Flat Grind Rip Blades

[James Jayko]

Hey all,

I'm trying to do some bridle joints, and I need to buy a flat grind blade. Would you get one with more or fewer teeth for this job? Seems like a box joint jig has more teeth, a rip blade has fewer. Any reason to choose one over the other?

I've used mine to make half lap joints for internal frames in cabinets.

[glenn bradley]

Box joint cuts are primarily crosscut operations so ore teeth = cleaner cut. Bridle joints are primarily rip cut operations so a 24 - 30 tooth FTG should do you fine. That said, I use a 50 tooth ATB+raker that I had made. These are often called 'groovers' (Amana 61368 for example) and are readily available. I just wanted one with an 1/8" kerf so I had it made special. For what you are doing any quality 24T FTG (https://www.amazon.com/Freud-24T-Heavy-Duty-Blade-LM72R010/dp/B0000225UD?th=1)should do you.

P.s. I've never had a bridle joint sag. My favorite door frame joint.

[John Kananis]

Why not a dado? For such a small piece as a bridle joint, it should work fine. You can also use a spacer (same size as the tenon) between the two outside cutters and cut both sides of the tenon in one pass. This is assuming you're using a tenon jig on the ts.

[Jim Becker]

Box joint cuts are primarily crosscut operations so ore teeth = cleaner cut. Bridle joints are primarily rip cut operations

Isn't that backwards, Glenn? ;) Box = rip; bridle = cross

[Jamie Buxton]

How big are the bridle joints? I've made large cabinet doors with them, so the joint was 3"x3". A bandsaw was far less scary than a tablesaw.

[Robert Engel]

Flat top blades with over 30T are going to be pricey.

Good justification for a dado set.

[glenn bradley]

Isn't that backwards, Glenn? ;) Box = rip; bridle = cross

OMG!!! More coffee - stat! Thank you Jim :D:D:D.

[Tom M King]

The Dewalt dado set cuts nice flat bottoms with sharp, square corners. I bought it for when I didn't want to use a "good" set, but it's surprised me at how good it is.

[James Jayko]

Its funny; I finally decided last night to cut it with the ATB blade that was available in the public shop I'm working in. I didn't use the 8" dado blade because it didn't cut deep enough.

Except, for a bunch of reasons (which ended up in a few trashed pieces of this box top), I was wrong and probably could have used the dado stack all along. I ask you all not to judge me for being an idiot.

[Rod Sheridan]

OMG!!! More coffee - stat! Thank you Jim :D:D:D.

Bridle and box joints are both rip functions as you are pulling long grain fibres out of the wood. Dovetails are also rip functions when sawing.

To visualize this, imagine a board as a bundle of long straws, when ripping you are cutting along the same axis as the straw’s long dimension, whether the bundle of straws is laying on the table, or standing vertically.


Regards, Rod

[Lee Schierer]

The Freud Glueline rip blade has flat top teeth and TCG and is reasonably priced. Half of the teeth are flat top half are TCG. It gives a nice flat bottom kerf and a smooth sidewall cut.
481561

[Curt Harms]

Why not a dado? For such a small piece as a bridle joint, it should work fine. You can also use a spacer (same size as the tenon) between the two outside cutters and cut both sides of the tenon in one pass. This is assuming you're using a tenon jig on the ts.

A dado would be fine with a dado set. My outside dado blades have tiny ears on the outside edge of the main blades. These leave a little groove. That wouldn't matter on a dado unless the ends are visible; it will be visible on something like a bridle joint.

[Jim Becker]

Bridle and box joints are both rip functions as you are pulling long grain fibres out of the wood. Dovetails are also rip functions when sawing.

To visualize this, imagine a board as a bundle of long straws, when ripping you are cutting along the same axis as the straw’s long dimension, whether the bundle of straws is laying on the table, or standing vertically.


Regards, Rod

Good point...my eyes were reading "bridle" but seeing "lap"...oy! Of course that applies to the "mortise" part of the bridle. The tongue is often cross-cut for convenience, but it depends upon the size of the components, too. Lots of ways to fry that fish!

[Mike Wilkins]

The Freud Glue-Line Rip blade has served me well for years. I don't remember but I think it is a 40-tooth blade, flat top grind. I use the full kerf version (.125). It cuts flat bottom kerfs and works well for cutting small drawer bottom grooves and mitered corners for splines.

[Rob Luter]

I went with a Freud LM72R010 10-Inch 24 Tooth FTG Rip blade for flat bottom kerfs. I mostly use it for cutting spline grooves.