Drill bits

[ldoodle]

Hey,

I'm looking to put recessed lights in my decking and sleepers* and the manual has 2 options for fitting them. I'd prefer option 2:

"Drill a 76mm diameter hole. Machine a 97mm diameter by 13mm deep counterbore."

Can someone advise where to get both bits, specifically the latter one.

Thanks

*Regarding the sleepers, obviously they're solid all the way through, whereas decking is 'hollow' once you're through the 25mm thickness or so, so how would a recessed light work in this scenario. Is it a bad/impossible idea?

http://www.saxbylighting.com/instructions/25702.pdf

 

[Burnerman]

You are into hole saw territory here.....drill the larger hole first, 13mm deep, followed by the smaller one to the depth required.
Use a solid hole saw (Starrett is a good make) and then it's chiselling to remove the waste.
John

 

[Deleted member 174758]

"Drill a 76mm diameter hole. Machine a 97mm diameter by 13mm deep counterbore."

Can someone advise where to get both bits, specifically the latter one.

The 76mm can be done using a self-feeding bit:

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• Deleted member 174758
• 27 Feb 2015
• 1

which are a cross between an auger bit and a Forstner bit or a saw tooth bit as Burnerman says. You'll need an extension bar to drive it all the way through a sleeper together (preferably) with a largish high torque drill capable of running at low speed (e.g. an SDS drill fitted with a 3-jaw chuck or a dry diamond drill).

97mm means that you need a rebate 10.5mm wide x 13mm deep. So I'd use a 1/2in plunge router fitted with a heavy rebate cutter, such as one of these fitted with a TB670 to give a 10.5mm rebate width. Should be possible in 2 to 3 passes with a heavy router. Of course it all depends if you have a big router

 

[Burnerman]

Never come across that one! It'll take a beast to drive it, I guess.
John

 

[ldoodle]

drill the larger hole first, 13mm deep, followed by the smaller one to the depth required. then it's chiselling to remove the waste.
John

That's not a bad (diy'er) method.

Unfortunately I don't have a router at all, let alone a "big" one

I think recessing one into a sleeper is a step too far (the mrs' idea!!)...

 

[Deleted member 174758]

DW brought them out a few years back. I don't think they sold too well because very few people stock them now. Good bits, though. And yes, they ideally take a bit more than an 18 volt cordless to drive, unless you like the smell of cooking batteries

Unfortunately I don't have a router at all, let alone a "big" one

Just think of it as "justification".....

 

[ldoodle]

I can't seem to find 97mm hole saws!

Think i'll use these in the sleepers: http://www.saxbylighting.com/index.php?pg=details&prod=199#

but still drill a hole (maybe 3/4 the length of the spike) for them to sit in.

 

[Dave54]

I've got a 1920s/30s American "Chicago" "Little Giant" rail spike driver here somewhere. 110V converted to a drill. Does about 3 rpm, and if it jams it pulls the Earth off it's axis. That might drive that. . .

Useful to know about those bits though!

 

[Dave54]

I'd wonder if a 95 mm hole saw might do the job. Might need a bit of easing with a chisel to get it to fit though. If you're settled on the other type though it's job done!

 

[Deleted member 174758]

I can't seem to find 97mm hole saws!

97mm is beyond the capabilities of any expanding bit I know of. There's always the Famag Bormax Fortsner bits in 95 or 100mm (and at those priced I'd be buying a router). Two other makers who do big cutters (Fisch and Star-M) don't go that big, and Clico are no longer around (not sure if they went above 3-1/2in either).

There's always Burnerman's original suggestion of a holesaw. The nearest Starrett get is 98mm in bi-metallic or 98mm in TCT, but there's normally some leeway in the sizing. Then hack out with a mallet and chisel (it won't be seen, so does it matter?). With that type of holesaw you'll need to budget another £15 or so for an arbor and pilot (which can be shared between holesaws)

 

[Dave54]

I went looking for a big expansive bit a while back, ended up being given a Record Power bit by a firm I used to buy a fair bit of stuff off. That's 75mm or thereabouts. Good tool but not big enough. I ended up drilling the waste out and using the router to clean up to get the hole I wanted. That was about 100mm IIRC.

TBH with something like this, you could get away with marking the job. drilling out most of the waste with something like a 30mm spade bit, and cleaning up with a chisel. I'd do the rebate (bigger) hole first, and be as careful as possible about the depth. A bit of a bodgy way to do it maybe, but you say J&K it won't be seen.

 

[Norcon]

I'd use a router with a profiling cutter and a 76mm bacho hole saw.
And swing the template orifice on the lathe.
Easy enough to do both with the router.

 

[ldoodle]

I'm seriously considering buying the decking from a local timber merchants (I've always used Travis' before for decking)... would they have the ability to do these holes?

Or do they really only do cuts?

 

[ldoodle]

**** it! Think I may buy a router. Been after one for ages anyway.

Without going too extreme, what's a reasonable 1/2" plunge router. I won't be using it everyday so longevity is not top priority, but accuracy is.

 

[Deleted member 174758]

You can buy a cheapo Silverline, Silverstorm, SIP or the like for which there will probably be ZERO spares backup after the warranty is up (based on other Chinese "no-name" tools), or for somewhat more money (£150 and up) there's the Hitachi M12VE which is pretty much the cheapest 1/2in plunge router available from any of the big name manufacturers. Like the others it's made in China, but at least being made by Hitachi (Japanese) the warranty and spares backup should be there. Amazon review are generally very positive. It's your call