1" rabbet cut

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J

JJsWoodShop

New User
JJ
I'm making the Bright Idea Candle Holder featured in Wood Magazine (July '09; issue 191) and have run into a snag.

The parts on this project are small. One part in particular is 3/8" thick, 4.5" in length and 1.5" wide. The directions advise to cut a 1/8" rabbet - 1" deep into the end of this piece.

I haven't been able to find a rabbet bit that is 1".

I tried to cut the piece using a dado blade set on my table saw and get OK results but the dado blade leaves ridges in the wood (which I can sand out with some degree of success). I tried using a 3/4" straight bit with my miter gauge on the router table but the depth is not even for some reason when I make the second pass.

My question is this: Is there such thing as a 1" rabbet bit? If so, where can I find one?

If there isn't a 1" rabbet bit - how would you make this cut?

I could use any advice you have to offer. I don't use my router table much and am perplexed at this time.

Thanks,

Jeff
 
ehpoole

ehpoole

Administrator
Ethan
On your router table you should be able to take a straight bit and, by referencing vertically against the fence (rather than the table), use your straight bit to create a 1" rabbet, just don't take off more than 1/2" the bits diameter in a single pass. Done this way you can avoid purchasing a 1"+ straight bit for your job. Always double-check that your fence is square to the table before making the cut and verify that it remains square when you apply pressure against the fence for the cut since you will be referencing off the fence with the workpiece stood vertically. Some fences benefit from some extra clamping (to stiffen the fence) or the additional of a supplemental fence (if the fence is especially short) when routing pieces vertically.

However, if your router table is properly setup and adjusted properly, you should have been able to make two or more passes with no discernable difference in depth. Usually your problem is indicative of a less than level router insert or a warped table (or a less-than-flat workpiece).

As for the dado set. If it is a good quality dado set (e.g. Freud, etc.) then the ridges should be barely noticeable and only at the outermost edge where the outer cutter's ATB cutters score the wood to prevent tearout. With a good quality dado set the scoring marks left by the outside cutters should be barely visible and will disappear entirely with either a few strokes of 120-grit sandpaper OR the application of a water-based glue (which will cause the wood fibers to swell and fill in).

HTH
 
J

JJsWoodShop

New User
JJ
ehpoole said:
On your router table you should be able to take a straight bit and, by referencing vertically against the fence (rather than the table), use your straight bit to create a 1" rabbet, just don't take off more than 1/2" the bits diameter in a single pass. Done this way you can avoid purchasing a 1"+ straight bit for your job. Always double-check that your fence is square to the table before making the cut and verify that it remains square when you apply pressure against the fence for the cut since you will be referencing off the fence with the workpiece stood vertically. Some fences benefit from some extra clamping (to stiffen the fence) or the additional of a supplemental fence (if the fence is especially short) when routing pieces vertically.

However, if your router table is properly setup and adjusted properly, you should have been able to make two or more passes with no discernable difference in depth. Usually your problem is indicative of a less than level router insert or a warped table (or a less-than-flat workpiece).

As for the dado set. If it is a good quality dado set (e.g. Freud, etc.) then the ridges should be barely noticeable and only at the outermost edge where the outer cutter's ATB cutters score the wood to prevent tearout. With a good quality dado set the scoring marks left by the outside cutters should be barely visible and will disappear entirely with either a few strokes of 120-grit sandpaper OR the application of a water-based glue (which will cause the wood fibers to swell and fill in).

HTH
Click to expand...

Thank-you very much! I would have never thought of that!
 
M

Mike Mendelsohn

New User
Mike
Cut the rabbet with your table saw. First cut a 1/8" deep saw kerf 1" from the edge, then raise the blade to 1", set the fence to 1/4" and cut the rabbet.

Mike
 
ehpoole

ehpoole

Administrator
Ethan
Mike Mendelsohn said:
Cut the rabbet with your table saw. First cut a 1/8" deep saw kerf 1" from the edge, then raise the blade to 1", set the fence to 1/4" and cut the rabbet.
Click to expand...

Just to add, this advice works best with Flat Top Grind (FTG) tablesaw blades as opposed to the more common (these days) Alternate Tooth Bevel (ATB) grind blades. If you can't find a suitable FTG blade (they are more common in 24-tooth or less blades) then the next best choice would be a Triple Chip Grind (TCG) blade which comes closest to approximating an FTG.

With ATB blades your blade heights will need to be near perfect (it can be done) to avoid the same scoring grooves left behind by your dado set due to the 'M'-shaped cutting edge of ATB blades.

I did not think to mention so in my earlier post, but whichever of these approaches you choose, it is wise to use featherboards to hold your work tight to the fence on your vertical cuts. The feather boards will allow you to hold everything tight while keeping your hands well away from the cutting edge. A sacrificial board of the same width as your project can then be used to push your work past the blade/bit and offers the bonus of preventing any tearout as the blade exits the work. On the tablesaw your featherboard should stop just ahead of the blade so that no lateral force is exerted against the blade (which can cause kickback). On the router table two featherboards, one ahead of the bit and the other behind the bit should be used.

If you don't have featherboards, a guide-board can be clamped straight across either's table to hold things tight to the fence. Since the guide-board does not exert any pressure (unlike spring-loaded featherboards) it is Ok for it to be clamped straight across the table, including the area of the bit/blade. Test the guide-board setup before you raise your blade/bit -- it should eliminate any free play and hold your work snug to the fence *without* binding at any point.
 
C

Charles Lent

Charley
Corporate Member
Mike Mendelsohn said:
Cut the rabbet with your table saw. First cut a 1/8" deep saw kerf 1" from the edge, then raise the blade to 1", set the fence to 1/4" and cut the rabbet.

Mike
Click to expand...


If you go this route, make sure you have a zero clearance insert in your table saw. Then follow the recommendations of ehpoole. A flat tooth blade will yield excellent results.

Charley
 
M

Mike Mendelsohn

New User
Mike
The Freud TCG Glue line rip blades (LM74 & LM75) do not cut a square bottom kerf. The teeth with the side cuts are 1/2 mm longer than the flat ground teeth leaving a groove in the middle of the kerf. Freud also makes flat ground rip blades with 24 teeth (LM72 and LM87) that cut a flat bottom kerf.

I have both blades in the full kerf versions (LM74 and LM72). The glue line gives a smoother cut and I use it for general ripping tasks. When I want a square bottom for rabbets, tenon jig cuts, narrow grooves for drawer bottoms etc, I use the regular rip blade.

Mike
 
mkepke

mkepke

Mark
Senior User
Jeff - I would make the cut on the router table and clean up the depth of cut problem with a swipe from a handplane. A #78 (duplex rabbet and fillister) is ideal, but even a common bench plane or block plane should work fine.

A 30s. job - assuming you have a decent handplane.

-Mark
 
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