Lower Z Axis Knee Bottoming Limit ?

Some of the prehistoric mills from way back in the late 1800's early 1900's, one in mind is the Brown & Sharpe No. 2 horizontal mill, you had to cut a hole in the floor in order for the table to lower to its furthest position. If you didn't have that hole, you would raise the mill up off its foundation. A little scary first time you did it!
 
Subwayrocket said:
Thanks Bob , I appreciate it. I put a glove on and smeared in Bel Ray motocross bearing grease on that screw last week. I'll get the bottom now that it's exposed.
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Put oil on the screw, not grease! I guess on the bottom end, grease on it is ok to keep the elements off of it. But don't grease the entire screw. Grease is not the proper lubricant for the elevation screw. Ken
 
Ok thanks. I was told the grease was fine. It does have a grease zerk there . What is the rationale behind not using grease on it ? Thanks for commenting, I appreciate it !
 
Grease zerk is for a oil filled grease gun on most machine tools. There are several threads on H-M on using a oil filled grease gun for grease zerks made for oil. Personally, on a mill, I would remove all of them grease zerks and replace with oil cups. Or better yet, plumb in a one shot oiling system on your mill. Ken
 
Thank Ken . Makes sense. I had a bench mill prior to this one. This mill does have one shot and I use it.
 
Lowered it gently by hand. I felt an obvious hard stop about 1/2" from the bottom . I raised it about a half inch above that and locked the stop there. DRO slide still had another inch to go ...and nothing interfering anywhere else .
Looks like I got about another extra inch .The little thing below the stop bolt is just a little snap on cover. Thanks all for commenting, I appreciate it ! ~Steve
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The problem with grease on machines is that it attracts swarf like a magnet and holds them tenaciously, and those chips will wear against the metal, your Z axis lead screw and nut in this case.
 
Even worse is the grease will hold oxidization, clay, & sand that fly through the air which makes the most aggressive lapping compound you'll find.

I raised my mill off the floor because the screw was bottoming on the floor & gained several inches. I have two mills & both will hit the quill at their upper limit.
 
If there is grease on the ways of your machine I would take it apart and clean it up, then reassemble with way oil. Those Alemite fittings are NOT for grease,
 
On the ways ? no, there is way oil as should be . This was under the knee .
 
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