How to mill large diameter holes

[Mercroft]

We have some large GluLam beams in our shop that we need to mill for recessed lighting and we're having troubles coming up with an efficient way to mill 7" diameter holes in the 4 5/8" thick material. Does anyone ave any tips? Trying to look into custom made Forstner bits or anything. OUr only guess so far has been to router out the holes but that is and will be very tedious. Any tips would be more than helpful
Dan

[colville6]

You can get 6 7/8" recessed lighting hole saws. The problem would probably be the depth of your cut. With regular wood I would say bottom out the saw, back it out, knock the waste out with a hammer, go in again with the saw. I don't know if a glulam would chip out as easily as plain wood.

Or, if you have access, come in from one side with the hole saw, take a long bit and drill the pilot all the way through, then come from the other side with the hole saw. Should get you close enough for a hammer blow to knock out the plug.

[JTTHECLOCKMAN]

You can use a circle cutter or you can use a router in a circle cutter jig.

[mike4244]

Where is this hole to be ? The can light is usually installed between joists.Does the beam carry a load like joists? If you make a hole 6-5/8" in diameter,how deep does it have to be?
Maybe I'm missing something here,seems to me what you want to accomplish will weaken the beam to the point of failure.

mike

[Axehandle]

I don't know how long of up cut bits they make but you could drill a through hole and rig a circle jig with the router from that hole and hit it from both sides?

Never done it before so I don't really know but if the bits had 1 7/8 inches of depth you would be golden.

[Routerman]

In place (the beam)? Then only for the Wallendas.
Working up side on a ladder/scaffold? Tough, tough proposition.
Hardware unacceptable?

[blackhat]

With the limited info about this situation, I would say step one is find smaller lights.

[WilliamHodge]

Do what a plumber would do. Plumbers are great at cutting large holes in structural material.

[JIMB49]

plumbers are danger on 2 legs
they just love to tear up structure
i do not think its a good idea to cut out that much of a glulam

[blackhat]

On principal, I agree with the concerns about weakening the member with that large a hole, but, this may not be a structural lam.

Before you go slamming plumbers, think about the designers, engineers and architects that do not leave sufficient space for systems, or omit properly framed chases and passes to save money or can't be bothered detailing them. You want 9' ceilings and don't want to spend money on walls taller than 9', give us web trusses to put duct in or accept that it will be below the trusses.