Basic(?) Milling question

[paulmichael1084Participant @paulmichael1084gmail-com]

<p style=”text-align: right;”>Now, this will doubtless have some people shaking their heads in despair. Old timers sat around the kettle at my first engineeeing job, I’m looking at you!</p>
<p style=”text-align: right;”>But the rest of us, I have no doubt, are wise enough to know that in engineering (and many other fields of human endevour) there is no such thing as a stupid question, just people too stupid to ask questions.</p>
<p style=”text-align: right;”>So here goes….</p>
<p style=”text-align: right;”>I have recently aquired a Wabeaco F1200 mini mill, which is rapidly becoming my new obsession. Yesterday I encountered a scenario where I wanted to mill a low profile billet directly on the bed, but the head would not go low enough. The only way I could see to do it would be to extend the….. quill? or is it the spindle? Anyway the spinny bit thay holds the tool, to extend that down as if I were drilling, then lock it down and then mill by moving the table in the traditional manner.</p>
<p style=”text-align: right;”>However I have never seen this done, and wasn’t sure if it was a REALLY bad idea or not. I read the manual several times, but no mention is made of this style setup\technique.</p>
<p style=”text-align: right;”>I’ve attached some pics and I would very much appreciate comments.</p>
To those who want to know how this story ends I lifted the billet up on paralells to lift it up

[John HaineParticipant @johnhaine32865]

Quill. Perfectly fine to do what you did. I tend to work by setting the work in a vice or clamping to the table then bring the quill down to just touch the surface and lock it. Then set the Z dro to zero and use the Z feedscrew to put on the cut. Best to minimise the amount of quill feed for maximum rigidity.
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[JAParticipant @ja]

I have a similar Wabeco mill but with a larger table.

I would lift the plate to be machined on to, let us say, 1″ high steel blocks. just as you have done. The clamping pieces look like Myford parts, just like what I would use. I would make sure that the clamping end was lower the the supported end (your fine photos do not make this clear). Obviously lock all the slides you are not using prior to machining. Machining a “T” slot is a brutal introduction to milling. It took me years to pluck up the courage to cut one in steel. Only a visit to a Myford’s open day convinced me that I could and I then did so without any difficulty.

As soon as you can get a good 3 axis DRO. Milling machines need DROs. On lathes they are just nice to have.

JA

[paulmichael1084Participant @paulmichael1084gmail-com]

<p style=”text-align: left;”>Thanks very much for the feedback.</p>
3 axis DRO on order, due Monday.

1. @ja cutting a slot in steel would have been preferable. I didn’t have a proper Ali cutter  so used one for steel which kept getting fouled up!
   Anyway got there eventually and it did the job

[PeteParticipant @pete41194]

No despair at all, if your not sure it would be foolish to not ask. Depending on the tool diameter, depth of cut and feed, it may not be a real issue. As a general practice, it would still be better to have the milling heads spindle retracted and locked while making your Z axis elevation changes by lowering the whole head for a few reasons. And cutting tee slots would in my opinion be definitely one where I’d do so. You already have a fair amount of collet chuck and tool length below the spindle bearings. And secondly, doing it that way moves the head down on the column which also helps with increased rigidity. The trade off I suppose is the head obstructs seeing the cut a bit. For parts like your doing, the common 1″,2″,3″ or 25, 50, 75 mm blocks are a handy and reasonably priced accessory for raising any part for clearance etc.

Unless there’s good reason for using the spindles Z axis such as a protruding feature on the part or caused by the part clamping. I keep my spindle retracted and locked and make any Z axis moves using my BP clones knee. Drilling, tapping, boring, reaming are about the only time I make use of the spindles Z axis movement. You also did a good job of moving the tee slot bolts as close to the part as possible. 👍

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