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How to true Nod on this mill?

Anyone know where I'm supposed to oil the quill? There's no oiling spout like on a Bridgeport.
 
Supporting the weight of your mill's head while tightening the gibs on it's horizontal slide may take a crane to lift it or one or two strong assistants.

Or a chunk of 4x4 between the table and head ... spindle nose 2nd choice, but maybe the only ... and jack it with the knee.

Also need to indicate the table with the cross slide before sweeping it with the spindle, to identify which is out of whack.

Matters for table mounted work. Somewhat less for a vise ... mill soft jaws and you're 'square' ... more or less.

Workarounds for those of us who grew up with junk ...
 
If I'm understanding correctly, you're saying the vertical spindle is not square to the table in the "nod" direction. You quoted 0.006", then 0.002".
The center of the spindle projects a point onto the table. The further away from this point you take your measurement, the larger it will be. So at what distance , or circle diameter are you taking the measurements you quote ?
Locking the jibs to take a measurement may give you a false reading. Surely the readings have to be made in the condition the machine is operating. I can understand locking the jibs in the overarm, with the comments about jacking it up before locking. But I'm not sure about the table jibs, as these need to allow table movement.
Maybe you need to measure the error in the condition the machine is being operated, then build in the appropriate compensation with shims, etc.
Bob
 
I would think that the classic way of measuring the angular error of the spindle would be:

1. Check the table top for flatness. If it isn't flat, then all bets are off.

2. Check that the table top is parallel to the dovetail ways that it rides on. To do this, put a DI in the quill and lock it while in contact with the table top. Then traverse the table left-right and front-back to the limits. It should show zero deviation on the DI. Again, if it isn't parallel to it's own movement axis, then all bets are off.

3. FINALLY, mount a DI on an offset arm mounted in the spindle. This allows you to sweep a circle on the table top. Any change in the DI's reading from left to right indicates the spindle axis is tilted that way. And any change in the DI's reading from front to back indicates a nod error in the spindle's axis.

The answer to over what distance the OP's errors were detected would be the diameter of the circle swept in step 3 above.



If I'm understanding correctly, you're saying the vertical spindle is not square to the table in the "nod" direction. You quoted 0.006", then 0.002".
The center of the spindle projects a point onto the table. The further away from this point you take your measurement, the larger it will be. So at what distance , or circle diameter are you taking the measurements you quote ?
Locking the jibs to take a measurement may give you a false reading. Surely the readings have to be made in the condition the machine is operating. I can understand locking the jibs in the overarm, with the comments about jacking it up before locking. But I'm not sure about the table jibs, as these need to allow table movement.
Maybe you need to measure the error in the condition the machine is being operated, then build in the appropriate compensation with shims, etc.
Bob
 
If I'm understanding correctly, you're saying the vertical spindle is not square to the table in the "nod" direction. You quoted 0.006", then 0.002".
Square to any table top means nothing at all. It is "Feel Good". Top of the table could be 10 degrees out and tapered or twisted and who cares?
There is nothing magic about any table top surface. This is rookie thinking. Nice but not never fully needed.
Square to axis travel is what one wants. Add that in such a mill there are two Z axis to worry about.
(this is going to confuse some so lets all hear it)
 
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Square to any table top means nothing at all. It is "Feel Good". Top of the table could be 10 degrees out and tapered or twisted and who cares?
There is nothing magic about any table top surface. This is rookie thinking. Nice but not never fully needed.
Square to axis travel is what one wants. Add that in such a mill there are two Z axis to worry about.
(this is going to confuse some so lets all hear it)
Tramming a BP is getting spindle square to table.....
 
Tram to the table top may not be tram to the cross travel movement, So with the knee/verticle gibs adjusted to about .0003 to <.oo1 and having a .002 or something rise or fall going cross-wise across the table I would put a sign on the machine "A .002 shim in 4" at front or back makes square.
This so the oporator might know what will make a fly cutter flat and also make end mill stepping across a part near flat step to step...and still that would not make it right.

The knee sets the saddle level travel, or not.

Even fly cutting the table top wont make it right if the cross travel would rise or fall the table. One might taper scrape the knee gibs ( the verticle gib) to find perfection or at least better...
.002 is pretty good IMHO
 
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Tram to the table top may not be tram to the cross travel movement,el, or not.
And which matters?
Do we slide a part on the table top when cutting or do we use the axis movement and travels?????
One of these skips the unknown error in the other.
One of these adds an error that should not be there.
Ideally you table top should be cut within 1 or 2 microns of the slide movements. (this fun to do)
Then the top is good and gives a good reference. Now one can set tram to this known surface +/- errors.
 
Found the error came back when setup like this and cranking the knee or the quill. Pushing on the quill I couldn't even get half thou of movement. Gibs are tight but the body to head connection definitely could be torqued more. I loosened everything and cleaned all the thick grease off the dovetails. It's much better now but still not perfect. Went from +/- .008 over the vertical travel of vise fixed jaw to around .0015. Still is way more than I want, and assume some of it might be the vice. I'll buy a new one in a couple weeks but in the meantime should I shim the vice, the jaw or just run it as is?
1000045640.jpg
 
Also, without starting a new thread does anyone know how to adjust backlash on x-axis on these mills? Looks identical to a supermax and a few other clones. I was able to adjust other ball screw axis but they were accessible. Looks like x-axis is not.
 

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