# How to cut a concave piece out of a 2x4-2x6



## chargersrool (Aug 5, 2014)

Im trying to find the best and fastest way to cut a cave out of a 2x4 or 2x6 
Ex. I heave a 4-5" diameter rod and I want the 2x4 that has a half circle cut into it, to fit perfectly around it.

Right now what I do is use a circular saw and move it back and forth. 

Any type of tool that can do this easier? or do I have to make a contraption that has about 6-7 circular saw blades to do this.


----------



## TimPa (Jan 27, 2010)

jig saw? hole saw?


----------



## hokeyplyr48 (Nov 12, 2013)

If I understand correctly, you can build a jig to move the piece on the table saw at an angle which will cut a cove into it


----------



## chargersrool (Aug 5, 2014)

jig saw creates a bend and I only need a half a circle not a whole circle. The hole saw will kick if you try to cut only a half out.. Here is a picture so you can see an example

http://postimg.org/image/vx4d1fbhl/

Say the 2x4 is doubled up so a jig saw wont be able to go through it.


----------



## Hunter (May 10, 2012)

You could use a hole saw and cut from the interior part of the board. You would have more waste, but you would also have a more precise cut.

Hunter


----------



## minuteman62-64 (Mar 15, 2012)

Hunter said:


> You could use a hole saw and cut from the interior part of the board. You would have more waste, but you would also have a more precise cut.
> 
> Hunter


That's the way I'd do it. An alternative: multiple passes with a router on a pattern?


----------



## PhilBa (Jun 30, 2014)

It's not 100% clear to me what you are asking. If you want a cove running the length of the 2x4 (ie the pipe is parallel to the length of the board), then hokeyplyr has the idea. If you don't have a table saw, I don't see a safe way to do it. If you want the pipe to be perpendicular to the length, then a bandsaw is the right way to go. Using a circular saw kind of scares me for either of those. The second could be done with a jig saw though you'd need a long blade. If you don't care how it looks, something like a "sawzall" could do it. A 4" hole saw could work if you butted the piece up to a sacrificial board of the same size.


----------



## bauerbach (Mar 25, 2012)

Im still not clear what the goal is based on the picture...


----------



## Maylar (Sep 3, 2013)

From the picture it appears you want just the end of the 2x4 cut in a half circle. Looks like a band saw opportunity. Or hole saw through the board and cut the circle in half.


----------



## chargersrool (Aug 5, 2014)

Sorry Im making it confusing, its just an odd question to ask I know. But what I need is to make a cove cut in the 2x4 or 4x4/4x6 to make it fit around a 5" diameter pole perfectly. The bandsaw wouldnt do. Any other ideas?
I appreciate the help!


----------



## minuteman62-64 (Mar 15, 2012)

The picture you provided doesn't show what I would consider a "cove" cut. Based on your last post, it seems to me that you want a 2 1/2" diameter "cove" running the length of a 2x4, cut on the 3 1/2" side.

If above is correct, seems like a table saw will do the trick. I've actually done a similar cut on my radial arm saw (although I probably wouldn't try it now that I am older and wiser).


----------



## PhilBa (Jun 30, 2014)

Are you looking to encase the pole completely in wood? Maybe you should describe what effect you are trying to create.


----------



## chargersrool (Aug 5, 2014)

Im creating a Gazebo, I must use the 5" diameter pole and 2x4/4x6 at the base of it. Ill draw up a better image on photoshop.

Im thinkin of just putting 5-6 5" circular saw blades together on a motor to achieve this.

http://postimg.org/image/k0wtd1z8d/
If this image doesnt explain what im trying to do with the wood, i dont know what else.. But there is no other method, i want to create this cove cut one way or the other.


----------



## mikeswoods (May 18, 2009)

Most often, a hole saw is used---rather an expensive bit--but fast and accurate---

with a little patience ,you could cut that curve with a coping saw a little sanding and you could get a perfect fit.


----------



## PhilBa (Jun 30, 2014)

OK, I get it now. Use a hole saw. Best if you have a drill press but if you are careful, a hand drill will do ok. Cut your board 4 inches longer than you want and drill the hole in the end so that the hole saw is fully supported.

By the way, your idea of mounting a bunch of saws on a motor is an accident waiting to happen.

Edit: Looks like mike beat me to it. a 5" hole saw is around $40 from home depot. You'll need a mandrel as well which is about $10-15.


----------



## bauerbach (Mar 25, 2012)

Id use a band saw... lacking, that, I would use a jig saw. would it be as spot on as a drill? maybe not, but it would be well within the tolerance for that type of job IMO.

Seems fairly easy infact.


----------



## FrankC (Aug 24, 2012)

That is not what I would consider a cove cut so I can see why there was some confusion, cuts like that in carpentry are what they made jig saws for.


----------



## PhilBa (Jun 30, 2014)

I bet the OP only has hand tools.


----------



## woodnthings (Jan 24, 2009)

*this is the issue*



chargersrool said:


> Im creating a Gazebo, I must use the 5" diameter pole and 2x4/4x6 at the base of it. Ill draw up a better image on photoshop.
> 
> *Im thinkin of just putting 5-6 5" circular saw blades together on a motor to achieve this.
> (don't do this!)
> ...













How many pieces will intersect at the base? Eventually, if there are too many, you will run out of diameter on which they will seat and have to taper them in like wagon wheel spokes. Why not just make a round hub with flats where the pieces rest, like a wagon wheel hub?

I think you are "overthinking" this issue, and a simple more basic solution is possible...:blink: Maybe rest the post on the top of the intersecting pieces rather than trying to "cove" the ends?


----------



## bauerbach (Mar 25, 2012)

I doubt all the boards will hit a post dead center of a plank. Unless its designed to be that way. 

OP, Im guessing your thinking all the vertical poles will land like the top orientation...

More likely you'll have the pole sitting somewhere across the gap between the surface planks like the 2nd diagram and you'll be cutting a semicircle out of the sides rather than the ends.

jig saw, band saw, if hand tools are required, perhaps a coping saw (might take a while)... a large hole saw, maybe even a router (a pass on each side and a top bearing guide)... About the only tool I wouldn't think to use would be any form of a circular saw.


----------



## minuteman62-64 (Mar 15, 2012)

Have a drill press? Instead of laying out $$ for a 5" hole saw, make a slightly undersized cut with your jig saw, then use a drum sander to bring it to final shape.


----------



## juice3250 (Mar 27, 2014)

Great idea minuteman. That would be the safest way, by far.

I was thinking if I were going to do this with the tools I have, I'd use drill press and jig saw. Then I'd clean it up with my round file and sand paper. But the best way would be to use a bandsaw or jig saw and then a drum sander on a drill press or even a hand held drill. You'll more than likely use the drum sander than a 5" hole saw on another project.


----------



## FrankC (Aug 24, 2012)

This is a gazebo, not a piano bench for goodness sake, it is outside in the elements, how it fits today will be different tomorrow.
Every day carpenters make this kind of cut with a jigsaw, really have no idea how this took on a life of its own.


----------



## bauerbach (Mar 25, 2012)

I agree, with one exception... I think most deck builders would make this cut with a chop saw lol. bevel around the pole? not likely.


----------



## Steve Neul (Sep 2, 2011)

chargersrool said:


> Im trying to find the best and fastest way to cut a cave out of a 2x4 or 2x6
> Ex. I heave a 4-5" diameter rod and I want the 2x4 that has a half circle cut into it, to fit perfectly around it.
> 
> Right now what I do is use a circular saw and move it back and forth.
> ...


I have a way to do this but first how experienced are you with saws?


----------



## Modfyd (Jun 25, 2014)

Why not cut slats of 3/4" wood to your likings and use a 5" hole saw to cut the holes out. Then just stack the slats on top of each other and glue as many as you'd like to get your desired height for the pipe. You'd see lots of different end grain patterns but it'll be strait and effective. On the plus side, it'd be stronger as one piece together rather than mating two separate pieces.


----------



## Modfyd (Jun 25, 2014)

And if you absolutely need only the half pipe cut, all you do is do the above directions and cut it in half with table saw.


----------



## Alex101 (Dec 9, 2013)

A bandsaw should work well on this. Why don't you think so?

Alex


----------



## Popsnsons (Oct 1, 2012)

Any rough cut. Band saw, jig saw or Forster bit. Then fine tune with spindle sander.


----------



## woodnthings (Jan 24, 2009)

*guys it's a gazebo, not a ....*

It's not a mantle clock, or a Steinway piano. We have yet to see why the post can't rest on a faceted block or what the actual construction is that requires such "precise" furniture quality joinery.. :blink:


----------

