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Thread: Drill press power downfeed

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    Supporting Member metric_taper's Avatar
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    Drill press power downfeed

    I had modified my lathe tail stock previously with a power feed. This proved to allow very large drill bits to be used without them grabbing, as the power feed can produce a very smooth slow feed rate, that my hand operation skill never produced. So I did the same for my drill press.
    My first iteration, I did not have the 10:1 reduction gear. And the Align 135 inch-lb power feed could not produce the slow feed end torque to drive the drill press rack gear directly. To install any one of these commodity power table feeds (mainly milling machine usage), you have to make (or it comes with) a mounting stand (that's what the instructions call this). You can see the stack up is one heck of a cantilever extension. And I put a wheel and crank knob for manual operation.

    Drill press power downfeed-2017-03-31-drill-press-power-feed-01.jpg

    The slot in the mounting stand to gear box was because I used a roll pin to connect the shaft between the rack gear shaft and planetary gear box shaft connection. I was not sure where that would be. It was an interesting cut with a horizontal rotary table, and end mill, with the first time I used coolant on the mill. Sorry I did not take photos of the piece parts.
    The project is incomplete as you can see the quill DRO that needs a linkage from the spindle to the readout. Too many unfinished tool projects.

  2. The Following 3 Users Say Thank You to metric_taper For This Useful Post:

    Paul Jones (04-11-2017), rossbotics (04-15-2017), tonyfoale (04-19-2017)

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    Supporting Member Ralphxyz's Avatar
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    How much weight is hang on the spindle shaft? Seems like it needs support.

    Ralph

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    Supporting Member metric_taper's Avatar
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    Quote Originally Posted by Ralphxyz View Post
    How much weight is hang on the spindle shaft? Seems like it needs support.

    Ralph
    That first mounting stand is bolted to the drill press main cast iron frame (with 4 counter sunk hex head socket bolts). And the weight of the gear box, mounting stand, power feed, and hand crank wheel and shaft are all depending on this. There is no radial loading of any of the shafts. The manual hand crank shaft is riding on a needle bearing of the power feed, with the gear box end clamped into its input gear socket.
    One problem I have, (and it's there without this change) is the main rack-pinion gear of the spindle down feed, as there is nothing to take the gear lash out of this. I've thought of ways of splitting the pinion gear, and spring loading it to maintain a zero backlash, but that requires destroying the original gear, or making a new one.
    Another problem is the spring return does not provide enough torque to lift the spindle weight, and back drive the 10:1 gear box, as there is some friction of the manual crank riding on the power feed bearing.
    I indicated that version 0.0 had the power feed driving the pinion shaft directly, and it did not have enough torque, that instigated this massive assembly. I make sure when I move this, not to use this cantilever "appendage" as a hand hold, the 1/4-20 screws probably would strip out from the cast iron.

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    Quote Originally Posted by metric_taper View Post
    I had modified my lathe tail stock previously with a power feed. This proved to allow very large drill bits to be used without them grabbing, as the power feed can produce a very smooth slow feed rate, that my hand operation skill never produced..
    Steve,
    You might be interested in an earlier post
    http://www.homemadetools.net/forum/l...7672#post86049
    Power feed built in.


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