Drilling blanks

Signed-In Members Don't See This Ad

klpeters

Member
Joined
Jan 10, 2017
Messages
5
Location
Souris P.E.I. Canada
I have been drilling some blanks using a 8 mm brad point drill bit, the top of the holes come out oblong shaped , so the tubes were not fitting well , I started using a 5/16 regular drill bit and then the 8 mm bit,seems to have fixed the problem , any idea why it does this .
 
Signed-In Members Don't See This Ad

WriteON

Member
Joined
Aug 21, 2013
Messages
3,271
Location
S. Florida
Welcome aboard. Are you drilling too deep and not withdrawing the bit enough? I like to drill about an inch...withdraw the bit and clean off...also blow out the blank. How long is the drill bit?
Careful when you get toward the end of blank...slow and carful until the bit goes through. Are you drilling wood or acrylic?

There is nothing wrong with pre-drilling with smaller bit first. Anything over 8mm and I pre-drill first.
 
Last edited:

randyrls

Member
Joined
Feb 2, 2006
Messages
4,823
Location
Harrisburg, PA 17112
The out of round condition may be caused by a bent drill bit or one that isn't equally sharp on both flutes. Other causes may be a drill press that isn't in line with the table or other misalignment.

Brad points tend to grab at one of the flute edges and "torque" the bit.

When I withdraw the bit to clear the flutes, I turn off the drill press, then reinsert the bit back into the hole before switching back on. I don't use brad points
 

WriteON

Member
Joined
Aug 21, 2013
Messages
3,271
Location
S. Florida
I am surprised at the "get rid of brad point" advice. Penn State includes a 7mm brad point with every mandrel. I have drilled over 500 blanks with brad points without issue.

Brads are ok for wood...tend to blow out the end on acrylic blanks.(for me they do)
 

JPW062

Member
Joined
Nov 3, 2016
Messages
156
Location
Ohio
I'm quite surprised to read people are having trouble with brad points wandering. That is what the design is supposed to stop. I have not had problems.
Are the tips broken?
Is it sharp?
Are you anywhere close to correct speed on drill press?
How are you holding it?
I think there is something else going on.

Unless this is mostly an acrylic issue. I am a real noob when it comes to acrylic.
 

BeeAMaker

Member
Joined
Jan 30, 2017
Messages
695
Location
Elkhart IN, USA
I'm quite surprised to read people are having trouble with brad points wandering. That is what the design is supposed to stop. I have not had problems.
Are the tips broken?
Is it sharp?
Are you anywhere close to correct speed on drill press?
How are you holding it?
I think there is something else going on.

Unless this is mostly an acrylic issue. I am a real noob when it comes to acrylic.

Poorly made (cheap) brad points will sometimes have the point Off-Center. This will cause the tip to wonder as it enters. Drill points will do the same thing if they are sharpened off center. It's always best to buy good drills in either case. "tool shop" don't cut it - no pun intended.
 

MRDucks2

Member
Joined
Jul 17, 2017
Messages
3,215
Location
Bristow, IN
I have had no problems with decent quality brad points on anything. Picked one set up at HF and took them back. When asked what was wrong, told them they wouldn't drill a round hole. Most of the bits weren't true. Spent 5x the money on another set and they work great.


Sent from my iPhone using Penturners.org mobile app
 

JPW062

Member
Joined
Nov 3, 2016
Messages
156
Location
Ohio
I use mostly the woodriver, which are not the cheapest, but also aren't very expensive. I have used dozens and never had this issue.
I have used some more expensive bits, probably none cheaper. Some of the more expensive brands do have better steel that stays sharp longer, but not much else is different.

If you put the drill in your press, turn it on, and the tip is visibly not running true, it certainly won't drill well. The type of bit is irrelevant at that point.
 
Last edited:
Top Bottom