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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Carpentry Questions >> Wood Drill Bits https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1106056328 Message started by Plumber on Jan 18^th, 2005, 1:52pm

Title: Wood Drill Bits
Post by Plumber on Jan 18^th, 2005, 1:52pm

Hello

I am installing plumbing and heating to a new house in Sussex, the client is keen to avoid pipes on view, the house is timber framed and the walls are stud partition approx 50mm at the point I need to drill and sometimes there is a double timber, I always insulate all my pipework, I need to drill holes in the stud work and need the hole to be 40mm to allow the pipe and insulation to pass easily through, what is the best drill bit to use, flat bits seem to take a long time to drill through and start to get very hot, the same for hole saws, I was hoping to get a 40mm Auger bit but the biggest I have found is 32mm any ideas

Thanks for your help

Title: Re: Wood Drill Bits
Post by woodsmith on Jan 18^th, 2005, 4:56pm

My first thought was a Forstner bit but these may not have the depth you need. Axminster Power tools sell sawtooth cutters they are about 130mm long and you can get them up to 50mm diameter.
http://www.axminster.co.uk/product.asp?pf_id=22801&recno=8

Title: Re: Wood Drill Bits
Post by chippysmith on Jan 18^th, 2005, 4:59pm

Forsner bits s/f pt. no 83345 or an expansive bit 17377 (I havn't used the latter) the forstner bits are very good

Title: Re: Wood Drill Bits
Post by Plumber on Jan 18^th, 2005, 7:46pm

Thanks for that, I knew there must be better wood bits around than the usual ones us plumbers use.

Title: Re: Wood Drill Bits
Post by trowelhead on Jan 18^th, 2005, 7:55pm

Am i stupid ;D or am i reading you are planning to drill a 40mm hole through a 50mm stud so therefore leaving 5mm either side? :o
If you need to you can call me stupid,its the way i read the question :-[

Title: Re: Wood Drill Bits
Post by Plumber on Jan 18^th, 2005, 8:10pm

No the stud is 100mm in width it is 50mm in depth.

There are some very good sets of Forstner bits availiable from 6mm to 51mm, is there an extension that you can get for these bits, as you say woodsmith they lack in depthe as some of the studs are double, so 100mm in total

Title: Re: Wood Drill Bits
Post by bstyle on Jan 18^th, 2005, 8:12pm

Could you not just insulate up to and beyond the studwork?

I never have any problems just using a hole saw, I do a lot of large holes through joists for waste pipes and they go through ok with a right angle drill

Title: Re: Wood Drill Bits
Post by woodsmith on Jan 18^th, 2005, 8:58pm

The Forstner bits lack the depth which is why I recommended the sawtooth bit. Axminster do two shank extensions one at 13mm and one at 1/2", £17.60 each so not cheap. I still think you would be better off with the Sawtooth cutter, and it will cut 100mm deep.

Forstner and sawtooth bits are not the fastest or easiest bits to use, an auger would be best but unfortunately they don't make one big enough. I'm not sure you would find a set of them so useful unless you need to make very clean holes.

Keith

Title: Re: Wood Drill Bits
Post by Plumber on Jan 18^th, 2005, 9:01pm

I do not like the pipework to touch the wood at all, there is no chance of any creaking noises if the pipe is not in direct contact with the timber.

Title: Re: Wood Drill Bits
Post by chippysmith on Jan 18^th, 2005, 9:50pm

If you have a local costco, they have a really good set of forstner/sawtooth cutters. Too cold to look in the van right now but will check tomorrow. I think they are forstener up to about 25mm then sawtooth

Title: Re: Wood Drill Bits
Post by JerryD on Jan 18^th, 2005, 10:02pm

wrote on Jan 18^th, 2005, 4:56pm:

Woodsmith, what's the difference between a Forstener bit and a Saw Tooth bit? They look the same to me.

Title: Re: Wood Drill Bits
Post by Windy Miller on Jan 18^th, 2005, 10:06pm

wrote on Jan 18^th, 2005, 4:59pm:

or an expansive bit 17377 (I havn't used the latter) the forstner bits are very good

I've got one of those expansive jobs and they are pretty good. I got it to drill mounting holes for monobloc taps in worktops, and I was well chuffed with the result.

Rochester Tools do them, but they are much dearer than the ScrewPhux ones. If you want one Plumber, I can get a deal from them, and you can pick it up next time you're over this way...

Windy

Title: Re: Wood Drill Bits
Post by woodsmith on Jan 19^th, 2005, 8:10am

Jerry the Forstner bits have 2 cutting edges wheras the sawtooth cutters have a sawtooth edge, basically it allows you to drill into end grain which Forstner bits won't.

Title: Re: Wood Drill Bits
Post by JerryD on Jan 19^th, 2005, 10:37am

wrote on Jan 19^th, 2005, 8:10am:

Jerry the Forstner bits have 2 cutting edges wheras the sawtooth cutters have a sawtooth edge, basically it allows you to drill into end grain which Forstner bits won't.

Many thanks :)