Rabbeting Technique Help

[knimac]

I need to put 2'' wide, 1/4 " deep rabbets around edges of cherry coffee table for inlay (top not yet assembled, so I am dealing with 4 pieces, two sides and two ends which will be mitred to form a picture frame effect after inlaid strips of contrasting wood glued into rabbet). My questions are whether the rabbeting is best done with dado blade or router bit in a table? Is it strictly a matter of preference? As in either case the blade or bit would only remove 3/4" with each pass, would you put first cut at the 2" mark and then work to the edge (ie. move the fence closer to the bit/blade on each pass, or start at the edge and make successive passes with the fence moved further from the bit/blade for each pass, finishing at 2"wide? or is again it just a matter of preference? Any input gladly received.

(Can I rout 1/4" deep 3/4" wide in one go or should first pass be shallower?)

[LCHIEN]

I think its a personal choice based on what works best for you.
For me, I find dado blades on the TS cut cleaner and straighter and faster.
And I'd sneak up on the 2" mark because I have a Ryobi micro adjuster (Micropositioner) and calipers - I measure the error, compute the distance to go and
tweak it in with the microadjuster. Every mark on the microadjuster is ~.016" (1/64th) and it's easy even to dial in part of a mark. I stop when I get within .010" of the desired value.

[Tom Miller]

I'd be inclined to do this with two cuts using a standard blade. Put the stock on edge to make the 2" deep cut, and then flat to make the 1/4" deep cut, allowing the ~2" x ~1/4" piece to fall away (i.e. not trapped between blade and fence.

Use feather boards, especially for the on-edge cut, to make sure you get a flat surface.

Regards,
Tom

[scorrpio]

I'd use a router.
Freehand: Use top bearing pattern bit. clamp something straight on top of your work, exactly 2 inches from edge. Set bit height to your guide thickness + 1/4". (Guide should be thick enough to have bearing riding against it). Make several passes until bearing rides against the guide.

Router table(preffered method): put in a 3/4" hinge mortising bit, set height to 1/4". Set fence so that about 1/2" of bit exposed, run all sides over it. First try on scrap to make sure the rabbet looks good. Move the fence back another 1/2", make another pass (same scrap piece first). After 3rd pass, see ho much material still needs to be removed, move fence back by that amount, maybe slightly less than that amount. Sneak up on 2", testing on scrap. Once at 2", do the final pass with your workpieces.

[LarryG]

I'd do it on the router table, using more or less the procedure Scorrpio describes. If you don't have a mortising bit, there's no need to run out and buy one ... an ordinary straight bit will work equally well.

If you use a router freehand, use an edge guide that attaches to the router's base, rather than a bearing-guided bit. When you're cutting a recess for an inlay you're essentially jointing the recess' vertical edge, and a bearing-guided bit will not reliably give you a straight enough line.

[atgcpaul]

I prefer to use a dado blade when doing rabbets. For me,
it's easier to run things past the fence than accurately
clamping a straight edge.

However, one point of concern is downward deflection
as you pass the board over the blade. If you don't
use a stiff throat insert (like those plastic ones that
come with the saw), you can actually push the board deeper
into the blade thus getting a deeper rabbet. If you're
doing inlay work, make sure your inlay piece will sit a
little proud of your finished surface so you can sand it
flush later.

Paul

[vaking]

I have never done 2" wide rabbets. If I needed that - I would have tested a jointer. A fence 2" from the edge, make auxiliary support surface 1/4" below jointer top, few shims for multiple passes. I heard jointers are supposed to be good for rabbets but never used it myself. 2" wide rabbet I think calls for a try.
What do others think?

[crokett]

Knimac,

Not sure if you've cut your rabbetts already, but I'd use a dado set rather than a router bit.

1. 2" is a lot of material to remove. The router will be working harder than the saw will.

2. Safety - If you use the router, start with the fence close to the bit and move it further away after each pass. If you start with the fence away from the bit and try to move it closer you create a situation where the feed direction is reversed and the wood will be launched across your shop. If you were doing this handheld this would be known as climb cutting. It creates a smoother cut but it is easy to lose control of the router.

With a dado blade you can start with the fence at either position