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Anyone rigged up a travel stop on an FP1 quill?

jariou

Cast Iron
Joined
Jan 20, 2008
Location
Cary, NC
Hi,

I have a project coming up that would require putting the head at an angle and repeatedly, every quarter inch or so, plunge an end-mill in the work for a depth of let's say 0.200". So, in the end, I get a series of equally spaced, equal depth, square-bottom round holes, all at the same angle to the top surface of the part.

So, to do this, I need to use the quill for the plunge, since it is not on the same axis of travel as the knee. I would like to have a way to repeat the depth of the quill plunge quickly and reliably, without having to watch the quill dial for every plunge. Is this something anyone of the members here has ever done?

The only obvious thing I can think of right now is to devise some kind of collar to lock to the part of the spindle that sticks out of the top milling head. It would seem that it would also require some kind of thrust bearing/washer that would rest on the top of the head so as to make the "mating" of the stop collar to the top of the head less dramatic when you reach your require depth.

Does this seem like a reasonable way to go? Am I missing something? Is there a much easier way to do this quickly?

I'm opened to any idea.

Thanks in advance.

Jacques
 
Your plan sounds reasonable to me. In fact I don't think you will need the thrust bearing washer. Take a look at the top of the head. I think the stationary part is rotating along with the sliding part of the spindle.
 
Thanks adh.

I'll check tonight.

If it is the case, it would simplify my idea considerably.

Jacques
 
My Acieras use the collar method for quill depth control. They are included from the factory. At the lower stop position the collar butts against a collar that rotates with the spindle, so there's no need for a thrust bearing.
 
Another solution to this is to use a Deckel "Fine boring head" (Feinbohrkopf). This has 100mm of travel and is set up so that you can use gage blocks and a dial indicator to measure the travel precisely. The gage block holder setup can also be rigged as a hard stop by inserting an 8mm rod instead of a dial indicator. Photo below.

102208d1394920025-cabinet-fp2-accessories-gloat-img_2510.jpg

Stupidly, Deckel did not think that the quill on the the standard vertical head should be used as a quill for machining, but only for "setup". That's why it has no stop and no good way to measure depth.

I would love to figure out a way to attach one of those small self-contained digital scales (0.01mm resolution, 0.02mm accuracy) to the quill on the standard vertical head. But I can't come up with a decent way to attach it at the bottom end.
 
Hi,



The only obvious thing I can think of right now is to devise some kind of collar to lock to the part of the spindle that sticks out of the top milling head.

Thanks in advance.

Jacques

This is a standard fitment on the later square head machines (FP2,FP3)
Don't own an FP1 so i can't say about that with certainty.

Don't need any thrust bearing. Would make it with a set screw, necked to fit into and bear on the drive slot on the spindle, that way when tight it will not mar the smooth cylindrical surface.

Cheers Ross
 
Here is my update on the situation.

I have good news and bad news!

The bad news is that the surface around the quill on top of the milling head is fully stationary, it does not rotate. So, it means that I would indeed need some sort of thrust bearing to protect that surface. It's not dramatic, I can see an easy way to pin such an assembly in place, but it's a bit anti-climactic after adh and Ross' optimistic replies.

The good news, however, is that, as a matter of fact, there is already a travel stop integrated into the quill as it is. That travel stop is the quill bottoming down at the end of its travel. So, it would be a matter of setting up the part at such a height that the end of "natural" travel of the quill coincides with my required depth of the feature.

It would be far from ideal because, then, the quill would be fully extended which, presumably, is a less optimally rigid setup than possible. I don't really know how serious this is. I will have to test it out to see how feasible this is.

Thanks for all inputs.

Jacques
 
Here are pictures to the quill at the top of the head and an other update yet.

This is a view from the top. The large black surface does not rotate.
20191104_202703.jpg

Here is the quill near the bottom of its travel.
20191104_202652.jpg

And here it is fully bottomed out bellow the top surface of the large mill head cap.
20191104_202646.jpg

My idea was to make a ring with a setscrew fitting closely to the quill. I was thinking making it about 1/4 inch thick or more so I have enough meat for the setscrew. But that means it would interfere with the top of the head when bottomed out requiring something to protect it.

But I just realized that I could make a taller ring that could be 1/4 inch thick or more for the top 1/4 inch or so and then it could slim down to just about the same thickness as the drawbar collar for just long enough so that the thicker part of the travel stop collar does not ever touch the top of the head.

Yes, I think that's the ticket! That would limit the full travel of the quill by 1/2" or 5/8" but that's a small price to pay for those occasions I would need this functionality.

I'm thinking that it could perhaps be made as two half circle parts to speed up the installation and removal of the stop on the quill. But it might be more work than removing the drawbar collar pin, removing the drawbar collar, removing or installing the travel-stop collar and reinstalling the drawbar collar. I'll start with a solid one piece collar first.

Thanks again everyone who helped me think this through. If you see flaws in my thinking, please feel free to critic.

Jacques
 








 
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