Forstner bit vs hole saw
Updated: 2026-10-23
You need a flat-bottomed recess, or a through-hole where the waste falls out as a plug. That is the Forstner bit vs hole saw choice. Drilling controls are on the [how to use a Forstner bit page](/hub/drilling-and-accessories/forstner-bit-40mm/sub/forstner-bit-40mm-how-to-use). Listing checks are on the [40 mm Forstner bit buying guide](/hub/drilling-and-accessories/forstner-bit-40mm/sub/forstner-bit-40mm-buying-guide). The geometry below was set against one review in the [40 mm Forstner bit comparison](/hub/drilling-and-accessories/forstner-bit-40mm), on 20 October 2026. There is no lab shoot-out, and no hole-saw brand is recommended here.
You need a flat-bottomed recess, or a through-hole where the waste falls out as a plug. That is the Forstner bit vs hole saw choice.
You need a flat-bottomed recess, or a through-hole where the waste falls out as a plug. That is the Forstner bit vs hole saw choice. Drilling controls are on the how to use a Forstner bit page. Listing checks are on the 40 mm Forstner bit buying guide. The geometry below was set against one review in the 40 mm Forstner bit comparison, on 20 October 2026. There is no lab shoot-out, and no hole-saw brand is recommended here.
Our top picks
| Badge | Product | Listed diameter | Tip stated | Machine note | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  TA-VIGOR TA-VIGOR 40 mm, carbide tip | 40 mm | Tungsten carbide | Bench drill, vertical drill or CNC; water on hardwood | 7.0 | about £9.46 | View offer |
| Alternative |  HSAWBIT HSAWBIT 40 mm, hex | 40 mm (minimum bore 39 mm) | High-speed steel | Hand drill or bench press; no impact driver | 6.3 | about £12.99 | View offer |
 ASNOMY ASNOMY 40 mm, carbide tipped | 40 mm (minimum bore printed as 1.56 inches) | Tungsten carbide tipped | Above 40 mm, listing prefers a fixed drill or a vice | 8.5 | about £11.89 | View offer |
On this page
What each tool actually removes
A Forstner bit leaves a flat bottom, so you can stop at 12 mm in an 18 mm board and still have a pocket. A hole saw is a toothed cup on a pilot. It leaves a plug, and the centre of that plug is a pilot hole. Hardware Tool Shop puts it plainly: the Forstner cuts the bottom, and the hole saw leaves the plug. Stop a hole saw halfway and you get a groove, not a floor. The Spruce says a hole saw cannot make that partial-depth pocket, and a spade bit tends to tear the fibres. A hole saw's pilot needs solid timber, so an overlapping second hole has nothing to bite. Woodcraft describes that Forstner geometry. One ASNOMY reviewer preferred a Forstner for their cut. That is one job.
Speed and size
A hole saw is often faster through the board because it only cuts the ring. Fine Power Tools calls it the quicker tool, and the Forstner the cleaner cut that can stop. That is one page's observation, not a British Standard. At 40 mm both tools exist. A rim run too fast scorches hardwood, and that burned hole is not cleaner than a hole saw. The listings that mention the machine want a drill or a press, not an impact driver.
Tear-out on the exit
Both tools can tear the exit face. Clamp a scrap under the board. A hole saw with backing is a fair choice for a cable hole through an 18 mm panel. If the hole must stop at 10 mm with a flat floor, the hole saw never offered that floor.
Which job gets which tool
Choose the Forstner bit for a grommet flange, a candle recess or a lock body that must not break through. Choose the hole saw when the plug is waste. A spade bit is only for a rough hole you will hide. Overlapping holes stay with the Forstner, because the hole saw loses its pilot. A concealed hinge is the exception: the usual cup is 35 mm, and neither a 40 mm Forstner nor a 40 mm hole saw drills it. If the drawing says 40 mm and the hole must stop, use the Forstner.
Common questions
Which leaves a flat bottom?
The Forstner bit. The rim and the cutters pare a floor, so you can stop inside the board and still have a usable pocket. A hole saw leaves a plug and a pilot hole. Stopped halfway, it is a groove, not a flat recess. That is the whole reason to put up with a slower Forstner cut when the bottom will be seen or will seat a fitting.
Which is faster for a through-hole?
Usually the hole saw, because it only cuts the ring and the centre falls out as a plug. Workshop comparisons describe it as the quicker tool for a hole that goes all the way through. One ASNOMY reviewer preferred a Forstner to a hole saw for their own cut. Treat that as a single review. A dull Forstner, or one run hot, will not feel quick.
Can a hole saw stop halfway?
It can stop, and what you get is a circular kerf plus the pilot hole, with the waste still in place. You do not get the flat floor a Forstner leaves at partial depth. If the job is a 10 mm pocket in 18 mm board, start with the Forstner. Chiselling out a hole-saw plug to fake that floor is a different, messier job.
Can a Forstner bit cut overlapping holes?
Yes. That is one of the shapes a centre-point bit can manage once the first hole exists, including a slot made of overlapping circles and a hole that breaks an edge. A hole saw wants its pilot in solid material, so the second overlapping cut has nothing to centre on. Woodcraft describes that Forstner geometry. It is not a trick a toothed cup copies.
Is a spade bit enough?
Only for a rough hole you will hide. A spade bit tears fibres and does not leave the flat, scored floor a Forstner is bought for. It is a poor stand-in for a 40 mm pocket and a poor stand-in for a clean through-hole if the exit face will be seen. Use it to rough out, then switch if the surface matters.
Do I need a backing board with either tool?
For a through-hole, yes. Both the Forstner rim and the hole-saw teeth can tear the exit face, and a scrap clamped underneath gives them something to cut into. A blind Forstner pocket does not need backing, because you stop before the point breaks through. The backing piece does not change which tool leaves a flat bottom.
Which one for a 40 mm cable grommet?
Use a Forstner bit if the grommet sits in a stopped flat recess and the far face must stay intact. Use a hole saw if you only need a 40 mm hole through the panel and the plug is waste. Match the grommet maker's hole size before you cut. A 40 mm tool is the wrong answer if the grommet is specified at another diameter.
Related pages
Sources
Public UK sources from the research digest, last checked on 20 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the product display for this comparison.
- HSE: PPE overview (retrieved 20 October 2026)
- Consumer Rights Act 2015, section 19 (retrieved 20 October 2026)
- Bosch Professional UK, 40 mm Forstner bit 2 608 577 019 (retrieved 20 October 2026)
- Hart Wholesale, Blum 71B3550 (retrieved 20 October 2026)
- Furnica, 35 mm hinge cup guide (retrieved 20 October 2026)
- Katz-Moses Tools, Forstner speeds (US shop, rule of thumb) (retrieved 20 October 2026)
- Famag Tool UK, classic 40 mm Forstner bit (retrieved 20 October 2026)
- amazon.co.uk listings for the ASINs in this comparison (retrieved 20 October 2026)