Author Topic: How do you dadoo?  (Read 3267 times)

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Offline Foghat

  • Posts: 45
How do you dadoo?
« on: July 18, 2017, 09:22 PM »
Hi,
I'm building a frame for the garden which is made of 2x4s on end, in a box, with one rib running down the center and another across the middle. Like a window pane. I want to make lap joints on the ends in the corners, and in the center where the two pieces cross.
I was happily cutting everything to length with the Kapex, and then was ready to cut the Dados in the ends and center pieces....which meant cutting half way (1 3/4") through the pieces. The Kapex can't do this. The depth cut stop only goes down so there's 1.5" clearance, I need 1 3/4. It won't come up high enough to allow me to do this. The Festool assistant confirmed this.
So I thought, ok, I'll do it on the MFT3 with my track saw going along on the right angle track. Again, this track won't come up high enough to put the 2x4 on edge under it.
The only thing I can think of now would be to use the track saw, on a free track, clamped to the piece of wood. I don't feel confident this will be:stable; accurate; easy.
Any ideas how to safely, and accurately cut these notches and dados?
Thanks.

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Offline Bob D.

  • Posts: 663
Re: How do you dadoo?
« Reply #1 on: July 18, 2017, 09:27 PM »
What other cutting tools do you have available?

Jig saw, bandsaw, hand saw(s) ?

How many lap joints do you need to cut. If only a couple do it by hand.
You'll be done before you figure out which power tool to use and set it up.
-----
It's a table saw, do you know where your fingers are?

Offline RKA

  • Posts: 916
Re: How do you dadoo?
« Reply #2 on: July 18, 2017, 10:00 PM »
You can do a trenching cut leaving 1.75".  Just put a 1.25" spacer across the fence, then place your 2x4 up against the spacer.  The spacer should bring the 2x4 far enough forward to clear the center of the blade so your trench is flat and not curved.
-Raj

Online DB10

  • Posts: 902
Re: How do you dadoo?
« Reply #3 on: July 18, 2017, 10:23 PM »
As AKR described. Expect a lot of dust though as the Kapex extraction won't be good when trenching.

Offline WarnerConstCo.

  • Posts: 4076
    • Warner Mill Works
Re: How do you dadoo?
« Reply #4 on: July 18, 2017, 11:24 PM »
Radial arm saw, table saw, etc.

Offline Foghat

  • Posts: 45
Re: How do you dadoo?
« Reply #5 on: July 19, 2017, 12:12 AM »
Thanks for the tips, gentlemen.
I don't have a bandsaw, or table saw, or radial arm saw.
I do have a carvex, r55, and the kapex, as well as hand saws.
I do use a spacer to bring the workpiece 2" out from the fence when cutting a dado, so the bottom is flat. I could chop down into the gap and then finish with a chisel.
Or put the piece on it's side and use the carvex to make a series of cuts and finish with the chisel. It will be tricky to make it a perfect fit, but it's not a piece of furniture, so it doesn't matter if it's not 100% flush.
I thought there might be another way to do it with the kapex.
I appreciate the help.

Offline tjbnwi

  • Posts: 5271
  • Cedar Tucky Indiana
Re: How do you dadoo?
« Reply #6 on: July 19, 2017, 12:16 AM »
Place a 1/4" spacer between the limit bolt and tab that limits the amount the head drops (or remove the existing bolt and install a longer one).

Tom


Offline Frank-Jan

  • Posts: 962
  • Dutch Canadian living in Belgium
Re: How do you dadoo?
« Reply #7 on: July 19, 2017, 02:07 AM »
Personally I use my cs70 for those cuts instead of the kapex, but if you attach your spacer to a sacrificial board that sits underneath your material it should work too.

Offline Birdhunter

  • Posts: 1977
  • Woodworker, Sportsman, Retired
Re: How do you dadoo?
« Reply #8 on: July 19, 2017, 05:19 AM »
Perfect job for a really good hand saw or am I missing something.
Birdhunter

Offline RKA

  • Posts: 916
Re: How do you dadoo?
« Reply #9 on: July 19, 2017, 08:06 AM »
Okay, I just tried it and I'm seeing what you're saying. The trenches are about 1.5mm too deep with the adjustment at the limit of its travel (as seen by the 3mm of overlap between the two kerfs).

The last pic is the stop that the adjustment screw hits when adjusting the depth. If you can add a shim of some kind here you should be able to get that extra little bit of adjustment you need to get a perfect half lap.
-Raj

Offline RKA

  • Posts: 916
Re: How do you dadoo?
« Reply #10 on: July 19, 2017, 08:07 AM »
Sorry, my first pic didn't load. Here it is.
-Raj

Offline Foghat

  • Posts: 45
Re: How do you dadoo?
« Reply #11 on: July 19, 2017, 09:26 PM »
Hi Raj,
It took me a few minutes to find that little notch, but I did. I found a small piece of plastic I beam which I trimmed and fit into that gap. I had to keep the head down, so it would stay lodged there, but after slight turning of the control knob, I managed to get the right depth. It worked like a charm once I had accomplished that.
Thanks so much for your help, it speed up my work immeasurably.
My project is proceeding apace.
cheers,
John

Offline RKA

  • Posts: 916
Re: How do you dadoo?
« Reply #12 on: July 20, 2017, 06:26 AM »
 [thumbs up]
-Raj

Offline RKA

  • Posts: 916
Re: How do you dadoo?
« Reply #13 on: October 19, 2017, 10:29 PM »
I needed to cut some half laps into a few 4x4’s and remembered this thread.  I fished around HD and found M6 nylon dowels that thread nicely onto the depth adjuster and give you enough flexibility to do these cuts. 
-Raj

Offline Holmz

  • Posts: 3992
Re: How do you dadoo?
« Reply #14 on: October 19, 2017, 11:38 PM »
Perfect job for a really good hand saw or am I missing something.

A cheap Japanese pull saw makes this stuff easy. (~30-40$)
And usually with a guide block piece it can rest against on the side to make it 90 degrees in yaw and in roll.

Offline Peter Parfitt

  • Magazine/Blog Author
  • *
  • Posts: 3744
    • New Brit Workshop on YouTube
Re: How do you dadoo?
« Reply #15 on: October 20, 2017, 12:09 AM »
You need the following to make perfect 90 degree dados:

   - Track saw cutting station either made with the Parf Guide System or use an MFT3

   - Guide Rail

   - Saw that fits the guide rail

   - Tall and short Parf Dogs

You can now cut super accurate dados until the cows come home.

Peter