- Joined
- Jul 2, 2014
- Messages
- 7,594
Mikey has the right idea for how to move a hole that is not in the correct place.
First, drills do not drill straight holes, round holes, accurately located holes, or accurate diameter holes. Drills remove bulk material. They are usually good and fast at removing bulk material. If you just want a hole they will often do the job "good enough" and "quick enough." Making the hole oversize can often make it work for the intended job, even if it is not pretty or accurate.
Second, boring bars and heads do not start holes or remove metal quickly. They locate the hole in the proper place. It takes considerable skill to finish a hole to the desired diameter with a boring tool, and is quite easy to overshoot a tight tolerance.
Third, a reamer does not start holes or locate holes. It is only good for making a hole to a specific final size, though even that can get fussy if you are chasing .0001" accuracy.
So, rough out the hole with an undersized drill, then bore it in the place it needs to be to close to final size, and then ream it to final size. Use the strengths of each type of tool to get accurate, repeatable results with very little chance of scrapping the part.
If you want to get the hole to an extremely round and accurate final hole size, precision finish lapping can do that for you.
Very few jobs require an extremely accurate hole, and it takes lots of time to achieve it. Use the tools above as needed to get to where you want to be.
First, drills do not drill straight holes, round holes, accurately located holes, or accurate diameter holes. Drills remove bulk material. They are usually good and fast at removing bulk material. If you just want a hole they will often do the job "good enough" and "quick enough." Making the hole oversize can often make it work for the intended job, even if it is not pretty or accurate.
Second, boring bars and heads do not start holes or remove metal quickly. They locate the hole in the proper place. It takes considerable skill to finish a hole to the desired diameter with a boring tool, and is quite easy to overshoot a tight tolerance.
Third, a reamer does not start holes or locate holes. It is only good for making a hole to a specific final size, though even that can get fussy if you are chasing .0001" accuracy.
So, rough out the hole with an undersized drill, then bore it in the place it needs to be to close to final size, and then ream it to final size. Use the strengths of each type of tool to get accurate, repeatable results with very little chance of scrapping the part.
If you want to get the hole to an extremely round and accurate final hole size, precision finish lapping can do that for you.
Very few jobs require an extremely accurate hole, and it takes lots of time to achieve it. Use the tools above as needed to get to where you want to be.
