X3 Mill tramming thoughts

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jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

X3 Mill tramming thoughts

Post by jmpharrington »

I have a Grizzly G0463 (Seig X3) Mill/Drill

https://www.grizzly.com/products/grizzl ... gKFKvD_BwE

I stripped it down, cleaned and reassembled it years ago, and its been under cover in the garage for quit a while. I decided to start making chips for construction of a 1" scale steam locomotive, and figured checking it for accuracy should be my first step. Using a Fowler DTI with 0.0005" graduations, I came up with the following:

Cranking the table 15.875” across the X axis provided a 0.0025” deviation from one end to the other (high on the right side).

Cranking the table 6.25” across the Y axis provided a 0.0005” deviation from font to back (high in the front).

Centering the table under the spindle and rotating the DTI in an approximately 14.5” diameter, I came up with the results in the attached sketch.
Tramming test.JPG
I’m not sure how much of this is a tramming issue, or if this is an issue with slight warpage/out of flatness with the table.

Tramming the column may take out some of the “Y” issue. This seemingly can only be done only by shimming the four bolts attaching the column to the base. Am I splitting hairs here?

Your thoughts?
Last edited by jmpharrington on Sat Apr 17, 2021 8:54 pm, edited 1 time in total.
kl7sg
Posts: 75
Joined: Thu Oct 08, 2020 12:00 pm
Location: Springtown, TX

Re: X3 Mill tramming thoughts

Post by kl7sg »

Hi,

I have G757Z that I use for manual machining.
I had a similar problem (when new) and discovered that the x axis gibb adjustment was a bit on the loose side.
Also, the head tilt was off a little bit.
Anyway I tightened up the gibb adjustment a little and adjusted the head tilt. Most of the deviation went away.

I think I still might have about 0.001" end to end; but, for what I am doing, it is OK.
Have a nice day,

Mike
pete
Posts: 2518
Joined: Tue Feb 10, 2009 6:04 am

Re: X3 Mill tramming thoughts

Post by pete »

Cranking the table in the X axis over that length won't give you an accurate measurement. Due to the minor but still unavoidable clearances between the dovetails that table is going to rock because of gravity. Do you have a fairly decent lathe that will turn parallel? If so start thinking about building a cylindrical square. I'd try and find something like a length of schedule 80 or better pipe 3" or more in diameter and at least half the length or more that the mill head travels on the column. With one and an indicator you use those to get the vertical column square to the table in both X,Y. Once that's done then tram the head to the table, then run the same check on the heads spindle travel to be sure it is actually square and does move parallel and in line with the now known to be correct column and the same in the Y axis. There's other methods of doing this but a cylindrical square is about the easiest and fastest way that I know of.

How was your indicator set up to check your Y axis? If the table really is rising having it reground or scraped might be a couple of options but that 1/2 thou isn't much. Videos save a whole lot of typing, https://www.youtube.com/watch?v=4HWuhbhySpw&t=2s while there about checking and aligning a cnc bed mill, most of them also relate to what checks to do on most manual mills. I'd recommend watching all of them so you do understand what's involved. It's a bit more complex that many think. On any machine tool slide there's 6 possible directions that single slide may be out including various combinations of all of them as well as having changes in direction for the inaccuracy's along the length of the slide.
jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: X3 Mill tramming thoughts

Post by jmpharrington »

pete wrote: Sat Apr 17, 2021 8:40 pm
How was your indicator set up to check your Y axis?
I had the DTI on an Indicol clamp setup, and cranked the table back and forth a few times to verify results.

Being new to this, and upon further reading/research, I now know that I need to check the squareness of the column first, then the head. I will approach this later today.

I have seen different methods - the one that seems most practical, given the tools I have, is to set up the DTI in a magnetic base attached to the head, and crank the head up and down, with the DTI run on the edge of a machinist square in both x and y axis. (Flipping the square 180 degrees and averaging the results in case the square is not square)

Once satisfactory either by first results or shimming the column, then go after the tram of the head.

Am I on the right track here?

Thanks
pete
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Joined: Tue Feb 10, 2009 6:04 am

Re: X3 Mill tramming thoughts

Post by pete »

Yep, that will be a good method as well. A bit touchy given the squares blade thickness, but it will work. And it's good you already know about averaging the errors from side to side that will be present in the square. Be prepared for a lot of work because it's not a direct linear measuring method. Being say .003" out in one direction doesn't mean a .003" shim will work given the base size verses the column length. Sometimes you have to add a shim to the already high side just to allow for the shim thickness you have available to bring the low side in. It's a fairly long, frustrating and pita job, but very satisfying once you get it correct. And you'll learn a lot.It's also not unknown once the column is vertical to the table in both directions that the heads spindle is then out in the Y axis. The only way of correcting that is either by hand scraping or again shimming.

Also one point I forgot to mention, ideally you also want the face of the column sitting exactly square to the tables X axis. Using an indicator on the table and indicating that column in across it's face using the tables X axis until it is square will work fine. That's done because if you ever want to tilt the head for any angle drilling or cutting you want the tool to not move in/out in the Y axis as the head rotates. Because of the factory machining inaccuracy's, the block the head rotates on may still not be 100% square to the X axis. But you can work on that sometime later if you already know the column is now correct. Also expect to see at least some column deflection as the head moves up/down just because of it's weight. Everything really is made of rubber when your doing alignment checks like this so absolute perfection may not always be 100% possible. I'd be interested in what your starting measurements are for it's factory alignment verses what you end up with. That will be good information for anyone in the future and those will show why all this needs to be at least checked.
jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: X3 Mill tramming thoughts

Post by jmpharrington »

On a positive note, my square is square, which made checking the tram of the column easier.

Also on the positive side, the X axis reads true (remarkably) over 4.5 inches, measured at multiple elevations of the head.
IMG_3070 vert.jpg
IMG_3072 vert.jpg
Unfortunately, the Y axis is off (forward) by 0.002" in 4.5", so it appears shimming will be required. The column bolt spacing front to back is 2.625". Using similar triangles, I SHOULD need 0.0012" shims in the front. Lacking any assortment of proper shims, is heavy duty aluminum foil (+/- 0.0015" as measured in 2 layers) acceptable to use in this application?

Also, before I shim, I will clean the mating surfaces between the column and base, to ensure that crud there is not the culprit.

Now off to contrive appropriate blocking/jacking under the head to raise the column enough to get in there...
pete
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Joined: Tue Feb 10, 2009 6:04 am

Re: X3 Mill tramming thoughts

Post by pete »

You got very lucky with that square and the X axis being correct.The aluminum foil could work but it's pretty soft and may extrude over some time due to the part weight and bolt tension. Brass or steel shim stock is surprisingly cheap given it's accuracy and the amount you get. Pre-cut shims usually have a U shape large enough to fit past and on either side of the mounting bolts so I cut mine in the same shape using common household scissors. That allows you to slip the shims in or out when trying various shim thicknesses a lot easier. Watch for cuts if you end up using any as the edges are really sharp. But even pop or beer cans can be cut up as a bit more durable and harder than the aluminum foil shim material.
jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: X3 Mill tramming thoughts

Post by jmpharrington »

Thanks Pete.

To address some of issues you raised earlier -
The head does not rotate, so I believe the the concern with it not being square when it does is not an issue. The column has alignment pins to the base that would prevent it from rotating.
I had concerns that the foil would be problematic as you advised. I ordered a steel shim stock assortment - should be here Friday.

Thoughts on tramming the head when I get there - It also has alignment pins that would limit any rotation if necessary. Note arrow in picture. Thoughts?
IMG_3075 arrow.jpg
Thanks
-Jimmy
John Hasler
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Location: Elmwood, Wisconsin

Re: X3 Mill tramming thoughts

Post by John Hasler »

I tram my square column mill by shimming the table.
jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: X3 Mill tramming thoughts

Post by jmpharrington »

John,
How is that accomplished?
pete
Posts: 2518
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Re: X3 Mill tramming thoughts

Post by pete »

Ok that ones set up a little different than the square column I have as an extra mill on the rear of my lathe. A bit surprising they didn't add head rotation, but that should make everything a bit more rigid anyway. About all you can do once the column is true is check the head tram. If the factory didn't get that quite correct you'll have to pull that alignment pin. Then get the head trammed true to the table and then maybe re-drill the alignment pin hole to the next larger size and add a larger pin. I suspect that pin does help a bit to lock things in place to prevent any movement between the parts. If it were me, I'd probably drill and tap the end of the new pin to take a bolt. That way if you ever do want to pull that pin it's then easy to use a small bolt and say a stack of washers to pull against to remove the pin. Even better would be to taper ream the hole and then use a taper pin, but not many have the reamers or pins.
jmpharrington
Posts: 102
Joined: Fri Oct 14, 2005 10:22 am
Location: Rockland County, NY

Re: X3 Mill tramming thoughts

Post by jmpharrington »

"If it were me, I'd probably drill and tap the end of the new pin to take a bolt."

That's how the current pons for the column and the head are set up.

With a generous amount of luck, the head may not need any rotation... :|
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