best way to cut rabbet on baltic birch ply?

[James Baker SD]

Wife wants 3 new doors in kitchen. Rather than allow me to do a really nice job and make nice doors, she wants to save the others and have the new ones match. Old doors are 3/4" plywood with walnut laminate on the surfaces. The doors have a rabbet on the back side about 3/8" deep and 3/8" wide to allow the door to partially set in the cabinet.


Question is what is the best way to cut these rabbets without making a mess of the layers of ply? I have a slider/shaper combo with the Felder Dado set and a rabbet cutter for the shaper. Since it is only 3 doors I am not worried about efficiency or speed, but do want the cleanest cut possible as I slice through the layers of the ply. i have already matched the laminate and have the panels for the door covered, but I can practice on pieces of scrap ply.


Thanks.

[Bob Hoffmann]

Not sure about the "best" way, but I would use the table saw to make a cut on the back side of the door the depth of the rabbit. Then, you can get rid of the rest with the shaper ...

The cut on the table saw will make a clean cut on the back of the door ... the shaper will be working on the edge of the ply, so there should be no problem with tear out ...

[Michael Kaplan]

IMO, the cleanest way is to make two cuts on the tablesaw, one with the piece horizontal on the table, the second with the piece vertical. Of course featherboards or the like will help with stability of the piece when vertical.

[John TenEyck]

Yet another approach would be my preferred way for only three doors, and that's using a handheld router using a rabbeting bit. Take 1/8" passes using a climb cut and there will be no tear out and the bottom corner will be square and not over or under cut.

John.

[Erik Christensen]

james

do you have a power feeder on your shaper? I make a lot of flat panel doors and use 1/2" plywood for the panel - I just run a rabbit around the perimeter to fit into the grooves on the rails/styles. I use the power feeder so it is a climb cut and even on the cross grain the edge of the rabbit is flawless. I can sneak up on the perfect fit by trimming a fraction off the panel tongue and just run that edge back through the shaper - with a climb cut the results have always been perfect.

[Mike Heidrick]

Id back the bb with a sacrificial sheet and make the cut on the shaper with the cutter I already own.

[scott vroom]

+1 climb cut, whether hand held or table router or shaper.

[James Baker SD]

I have a power feeder. Please refresh my memory as to what a climb cut is. Feeding in the direction that the cutter wants to pull the workpiece anyway?

[Rod Sheridan]

I have a power feeder. Please refresh my memory as to what a climb cut is. Feeding in the direction that the cutter wants to pull the workpiece anyway?

James, a climb cut is a cut in the same direction as cutter rotation, it can only be done with a stock feeder.

I would use the feeder and the rebate cutter on the shaper, that's what the machine is designed for............Regards, Rod.

[Erik Christensen]

James - yes that is exactly what a climb cut is - you really need to try it with your power feeder - the cut quality is amazing. Only down side is the mess - the cutter rotation tends the throw the chips across the table in the direction of feed/rotation instead of back into the dust shroud. if I am doing more than a few cuts I tend to move the shaper to the garage door and position it so the chips get flung out in my driveway rather that all throughout my shop - lot easier to cleanup with leaf-blower vs broom

[Max Neu]

Do the doors have a round over on the face?If so,you might want to do that first.

[James Baker SD]

door edges are beveled at 78 degrees (12 degrees off perpendicular). easy cut with the table saw. Whole kitchen is full of weird angles, many of the cabinets have sides at 78 degrees relative to wall and doors.

[Rick Potter]

This is obviously not a rabbet, but it does show the difference between a normally cut 1/4" X 1/4" groove cross grain in cheap prefinished plywood, and a climb cut in the same piece.



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This was done on a router table with no power feeder. When making cabinets with the Sommerfeld T&G method, he recommends doing this. Self feeding seems fairly easy to control, probably because it is not a large cut, and I use feather boards set pretty tight.

[scott vroom]

James, a climb cut is a cut in the same direction as cutter rotation, it can only be done with a stock feeder.

I would agree with that for hardwood. Plywood is a different story. I routinely climb cut grooves in plywood for cabinet carcass assembly. It does not grab and throw like hardwood. I consider it a safe operation on a router table. And yes, it does throw the chips forward but the quality of cut is worth the mess IMO.

[glenn bradley]

I just score the line with a razor knife and use a dado stack . . . a good quality dado stack. As you can see from the responses, the "best" way is different for different folks. Try a few test cuts and pick your own "best".

[Rich Engelhardt]

This was done on a router table with no power feeder. When making cabinets with the Sommerfeld T&G method, he recommends doing this. Self feeding seems fairly easy to control, probably because it is not a large cut, and I use feather boards set pretty tight.He also highly recommends (touts?) his ~ $30 featherboard for making the climb cut.
Even though I have yet to use it - the ~ $30 featherboard, IMHO it's a worthwhile investment. The thing is - - substantial...

[Mike Schuch]

I just score the line with a razor knife and use a dado stack . . . a good quality dado stack. As you can see from the responses, the "best" way is different for different folks. Try a few test cuts and pick your own "best".

Yes, if you are worried about tear out just score the wood with a razor before cutting the rabbets how ever you prefer. I too prefer a good sharp dado stack.

[Garth Snyder]

Plywood is a different story. I routinely climb cut grooves in plywood for cabinet carcass assembly. It does not grab and throw like hardwood. I consider it a safe operation on a router table.
+1

I was extremely leery of doing this (climb rabbeting on plywood) even after watching Mark Sommerfeld's videos. But after trying it out I got over my apprehension pretty quickly. Just crank a featherboard in tight and push the panel in a smooth, controlled manner. You'll feel a few small "grabs", but featherboard pressure will keep everything well under control.

I don't have Sommerfeld's magic featherboard - just a generic one.

I think the key word to emphasize here is "panel". Panels provide adequate mass and surface area to make the operation safe, but I wouldn't use this technique on small parts.

[James Baker SD]

I made the rabbets today, not sure I chose the best way, but being new to using a shaper I did it the way I felt safe. Mounted a 6" diameter by 2" cutting edge rabbet head on the spindle. That is a lot of mass spinning and a bit scary looking. Decided to lower the cutter head down into the table and have it protrude up the 3/8" necessary for the vertical dimension. Tricky part was knowing where to set the fence since the edge being worked was at a 74 degree bevel (I mistakenly said 78 degree in earlier post), I wanted my rabbet depth measured from the midpoint of that bevel, but the lower (wider) edge of the bevel is what would contact the shaper fence. Thank goodness for CAD programs so I could draw the situation and then ask the program to measure the proper setting for the fence. Used air clamps to hold the workpiece to a sliding table, and pushed the table manually past the cutter head. Cuts are nice and clean and I felt safe with most of the spinning mass out of sight below the table and my hand just push the sliding table. Result of good enough for the project. Did not want to try a climb cut, was just afraid of that much spinning mass.

Thanks for all the suggestions I got. End result is I am satisfied.

[Allan Speers]

James, a climb cut is a cut in the same direction as cutter rotation, it can only be done with a stock feeder. .


FWIW, it can also be done with a router attached to a track. I do this all the time with my Eurekazone kit & a spiral bit.

[Keith Weber]

I understand what a climb cut is, but the pic someone posted showed a narrow groove and the difference between climb and conventional cutting. I don't see how the terminology applies to grooves, since it doesn't make a difference which way you feed wood into a router if cutting a groove the size of the bit. Now if the bit is narrower than the groove, the terminology would apply on subsequent, offset passes, but the first would still be a plunge cut.

Of course, I'm assuming that those were cut with a straight bit. Maybe they were cut with a slotting bit.

[Allan Speers]

I understand what a climb cut is, but the pic someone posted showed a narrow groove and the difference between climb and conventional cutting. I don't see how the terminology applieshttp://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png (http://www.sawmillcreek.org/#96053397) to grooves, since it doesn't make a difference which way you feed wood into a router if cutting a groove the size of the bit. ....

AFAIK, a rabbet is always a groove cut on the edge of the stock. You're thinking of a dado, no?

[Keith Weber]

AFAIK, a rabbet is always a groove cut on the edge of the stock. You're thinking of a dado, no?

I was referring to the pic by Rick Potter (post 13), where he differentiates between a climb cut and a regular cut in a groove (dado).

[Pat Barry]

This is obviously not a rabbet, but it does show the difference between a normally cut 1/4" X 1/4" groove cross grain in cheap prefinished plywood, and a climb cut in the same piece.



314322



This was done on a router table with no power feeder. When making cabinets with the Sommerfeld T&G method, he recommends doing this. Self feeding seems fairly easy to control, probably because it is not a large cut, and I use feather boards set pretty tight.

I wouldn't call that a climb cut unless you did it with a dado blade and table saw. That's just the same cut from another direction for a router bit. The bit don't know which is which.

A climb cut refers to cutting in the same direction as the bit rotation and for a router bit it is totally not applicable to dadoes as far as I can see.

Doing freestyle climb cuts such as rabbets is a recipe for disaster and injury. You better be sure to take light, depth controlled passes or you will shoot that workpiece across the room so fast you won't know what hit you.

[Rick Potter]

OK,

For clarification..........That pic shows grooves cut with the groove half of a T&G router set. In other words, it was cut with a slotting cutter, not a straight bit, so it was most definitely a climb cut.

The feather board was a Bench Dog, regular type, bought on sale at Rockler for about $8, and set a bit tighter than normal.

[Pat Barry]

OK,

For clarification..........That pic shows grooves cut with the groove half of a T&G router set. In other words, it was cut with a slotting cutter, not a straight bit, so it was most definitely a climb cut.

The feather board was a Bench Dog, regular type, bought on sale at Rockler for about $8, and set a bit tighter than normal.
Thanks for clarifying Rick. Now it all makes sense.

[Allan Speers]

Ahh. OK.

- but his post was a red herring. We were discussing rabetts, thus the talk about climb cuts & the need for support when making them.