PM727M DILEMMA

I should be able to, problem is i dont have a height guage, if its like the ones i use to use.
 
When i attached my square to the table and lower the quill, there was .005 of devation over 3". I havent checked this since re-shimming the mill.
 
Brad125 said:
I should be able to, problem is i dont have a height guage, if its like the ones i use to use.
Click to expand...
You shouldn't need a height gauge - just a precision square and the ability to mount an indicator on the head or in the spindle. Did you watch the video?
 
davidpbest said:
You shouldn't need a height gauge - just a precision square and the ability to mount an indicator on the head or in the spindle. Did you watch the video?
Click to expand...

Yes, i squared my column to the table using a precision square laid on the table and a magnetic base indicator holder mounted to the dovetail slide directly behind the head, shimmed the column square to the table. Then trammed the head to "0" with the table. The problem comes when i raise the head, everything should be "in-line" but its not. The higher i go the more the head leans to the right, even with the colums squared, and the head trammed to the table. The devation seems to increase equally as the head goes up. Example: my head lowered to the table and trammed "0", then head is lifted 3" and the error is .0075, finally the head is raised to 6" and the error increases to .0155.
 
Brad125 said:
When i attached my square to the table and lower the quill, there was .005 of devation over 3". I havent checked this since re-shimming the mill.
Click to expand...
If the column isn't trammed properly, or is not straight, or there is slop at the gib, your quill check is meaningless. Get the column in tram first by checking the head movement against the precision square secured to the XY table. If every 2" of head travel yields the same variation reading on the indicator, chances are good the column is straight but out of tram. If the measurements differ more than a few tenths for every 2" of head travel, then the column probably isn't straight or there is looseness in the head-to-column connection (probably the gib). Once the column is proven to be 90-degrees to the XY table, you can check the quill to see if it precisely follows the column axis using the same method. If it does not, then the head-to-column mount needs to be adjusted/shimmed.
 
davidpbest said:
If the column isn't trammed properly, or is not straight, or there is slop at the gib, your quill check is meaningless. Get the column in tram first by checking the head movement against the precision square secured to the XY table. If every 2" of head travel yields the same variation reading on the indicator, chances are good the column is straight but out of tram. If the measurements differ more than a few tenths for every 2" of head travel, then the column probably isn't straight or there is looseness in the head-to-column connection (probably the gib). Once the column is proven to be 90-degrees to the XY table, you can check the quill to see if it precisely follows the column axis using the same method. If it does not, then the head-to-column mount needs to be adjusted/shimmed.
Click to expand...


Thanks for the tips, see my above post. I responded same time as you. Just incase you missed it
 
Brad125 said:
Yes, i squared my column to the table using a precision square laid on the table and a magnetic base indicator holder mounted to the dovetail slide directly behind the head.
Click to expand...
This is not good technique for precision measurement. Your reference should be from an indicator in the spindle to a precision square on the surface of a locked-in-position XY table.
 
davidpbest said:
This is not good technique for precision measurement. Your reference should be from an indicator in the spindle to a precision square on the surface of a locked-in-position XY table.
Click to expand...

I tried that way before, i dont remember the results. I should have documented it. However, the tech guy at PM said that was the wrong way to do it. He said the square the column with the table 1st, then tram the head to the table.
 
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