Re: [CAD_CAM_EDM_DRO] Re: Tabel to spindle clearance of small CNC Mill

This might seem like a wise ass answer, but the more Z travel the
better. We've got a mill here with 15 inches of Z travel and it isn't
enough. Yesterday we had to bore a deep hole (passage) in the end of an
8" block. We had *just* enough room to do it:

vice: 3"
block: 8"
drill bit: 6", but only 4" sticking out of the collet. It was stuck all
the way in the collet, right up to the drawbar threads. To get the hole
depth we needed, we had to drill a bit then lower the bit in the collet
and drill some more. We could hardly clear the chips out of the hole
because the fluting just cleared the block.

Yes, we might have gained 3" of travel by not using the vice. We could
have used an angle plate... However, what if I would have needed to use
a boring head on that hole ?

There are lots of bargains on used Bridgeports and China made clones out
there. Given the price of "table top" mills and the price of the fore
mentioned mills, I'd much, much have one of the latter machines,
especially when it will be CNC'd.

"When betting on two boxers of otherwise equal talents, abilities, PICK
THE BIGGER ONE."

Kim

On Wed, 2003-11-05 at 06:53, rotarysmp wrote:
> Thanks for the response Jon, my interest is not miniture stuff like
> watches. A concrete use will be parts for homebuilt aircraft. I would
> like to make a model gas turbine to the Thomas Kamp plans. I do have
> a friend who keeps trying to get me to make the parts he breaks on
> his model helicopters, but you can buy them for less than my time :)
>
> I was tending towards installing the head with 100mm between the
> spindle nose and the table with the knee fully raised.
>
> Regards,
> Mark
>
> I am thinking of about 100mm between the with the
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> >
> >
> > rotarysmp wrote:
> >
> > >I have a Deckel G1L frame which will be getting an MT3 milling
> head
> > >grafted onto it. It will be converted to CNC, and used for hobby
> > >work, mostly one off or short runs, in Al and Steel.
> > >
> > >The Z travel is 300mm. No quill travel.
> > >
> > >Table is 600x250mm with X travel = 300mm and Y =150mm
> > >
> > >What would you recommend for a minimum spindle nose to table
> distance?
> > >
> > >
> > it depends on what you plan to do with the machine! If you are
> going to
> > machine pocket watch parts, you don't need much space there. If you
> > are going to bore engine blocks, you probably don't have enough.
> > But, you should be able to get a decent size Jacob's chuck on an MT3
> > arbor, put a 1/2" jobber's length drill bit in it, and still have a
> > couple of
> > inches below the drill tip. That is generally going to be your
> longest
> > tool. One other long tool is a boring head with a relatively long
> boring
> > bar in it.
> >
> > Jon
>
>
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