Correct Center Drill Depth
Correct Center Drill Depth
(OP)
Currently specifying the C-Drill diameter/number & programming its depth based on the drill bit that will follow it. I try to use a C-Drill large enough to get a funneling action on the following drill bit... Say a #6 C-Drill for a ½” drill bit.
Shop floor operators constantly want to run a standard #1 or #2 C-Drill that is already in the tool changer regardless of what diameter drill bit will follow it. I’ve seen operators edit/replace a #6 C-Drill with a #1 C-Drill and the following drill bit is a ½”.
We have had some issues with hole location. Does anyone know of a written or acceptable procedure?
Shop floor operators constantly want to run a standard #1 or #2 C-Drill that is already in the tool changer regardless of what diameter drill bit will follow it. I’ve seen operators edit/replace a #6 C-Drill with a #1 C-Drill and the following drill bit is a ½”.
We have had some issues with hole location. Does anyone know of a written or acceptable procedure?





RE: Correct Center Drill Depth
How about a stubby 90 or 120 degree spot drill, where one size more or less fits all? Good for forming a pre-tap chamfer too. You could do a little testing to evaluate drilled hole location accuracy.
Without shop discipline, on the part of operators and supervisors, no written standard is going to help much.
Just for fun, take a look at my free drill depth calculator. Includes center drills, spot drills, and countersinks. Great minds think alike.
http://bellsouthpwp.net/r/s/rsnmar/Drills.zip
RE: Correct Center Drill Depth
I can't build Rome in a day but a good standard or rule of thumb I could reference on this issue would go a long way.
BTW, I have had some junior programmers download & start using your speed & feed macros; it has been very well received.
RE: Correct Center Drill Depth
RE: Correct Center Drill Depth
I like running a .5 90deg. spot drill. Takes care of 99% of what I have to drill tap or interpolate later. 90 is the best because of the ease of determining your diameter. You're gonna drill a .375 hole, drop the spot down to .190. Gives you a light chamfer on the hole as well as providing an accurate drill position. Some brands of spot drills will vary on accuracy, but ma ford is top notch. Still, if you're on a budget, key will work fine. Just be sure to creep in on the z depth before you get carried away.
RE: Correct Center Drill Depth
Where can I download the speeds and feeds macros? I don't see them on the website.
Thanks
RE: Correct Center Drill Depth
I'm not allowed to publish a link unless someone asks for help. :)
It's actually a small, powerful Windows program (beta) that does feed/speed/cycle time/horsepower calculations for different tools and materials. Also has detailed thread data, volume + weight calculator, drill depth calculator, other goodies.
A much-improved update will be available in a week or so. Let me know if you want to be notified.
All free, no gimmicks.
Mike rainey47@bellsouth.net
http://bellsouthpwp.net/r/s/rsnmar/MECon...
RE: Correct Center Drill Depth