How Bad is it to Drill on a CNC Router?

I had long heard (and myself repeated) that drilling on a CNC router was less than ideal. But just how bad is it to drill materials at 10k RPM? That's what I wanted to find out for myself.

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[coasmechteranic]

You really drilled this point home. Much less boring than I thought it would be. Hopefully, this vid will keep people from milling around, and be productive with their CNCs. Great work staying on the cutting edge of helpful vids!

[panaxion]

I've drilled almost a million holes with a 2.2kW VFD spindle on my, a basic HSS black oxide coated stub drill can do 300k+ holes in hardwood if you get your feed rates right. The challenge is having a very fast Z axis, which most routers do not. With a 4mm drill bit, I drill at about 0.2mm/tooth, or 0.4mm/revolution of the router bit. I run at 18000rpm typically, which is only 7200mm/min or 120mm/s. Its a hard, fast punch and pulling out of the hole is critical to not burning. I run a compressed air jet on the drill bit for cooling and chip clearance, with this setup I can drill a 14mm deep drill every 0.7 seconds. I don't peck drill, just punch in and out hard and fast.

[adama]

Horray for VFD spindles. The water cooled ones work well down to 6k rpm.

[kylejacobs]

I drilled 2x 1000 hole grills in polycarbonate with a 1.8mm PCB drill and it worked surprisingly well. Biggest issue I had was that stringy chips would wrap a bit on the drill and eventually enough would be present to cause some heat buildup on the surface causing a tiny bit of surface melting affecting the finish. I was not going to led the build up reach the point where the bit broke, so I ended up pausing every 30-50 holes to clear the drill.

By the end it was clear there was a bit of wear on the drill because the bit needed to be cleaned slightly more often, but it was still working like a champ.

[jamesshimek]

Another idea to help those out with drilling, I use a V bit to spot drill all my holes, even in aluminum, for layout purposes. I can CNC out the piece with all it's geometry minus the holes and then drill press said holes. If the holes are center drilled, even drilling 100 holes or so, manually drilling the holes goes way faster! Wished I had this video before I found out the hard way that drill bits in a router lead to sadness.
Thanks Winston

[Askjerry]

4:25 - This is one of the key reasons I suggested that you change out the router for a PWM or PWM with analog converter type SPINDLE. I can ramp the speed down to 1000 RPM which gives me a lot more control over the process. Additionally, even though it takes a secondary machine pass, I will install a center drill which is very short to make a pass that just goes in perhaps 0.5 to 2.0 mm leaving a great starting hole. If the hole is slightly large, it just means you have a small chamfer on the finished hole. Then I will do the finish pass with straight or peck drilling as needed. The spindle is also MUCH more quiet as I will demonstrate. I had a water cooled when i made the video, but the air cooled use the outer body of the device for heat dissipation and are about as quiet. (And yes, I stated the airflow backwards.)

[skellious]

omg the "This Old Tony" setting was amazing.

[iancrossley]

I had a project where I had to drill 14, 000 1/16" dia holes in 1/4" acrylic. I used a standard
split point HSS drill. I turned on the router at 8am and left for a meeting in NYC. I got home
at midnight and it had just finished - it clocks the time the job took. The piece was perfect.
I did a two pass peck and converted circles to drill points so that is would never move horizontally.

[JesseSchoch]

A decent approach is to just use a spotting drill to position your holes with a depth of 1 or 2 mm and finish them on a drill press.

[bluustreak]

Edit: Oh haha, I posted this too early. you say the same stuff later on in the video.

Thinking in terms of surface speed and chipload is often more relevant than feeds and speed.
High RPMs is not an issue in itself, it is high RPM in combination with too large circumference = high surface speed.
Else there wouldn't be a need for tiny 70Krpm drills :)

Also, using a 1/4 inch (6.25mm) drill in wood at 10K rpm gives a surface speed of nearly 200m/min, where the highest recommended speed in wood is 70m/min.
Even the 1/8th inch drill pushes this limit a fair bit.

With the same simple pattern, using a 1/16th inch drill would be a-ok with 10K rpm, but then of course there are other suboptimal factors.

Just felt like posting my thougts in the matter.
Good channel!

[FusionMan-evyh]

Try using a wood drill bit instead of a coated drill that was meant for steel.

[davidbezinque]

Great video, I had to make 8 "bed of nails" for the physics department here at Fresno State University. Each one required 6500 #43 holes for the roofing nails. I did the first one by hand and almost went postal. The second one I did on our Bridgeport mill. I hooked up a stepper and Arduino to move the X axis for about 155 holes at a time. Still drove me nuts! I then purchased an X-Carve! I used Fusion 360 to make a square grid of about 2000 holes, and this worked great! The bed of nails were done in 4 segments each segment taking about 4 hours. I burned up six #43 drill bits and Broke 3 during the process. I should be noted that my Dewalt router quit shortly thereafter, but was repaired under warranty. I felt a little guilty about that. Driving all those nails is another story.

[besssam]

I drilled many many 8mm(5/16") diameter holes in 1"(25mm) 6061 aluminium using a diy CNC with VFD speed control. Doing it using a router from a hardware store is more challenging and dangerous.

[therealstubot]

I've only drilled successfully twice on my CNC router. Both times doing shallow holes in wood, with very small bits. I tried many times, but always ended up destroying something. I tried lowering the min RPM in the VFD and that resulted in slower spindle speeds, but no torque at all, resulting in stalled spindle while the Z continued to feed down. At min RPM ( 9000 ) there's plenty of torque, but without flood coolant, aluminum welds to the bit and things break again. I've adopted doing a boring operation and that seems to work every time.

[jadeedwards]

If you are looking for some good short drill bits try looking up “screw machine style drill bit set” they are just short dill bits that have a higher rigidity

[MarcusWolschon]

You forgot reason #3 .
The bearings in the spindle and their mounts are not made for axial loads but .
I pushed my small ATC spindle (CNC mill, not 2.5D router) up inside it's casing because the bearings where press-fit while drilling POM.

[chadkrause]

I am the CNC guy for my robotics team. We have a laguna swift 4x4 router. We drill all the time. We mainly cut aluminum, but also plastic and wood on occasion. We use carbide drill bits (HSS sometimes too), and the key is just just feed the hell out of it. I mainly do .191 holes in aluminum and I drill at .002 ipt at 18000rpm with a carbide drill. Cuts thousands of holes before needing to change. No pecking at all.

The vacuum table we made with a .125” drill, we fed 120ipm at 18000 rpm. Drilled 4, 000 holes no problem

You can do it, don’t be afraid

[QuinnHale]

It seems to me that this is a non issue if you have control over your spindle speed. I use a VFD, and adjust my spindle speed all the time depending on the bit, material, and operation. I use UCCNC for my control where I can tweak spindle speed on the fly if I need to. Pretty important for most any operation.

[minigpracing]

You can get single flute spiral drill bits, but it looks like the common sizes are tiny with 1/8 inch shank, or common sizes in a much larger shank for big machines. Bit of I've never used any of these before.

[the-THORNSPAWN]

We drill hardwoods all the time with standard drill bits but it helps having a 9hp spindle that still has usable torque at the 3500rpm we use.