kartracer55
Aluminum
- Joined
- Nov 17, 2005
- Location
- NJ
OK, as you guys all I know I am new to machining (if you can call it that at this point) and I am trying to learn proper procedure for drilling holes. Lets talk about "regular" materials, nothing crazy. Just aluminum, steel and some stainless. I have a few questions about various different aspects here:
1: Starting. I was recently confused about the proper procedure for starting a hole, so after some searching, It seems that a center drill is NOT a valid method for piloting a hole, and that I should be using a spotting drill with an angle GREATER than that of the drill bit. Am I correct in this? Would it be the end of the world if I did use a center drill to get my holes started? I am on a major budget here and can not invest in tons of different length/angle drills. I am also learning for my own personal benefit, I am not a machinist.
2: Sizing it up. Whenever I drill by hand I always drill a small pilot hole, and final drill to the hole I need. It seems that this is not the proper procedure? What I understand is that I am better off just getting the hole started by the proper method above, and drilling with the correct drill size? Also, if a regular twist drill should not be used to enlarge a pre-existing hole, what is the proper method? I am not talking about going up a few thousandths, I mean like going from a 1/4 to 1/2 in hole?
I ask this on here because you guys know your stuff, and many older machine shop txt books I salvaged a few years ago suggest using a center drill for getting a hole started and now I question what these books tell me.
Thanks
Jim
1: Starting. I was recently confused about the proper procedure for starting a hole, so after some searching, It seems that a center drill is NOT a valid method for piloting a hole, and that I should be using a spotting drill with an angle GREATER than that of the drill bit. Am I correct in this? Would it be the end of the world if I did use a center drill to get my holes started? I am on a major budget here and can not invest in tons of different length/angle drills. I am also learning for my own personal benefit, I am not a machinist.
2: Sizing it up. Whenever I drill by hand I always drill a small pilot hole, and final drill to the hole I need. It seems that this is not the proper procedure? What I understand is that I am better off just getting the hole started by the proper method above, and drilling with the correct drill size? Also, if a regular twist drill should not be used to enlarge a pre-existing hole, what is the proper method? I am not talking about going up a few thousandths, I mean like going from a 1/4 to 1/2 in hole?
I ask this on here because you guys know your stuff, and many older machine shop txt books I salvaged a few years ago suggest using a center drill for getting a hole started and now I question what these books tell me.
Thanks
Jim