Regardless of HSS/Carbide — You would want to choose a drill for your material and application first. You would then want to complement the drill you’ve selected with a spotting drill of a wider angle. The wider angle will ensure the drill engages the material safely (as “Figure 1” shows).

How to measuredrillbitangle

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I’m surprised to see no mention of 135° split point cobalt drills which I’ve used a lot with no spot drill necessary! I’ve also worked in Aerospace and NASA related hardware that mostly used tighter tolerances on hole location and sizing that required a chamfer or break all edges call out on the print. One company that I worked at was primarily making hydraulic, oil, and fuel filtration systems for many of our commercial airline industry and military fighting jets. We always utilized a 90° spot drill and most often followed with a 118° or a 135° dŕill and these surely had tight tolerances that were easily kept… Multi billion dollar company that made filtration for the F18’s all the way through the B2 Bomber that had a price of $250,000.00 for each one and it requires 8 total…

How to measureangle for drill

Using a larger angle drill will allow the drill to find the correct location by guiding the tip of the drill to the center. If the outer diameter of a carbide drill were to contact the workpiece first, the tool could chip. This would damage the workpiece and result in a defective tool. If the two flutes of the drill were slightly different from one another, one could come into contact before the other. This could lead to an inaccurate hole, and even counteract the purpose of spot drilling in the first place.

The main reason “center drills” are 60 degrees is so that you can prepare the end faces of lathe workpieces that need tailstock support. The most common tailstock centers are 60 degrees (included), hence the most common center drills are 60 degrees. Sounds like you are using a combined “center” drill as a spot drill.

Last question: what’s the difference between your two types of spotting drills: on-center (type I) vs ahead-of-center (type II)?

When drilling into an extremely irregular surface, such as the side of a cylinder or an inclined plane, this tool may not be sufficient to keep holes in the correct position. For these applications, flat bottom versions or Flat Bottom Counterbores may be needed to creating accurate features.

I drill cast aluminum with a .047 DIA 3 flute carbide drill made for aluminum from Harvey Tools. I do not use a spot drill and I do not peck drill. I drill almost to a 3xD depth and I can drill over 75.000 holes without having any issues with tool breakage. The holes are always in the correct position and I don’t have any issues with tools walking.

I have to disagree here. We use carbide drills as small as 1.6mm to drill Inconel and titanium with great results in both tool life and accuracy, pecking is an absolute must as any “stringy” swarf build up in the flutes will snap your drills in no time. HSS drills are better suited to Softer materials up to 316 stainless steels.

Drillpointanglechart

Drilling an ultra-precise hole can be tough. Material behavior, surface irregularities, and drill point geometry can all be factors leading to inaccurate holes. A Spot Drill, if used properly, will eliminate the chance of drill walking and will help to ensure a more accurate final product.

Drillpointangle fordifferent materials

On-center Spot Drills design reduces walking and minimizes the flat at the bottom of the spot. These tools are ideally suited for starting smaller-diameter drills and shallow spots. Ahead-of-center Spot Drills design improves tip strength. These tools are ideally suited for larger-diameter drills and tougher materials.

Let’s say I’m cutting 1/4-20 UNC 2A internal threads and targeting a 0.201″Ø hole. I’m using a 0.2009″Ø drill (130° angle) and a 0.201″Ø reamer. I’d go with a 140° spot drill but what diameter?

A Spotting Drill’s purpose is to create a small divot to correctly locate the center of a drill when initiating a plunge. However, some machinists choose to use these tools for a different reason – using it to chamfer the top of drilled holes. By leaving a chamfer, screw heads sit flush with the part once inserted.

The drill bit size chart provides equivalent sizes for letter, metric, wire gauge, and fractional drill bit sizes, allowing the user to select the correct drill bit for their project.

I dont feel this is correct. A drill tip magnified, you cant get a cutting edge. So if the tip touches first, for a split second it smears. I have spotted many 90 deg holes and never experienced “shock loading”. Thats why center drills are 60 deg. Lets the cutting edge of drill engage before the drill tip. Should you guys discontinue your 60 – 100 deg spot drills?

Carbide drills are excellent in cnc machines. most manual machines can’t even spin a carbide drill to it’s proper sfm. You can drill without pecks on a cnc

To understand drill walking, think about the act of striking a nail with a hammer, into a piece of wood. Firm contact to a sharp nail into an appropriate wood surface can result in an accurate, straight impact. But if other variables come into play – an uneven surface, a dull nail, an improper impact – that nail could enter a material at an angle, at an inaccurate location, or not at all. With CNC Drilling, the drill is obviously a critical element to a successful operation – a sharp, unworn cutting tool – when used properly, will go a long way toward an efficient and accurate final part.

Angle for drillbit

It’s good to know that you need to have the proper spot angle when drilling concrete. My brother wants to drill some concrete that he has on his property, and he wants to make sure he goes about doing it properly. I’ll pass this information along to his so that he can properly drill his concrete.

Ideally, the center of a carbide drill should always be the first point to contact your part. Therefore, a spotting drill should have a slightly larger point angle than that of your drill. Common drill point angles range from 118° to 140° and larger. Shallower drill angles are better suited to harder materials like steels due to increased engagement on the cutting edges. Aluminums can also benefit from these shallower angles through increased drill life. While these drills wear less and more evenly, they are more prone to walking, therefore creating a need for a proper high performance spot drill in a shallow angle to best match the chosen drill.

Angle for drillbitformetal

If a spotting drill with a smaller point angle than your drill is used, your drill may be damaged due to shock loading when the outer portion of its cutting surface contacts the workpiece before the center. Using a drill angle equal to the drill angle is also an acceptable situation. Figure 1 illustrates the desired effect. On the left, a drill is entering a previously drilled spot with a slightly larger angle than its point. On the right, a drill is approaching an area with an angle that is far too small for its point.

Typically you will see in drill design that the harder the material (or the more difficult it is to machine) the point angle increases. This allows for a stronger point. Also as you increase the point angle you reduce the radial forces so you start to see less pushout on the backside on through holes. The spotting drill’s geometry ensures a drill begins its job efficiently, where it will be doing most of the actual work.

You never want to use a smaller drill to spot with. The whole point of spotting is to put a spot for your drill to follow/start with that is in the exact position that you want. A smaller drill as a spotting tool will flex and walk and your actual drill will follow that point and be off location or cut on an angle. You need to spot with a rigid and/or stubby tool so that it transfers exact location.

If I had to drill into some concrete, I’d for sure make a spot drill. That way, I can be sure that my larger drill would be in the same place. However, I would have to go out and purchase all these tools as I don’t have any in my possession.

In the article, you mentioned the importance of matching the spot drill angle to the drill angle for optimal results. How does the material being drilled influence the choice of spot drill angle, especially when working with composite materials or layered materials with varying hardness?

Drill Bit Size Chart Drill Size Diameter (inches) Diameter (mm)   Drill Size   Diameter (inches)  Diameter (mm)    Drill Size   Diameter (inches)  Diameter (mm) #107 0.0019 0.0483   #26 0.147 3.7338   X  0.397 10.0838 0.05 mm 0.002 0.05   #25 0.1495 3.7973   Y 0.404 10.2616 #106 0.0023 0.0584   3.8 mm 0.1496 3.8   13/32 in 0.4063 10.3188 #105 0.0027 0.0686   #24 0.152 3.8608   Z 0.413 10.4902 #104 0.0031 0.0787   3.9 mm 0.1535 3.9   10.5 mm 0.4134 10.5 #103 0.0035 0.0889   #23 0.154 3.9116   27/64 in 0.4219 10.7156 #102 0.0039 0.0991   5/32 in 0.1563 3.9688   11 mm 0.4331 11 0.1 mm 0.0039 0.0991   #22 0.157 3.9878   7/16 in 0.4375 11.1125 #101 0.0043 0.1092   4 mm 0.1575 4   11.5 mm 0.4528 11.5 #100 0.0047 0.1194   #21 0.159 4.0386   29/64 in 0.4531 11.5094 #99 0.0051 0.1295   #20 0.161 4.0894   15/32 in 0.4688 11.9063 #98 0.0055 0.1397   4.1 mm 0.1614 4.1   12 mm 0.4724 12 #97 0.0059 0.1499   4.2 mm 0.1654 4.2   31/64 in 0.4844 12.3031 #96 0.0063 0.16   #19 0.166 4.2164   12.5 mm 0.4921 12.5 #95 0.0067 0.1702   4.3 mm 0.1693 4.3   1/2 in 0.5 12.7 #94 0.0071 0.1803   #18 0.1695 4.3053   13 mm 0.5118 13 #93 0.0075 0.1905   11/64 in 0.1719 4.3656   33/64 in 0.5156 13.0969 0.2 mm 0.0079 0.2   #17 0.173 4.3942   17/32 in 0.5313 13.4938 #92 0.0079 0.2007   4.4 mm 0.1732 4.4   13.5 mm 0.5315 13.5 #91 0.0083 0.2108   #16 0.177 4.4958   35/64 in 0.5469 13.8906 #90 0.0087 0.221   4.5 mm 0.1772 4.5   14 mm 0.5512  14 #89 0.0091 0.2311   #15 0.18 4.572   9/16 in 0.5625 14.2875 #88 0.0095 0.2413   4.6 mm 0.1811 4.6   14.5 mm 0.5709 14.5 #87 0.01 0.254   #14 0.182 4.6228   37/64 in 0.5781 14.6844 #86 0.0105 0.2667   #13 0.185 4.699   15 mm 0.5906 15 #85 0.011 0.2794   4.7 mm 0.185 4.7   19/32 in 0.5938 15.0813 #84 0.0115 0.2921   3/16 in 0.1875 4.7625   39/64 in 0.6094 15.4781 0.3 mm 0.0118 0.3   4.8 mm 0.189 4.8   15.5 mm 0.6102 15.5 #83 0.012 0.3048   #12 0.189 4.8006   5/8 in 0.625 15.875 #82 0.0125 0.3175   #11 0.191 4.8514   16 mm 0.6299 16 #81 0.013 0.3302   4.9 mm 0.1929 4.9   41/64 in 0.6406 16.2719 #80 0.0135 0.3429   #10 0.1935 4.9149   16.5 mm 0.6496 16.5 #79 0.0145 0.368   #9 0.196 4.9784   17 mm 0.6693 17 1/64 in 0.0156 0.3969   5 mm 0.1969 5   43/64 in 0.6719 7.0656 0.4 mm 0.0158 0.4   #8 0.199 5.0546   11/16 in 0.6875 17.4625 #78 0.016 0.4064   5.1 mm 0.2008 5.1   17.5 mm 0.689 17.5 #77 0.018 0.4572   #7 0.201 5.1054   45/64 in 0.7031 17.8594 0.5 mm 0.0197 0.5   13/64 in 0.2031 5.1594   18 mm 0.7087 18 #76 0.02 0.508   #6 0.204 5.1816   23/32 in 0.7188 18.2563 #75 0.021 0.5334   5.2 mm 0.2047 5.2   18.5 mm 0.7284 18.5  #74 0.0225 0.5715   #5 0.2055 5.2197   47/64 in 0.7344 18.6531 0.6 mm 0.0236 0.6   5.3 mm 0.2087 5.3   19 mm 0.748 19 #73 0.024 0.6096   #4 0.209 5.3086   3/4 in 0.75 19.05 #72 0.025 0.635   5.4 mm 0.2126 5.4   49/64 in 0.7656 19.4469 #71 0.026 0.6604   #3 0.213 5.4102   19.5 mm 0.7677 19.5 0.7 mm 0.0276 0.7   5.5 mm 0.2165 5.5   25/32 in 0.7813 19.8438 #70 0.028 0.7112   7/32 in 0.2188 5.5563   20 mm 0.7874 20 #69 0.0292 0.7417   5.6 mm 0.2205 5.6   51/64 in 0.7969 20.2406 #68 0.031 0.7874   #2 0.221 5.6134   20.5 mm 0.8071 20.5 1/32 in 0.0313 0.7938   5.7 mm 0.2244 5.7   13/16 in 0.8125 20.6375 0.8mm 0.0315 0.8   #1 0.228 5.7912   21 mm 08268 21 #67 0.032 0.8128   5.8 mm 0.2284 5.8   53/64 in 0.8281 21.0344 #66 0.033 0.8382   5.9 mm 0.2323 5.9   27/32 in 0.8438 21.4313 #65 0.035 0.889   A 0.234 5.9436   21.5 mm 0.8465 21.5 0.9 mm 0.0354 0.9   15/64 in 0.2344 5.9531   55/64 in 0.8594 21.8281 #64 0.036 0.9144   6 mm 0.2362 6   22 mm 0.8661 22 #63 0.037 0.9398   B 0.238 6.0452   7/8 in 0.875 22.225 #62 0.038 0.9652   6.1 mm 0.2402 6.1   22.5 mm 0.8858 22.5 #61 0.039 0.9906   C 0.242 6.1468   57/64 in 0.8906 22.6219 1 mm 0.0394 1   6.2 mm 0.2441 6.2   23 mm 0.9055 23 #60 0.04 1.016   D 0.246 6.2484    29/32 in 0.9063 23.0188 #59 0.041 1.0414   6.3 mm 0.248 6.3   21/23 in 0.913 23.1913 #58 0.042 1.0668   1/4 in  0.25 6.35   59/64 in 0.9219 23.4156 #57 0.043 1.0922   E 0.25 6.35   23.5 mm 0.9252 23.5 1.1 mm 0.0433 1.1   6.4 mm 0.252 6.4   15/16 in 0.9375 23.8125 #56 0.0465 1.1811   6.5 mm 0.2559 6.5   24 mm 0.9449 24 3/64 in 0.0469 1.1906   F 0.257 6.5278   61/64 in 0.9531 24.2094 1.2 mm 0.0472 1.2   6.6 mm 0.2598 6.6   24.5 mm 0.9646 24.5 1.3 mm 0.0512 1.3   G 0.261 6.6294   31/32 in 0.9688 24.6063 #55 0.052 1.3208   6.7 mm 0.2638 6.7   25 mm 0.9843 25 #54 0.055 1.397   17/64 in 0.2656 6.7469   63/64 in 0.9844 25.0031 1.4 mm 0.0551 1.4   H 0.266 6.7564   1 in 1 25.4 1.5 mm 0.0591 1.5   6.8 mm 0.2677 6.8   25.5 mm 1.0039 25.5 #53 0.0595 1.5113   6.9 mm 0.2717 6.9   1-1/64 in 1.0156 25.7969 1/16 in 0.0625 1.5875   I 0.272 6.9088   26 mm 1.0236 26 1.6 mm 0.063 1.6   7 mm 0.2756 7   1-1/32 in 1.0313 26.1938 #52 0.0635 1.6129   J 0.277 7.0358   26.5 mm 1.0433 26.5 1.7 mm 0.0669 1.7   7.1 mm 0.2795 7.1   1-3/64 in 1.0469 26.5906 #51 0.067 1.7018   K 0.281 7.1374   1-1/16 in 1.0625 26.9875 #50 0.07 1.778   9/32 in 0.2813 7.1438   27 mm 1.063 27 1.8 mm 0.0709 1.8   7.2 mm 0.2835 7.2   1-5/64 in 1.0781 27.3844 #49 0.073 1.8542   7.3 mm 0.2874 7.3   27.5 mm 1.0827 27.5 1.9 mm 0.0748 1.9   L 0.29 7.366   1-3/32 in 1.0938 27.7813 #48 0.076 1.9304   7.4 mm 0.2913 7.4   28 mm 1.1024 28 5/64 in 0.0781 1.9844   M 0.295 7.493   1-7/64 in 1.1094 28.1781 #47 0.0785 1.9939   7.5 mm 0.2953 7.5   28.5 mm 1.1221 28.5 2 mm 0.0787 2   19/64 in 0.2969 7.5406   1-1/8 in 1.125 28.575 #46 0.081  2.0574   7.6 mm 0.2992 7.6   1-9/64 in 1.1406 28.9719 #45 0.082 2.0828   N 0.302 7.6708   29 mm 1.1417 29 2.1 mm 0.0827 2.1   7.7 mm 0.3032 7.7   1-5/32 in 1.1563 29.3688 #44 0.086 2.1844   7.8 mm 0.3071 7.8   29.5 mm 1.1614 29.5 2.2 mm 0.0866 2.2   7.9 mm 0.311 7.9   1-11/64 in 1.1719 29.7656 #43 0.089 2.2606   5/16 in 0.3125 7.9375   30 mm 1.1811 30 2.3 mm 0.0906 2.3   8 mm 0.315 8   1-3/16 in 1.1875 30.1625 #42 0.0935 2.3749   O  0.316 8.0264   30.5 mm 1.2008 30.5 3/32 in 0.0938 2.3813    8.1 mm  0.3189 8.1   1-13/64 in 1.2031 30.5594 2.4 mm 0.0945 2.4   8.2 mm  0.3228 8.2   1-7/32 in 1.2188  30.9563 #41 0.096 2.4384   P 0.323 8.2042   31 mm 1.2205 31 #40 0.098 2.4892   8.3 mm 0.3268 8.3   1-15/64 in 1.2344 31.3531 2.5 mm 0.0984 2.5    21/64 in 0.3281 8.3344   31.5 mm 1.2402  31.5 #39 0.0995 2.5273   8.4 mm 0.3307 8.4    1-1/4 in 1.25 31.75 #38 0.1015 2.5781   Q 0.332  8.4328   32 mm 1.2598 32 2.6 mm 0.1024 2.6   8.5 mm 0.3347 8.5   1-17/64 in 1.2656 32.1469 #37 0.104   2.6416   8.6 mm 0.3386 8.6   32.5 mm 1.2795 32.5 2.7 mm 0.1063  2.7   R 0.339 8.6106   1-9/32 in 1.2813 32.5438 #36 0.1065 2.7051   8.7 mm 0.3425 8.7   1-19/64 in 1.2969  32.9406 7/64 in 0.1094 2.7781   11/32 in 0.3438 8.7313   33 mm 1.2992 33 #35 0.11  2.794   8.8 mm 0.3465 8.8   1-5/16 in  1.3125  33.3375  2.8 mm 0.1102 2.8   S 0.348 8.8392   33.5 mm 1.3189 33.5 #34 0.111 2.8194   8.9 mm  0.3504  8.9   1-21/64 in 1.3281 33.7344 #33 0.113 2.8702   9  0.3543 9   34 mm 1.3386 34 2.9 mm 0.1142 2.9   T  0.358  9.0932   1-11/32 in 1.3438 34.1313 #32 0.116 2.9464    9.1 mm 0.3583 9.1   34.5 mm 1.3583 34.5 3 mm 0.1181  3   23/64 in 0.3594 9.1281   1-23/64 in 1.3594 34.5281 #31  0.12 3.048    9.2 mm 0.3622 9.2   1-3/8 in 1.375 34.925 3.1 mm 0.1221 3.1    9.3 mm 0.3661 9.3   35 mm 1.378 35 1/8 in 0.125 3.175   U 0.368 9.3472   1-25/64 in 1.3906 35.3219 3.2 mm 0.126  3.2   9.4 mm 0.3701 9.4   1-3/8 in 1.375 34.925 #30 0.1285 3.2639   9.5 mm  0.374 9.5   35 mm 1.378 35 3.3 mm 0.1299 3.3   3/8 in  0.375 9.525   1-25/64 in 1.3906 35.3219 3.4 mm 0.1339 3.4   V 0.377 9.5758   35.5 mm 1.3976 35.5 #29 0.136 3.4544   9.6 mm 0.378 9.6   1-13/32 in 1.4063 35.7188  3.5 mm 0.1378 3.5   9.7 mm 0.3819 9.7    36 mm 1.4173 36 #28 0.1405 3.5687   9.8 mm 0.3858 9.8   1-27/64 in 1.4219 36.1156 9/64 in 0.1406 3.5719   W 0.386   9.8044   36.5 mm 1.437 36.5 3.6 mm 0.1417  3.6    9.9 mm 0.3898 9.9   1-7/16 in 1.4375 36.5125 #27 0.144 3.6576    25/64 in  0.3906 9.9219   1-29/64 in 1.4531 36.9094 3.7 mm 0.1457  3.7    10 mm 0.3937 10   37 mm  1.4567 37 The drill bit size chart provides equivalent sizes for letter, metric, wire gauge, and fractional drill bit sizes, allowing the user to select the correct drill bit for their project.

Drillangles PDF

I use the largest spot drill that will fit in that area. rigidity. then I only spot to a depth to create a diameter .01/.015 over the desired diameter of the hole.

I disagree with the statement: “Thats why center drills are 60 deg. Lets the cutting edge of drill engage before the drill tip.”

I appreciate what you said about using the center of the carbide drill. I need to hire a crew to drill a hole in the backyard. I want it wide enough for a pool.

To mitigate any variables working against you, such as an uneven part surface or a slightly used drill, a simple way to avoid “walking” is to utilize a Spotting Drill. This tool is engineered to leave a divot on the face of the part for a drill to engage during the holemaking process, keeping it properly aligned to avoid a drill from slipping off course.

Somewhat random question I hope you can answer. I have googled and searched forums and have come up empty handed. When we say “NC Spot Drill” what does the NC stand for? I may feel dumb when I hear the answer, but no dumber than I do after pondering it…! Thanks.

we also use a lot of Dream Drills. no spot required and no pecking in 304 stainless. time savers and last forever running at the companies recommended feeds and speeds.

Thanks Guy! The problem with using a spot diameter the same as the drill diameter is that Harvey doesn’t make a spot diameter in 0.2009″ (I doubt anybody does). There’s 0.187 and then 0.25. If I go with the smaller diameter then I fear the point angle will wear unevenly (“shock load”). If I go with the bigger diameter then, well, I’m making a bigger hole than I want.

I’ve seen it recommended to spot with an angle smaller than the drill tip angle when using a H.S.S. drill. I’ve also seen the same recommendation for soft materials as aluminum vs steel. I’ve had the best results by always spotting with an angle greater than the drill angle, soft or hard materials, HSS or Carbide drills. I think HSS is more forgiving for sure vs carbide. I’ve used plain old center drills in stainless steel as they are cheap and hold up well then drilled with HSS drills. Works fine but I cannot attest to the accuracy as at that place we really never checked parts on a CMM.

Whydrillbitangleis 118

Few CNC machining applications demand precision like drilling. The diameter hole size, hole depth, part location, and finish are all important and provide little recourse if not up to specifications. That said, accuracy is paramount – and nothing leads to inaccurate final parts faster than drill walking, or the inadvertent straying from a drill’s intended location during the machining process. So how does drill walking occur, and how can one prevent it?

Spotting drills spend such little time in the cut, it should be chosen off of the drill angle. The drill angle is what should be dictated by the material.

Excellent way of telling, and nice paragraph to get data about my presentation topic, which i am going to deliver in college.

Using a carbide drill in a CNC milling machine would be a poor choice. If you are peck drilling the carbide is going to take a beating. If the material is too hard I would use a carbide endmill in a High Speed milling machine. If possible I would use a undersized HSS drill when the material is soft……say prior to heat treat. Then finish the holes in a High Speed Milling machine with a 4 flute CEM.

Would you consider adding to this article consideration for the practice of spot drilling using a much smaller drill bit? I was taught that spotting with a smaller drill bit works just as well since the outer diameter of the final size drill will not engage first, it would be the core that would center and engage first.

I’ve seen the recommendation to use a smaller angle when spotting for HSS drills and a larger angle when spotting for carbide drills. Do you have any thoughts on that? Would you recommend using a larger spotting angle regardless of the drill material or workpiece material?

Hi Mike! Thank you for your comment and reaching out to us with some inquisitive questions. When drilling, the chisel angle – the very tip of the point angle, comes in contact with the work piece. Because you have the two cutting lips overlapping here, you form a chisel angle where actual cutting is not happening. Here, you want enough thrust for the drill to penetrate the material and then the chisel angle starts to extrude the material. The longer the chisel angle, the more durable the tip is but you will need more thrust in order to penetrate the material. Bringing this into the context of spotting, we can see why if you just barely touch the material you will get more rubbing and less cutting. We feel like you bring up a great tip here, no pun intended, that when spotting you want to take enough of an axial depth in order to go past the chisel angle and actually start cutting the chip. Next, using the term “shock loading” may not be the best description on what is happening when you contact somewhere on the point angle first. Shock loading typically comes from interrupted cuts so as long as the point angle is symmetrical and located perfectly, that should not be happening. What we want to get across here is that this is not the ideal way of spotting because of how the drill will now wear unevenly along the point angle and may lead to chipping. For example, if the drill always contacts half way up the point angle, you will start to see more wear there than what is happening close to the chisel angle. Historically, and with softer materials, this was less of a concern but with the advent of tougher and high temp alloys, we would recommend staying away from this. A flatter point angle on the spotting drill will help relive extreme stress on the lip of a drill in these materials. Ultimately, it is up to the machinist to weigh the pros and cons of any operation and we just want our readers to understand more on what is going on. Finally, as mentioned before, everyone has their way of doing things. We have heard that our customer use spotting drills as a combination tool and leave a chamfer at the top of the hole with them. This is why we offer such a large range of included angles to help with ideal spotting situations to help saving room in your tool carousel. We hope you find this information useful and if you are having any more questions or any challenges with our line, from smearing to angle selection or anything between, please contact our experienced tech team at 800-645-5609 or email at [email protected].

Hey Brad, In the circumstances like these, we suggest using a larger spot drill but do not drill fully to the OD of the spot drill.