Prolonging Tool Life of Deep Hole Drills by Using the Appropriate Pilot/Starter Drill
Guest Blog by Cory Cetkovic, Product Manager, Sphinx, Big Kaiser
Selecting the appropriate pilot drill is critical to maximize performance and tool life of a succeeding deep hole or micro drill. The purpose of a pilot drill is to create a clean, consistent working surface for the succeeding drill to enter the workpiece.
Important aspects such as diameter tolerance and point angle (Figure 1) are often overlooked leading to inconsistent, unacceptable results.
A pilot drill diameter should be slightly larger than nominal diameter, whereas the succeeding drill diameter should be smaller. This is often accomplished using positive and negative tolerances respectively (Figure 2). Selecting the incorrect pilot drill diameter can lead to premature failure of the succeeding drill as it will enter the pilot hole using its margins rather than its center-cutting point.
It is also important for a pilot drill’s point angle to be equal to or larger than that of a succeeding drill. The purpose of a larger point angle is to guide the succeeding drill to centerline while preventing its corners from colliding with the point angle left by the pilot drill. Using a pilot drill with a smaller point angle usually results in chipped corners on the more expensive deep hole drill after drilling 10-20% of the expected tool life.
10/9/2019 08:57:48 pm
I never thought about how choosing the correct diameter drill affects the amount of durability of a wrong diameter drill. My well needs drilled and my landlord has informed me that my source of groundwater is pretty deep underground. These tips made me realize I should hire a professional to do this precision deep hole drilling.
2/14/2022 02:29:21 am
These are great tips, It is also important for a pilot drill’s point angle to be equal to or larger than that of a succeeding drill. Thanks!
2/17/2022 10:34:25 pm
Using a pilot drill with a smaller point angle results in chipped corners on the more expensive deep hole drill after drilling 10-20% of the expected tool life. Great!
3/1/2022 01:24:32 am
These suggestions convinced me that I should hire a professional to perform this precision deep hole drilling.
11/8/2022 09:35:54 am
This is a great article! I'm glad I found it while searching for similar content because the information is not only helpful, but it's also practical with the included images. After reading it, I learned many things I can apply to my project. Keep up the excellent work!
11/9/2022 04:56:58 am
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12/2/2022 04:52:36 am
Thanks for sharing such a great information. Its really helpful. I always search to read the quality content. Thanks
1/10/2023 06:05:03 am
The management of runout, which grows with cutting tool length, is one of the biggest issues in deep hole drilling. Runout will increase noticeably if, for example, a cutting tool with a 6 diameter is swapped out for one with a 30 diameter. The increased runout caused by longer tools can be mitigated by a more precise toolholding technique or machine tool.
3/8/2023 09:51:35 am
I want to get a nice water well, but I'm not sure how to put it together. It's good to know that proper drilling method is really important when it comes to drilling a well like this. It would definitely be a good idea for me to get a professional to help me out with this.
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