Category: CNC

A hand-held router is an amazing tool for cutting and trimming composite parts. Here are some tools that I really like. Most of these can be used in a die grinder (not the ones with a bearing) for free-hand work and trimming. Be careful – they’ll mess you up if you get a glove or piece of clothing tangled up – ask me how I know!

From the left:

1. Carbide burr for carving foams and honeycomb. This has big teeth and can be used for carving in a router or a die grinder. It is definitely a bit grabby so be careful! One common brand is Sabuur Tooth.
2. Carbide burr router and die grinder bits. These are very common and have a diamond-cut pattern. They aren’t very expensive and can plunge (with the right tip geometry) and slot beautifully. The rounded ones are great for carving and shaping solid laminate with a die-grinder.
3. Diamond grit router bits. The three groups on the right are all diamond coated cutters. The middle three are for slotting and milling solid laminate. They don’t take much of a bite because the effective “flutes” are very small – but they leave a nice finish. The flush trim and radius bearing bits work just like their wood-cutting cousins – just slower and with nastier dust! On the far right, the mounted wheel cutters are great for trimming parts at an offset from a flange or for free-hand cutting with a die grinder. This can be scary, so always use the smallest wheel you can if you aren’t mounting one of these in a router! An remember dust collection – these tools make a huge mess. All the diamond tools are from Bodi Company though they are available from other manufacturers and can be made custom for specific profiles or applications.

Most of these can also be used in a CNC router – not the ones with bearings or the carving-specific burrs – but the shank-mounted diamond and carbide cutters can make automated trimming an option. If you are doing deep slotting dust clearing will be a problem so you don’t bind things up and create excess heat. Again – this will be a huge mess so good dust extraction is essential!

I am devoted to the Festool routers for their excellent dust control – even though they are very expensive and initially it was hard to get over that. They have a rotating “cup” that fits below the base plate of the router, and for edge work (trimming to a pattern, radiusing, de-coring, etc.) this catches an incredible quantity of the dust created. They are worth looking into if this is an every-day kind of work in you shop or factory.

I’ve been working on some small pieces of hardware to attach fasteners to composite parts. Given the strength of methyl methacrylate and epoxy adhesives for gluing dissimilar materials, there are plenty of applications where you can just surface bond fasteners. I am testing the size of the flange needed and how the bond-line holds up to various torture.

My plan is to document the process of gluing these parts and test various adhesives. Plexus MA830 works very well so far, and since it also glues Markforged Onyx (Nylon) parts very well, I’ll test them too!

The lathe skills are not pro-level yet, but I am loving the learning.