Irwin 10502807 4X Blue Groove Flat Bit, 13mm x 152mm
Product description
What it’s for (and why the groove matters)
An Irwin 10502807 flat bit like this one is built for drilling flat-side holes in wood and similar materials where you want a cleaner, steadier cut than you’d typically get from a basic twist bit. The “Blue Groove” naming is relevant in practice: it’s aimed at chip relief, so waste has somewhere to go while you drill. That can help reduce how much the bit clogs up mid-job, especially if you’re drilling repeatedly or working through thicker sections.
On paper, the design leans into smoother cutting. Irwin also specifies an increased relief angle (from 12° to 17°). That small change can make a noticeable difference in how the cutting edge handles resistance. It’s not magic, and you still need to keep the drill straight, but the geometry is clearly meant to improve performance under load.
At a glance
This model is listed as a 4X Blue Groove Flat Bit with: - Size: 13mm - Bit length: 152mm - Shank length: 157mm - Diameter (as given): 6mm
There’s also a clear “for drilling” focus: it’s sized for the bigger, flat-bottom style of hole you might need for certain woodworking setups, repairs, or project builds.
Key takeaways for buying
If you’re choosing a flat bit, the real question is whether your project needs this style of hole. Flat bits generally make sense when you want a larger diameter hole and a flatter profile than what you’d get from standard twist drilling.
It makes sense if you’re: - drilling into timber where chip evacuation is a practical concern - doing jobs that involve a bit of steady pressure over a longer run - trying to avoid the “bit packs up and slows down” feeling halfway through
It’s not the best match if you’re after a lightweight, general-purpose drilling tool for everything. In that scenario, you might find you’d be better off with a more versatile bit type, because flat bits are often more task-specific.
You may want to skip it if your priority is compactness above all else—this one has a 152mm working length, so it’s meant for reach, not for tight toolboxes.
What stands out in use
Where this bit’s design shows up is during the boring stage of a job: starting cleanly, then maintaining a consistent cutting action as the bit takes in material. The increased relief angle (12° to 17°) is there for a reason—less binding tendency and better handling of resistance.
A practical micro-example: imagine you’re drilling a 13mm hole through a wooden panel for a fixing or fitting. With a flat bit, you often get a more defined hole shape for that diameter. As you pull the bit out to clear waste, the “groove” concept helps keep chips moving rather than smearing or piling up immediately.
Tech specs
- Name: Irwin 10502807 4X Blue Groove Flat Bit
- Type: Flat bit
- Size: 13mm
- Dimensions: 13mm x 152mm
- Shank Length: 157mm
- Diameter: 6mm
- Relief angle: increased from 12° to 17°
Who it suits (and who should be careful)
It suits you if you’re the sort of DIYer or workshop user who already knows you need a flat bit for the job. If you’re working on wood-based projects and want a bit designed to handle drilling resistance more confidently, this kind of geometry and chip relief approach is worth considering.
Better avoided if: - you’re drilling very occasional holes and want one bit to do everything - your projects require lots of different diameters, depths, or materials and you don’t want to manage a “bit for the job” collection - you expect it to behave exactly like a multi-material twist bit (it’s built for a different drilling style)
Buying verdict
Is it worth it?
Worth buying if you specifically need a 13mm flat bit with a 152mm drilling length, and you care about how the bit manages cutting resistance (the 17° relief angle update and groove-style chip relief are clearly aimed at that). It’s the sort of bit that earns its keep on straightforward, repeatable drilling tasks where hole shape and chip control matter.
It may not be worth it if you mainly do general drilling across many materials. In those cases, flat bits can feel a bit specialised, and you might get better overall value from a more universal approach.
Quick FAQ
FAQ: common questions before you buy
What does “4X Blue Groove Flat Bit” tell me? It points to a flat bit intended for improved chip relief during drilling, with a design that includes an increased relief angle.
Is the 13mm size right for my hole? Based on the listing, it’s sized for a 13mm hole. If your project calls for a different diameter, you’ll need a different bit.
How deep can I drill with it? The working size is given as 13mm x 152mm, so the bit length you’re drilling with is 152mm (as listed).
Will it fit my drill? You’ll want to check compatibility using the shank/diameter info provided in the listing, as tools and chucks vary.