Drilling Perfect Hole in Round Bar

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Historian
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Drilling Perfect Hole in Round Bar

Post by Historian »

Many times in smithing you need to find the center of a round
stock held in a vise in order to drill down perpendicular to the length.
using centering tools and calculating without a DRO on hobby
lathe is problematic.

Here one clever way of accurately lining up a drill bit:

<< https://www.youtube.com/watch?v=eUTWtHO ... 4.64221933 >>
Historian
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Re: Drilling Perfect Hole in Round Bar

Post by Historian »

Added technique for machining many thin precision washers*
of varying thicknesses.

<< https://www.youtube.com/watch?v=lGsA_q4guwM >>

* Worked great for machining ring spacers for precision
focal length for optical ranger/laser finder test.
Fulmen
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Re: Drilling Perfect Hole in Round Bar

Post by Fulmen »

Jeeez. I broke one of my rules this time and was promptly disappointed. Nothing wrong with the trick itself, but 3 minutes of talk and more talk to explain something that could be done with a single image?
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T-Rex
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Re: Drilling Perfect Hole in Round Bar

Post by T-Rex »

If you can accurately align the drill bit w/ the bushing, w/o the use of dials, then this "trick" is overengineered.

Just put the round bar in your chuck, align it inside the chuck jaws (while the piece is fixed), as best you can, and replace the bar stock w/ your drill bit.
Centered w/o dials or indicators.


Yes, too many "instructional" videos are 9-1/2min of talk and 30sec of to the point.

But, keep em coming, Historian. :D
Last edited by T-Rex on Sun Feb 05, 2017 12:38 pm, edited 1 time in total.
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Historian
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Re: Drilling Perfect Hole in Round Bar

Post by Historian »

T-Rex wrote:If you can accurately align the drill bit w/ the bushing, w/o the use of dials, then this "trick" is overengineered.

Just put the round bar in the your chuck, align it inside the chuck jaws (while the piece is fixed), as best you can, and replace the bar stock w/ your drill bit.
Centered w/o dials or indicators.


Yes, too many "instructional" videos are 9-1/2min of talk and 30sec of to the point.

But, keep em coming, Historian. :D

Super! Amazing the smarts that our brethren have ... shall use instead.
Like the old Biblical thought: "Cast thy bread upon the waters ... and you
will have soggy bread" :)

Thank you again for sharing your experience.

Best.
crazyelece
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Re: Drilling Perfect Hole in Round Bar

Post by crazyelece »

Or spot face it with an end mill and drill.

If it needs to be really precise; spot face with end mill, drill with centering spot drill, drill with undersized short drill, drill with undersized full length drill, finish with reamer.
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T-Rex
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Re: Drilling Perfect Hole in Round Bar

Post by T-Rex »

crazyelece wrote:Or spot face it with an end mill and drill.

If it needs to be really precise; spot face with end mill, drill with centering spot drill, drill with undersized short drill, drill with undersized full length drill, finish with reamer.
Yes, but how did you indicate center?
That was the "trick" of the video.
Unless your end mill was the same diameter as the bar to be drilled through and you indicated from that. :D
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crazyelece
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Re: Drilling Perfect Hole in Round Bar

Post by crazyelece »

T-Rex wrote:
crazyelece wrote:Or spot face it with an end mill and drill.

If it needs to be really precise; spot face with end mill, drill with centering spot drill, drill with undersized short drill, drill with undersized full length drill, finish with reamer.
Yes, but how did you indicate center?
That was the "trick" of the video.
Unless your end mill was the same diameter as the bar to be drilled through and you indicated from that. :D
That's not a hardened bushing, so that trick isn't going to get a perfectly placed hole, just straight

Eyeballing the spotface should get you damn close to the same "precision"

FWIW, when I want to drill a straight hole on the center and it just has to be "close enough"; I lock it in the vise and use a v block on top. Bring a endmill down on the vblock and move X until the endmill touches flat. Spot face and drill. Not real precise, but good enough for hitch pins, castle nut pins, etc.
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