I like the idea of drilling out the center of the 3/8" holes with the 1/8" bit and then milling out to full size. I’m assuming the latter would be done at full depth to spread wear along the length of the cutter.

Working with composite lumber can be a rewarding experience, especially when you know the right techniques. Whether building a deck or crafting outdoor furniture, understanding how to cut, drill, and fasten composite materials is essential. Compared to traditional wood, composite lumber has unique properties requiring a slightly different approach.

In the Shapeoko, with a spindle capable of running well at low RPM the limit seems to be how hard the Z axis can push down to meet the feed per revolution required to be cutting instead of rubbing. I’m up to about 4,000RPM on the 4mm bits now. At a certain point increasing the RPM and Z feed rate the whole X gantry starts to vibrate and I chicken out and back off. In Aluminium I add small amounts of Isopropanol as lubricant as that’s largely ‘self cleaning’ as it evaporates away.

Drilling composite lumber requires precision to maintain its integrity. I learned this firsthand while assembling a new deck using composite materials. Here's what worked for me and might help you, too.

Machining drilling and fastening composites guidepdf

Maya is a sustainability advocate and expert in eco-friendly living. With a passion for reducing waste and adopting sustainable practices, she guides readers on making environmentally conscious choices for their homes and gardens.

IMO 0.001 feed per rev is pushing the minimum I would go, that’s 0.0005" chipload and starts to get iffy on the chips ability to carry the cut’s heat with it. A thicker chip will be better for heat management and should help break them which can be easier on the tool. Ive found that 0.002-0.004" FPR is the magical sweet spot for carbide drills (depending on helix). Might require an HDZ or other ballscrew Z axis to push them with enough force though.

Instead of retracting a drill, you could go right into milling with the same tool in the same hole with it already at full depth.

25Deg Right Hand Helix, Two Flute, 118Deg Four Facet Point. Milling & Special Form Tools. Loc-Line® Modular Hose System. Vises & Work Holding. Ultra-Tool® USA Part #52008. Hand Tools. SPT is an Authorized vendor of ULTRA TOOL/TOOL ALLIANCE.

Hidden fastening: These provide a clean look with no visible screws. My first time using hidden fasteners, I was amazed by the smooth finish. Composite deck clips slide into grooves on the board's edge and attach to support structures.

To avoid tool changes and having to revisit the same holes, the 3/8" holes could be done with a combo drill / end mill. I would think the style with the twist-drill type point would be best (what they call “Drill Style - 2 Flute” here):

“The threshold for aluminum is something like 60,000 sfm, which is enormously fast,” he said. “I’ve seen aluminum run at 24,000 sfm with an uncoated carbide insert, and it didn’t harm the aluminum or the insert. I tell our customers that, within a safe working environment, don’t be afraid to crank it up because I’ve seen that higher speeds in aluminum gets you both better tool life and a better surface finish.”

Tested on scrap 1/8" plate, drilled all in one go. I read up on peck drilling and that wasn’t recommended unless you’re going deeper than 3x the diameter of the bit. This page seemed to have some good recommendations on peck depths:

Solid Carbide Stub Drills Ideal for drilling steel, cast steel, cast iron, titanium, nickel alloy and aluminium Micrograin carbide Sizes available from 1.0mm - 13.0mm Dimensions  Drill Diameter Flute Length Overall Length 1mm 12mm 34mm 1.5mm...

Composite lumber maintenance is simpler than wood maintenance but still necessary. Regular cleaning with soap and water prevents mold and dirt build-up. I once discovered that letting leaves accumulate led to stains, which prompted more frequent cleanups. Avoid pressure washing so the surface doesn't get scuffed. Look for specialized composite cleaners to remove persistent stains without damage. Applying a finish every few years helps protect the color and surface. Place heat-resistant mats to prevent heat damage if using a grill or fire pit nearby.

Using the right techniques during installation boosts composite lumber's performance. I learned that lesson the hard way when fasteners weren't aligned correctly on my first deck project, causing some boards to shift over time. Checking fastener alignment is crucial. Here are some quick tips to guide you:

Composite lumber blends wood fibers and plastic, making it durable and weather-resistant. I remember my first project with this material—building a deck for my friend. Faced with the task, I noticed its smooth surface and consistent color, which set it apart from regular wood. Key ingredients include recycled materials, which contribute to sustainability. Popular uses include decks, fences, and railings due to their low-maintenance appeal. Typically, it mimics natural wood textures and comes in various colors.

Position fasteners at the center of joists: This distributes weight evenly and prevents wobbling. Centered placement minimizes board movement, providing a stable structure.

I like the video. I wonder if some of the setups where the mill head is angled over could be avoided with fixturing that holds the workpiece at an angle (or one of those tilt-type tooling vises).

Also, this video spurred me to learn something new - that the term quadriplegic includes people affected with partial paralysis of the limbs. I had always associated the term with complete paralysis previously.

Thanks for posting this I am looking into drilling on a cnc router for a friend that needs to drill hundreds of holes in 3/16 aluminum bar stock.

With this thickess of material, the chip being as tightly spiraled as it is, and it being aluminum, I’m not too worried about chip wrapping. Also, it’s on a pretty clear expanse of flat plate. If you’re drilling down inside a pocket or close to a step or a clamp, you can get the “weed-whacker” effect where the chip hits something and bounces back toward the tool. If it doesn’t break, it could potentially wrap.

Yes, the mill/drills could be one of those situations where you compromise some of the attributes of each of the two tools by combining them into one. This page recommends 130 to 140 degree angles for aluminum:

The holes will be drilled prior to bending with only 2 holes being drilled in a angle jig. I had him try it flat but those hinge holes deformed when bent so they have to be done after the bend.

Fascia fasteners: Specifically designed for fascia boards, these screws prevent mushrooming and expansion. Their small heads disappear into the board for a sleek finish, perfect for enhancing visual aesthetics without hassle.

Master working with composite lumber with these tips for cutting, drilling, and fastening. Learn techniques to ensure precision and durability in your construction projects.

I was using a clearance plane of Z 0.125" and went down to Z -0.166" (0.125 material + 0.021" drill point + another 0.020" to make sure it went all the way through). 0.291" total travel at 10 IPM is about 1.75 seconds. Rapiding back up out the same distance at 100 IPM would be about 0.175 seconds. Total cycle time of about 1.93 seconds.

Working with composite lumber requires choosing the right tools for precise cuts. Here's how I tackle this material effectively.

Pre-drilling is crucial for composite lumber to prevent splitting. Using the right drill bit size makes a big difference.

I went with 10,000 rpm for a surface speed of 233 SFM and feed rate of 10 IPM for 0.001" per rev. Put a little drop of 3-in-1 oil on the plate and a little on the bit and voila!

Weather can impact composite lumber and its installation. In hotter climates, boards may expand, affecting spacing. In colder regions, contraction might cause gaps. I remember a chilly morning when my project showed gaps overnight, and adjusting the spacing fixed the issue. Moisture is another factor; it's best to install on dry days for proper expansion gaps. UV exposure can cause slight fading over time. UV-resistant finishes can help maintain color—plan for ventilation to reduce moisture build-up under the boards.

I’ve found that both chip extraction and some small amount of lubricant / coolant are key to using the carbide drills and not getting a hot workpiece, I’m not up to the SFM where the temperatures start to drop back down and I’m not sure this machine can get there.

I’m hoping he can reliably run an 1/8" stub drill with air blast and light lubricant mist. He needs 1/8" and 3/8" holes. My thinking is drill everything with the 1/8" drill then use a 3mm Datron single flute stub mill to go from 1/8’ to 3/8" where needed.

Drive screws at a 45-degree angle for optimal grip: Angled screws offer better hold and minimize board splitting. This method provides a strong bond, making fastening secure and reliable.

Machininggraphite

These Are Specifically For Use On Aluminium 90 Degree Point 2 Flute Standard Length Micrograin Carbide Dimensions  Cutting Diameter Flute Length Overall Length Shank Diameter  3mm 8mm 50mm 3mm 4mm 10mm 50mm 4mm 5mm 15mm 50mm 5mm 6mm 15mm...

Precise techniques matter for effective drilling. Start by marking the drilling spot with a pencil or an awl to guide the bit. Keeping the drill steady is key; otherwise, the bit can wander. Maintain consistent pressure and speed while drilling through the composite material to avoid overheating. Cooling the bit occasionally minimizes heat buildup and material damage.

He has been hand machining and drilling 1000’s of holes to make adaptive reachers for quadriplegics every year for the past 20 years on an old bridgeport knee mill so I’m excited to help my friend to get into doing Cnc work for the first time. His tools changed my life and I couldn’t live independently without them so to help him help others is a pleasure and the least I can do.

Machining drilling and fastening composites guidepdf download

Those Kyocera PCBs I have are 130 degree. I think the angle is slightly different when they get over a certain size ( I think I saw that in the ebay listing description for them).

I pretty regularly use a carbide spot drill to pre-drill holes to then open out with an end mill running a bore or adaptive toolpath in Aluminium, I started doing that after killing a couple of endmills in the initial helical ramping.

Fastening composite lumber seems straightforward, but careful selection of fasteners enhances durability and appearance. Using the right types makes a significant difference.

Working with composite lumber offers numerous opportunities to create durable and attractive outdoor projects. I've found it incredibly rewarding to see a sturdy and stylish deck come together using these materials. Remember, attention to cutting, drilling, and fastening techniques unlocks the best results.

I’ve also used regular ‘jobber’ drills in the spindle for repetitive drilling ops where I didn’t want to wear out nice carbide tooling and that works well too, at well under $1 per drill bit you just replace them as they blunt.

Can you let us know what machine you’re using and what grade of metal it is? The hole looks clean but I can’t help feeling that the spiral chip would get really tangled up if drilling a lot of holes.

150-400 SFM is the recommended surface speed for drilling aluminum with carbide and this calculator recommended 0.0008 to 0.0018" per rev for the feed.

Yes it will ramp down to full depth then open it up. I figured pre drilling will help take the plunging load off the endmills work and speed up the cycle time. The work will be done on a Tormach 24r which is a linear rail ball screw machine that should be fairly rigid. Had the HDM foot print been large enough I would of had him go that route but he needs 40" of travel for his parts.

True - this is definitely a thin chip at 0.0005". I’m fairly confident that I could double the feedrate without issue. I will have to try that next time I fire up the machine.

High Speed Machining (HSM) What is High Speed Machining (HSM)? High speed machining (HSM)--also called trochoidal milling, adaptive clearing,

Selecting the correct drill bit size is fundamental when working with composite lumber. Typically, a bit that's slightly smaller than the screw's shank is ideal. For standard deck screws, a 1/8-inch bit often works best. This helps create a snug fit without damaging the material.

Those ones you show look like they have a decently high helix angle, which was also recommended in the above link. I’d say give 'em a try if the price is reasonable. I don’t think the tip angle is going to be super-critical. 118 is the common angle for jobber drills that have been used for years and years.

Finally got around to trying this out. 0.089" (2.25 mm) is the tap drill size for a 4-40 thread. Carbide circuit board drills are typically 1/8" shank and come in a range of sizes, including sizes larger than 1/8":

I looked into them as the first option but I don’t know long the sharp point will last with non stop drilling. From my understanding they are for light drilling not for constant drilling as the point quickly wears out. I couldn’t find any drill mills with 118 degree tips.