# cut circular hole in 5/8" plywood



## angusmdmclean (Jun 28, 2010)

I need to cut a hole 4" in 5/8" sub floor plywood. I see 2 optional ways of doing this. 

The first one is to buy a hole saw and use it with my Bosch drill. I would buy a 4" hole saw plus an arbor.

Alternatively I believe this could be done with a jigsaw.
The hole needs to be a precise 4" circle.

Please can I be advised as to the best way of doing this.

Thank you;

Angus


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## Big Dave (Sep 16, 2006)

If you want it precise then use the hole saw.


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## H. A. S. (Sep 23, 2010)

Agree, with the holesaw.


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## cabinetman (Jul 5, 2007)

A 4" hole saw would be the easiest way if you have a drill that'll turn it. A saw that size ain't gonna be cheap.

If it's a sub floor why does it have to be "precise"?












 







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## klr650 (Apr 4, 2010)

Yeah I'm thinking the "precise" part might not be what the poster thinks. Personally I'd use a jigsaw with a thin blade and just take my time with it. It won't be "precise" but to a casual observer it would be circular.


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## GeorgeC (Jul 30, 2008)

angusmdmclean said:


> I need to cut a hole 4" in 5/8" sub floor plywood. I see 2 optional ways of doing this.
> 
> The first one is to buy a hole saw and use it with my Bosch drill. I would buy a 4" hole saw plus an arbor.
> 
> ...


Please define precise. As you can see from remarks this makes a big difference in how you cut the hole.

G


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## angusmdmclean (Jun 28, 2010)

*cut hole in 5/8" plywood*

it is to make a hole in th esubfloor to accomodate a shower drain. I want it to be a good fit to the shower drain.

Angus


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## cabinetman (Jul 5, 2007)

angusmdmclean said:


> it is to make a hole in th esubfloor to accomodate a shower drain. I want it to be a good fit to the shower drain.
> 
> Angus


You should be able to cut it close with a jig saw if you are careful. Use a narrow blade. There will be some type of shower floor going on top right?












 







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## jschaben (Apr 1, 2010)

angusmdmclean said:


> it is to make a hole in th esubfloor to accomodate a shower drain. I want it to be a good fit to the shower drain.
> 
> Angus


I think I would do that job with a router or rotozip with a circle guide:smile:


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## klr650 (Apr 4, 2010)

angusmdmclean said:


> it is to make a hole in th esubfloor to accomodate a shower drain. I want it to be a good fit to the shower drain.
> 
> Angus


That clarifies it greatly - use a jigsaw or rotozip. you don't want it to be precise unless your powers of measurement are superhuman. You'll inevitably end up with some off-center to the drain pipe and be glad you have some slack on either side of it. Not to mention the floor will contract and expand with any moisture making the hole imperfect anyways.


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## angusmdmclean (Jun 28, 2010)

*precise hole in 5/8" pywood*

yes; there will be a mud prepan going on top of teh plywood. The lip of the shower drain be level with the mud


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## angusmdmclean (Jun 28, 2010)

*cut hole in 5/8" plywood*

I seems that a jigsaw is held by the jury to be a good option. Now can I be advised as to which one to buy? Also any technical tips for cutting the circle our of he 5/8" is much appreciated. First you draw a circle...........................................

Angus


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## cabinetman (Jul 5, 2007)

angusmdmclean said:


> I seems that a jigsaw is held by the jury to be a good option. Now can I be advised as to which one to buy? Also any technical tips for cutting the circle our of he 5/8" is much appreciated. First you draw a circle...........................................
> 
> Angus


Use a narrow blade. Drill a hole on the inside of the circle to start the cut...go slow. Make sure the backside is clear so you don't cut anything but the plywood.












 







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## woodnthings (Jan 24, 2009)

*Me thinks this is all too much precision*

If you saw a plumber install a shower drain it would be a series of rough pencil marks, off a tape measure. locate the center, then a hole saw with about a 1/2" gap around the drain fitting to allow for some movement on the install...and to prevent any noise from weight on the floor pan causing a squeak. This sort of accuracy is not really need here.....:no: bill 
BTW some shower pans are bedded in concrete, others use foam, I used pressure treated wood stacked up to support the pan evenly.

These links will help:
http://www.buzzle.com/articles/shower-drain-installation.html
http://search.yahoo.com/search?ei=utf-8&fr=ytff1-tyc7&p=shower%20drain%20hole%20saw&type=


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## Corbin3388 (Jan 22, 2011)

woodnthings said:


> If you saw a plumber install a shower drain it would be a series of rough pencil marks, off a tape measure. top ;locate the center, then a hole saw with about a 1/2" gap around the drain fitting to allow for some movement on the install...and to prevent any noisy from weight on the floor pan causing a squeak. This sort of accuracy is not really need here.....:no: bill
> BTW some shower pans are bedded in concrete, others use foam, I used pressure treated wood stacked up to support the pan evenly.
> 
> totally agree with this if you dont leave room your going to have a rough time with install. the wood doesnt help with water proofing and the drain pipe should be secured after pan install to allow it to move a tad if necessary. IMO by cutting this exact you are asking for alignment issues. good luck


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## angusmdmclean (Jun 28, 2010)

*cut hole in 5/8" plywood*

Please can you explain why it is possible to have a squeak. What is the source of the squeak. I certainly wish to avoid ending up with this.


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## cabinetman (Jul 5, 2007)

angusmdmclean said:


> Please can you explain why it is possible to have a squeak. What is the source of the squeak. I certainly wish to avoid ending up with this.


If the plywood isn't supported and it has room to move up and down, weight on the shower pan can make it move.












 







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## Corbin3388 (Jan 22, 2011)

That sort of a broad question. Short answer is flex. 
Floors are usually are built with 2x6's or 2x8's spanning the room every 16-24 OC (on center). On top they put ply wood usually CDX. When screws or nails fail to keep their hold due to age or settling you get squeaks. 
Fiberglass shower pans/tubs squeak due to them not being supported properly underneath. If you look under them they usually have a piece of foam. That's what it's there for. Some use mortar to set them. 
I personally dislike the fiberglass pans and don't use them or the 30-40mil liners opting for the more traditional hot mop and concrete method. It's a little more on the $$ side but IMO a better set up.


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## dbhost (Jan 28, 2008)

Yep, jig saw, with a decent blade. You aren't really needing precision in a plumbing rough in. You need a hole that the pipe can pass through...


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## angusmdmclean (Jun 28, 2010)

*cut hole in 5/8" plywood*

Thansk to all for help and comments: the plywood will be further supported by my placing additonal blocks of wood reinforcing the joist support of plywood. I am cutting out a section at the edges of the below joists. I will insert wood blocks and attach them to the existing joists. The new piece of plywood inserted will thus sit on top of the new wood blocks insertd. Other blocks of wood at right angles may be added to provide further support. I do not want to have a squeak. I wil send pictures/drawings to explain better.

The alignment of the shower drain with resepct to the cut hole, U shaped trap and the drainage pipe troubles me. I will explain why.

Thank you,

Angus


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## Emil VolK (Jun 4, 2011)

Narrow blade with a jigsaw is needed: please can someone stipulate the size of blade needed to cut hole 41/4 " diameter in 5/8" plywood.

I need to buy a jigsaw and blades.


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## Corbin3388 (Jan 22, 2011)

Any size blade is good as long as it's for wood. The only variable is if your jig saw takes T-shank blades or not

Sent from my iPhone using Wood Forum


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## knothole (Jul 5, 2011)

Buy the hole saw.


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## Corbin3388 (Jan 22, 2011)

knothole said:


> Buy the hole saw.


This is for a plumbing rough in.

Sent from my iPhone using Wood Forum


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## Emil VolK (Jun 4, 2011)

to be abel use T shaped blades is a good option to have?

EMIL


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## tcleve4911 (Dec 16, 2006)

Emil VolK said:


> I need to buy a jigsaw and blades.


Bosch jigsaw with bayonet blades


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## angusmdmclean (Jun 28, 2010)

any more recommendations for a jigsaw to cut a circular 4 1/4" hole in 5/8" plywood and blades to use? This is for a hole to accommodate a shower drain.

Suggestions are most welcome, since I have never used a jigsaw and cannot evaluate them


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## klr650 (Apr 4, 2010)

I have a Hitachi, with T-shank blades.

Unless you're going to use this thing a lot, I wouldn't splurge. Get something basic, no fluff. Don't obsess over thin blades, most jigsaw blades are purpose built to allow cornering, just make sure the blade is very aggressive. Might want to stay away from bi-metal blades until you're positive you won't sever electrical wires or pipes.

You might still consider using a hole saw for the drill. Depends on how big the hole needs to be, but a 3" core bit would be vastly cheaper than a jigsaw - just remember to make the hole larger than the pipe.


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## Roger Newby (May 26, 2009)

call a plumber


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## Biscobob (Jul 25, 2011)

Roger Newby said:


> call a plumber


It ain't rocket science, either do as Roger says or just go for it and and get it over with. You could have screwed it up and fixed it half a dozen times by now. :wallbash: Seriously man, quit obsessing.


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## johnnie52 (Feb 16, 2009)

Most any sabre (jig) saw will work just fine to cut 5/8" plywood. I prefer the kind with variable speeds so that I can control the speed with the trigger. Just drill a 3/8" hole near the 4 1/2" circles inner mark to stick the saw blade through then follow the line around. Since this is for a shower drain though I'd make the hole slightly larger than 4 1/2" so it will be easier to align the drain pipes.

Built from the shower drain to the main drain instead for coming from the drain then trying to mate perfectly with the shower.


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## angusmdmclean (Jun 28, 2010)

Thansk: I have borrowed a jigsaw Id have cut holes that will be good enough. I am just trying to learn the technique properly. I may need to buy a narrower blade thatn I have now.

Angus


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