Any tool to make 120-125mm holes in wood

Hi there,

So is there any tool to make those holes, I want to make them to put the exhaust fan.

haven't really seen a hole saw that big, but I imagine they probably exist. I would say get a protractor and make a 120mm circle, drill a hole near the edge on the inside of the circle, then use a jigsaw to cut your hole.

google '4.75 hole saw' or use a router or jigsaw. I prefer high powered lazers. but that's dangerous.

they make holesaws that big but they are pricey &you also need a heavy duty drill so my advice would be to follow the above advice

massah said:

haven't really seen a hole saw that big, but I imagine they probably exist. I would say get a protractor and make a 120mm circle, drill a hole near the edge on the inside of the circle, then use a jigsaw to cut your hole.

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agreed, if you dont have a jig saw a hack saw will work but it takes alot longer.

A buddy loaned me a hole saw kit that contains ten sizes of hole saws up to 5 inches (127mm). He says he got it at Harbor Freight real cheap. I used it to drill holes in wood for 4" ducting - worked like a champ. The larger sizes need a pretty powerful drill, however.

Thanks for the replies everybody I do have a jig saw and that what I used last time to make the hole but it's a bit difficult to make it strait so I wanted to know if there was any other way to do it. If the hole saw that size is that expensive and they require heavy dutty drill as stated before, I was thinking of another option.

I was thinking that maybe I could use a "standard" 90-110mm hole saw and then use a pvc adapter from 90-110mm to 120mm. The problem of doing this that I can see are two. One is that I'll need more space to install the fan coz that will add a few cm to the length and the other is that the air flow will be reduced.

I don't know if it would be worth it, what do you guys think ?

lince said:

Thanks for the replies everybody I do have a jig saw and that what I used last time to make the hole but it's a bit difficult to make it strait so I wanted to know if there was any other way to do it. If the hole saw that size is that expensive and they require heavy dutty drill as stated before, I was thinking of another option.

I don't know if it would be worth it, what do you guys think ?

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I think you would be better off going with standard sizes through whole project. In this case would be 4" or 110mm OD (outside diamenter). Yes they make reducers in range of sizes. Without anymore info it's hard to tell you exactly what you need.

simple circle jig for jig saw <don't know how well it will work, I'd just do it by hand and seal up the gaps.

lince said:

Hi there,

So is there any tool to make those holes, I want to make them to put the exhaust fan.

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I actually own a hole saw that big. it cuts from 2" to about 2' circles. It is probably overkill for what you want. I do however, have multiple 2-6" hole cutters. I have one of these, for instance:

http://www.harborfreight.com/adjustable-circle-cutter-37370.html

for 7$ its a great deal and it does 5" + holes. They also have other ones like that in the store. You can also buy a dremel. They have attachments for cutting circles.

Also, I use cheap 10-15 dollar drills to cut 2 foot holes in plywood using my big cutter. Any drill will work cutting a 5" hole.

Xcon said:

simple circle jig for jig saw <don't know how well it will work, I'd just do it by hand and seal up the gaps.

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Great video, I gotta try that method, thanks mate I may even try to build one of those lazy susan lol looks good

Carthoris said:

I actually own a hole saw that big. it cuts from 2" to about 2' circles. It is probably overkill for what you want. I do however, have multiple 2-6" hole cutters. I have one of these, for instance:

http://www.harborfreight.com/adjustable-circle-cutter-37370.html

for 7$ its a great deal and it does 5" + holes. They also have other ones like that in the store. You can also buy a dremel. They have attachments for cutting circles.

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Carthoris said:

Also, I use cheap 10-15 dollar drills to cut 2 foot holes in plywood using my big cutter. Any drill will work cutting a 5" hole.

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Those cutters look good, I gotta check if I can find one of those around here. The idea about the dremel is good as well, didn't think about that one, I'll try a cheaper method first and we'll see then