question on drill bit size

[las3r]

Hey guys i need some help on finding out what is the closest drill bit i can buy that will not go over 3/4" but very close to to 3/4" ???

The part i have is 3/4" OD and i need to have it a tight fit so i need a it close so i can sand the remaining to make it fit perfect thanks for the help.

 

[precisionworks]

19mm = .748"

A 19mm reamer will do a much nicer job than a 19mm twist drill if size & straightness are important.

 

[gadget_lover]

Precisionworks is correct. A reamer will give you a round hole that is a given size and straight.

A drill (and drill press or hand drill) are terribly inaccurate when you start talking about thousandths. The point of the drill bit may move in a .010 circle and still be considered "within specifications". On top of that, a drill bit that is ground incorrectly can make a hole that is oversized.

It's best to make some test pieces to figure out what the result will be. Then drill the holes that are important.

Dan

 

[KC2IXE]

OK, if you really want a TIGHT fit, drill say 23/32, and then REAM to .748 for a press fit. Want a non press fir that is TIGHT? REAM to .750. Drills are a 'rough' tool. REAMERS make exact size holes

The old rule of thumb for someone running a jig bore (which was used for making exactly on size and position holes

Drill to make a rough hole, THEN BORE the hole undersize by say 1/32nd of an inch for LOCATION and straightness, then REAM for size. That is how you get an on location, straight on sized hole

 

[las3r]

Awesome thanks guys, ill post back on the results