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Knob to change from drill press feed to fine feed?

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Cadillac STS

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#1
When I got my RF 31 it had been damaged and the knob that usually turns to allow the drill press arm feed or fine feed was broken off.

When I try to turn the stub of a knob with pliers it won't budge. Stuck on fine feed and fine feed works well.

Question is how does the knob usually work? Is it just an ordinary right hand thread knob and I should put more pressure trying to loosen it? Is it supposed to pull out first and then turn? Is it left hand turn so when I am trying to loosen it is really tightening? How does one use that knob regularly to change from one to the other? Never having used one without it broken I don't know.

Any ideas of what may have been damaged with the knob being broken off if anything. It was hit hard with a hammer like object to break it.

Since I use the fine feed and don't really need the drill press feed should I leave it alone because loosening it might do something and make the fine feed not work with whatever damage there may be in there? For someone who has had it apart and knows what is on that shaft is there something that could be broken and would be a problem if that knob is loosened?
 

TomS

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#2
When I got my RF 31 it had been damaged and the knob that usually turns to allow the drill press arm feed or fine feed was broken off.

When I try to turn the stub of a knob with pliers it won't budge. Stuck on fine feed and fine feed works well.

Question is how does the knob usually work? Is it just an ordinary right hand thread knob and I should put more pressure trying to loosen it? Is it supposed to pull out first and then turn? Is it left hand turn so when I am trying to loosen it is really tightening? How does one use that knob regularly to change from one to the other? Never having used one without it broken I don't know.

Any ideas of what may have been damaged with the knob being broken off if anything. It was hit hard with a hammer like object to break it.

Since I use the fine feed and don't really need the drill press feed should I leave it alone because loosening it might do something and make the fine feed not work with whatever damage there may be in there? For someone who has had it apart and knows what is on that shaft is there something that could be broken and would be a problem if that knob is loosened?
Yes, it's a right hand thread. The fine feed mechanism is a male taper that engages a female taper when the knob is tightened. Turn the knob CCW to disengage the fine feed and CW to engage it. There is a spring that pushes the two pieces apart. Look at figure 2 in the attached RF-30 manual.
 

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RJSakowski

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#3
I don't know about the RF 31, but my mill/drill has a cone which is pushed into contact with a socket for fine feed by the knob. There is a spring which pushes it out when the knob is loosened.
 

Cadillac STS

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#4
Would it be better to just put a big pipe wrench on it and try to turn it off or since the top of the knob is missing cut the nut off with a dremel tool and remove it in pieces. Trying not to damage anything.
 

TomS

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#5
Would it be better to just put a big pipe wrench on it and try to turn it off or since the top of the knob is missing cut the nut off with a dremel tool and remove it in pieces. Trying not to damage anything.
Look at Figure 2 in the manual I sent you and you will see a knob that compresses the males taper/cone into the female taper/cone. On mine it's a 10mm hex headed bolt fused to a 3" round plastic knob. Make sure the compression knob and it's screw are removed. Figure 2 doesn't show it but there is a coil spring between the male tapered piece and the female tapered piece that should push them apart. If you try to force it off with a pipe wrench you run the risk of stripping or breaking the worm gear/wheel fine feed mechanism and possibly the pinion gear that runs in the rack on the back of the quill.
 

Cadillac STS

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Look at Figure 2 in the manual I sent you and you will see a knob that compresses the males taper/cone into the female taper/cone. On mine it's a 10mm hex headed bolt fused to a 3" round plastic knob. Make sure the compression knob and it's screw are removed. Figure 2 doesn't show it but there is a coil spring between the male tapered piece and the female tapered piece that should push them apart. If you try to force it off with a pipe wrench you run the risk of stripping or breaking the worm gear/wheel fine feed mechanism and possibly the pinion gear that runs in the rack on the back of the quill.
That is what I wanted to know. I’ll leave it alone for now. Have another drill press. And it is working as a CNC mill the quill works and I would risk breaking it.
 
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