Brad Point Bit Issues...

Signed-In Members Don't See This Ad
H

HoratioHornblower

Member
Joined
Oct 31, 2011
Messages
300
Location
Columbia, SC
Hi all, I recently ordered some stuff from a site and I had ordered some standard bits. (those that are the cheapest option) Two of the bits were out of stock I guess so the company replaced the standard bits with Brad Point Bits, which is I believe an up grade. Sadly though, when I use at least the one brade point (haven't tried the other) it makes the hole much bigger at the entry point than the exit! :mad: Does anyone else have trouble with this? I have used a center drill with it, and once I believe I didn't and both times I had the same results. I am drilling on the lathe and I don't have this problem with other bits that are not brad points. Any thoughts? I am not trying to bash the company, just figure out what the problem is and if I should get a new bit. Thanks!

David​
 
Signed-In Members Don't See This Ad
T

TerryDowning

Member
Joined
Apr 27, 2011
Messages
520
Location
Newhall, CA
A few things to check and some questions to ask

Is the bit straight? A bent bit (even slightly bent) can create a larger hole than advertised.

Is the bit properly seated in the chuck? I don't know how many times I skipped properly seating a bit in the chuck and ruined my work.

Is the bit sharp? Just because a bit is new does not mean it is sharp.

Are you drilling wood or plastic? Drill bits have a tendency to follow a grain line when drilling wood even when drilling on the lathe. It's happened to me with a collet chuck. Drill bits can flex especially if they are long.

Check the alignment of your lathe and make sure that the stock you are drilling is centered in the chuck and turning straight. I've had this happen too. Blank off center in the scroll chuck, alignment good, drilling slow. darn hole is larger where I started. Careful inspection revealed there was a slight bend in the blank and was turning slightly out of round where the bit enters the blank. Not by very much, but enough to really frustrate me with that larger starting hole.
 
Jgrden

Jgrden

Member
Joined
Mar 27, 2009
Messages
6,287
Location
hOUSTON, Texas
The brad points are the only way to drill wine cork, and at a high speed and yes, there is a difference between the opening and the end. That being said, a more experienced person than me can explain why and I will also be watching for the correct answer.
Thank you for bringing it up. An issue that might be causing this for me is the chuck that holds the cork. It needs to be in all the way and that is not always the case.
 
H

HoratioHornblower

Member
Joined
Oct 31, 2011
Messages
300
Location
Columbia, SC
Thanks Terry!

I think that my tail stock is slightly lower than the headstock which was causing the run out. I will have to look into fixing this!

David
 
You must log in or register to reply here.
Previous Next
Top Bottom