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What purpose of screw in Forstner Drill Bit shank

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Dominik Pierog

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Hello.
I cleaning my old forstner drills and one have this little screw in shank.
I unscrew it and there was only piece of grease inside. This is a blind threaded hole.
screw.JPG
 

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Rorschach

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Might be for adding an extension shank but I suspect it is a remnant of the manufacturing process.
 

Dominik Pierog

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This screw have diameter like 2-3mm and proper extension looks that



Rorschach":3u3c8nze said:
Might be for adding an extension shank but I suspect it is a remnant of the manufacturing process.
If its remnant of the manufacturing process why they bother to put screw inside?

Maybe drawbar?
 

Inspector

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If it was originally made with a Morse Taper then a drawbar makes sense. If it was always a parallel shank then I don't see a purpose in a draw bar. Does it look like it might have been modified? The screw in it might just be to keep the threads clean until needed.

Pete
 

Dominik Pierog

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No its was brand new buy in local store years ago. It have standard 10mm shank.
 

Chrispy

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It's for setting the length in a drilling machine, you adjust the set screw which then bottoms out on the chuck/collet , then you can remove and replace in machine without resetting depth stops etc. Hinge boring machine.
 
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