Precision drilling with a drill press
 

I have a drill press and calipers (analogue) a t-square and all and every time I try to drill something I am always concerned my measuring did not line up spot on. This weekend I am planning on drilling my own lcg slash chassis for my sons truck and I am going to be needing to get some exact measurements and holes. How do you guys do it?

This is what I was thinking. Use the calipers to measure existing holes, mark with a fine pencil or sharpie. Use and extremely small drill bit to create a guide hole then hit it with the larger bit. What say you all? Is there a better way?

Re: Precision drilling with a drill press
 

probably need to center punch it first.then small drill .

Re: Precision drilling with a drill press
 

mark out where you want the hole then use a center punch to put a dent, then id your drilling like a 1/2" hole, use a smaller drill bit as a pilot hole then progress with bigger bits until you have the size you want.

if your only planning on using like 1/8" drill bit or something than use center punch then use the drill bit of choice. no need for a pilot hole."thumbsup"

Re: Precision drilling with a drill press
 

Sometimes when I need to do manual work like that I will scribe an intersection where the hole is going to be.. If you have a 1" sqaure part and you need to drill a hole directly in the center.. Set your caliper to .500" and hole one jaw of the caliper along the side of the part while sliding the caliper across the part using the other jaw of the caliper as a scribe. Do it lightly as to not damage the caliper. Its much more accurate than using a straight edge or T-sqaure. Also if you use paint or blueing on the part first, the scribe will show up much better.

Then, once you have an intersection, the center of your hole will be right in the middle. Use a very sharp punch for a small indent and then drill.

You can use your caliper to measure the location after the hole is drilled. Measure the size of the hole, divide by 2 and then add that number to the number you get when you measure the part from the end of the part to the edge of the hole.

IE.. Part is 1", hole is .125", the measurment from the outside of the part to the edge of the hole should be .4375 if the hole is centered.

Re: Precision drilling with a drill press
 

Use the old addage, "Measure twice, cut once." I end up measuring about 5 times, haha

I work in a fab shop, so measuring out holes, cuts, etc is normal. One thing I do is "burn an inch" (depending on what I'm doing). Start your measurement at 1". Just be sure to remember to subtract that 1"

Make sure to center punch. I assume since it's an RC you'll prob just drill an 1/8" hole. You don't need to do a pilot hole. However, if you chuck the bit at the smooth part (where the shaft is smooth), the bit MIGHT bend and walk if you press too hard. Choke up on the bit, like you would a baseball bat, so there's only 1/2" of the end sticking out. There're no rules against it, and it'll keep the bit from bending

If the hole DOES come out to be a little off, the you can always oval out the hole (put the bit through the hole, and press in the direction the hole needs to go. The cutters will do their thing.) Masure sure the part is close ot the chuck so you don't snap the bit. OR you can just step up to the next size bit and make the hole a little bigger (will only work if it's just barely off

Re: Precision drilling with a drill press
 

I draw my parts up in autocad and print it out full size. Tape the printout on to the metal and use a center punch to mark all of my holes.

Re: Precision drilling with a drill press
 

If you're drilling through thin material, I would stick with your original pilot hole idea. I always do a pilot hole if it's something important and I want the hole to turn out nice, but I'm kind of finicky that way.

If you're concerned with getting your center punch exactly where you want it, you can try one of these:

Optical Center Punch, 9x Magnification - Optical Center Punches - Measuring and Layout Tools - 1ARZ1 : Grainger Industrial Supply

Re: Precision drilling with a drill press
 

We have one of those at work. Very handy!!

Even though you are using a drill press, Clamp you peice to the table good so there will be no chattering or wandering.

Re: Precision drilling with a drill press
 

If you're doing thin stuff (sheet metal, PC board material, Delrin sheet, etc.) and doing holes ~1/4" and up, do a pilot hole and finish off with a Uni-Bit. It makes nice round holes.
In any other thickness material, carefully mark your holes, center punch then pilot drill.
I actually make 1/8" drills just for pilot holes. I take used bits, break them off so there is ~3/4" of the twist left, grind to a shallow angle split point. They don't tend to walk, even without a center punch mark.

Re: Precision drilling with a drill press
 

if im drilling soft materials like delrin or other plastics i use wood drills as they have a point on the end. much easier to see the mark, and also don't run off. don't know if they would be tough enough for aluminum, but never tried

http://www.thebigboystoyshop.com/ekm...it-37440-p.jpg

Re: Precision drilling with a drill press
 

All of the advice so far has been good.. You can use several good methods to achieve a good hole location. Along with the ones mentioned I would suggest clamping the part to the drill press table. If you locate the hole and scribe it, you can use a center drill or a spot drill and bring the chuck down on top of the hole to get it lined up.. you can gently press down on top of the marked hole with the tool (without spinning it) to leave a mark on the part...then once you have it adjusted to your liking, you can clamp the part to the table, spot or center drill it and then bring the chuck back up, swap to the drill and then drill it.