machine, assuming doing so is important to you. The existing condition will yield problems if you attempt any tight tolerance work, depending on the degree of precision you hope to achieve. My personal goal would be to have no more than a thou in five inches. I generally mess with my mill until error reads less than a half thou over a circle of about 8".

Harold
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