3.175mm — Best suited to intricate detail work, tight internal corners, and smaller components. Handles sheet materials up to 18mm, making it a capable all-rounder for detailed cabinet work and fine CNC profiling.

4mm — A step up in rigidity for small to medium parts. Good for detailed cabinet components, smaller drawer fronts, and decorative profiling.

5mm — Versatile for general purpose cutting across MDF, MFC, and plywood. Handles most standard sheet thicknesses comfortably in a single pass.

6mm — Our median size and the one we recommend to most customers. A great all round choice that allows fast feed rates while comfortably cutting through most 18 mm sheet materials in a single pass.

6.35mm (1/4") — Identical performance to the 6mm but sized for machines with imperial collets. If your CNC runs a 1/4" collet, this is your 6mm equivalent.

8mm — Built for heavier duty cutting and higher feed rates. Ideal for production environments cutting thicker sheet materials, solid wood composites, or where maximising output per pass matters.

10mm — For demanding production cutting in thicker panels. Greater core strength reduces deflection at higher feed rates. Well suited to workshops running consistent volume through 18–25mm sheet materials.

12mm — The largest in the range. Maximum rigidity, maximum cutting depth. Built for heavy production work and thicker composite panels where smaller diameters would flex or underperform.

Compatible with every 3-axis CNC machine without exception. Whether you're running a entry-level hobby machine or a professional production router, every size in our compression cutter range will fit and perform. If your machine has a collet that accepts the shank diameter, it will run our cutters. That covers every machine you're likely to be running: Shapeoko, Shark, ShopBot, BobsCNC, Genmitsu, Stepcraft, Openbuilds, SainSmart, Trend Smartbench, FoxAlien, Mantech, and every other 3-axis CNC in between. No compatibility concerns, no special requirements.

Every size is also fully compatible with all wood-based sheet materials including MDF, MFC, melamine faced MDF, birch plywood, hardwood plywood, HPL, veneered panels, and all standard laminates. If it's wood and comes in sheet form, our compression cutters will cut it cleanly.

Check out our Micro Grain Solid Carbide Spiral Compression Bit, featuring 2 flutes and built to outlast standard solid carbide bits, a claim we've tested meticulously to back up. Available in sizes from 3.175mm to 12mm with a range of cutting lengths to match.

What is Micro-Grain Solid Carbide?

Micrograin solid carbide uses carbide grains down to 0.5 to 0.8 microns, versus 2 to 5 microns in standard carbide. Finer grain means a harder edge without the usual loss in toughness, so it resists chipping and heat softening under load. Result: the edge stays sharp and accurate far longer, especially when compared to standard solid carbide bits.

These compression bits are built for CNC and router applications requiring high feed rates and clean compression cuts. They work great across wood sheet materials, giving a consistent edge on both the top and bottom of the panel.

The bit can also be used as a pocketing tool, provided the pocket is deep enough to engage both the up cut and down cut portions, which ensures a clean finish. That engagement depth varies tool to tool depending on cutting length.

• Orders placed before 2pm UK time, Monday to Friday, are dispatched the same day. Selecting next day delivery means your order will arrive within 24 hours; standard delivery typically arrives between 48–72 hours.
• Orders placed from australia will arrive within 5-7 working days, full tracking is included.
• Customers are responsible for return shipping unless the return is the result of our error, such as receiving an incorrect or defective item. After 60 days, refunds or store credit may be offered at our discretion.
• If your order arrives defective or not fit for purpose, email info@routerbits.co.uk and our team will take it from there.