Forstner Drill Bits

[Mikegtr]

Two questions regarding Forstner bits:

a) ‘Wave’ or ‘Saw’ tooth cut. A big difference in the quality of the cut?

b) Anybody use the ‘Adjustable Forstner Bit’—22mm to 50mm? Does it work OK?

 

[Chief Sawdust Maker]

I tend to use saw tooth for end grain and wave for side grain
There is a big difference in quality depending on price, from experience the cheap ones are ok in soft wood but as soon as you are heading for hard wood then you will need to spend the cash
I also tend to shorten the point on them a little especially if drilling blind holes to near the base of the material
Not used an adjustable one but from memory Axminster do one in their turning section aimed at producing a number of diameters for if you were producing pepper and salt mills on a lathe

Hope this helps

D

 

[fleyh]

Two questions regarding Forstner bits:

a) ‘Wave’ or ‘Saw’ tooth cut. A big difference in the quality of the cut?

Answer:

b) Anybody use the ‘Adjustable Forstner Bit’—22mm to 50mm? Does it work OK?

It does work (not as clean cut as dedicated size bit) - but it is sca-a-a-a-ry.
I only use it when I can't figure out any other way of doing the hole.

 

[Mikegtr]

Thanks for the good info—much appreciated.

 

[spanner48]

Two questions regarding Forstner bits:

a) ‘Wave’ or ‘Saw’ tooth cut. A big difference in the quality of the cut?

b) Anybody use the ‘Adjustable Forstner Bit’—22mm to 50mm? Does it work OK?

I've had an adjustable Forstner bit for decades. It works - in a swing brace; i'm not sure in a power drill: it takes off a good shaving at each turn.

Essential is to keep it sharp – particularly the peripheral 'wings', which need to be carefully sharpened from the inside

 

[jb94]

I’d recommend the Bosch professional forstner bits, they’ve got a wave edge and are wickedly sharp. You get wafer thin shavings in both hard and soft wood and clean edges.

 

[Phil Pascoe]

Don't even think about Aldi/Lidl offerings.

 

[johnnyb]

I've had freud imperial ones for decades and we're not expensive these are neither sawtooth or wave and drill well in cross and long grain. There also are easy to sharpen. The aldi lidl ones are not as good but still usable (being soft and roughly made) some of the expensive drills are eye watering(famag) superb but no better than my freud which were £20 for 5 upto 1 inch.

 

[johnnyb]

Ps my 3/4 freud forstner has drilled thousands of through holes in hardwood making a product I sell. It's much harder to drill a clean through hole in softwood imho.

 

[johnnyb]

https://www.amazon.co.uk/Freud-PB-1...=freud+forstner+bit+set&qid=1716793265&sr=8-3

 

[Phil Pascoe]

Usually dispatched within 6 to 7 months

 

[Chubber]

If I were to introduce the suggestion of a 'flat bit' at this point I would probably be laughed out of the park!

Having recently finished several years volunteering in a railway carriage restoration workshop you often didn't know what you are drilling into. With reclaimed wood and components, I learnt early on that a Forstner bit, more so in larger sizes is an expensive item and difficult to bring back to peak sharpness after you have hit the remains of a 2" No 14 steel screw.

Once, having been loaned a 32mm Milwaukee flat bit with long well ground spurs to drill 3" iroko I was so impressed with the clean entry I bought a set -

https://www.screwfix.com/p/milwaukee-flat-wood-drill-bit-set-8-pcs/781fj

I commend them to the house when you don't want to splash out on that size Forstner for what may be just one job, they are a world away from a set of B & Q pointing trowels!

 

[johnnyb]

I also favour flat bits in general on site. In bigger sizes without care they can hurt your wrist. Damhik

 

[Sideways]

Flat bits work best when spun as fast as possible. Put them in your fastest handheld on full, not a 1/4" hex driver and if in a pillar drill, don't be lazy, move the belt and get the speed right up.

Good question about the Forstners, I'm learning from the replies

 

[Orraloon]

I also favour flat bits in general on site. In bigger sizes without care they can hurt your wrist. Damhik

Same with forstner bits in a hand held. Anything over 25mm I only use in the drill press.
wallace and gromit electric drill - Google Search
Regards
John