Tramming the nod

If the mill has the nod option then adjust it on the table in front to back and side to side. With the arc of the indicator to the edge front to back . If your mill doesn't have the nod then you'll need shims and have to shim the back of the mill mount to the base . It's tricky can be done. Stefan Gottswinter, on YouTube used an epoxy to cure his mill problems . He's very very good as a machinist .
 
Silverbullet said:
If the mill has the nod option then adjust it on the table in front to back and side to side. With the arc of the indicator to the edge front to back . If your mill doesn't have the nod then you'll need shims and have to shim the back of the mill mount to the base . It's tricky can be done. Stefan Gottswinter, on YouTube used an epoxy to cure his mill problems . He's very very good as a machinist .
Click to expand...
The mill column is bolted down, no adjustment. I saw him use shim stock, but not the epoxy, unless he did it after the X axis on the video I watched..
 
If you tram the table and it is good. Then tram the vice and it is not good. Then the vice is what is out of square with the spindle and not the spindle. You may have to rework the vice to make it square. If you shim the nod to the vice that is out of square you will then be out of square if you need to use just the table without the vice.
 
There are a couple of things to check for nod when it comes to dovetail column mills. One is spindle to table and the other is spindle to column. The following Hoss Machine link shows how to check the column to spindle nod. G0704 Tramming Part 1.wmv

The best I could get my PM-932 was .002" over 8" in "Y" which is not too bad. Keep in mind you have to have some gib clearance or the head won't move up and down. If snugging up the gib doesn't correct the nod problem then scraping or machining of the head to column slide may be necessary. Let us know what you find when running the Hoss Machine test.

Or as Billh50 said what you are describing could be a vise problem.
 
Thank you everyone. I will go back and recheck. I may have let a damaged box during the vice shipping go by, and should not have. There was a forklift hole in the end of the box, but no real physical damage that I could tell. OH BOY...
 
Aukai said:
The mill column is bolted down, no adjustment. I saw him use shim stock, but not the epoxy, unless he did it after the X axis on the video I watched..
Click to expand...
I have a G0755 and had to shim the base of the column When I set it up. Have not needed to adjust again (touch wood!)
When you are checking the tram you need to ensure that the locks on the column are done up.
 
Don't have your mill, but like it has been mentioned above, IF your column is perfectly straight I would check the tightness of the ribs, there are probably several adjusting screws long their length. You don't want them too tight so as to put too much friction on the movement of the head.
Checking the squarely of your presumedly square vice is also suspect. Lock the column before measuring.
Good luck.

CHuck the grumpy old guy
 
My old mill dosen’t Even have nod? A little shim stock under the vise and a dial indicator in the spindle and all’s well. After a few minutes.
Thanks ron
 
Are you using a drill chuck to hold an indicator tool? If so, that's probably your problem. I don't know of too many drill chucks that hold better than a few thou runout at the jaws. When clamping an indicator to a mill, use an appropriate holder that grabs onto the outside of the spindle.

I have an 8" diameter bearing race. They tend to be highly precision ground. Lay it flat on the table and adjust the indicator probe such that it circumscribes exactly on the flat edge of the bearing race. The indicator must be affixed to the rotating part of the spindle. From the top side of the mill head, turn the drawbar shaft with your fingers while you watch the indicator. Adjust mill accordingly.

Once the table is flat, check the back jaw of your vise. Adjust vise accordingly (or buy a very expensive vise).

Regards

Ray C.
 
Oh, one other thing... If you're adjusting nod by shimming the column (which is how I do it) use a torque wrench and the same bolt sequence when you tighten the bolts.
 
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