Forstner bits
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Discussion

Simpo Two

Original Poster:

89,716 posts

283 months

Monday 15th March 2010
quotequote all
I'm looking to replace a set of flat drill bits which, being cheap, now have a significant wobble on them and are most unpleasant to use. Now I can buy more expensive flat bits:



or maybe these babies:



- but I wondered if Forstner bits would work instead?



I know they're designed to cut round corners or something, but are they good for drilling normal holes as well?

In short, what's the best for drilling large holes cleanly and quickly?

mackg

152 posts

198 months

Monday 15th March 2010
quotequote all
what will you be drilling? I would only use forstner bits in a drill press really. I'm not sure if the ones in the picture are the '3 D ' ones though and can't really think why I would need them.

I'm not a big fan of DeWalt bits, Bosch do a good set of flat bits or look at Irwin

Plotloss

67,280 posts

288 months

Monday 15th March 2010
quotequote all
Augers.

Simpo Two

Original Poster:

89,716 posts

283 months

Monday 15th March 2010
quotequote all
Thanks - the likely material will be wood or chipboard, doorlocks etc. I do have a bench drill but most of the usage would be 'freehand'.

Irwin do a set of 'Blue Edge' flat bits for about £22 which looks tempting but maybe the fat 'normal' drills would handle better?

Simpo Two

Original Poster:

89,716 posts

283 months

Monday 15th March 2010
quotequote all
Plotloss said:
Augers.
Ah, you mean the middle ones?

I do actually have a big set of auger drills but they have square shanks for a brace and bit, so don't fit in a normal chuck. I have a hunch they'd bite/pull too fast for an electric drill, being designed for hand operation - what do you think? Is there an adaptor?


shirt

24,544 posts

219 months

Monday 15th March 2010
quotequote all
joiners use forstner bits for boring a recess into newel posts why not? those flat ones really annoy me tbh.

Simpo Two

Original Poster:

89,716 posts

283 months

Tuesday 16th March 2010
quotequote all
This is like the set I already have:



Note the square section where it goes in the brace chuck. Anyone know a way to use them in a conventional 3-jaw chuck?


robinhood21

30,946 posts

250 months

Tuesday 16th March 2010
quotequote all
Cut the square bit off! Mind, it does go through the likes of joists at a fair turn of speed and, puts an undue amount of stress on the drill motor.

hairyben

8,516 posts

201 months

Tuesday 16th March 2010
quotequote all
Augers are good if the drills reasonably powerfull.

Lot of cheap flat bits out there, only good if you regard them as disposable, if like me you hit nails screws masonry etc on a regular basis. If you want a set for precision work buy quality, the mickey mouse titanium coating doesn't count for squat BTW.

B17NNS

18,506 posts

265 months

Tuesday 16th March 2010
quotequote all
Forstner bits are good for precision stuff. If you want to fire biggish deep holes through joists and the like i'd recommend auger bits.

http://www.screwfix.com/prods/71203/Drill-Bits/Woo...

Edited by B17NNS on Tuesday 16th March 18:18

Simpo Two

Original Poster:

89,716 posts

283 months

Tuesday 16th March 2010
quotequote all
That's good, thanks. I think I'll keep the old augers for sentimental reasons (I found out they're called 'Jennings pattern' - there's no central column) and buy a set of new ones.

Or of course just use a brace and bit old-style smile

Simpo Two

Original Poster:

89,716 posts

283 months

Thursday 18th March 2010
quotequote all
Just to conclude, I rang Axminster Tools today, spoke to a very knowledgeable chap and decided on these:

www.axminster.co.uk/product.asp?pf_id=22051&na...