Rabbet Cut On Long Piece of Trim ShipLap Joint - Best Tool to Use?

[Dan Aims]

Hi everyone, I am a novice with wood work. I was hoping to get some advice and/or pointers on my best options for adding a 1/2" wide and 1/2" long rabbet on a piece of trim.

I have a small router table but the piece of trim I am working with (which is pvc) is 18' long x 5" x 1". I am rabbeting the 5" side so I can connect the trim boards on my belly band (aka watertable).

I have a handheld plunge router as well. Would the best way to get this rabbet done be by buying a 1/2" rabbet bit? I have straight bits and the router does have a fence attachment. I just tried doing it with the straight bit and fence attachment but got a bounce in towards the middle of the fence attachment which has a space for the bit to not get snagged on.

This is final trim for the outside so I need to hit this pretty accurate. Should I buy a 1/2 rabbet bit for the router?

.

[pat warner]

No surprises with a 1/2 rabbet bit. But it is 1.5 in D, a large cutter for a novice.
Do it in stages, maybe 1/3, 1/3, 1/3. Practice on scrap.

[Dan Aims]

Thanks for the reply pat.

When you mentioned "D" I am going to assume depth correct? So you mean to do 3 depths adjustment while cutting?

[Joe A Faulkner]

You could easily do this with a circular saw and cross cut jig similar to what is often used to cut vinyl siding to length. Set the depth of your saw to 1/2" and make multiple passes to cut your dado. You might need to touch it with a chisel. You could easily build a similar jig for your router. Here is a you tube on a cross cut jig. I've always seen these built using a 10' or 12' 2x10 thrown across a couple of saw horses - which is way better than working off the ground. https://www.youtube.com/watch?v=dqaRyS5u4C4.

Here's another variation: https://www.youtube.com/watch?v=vss24Y6aMdQ

[Dan Aims]

Hi Joe,

That is very interesting. Never thought of doing it this way. I would have to do a multiple passes but it would be an option.

I am in the middle of doing siding so I might actually build this jig to help with my cutting! Going to look up some plans.

[Jerry Miner]

I don't quite get your "bounce in" issue, but a simple T-square router jig with a straight bit would probably be my approach.

BTW-- Pat Warner referred to a 1.5 D bit. This means 1.5" in Diameter-- a large bit for a beginning router user.

Straight bit, well guided, will make this cut. No need for a giant rabbet bit.

[Wayne Lomman]

Dan, use a straight cutter with fence on your router but screw a piece of scrap timber to your fence to bridge over the gap then you won't get the drop in effect. Cheers

[Dan Aims]

Hi guys attracted is a photo of my router and the included attachment. Also a photo of the bounce in.


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[Jerry Miner]

OK. I get the "bounce in". Pics help a lot.

I think this is a technique issue: You need to put pressure on the leading portion of the fence for the beginning of the cut, and on the trailing portion of the fence for the end of the cut (similar to feeding material through a jointer.)

You are getting the "bounce in" when the leading portion of the fence goes off the edge of the work, and your technique pushes the bit into the work, pivoting on the front edge of the trailing portion of the fence. Putting pressure on the trailing portion of the fence will prevent this pivoting action.

Practice this cut on scrap, changing the way you apply pressure to the fence. You'll get it.

(Or switch to a T-square jig)

[Dan Aims]

Thanks for all the feedback and suggestions. I ended up using the attachment that is in the picture and slowly lead the front similar to how jerry mentioned. Only saw a little bounce which I just realized won't matter much since its on the inside of the joint.

[Erik Christensen]

If it was for a just a few pieces I would use the depth stop on my miter saw & make multiple cuts - For a larger run to make changeover worth the effort I would put a dado set on my RAS.

lots of time the 'best' tool is one you already have and are familiar with using