out of position vertical mill

I've got a question (or a few) for the experienced machinists who generously contribute so much to this group.
At my school there are two machine shops. The kind machinists once
told me about the versatility of the vertical mills. They explained how the upper components can swivel, turn and be repositioned. The ram? it appears can be moved 90 degrees away from the table off to the side or behind the mill, and the head can be pivoted into compound angles.
My question(s): Does anyone ever actually use these non-standard positions for the mill? Doesn't the rigidity get lost at such long lever arm lengths away from the table? Anybody got some pictures? What is actully worked on in these settings? How is it mounted? This stems from concluding you can't put a v-8 350 block on the table of a small mill and work on it.
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While I've seen it done, I've never had occation to do it myself.

Knee mills of this type aren't very sturdy anyway, no matter how close the head is to the base/turret. There are too many joints between the cutter and the table. It's pretty easy to run such a machine so hard as to knock it out of square. This is agravating, but then there are always comprimises.
Quills are nice, but they also cause instability as well. Mills without quills are very capable of ripping down blocks, but they are virtually incapable of drilling a hole.
Regards,
Robin
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Not true, I think you need to think about this some more.
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Try and charge $65/hr while cranking the knee to drill a hole.
Regards,
Robin
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The machines with fixed spindles that I have seen had #40 or #50 tapers, they also have power feed built in. I have drilled 1 1/2" diameter holes with them for hydraulic valves and then bored them.
Richard W.
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You're right about larger holes. As long as you have a good selection of feeds available, those machines would ideal for holes that are difficult to push by hand (assuming the machine has adequate Z clearance)
Regards,
Robin
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"Robin S." wrote:

only cant drill "out of position holes" or holes not parallel the spindle c/l
John.
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Yep! Those amongst us that have such machines do, on occasion, take advantage of their capabilities. Mind you, the vast majority of use such machines get is in the right angle position, but there's nothing quite like having the capability to rotate the turret, advance the ram, or tilt the head in two directions when a particular job calls for any of those features.
Without a specific case at hand, it's difficult to explain how valuable they can be. One that readily comes to mind could be that you have a long piece, somewhat longer than the table travel. You prefer to not reposition the piece, for reasons best known to you. What you do is set it up on the table to your convenience, then rotate the turret such that you can machine the entire piece in two steps. The first step cuts one end of the part, the second step the other, after repositioning the turret. That necessitates reorienting the spindle to the part, but it does prevent setting up the part a second time, which in some cases can be good.
You do give up a small amount of rigidity in machines like a Bridgeport. If you've ever run a Gorton Mastermil, for example, you'd readily see that the Bridgeport is quite light duty by contrast. All of that can not be attributed to the flexibility of the Bridgeport, however. A Mastermil outweighs a Bridgeport considerably.
The benefits of a flexible machine like a Bridgeport outweigh any of the negatives tremendously. Aside from the purchase price of Bridgeport mills, which used to be very reasonable, it was the secret to their success.
Harold
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rfm snipped-for-privacy@yahoo.com wrote:

Sure. The more extreme the position, of course, the less rigid the machine is. But, there are times when you just can't do some setup with the spindle vertical. Generally, taking shallower cuts at lighter feed rates can compensate for the reduced rigidity.
I think a LOT of this sort of work is now done on CNC machines without altering the mill's basic setup. Also, in many cases, multi-side access and multi-axis machining can be done with one or two rotary indexers holding the workpiece. Moving the workpiece this way leads to much more predictable positioning than trying to loosen and swing various pivots on a Bridgeport-syle machine, and then pick up the coordinate references. But, you certainly can't position a big-block V8 very well even on a Series-II Bridgeport. Heads might be done on a benchtop mill, but the block requires a pretty big work envelope if you are going to machine all over the block. If you need to plane the deck, that might not be too bad.
Jon
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I swivel the head on my Bridgeport fairly often to machine angles.
Here is an extreme example: you have a round piece of 8" billet stock steel 30" long. You hump it up on your mill table on 2 herkin V-blocks and get it straight and clamped down. Now you have to mill a deep V in *one end*. What you do is, you slew the ram around to about 45, extend it way out, put on the BP right angle head, dial in the head so its axis is parallel to the workpiece, put in your V cutter and use your Y feed to mill the vee on the end. - GWE
rfm snipped-for-privacy@yahoo.com wrote:

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On 11 Dec 2004 19:44:15 -0800, rfm snipped-for-privacy@yahoo.com wrote:

Absolutely! I've used the tilts and pivots for many things, angled holes in extruder plates, dies, even just milling odd angles on the edge of pieces. Milling rubber shredder knives to sharpen them, a lot of other uses. The further out the ram is extended, the more rigidity is lessened, but it becomes a matter of using common sense in choosing cutters and depth of cut. Swiveling the head to the side so a long piece can be clamped to the edge of the table or on an angle plate, many uses for the tilts, swivels, pivots.
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:I've got a question (or a few) for the experienced machinists who :generously contribute so much to this group. : :At my school there are two machine shops. The kind machinists once :told me about the versatility of the vertical mills. They explained :how the upper components can swivel, turn and be repositioned. The :ram? it appears can be moved 90 degrees away from the table off to the :side or behind the mill, and the head can be pivoted into compound :angles. : :My question(s): Does anyone ever actually use these non-standard :positions for the mill? Doesn't the rigidity get lost at such long :lever arm lengths away from the table? Anybody got some pictures? What :is actully worked on in these settings? How is it mounted? This stems :from concluding you can't put a v-8 350 block on the table of a small :mill and work on it.
Not an engine block, but I once had the base casting for my "$200" bandsaw mounted on the table of my little Clausing 8520 mill so that I could re-bore the pivot holes. The mill's ram was pivoted 90 deg and the head tilted 90 deg so that the quill was horizontal and pointed directly toward the front of the machine. Looked ridiculous to see that casting up there on the table, but it worked just fine. The lever arms in that position aren't any longer than normal, just oriented differently.
It's not the sort of capability you use often, but when you need it, you _really_ need it. Simple tilting of the head is a lot more common.
--
Bob Nichols AT comcast.net I am "rnichols42"

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rfm snipped-for-privacy@yahoo.com wrote:

A lot of machinists don't even know that you can rotate the top of the head where the motor mounts around the quill axis to get better clearance when you tilt the head back or to the side.
John
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