Drill a hole from 55mm to 57mm or 58mm

[mattias4815]

I have six halogen spotlights that are recessed in a canopy under the kitchen cabinets. Now one of the fittings has broken and I plan to replace them with LED spotlights.

My current spotlights are in a 55mm hole. The new LED spotlights require a 58mm hole.
The cables from the spotlights run in a routed channel in the canopy and then behind the kitchen cabinets up to a transformer located on top of the kitchen cabinets.

My plan is to use the cable from the old spotlights to pull the cable from the new spotlights.

I see two difficulties:

1. Drilling out the existing holes from 55 mm to 58 mm. I prefer not to use a hole saw with a center drill as I will then drill a hole in the under-cabinet. Are there hole saws at 58mm? According to this thread, it seems difficult to find. If I choose one at 57 mm, it is only 1mm per side that needs to be drilled out. I see a high risk that this won't go well. Do you have any tips?

2. The second difficulty is that I don't want to cut the existing cable as I want to use it to pull the cable from the new spotlight. Do you have any tips here?

Attaching two images:




Best regards,
Mattias

 

[Keld]

If you take down the skivan, you can use a rasp.

 

[Strip]

Rotating file maybe.

 

[ensamresande]

Get/borrow a small hand router (like an edge router) + a template bit; and take a scrap piece of plywood and drill a 58 mm hole to use as a template. Route each hole in two passes and tape the cable to the "opposite" side, and it should be fine.

(or get other spotlights that fit 55 mm holes?)

 

[useless]

A rotating file in the drill might be the easiest. If you're going to cut with a hole saw, you first need to saw a hole in a rigid board and attach it centered over the old hole to guide the hole saw correctly. A lot of work to carve away a few mm... It doesn't need to be perfectly round and perpendicular edges since the fixture should cover a few mm?

 

[Dekker]

if there is a significant difference in size between the hole saws, it's possible to place a smaller diameter on the larger one in the adapter, so the smaller one guides in the old hole. Since the smaller one is placed after the larger one, it protrudes more, but this requires having both sizes, and that the smaller one fits inside the larger one (i.e., there is a sufficient size difference between them)

 

[prototypen]

Useless has the simple solution that works, have done so myself.

Protte

 

[mattias4815]

Thank you for the good response. I'll go with the rotating file solution.

 

[corre]

Saw through a board with the new hole saw, then use that hole as a guide for the hole saw when cutting the old one. This way, you don't need a pilot drill or other fixtures. Secure the board with one or two clamps.