Horizontal Mill - drilling

[G Caputo]

Hey all,

 

When drilling on a horizontal bar mill, how many of you use the "W" axis versus using the "Z" axis? What are the pros and cons of each? A discussion came up here recently and I am just trying to get a wider viewpoint on the subject.

 

Thanks,

[mayday]

I prefer the Z for drilling. boring is a different matter. to elimenate spinde sag while boring I use the W with the z out far enough to get to depth. just do your edge pickup with the Z out. depends on machine type i suppose

[Mike Mattera - TFM]

Higher precision usually means drilling/boring the table. The quill will tend to sag as it comes out of the head stock.

 

Mike Mattera

[G Caputo]

Mike and Mayday,

I am just talking about a simple, say 3/4" - 1" drill into a piece of steel. Nothing fancy about it. Maybe I wasn't clear, but what is "preferred" or "recommended" the spindle "W" axis moving or the table "Z" axis moving and why?

We are talking decent size machines, cat50 taper, no other issues at all except which axis should be moving. I got the "Why aren't you using the spindle to drill" question the other day and believe it or not, the only real reason I had was "because this is how we have always done it". I myself really don't know any reason why one way is better than the other. I was hoping all fine folks could enlighten me on the subject. HTH clarify things.

[Mct010]

Well personaly I have Spindle do all the drilling/tapping and reaming, because its faster then moving the saddle in and out.

I always move the spindle even when circle milling.

 

I move the saddle up as far as as I can, and use the spindle at all others times, and If your boring, its still better to use, if you have a 5" spindle, it really don't sag, unless its a really deep hole, use a indicator on it and see, line boring though I use saddle and set the job up that way, but i have pushed the limit and used the saddle and spindle. just my 2cents

 

Mike

 

ps,if u move the saddle with a indiactor on the spindle, and it doesn't stay at zero, the head needs set again.

[crazy^millman]

I have also seen line boring done using a back support on the table if doing deep bores throguh. I have also seen a 24 inserted borning bar with .5 per insert change in dia for step bore on injection tubes. I have seen mandrels used as support for deep bore. Me personally I always got the table close as possible and then used the spindle and like siad with a 5" spindle I have take a 6" spade bit and drilling 4150HT with no problem depends on the machine the setup and how much you trsu all of the above as wels as you abilites and what you think is right and they way uoi want to apporach it.

 

Good luck