OT: Router bit bearing question

[smontanaro]

I have a question for the woodworkers in the group. Maybe I am going about this all wrong. If so, perhaps you can steer me in the right direction. I want to cut a 3/8" square rabbet on the edges of four pieces of wood (making boxes from 3/4" plywood which has been cut to size). The idea is for the two rabbets on adjacent edges to interleave to create a stronger joint than a simple butt joint. I'm having trouble seeing how I'm going to cut these rabbets with my router and current bits.

I have a handful of bits for my router and only use it infrequently, so I'm hardly an expert. In particular, a I have a Freud rabbeting bit (# 32-100). It has a 1-1/4" diameter cutter and a 1/2" bearing, so it will cut a 3/4" deep rabbet. I want to cut a 3/8" x 3/8" rabbet. Adjusting the depth of the router is no problem, but I can't seem to see my way clear to the other side of the rabbet. (I assume if I had a router table this would be a no-brainer.) I thought I would just buy a 7/8" diameter bearing to enable the shallower cut, but that seems to be a (rotating) unicorn. I can't seem to find one with the right ID for the router bit (3/16", I believe). I would just cut the too-deep rabbet and trim to size with my flush cut bit, but I don't think that's going to work here (both rabbets will be too large in one dimension, so I can't glue up the joint then trim the excess).

[CaptStash]

The best solution would be to buy the correct router bitt. That's sort of one of the keys to woodworking - use the right tools. But since you are not a frequent router user, there are a few options:

#1) Clamp a guide on to the board that is the correct distance from the edge of the board such that you wind-up with a 3/8" rabbit. You'll definitely need to use some scrap lumber to get the distance off exactly right.

#2) This would be harder, but you could rip a few pieces of scrap down to 3/8" thick, and use it on the end of the plywood as a sacrificial shim.

#3) I think this is your best bet. Scrap the plan to interweave, and cut a 3/4" by 4/8" rabbit on two of the four boards. Trim 3/4" off of the other two (maybe 3/8" depending on how you had originally planned to assemble the interwoven parts?). Glue and screw your way to glory.

Note: #1 & #2 would be tough to get accurate enought that you'd get perfect joints. I'd go with #3 myself.


Saul aka CaptStash....

[DaveS]

I think Infinity Cutting Tools probably has the bearing that you are looking for (worth sending an email even if you can't find it on the website).

That being said, have you considered getting a router table? Seuper useful, and I've heard good things about some of the lightweight tables that breakdown easily.

[C40_guy]

You could do part or all of this with a jigsaw, or cut part of it with a table saw (or even a chop saw) and finish it off with the jig saw.

You could also internally strengthen the joint with a 1x1 or 2x2 piece of pine.

[batman1425]

Just a heads up - make sure your stock is actually 3/4. Most ply from big box stores isn't actually 3/4" nominal width. It's usually either 16th or 32nd shy of that for cost savings. True 3/4" ply is available, but harder to find and more expensive.

[robt57]

seems table saw get it done less fiddly and tilty etc.

[C40_guy]

Originally Posted by robt57

seems table saw get it done less fiddly and tilty etc.

Table saws can be quite versatile...

I used a table saw to shave down the ends of some oak pieces for overlapping joints for a 2x3 frame (dog gate). Seemed to be the easiest way to do it... I also inserted dowels in each joint, mostly for appearance...I was using dowels for the slats of the gate. Came out pretty nicely...I made three several years ago...now I should probably make one or two more...

That was when I had a somewhat portable table saw...now I'm just getting to know exactly what my ShopSmith table saw can do (PO left it for me when we bought the house...)

[robt57]

Originally Posted by C40_guy

Table saws can be quite versatile...

Especially when you learn how easy simple jigs and sleds are to make for less common tasks... Usually by cutting wood for the jigs/sleds on said table saw.

[batman1425]

I wish I had room for more than the little Delta Shopmaster that I got for free 10 years ago but am short on square footage. Luckily, a good friend has a full shop in his basement with all the goodies, including a nice sawstop that I can use when I need it.

[woodworker]

Router table would make this simple, but if you don't have one available, I agree with the others that a table saw would work, assuming that you have a workable sled or jig. I'm not a big fan of a rabbet joint. If you decide to use it, I'd add (I know, it's heresy) screws, set them in, and get a plug cutter to cover them.

[unterhausen]

I use the 1/4 1/4 1/4 method with a dado blade on the table saw to make drawers. Not quite the same as what the OP is suggesting, but probably stronger.

OTOH, there are plenty of rabbit bearing sets on amazon with a 7/8" bearing. Search for Multi-Rabbet Top Mounted Bearings Replacement Kit Rabbeting Router Bit Ball Bearing Guide Set

[C40_guy]

Originally Posted by robt57

Especially when you learn how easy simple jigs and sleds are to make for less common tasks... Usually by cutting wood for the jigs/sleds on said table saw.

Eggsactly.

It's amazing what you can do *to* wood *with* wood...

Case in point...I made a desktop from cherry lumber. It sits on a sitting/standing desk base. Needed to biscuit and glue the individual pieces together, then clamp them. So rather than spending $300 on 36" clamps, I made a jig out of 2x4s and wedges, made from, um, wood, to create the pressure. Seemed to work...I'm typing on the desk now.

[HenryA]

I'd do it on the table saw or buy a bit made for what you want. The 2 rabbets are not that much of an improvement. More complex joints will help align the joint during assembly and provide some additional mechanical strength.

A tongue and groove would be pretty easy on a table saw. Biscuits or a spline would be another away to skin this cat. A butt and spline would be fairly simple to set up.

Some bits are on this page--

https://www.rockler.com/power-tools/...ry-router-bits


Another solution is to use a better glue. Epoxy from West Systems will make a great strong joint.

[Clancy]

If I understand you, you want to make a double rabbet joint?

A better, simpler, and stronger joint would be to route the ends of two sides 3/4 x 1/2 leaving a lip of 1/4 inch thick protruding 3/4 inch. If I understand the bit you have this should be easy enough.

Leave the ends of the other two sides alone. These ends will sit-in the rabbets you cut.

Join using the recommended epoxy, plywood has 1/2 end grain typically and end grain makes a very poor joint. Don’t use too much epoxy, and clamp it.

After its dry, drill and countersink screws to reinforce, being careful. If you’re using 3/4 inch for the bottom do the same thing.

Not real sure where a jig saw comes into all of this.

[smontanaro]

Thanks for all the replies.

My table saw (my dad's old early 50s Craftsman - cast iron top and extensions) is up at the vacation house in Michigan (has been there for a few years). I may be able to run up and get it in a few weeks, but I'm not entirely sure I will be able to fit it in my Golf Sportwagen (maybe if I take off the extensions and break down the cart or make two trips). I have made various jigs for it in the past. I'm sure I could whip something up for this task. I'm going to make several boxes (actually, the idea is that the boxes will replace an old cabinet in the kitchen. I'm trying to execute my wife's vision (she of the plywood boxes). I think the rabbeted joints will expose less end grain on the plywood (which is more expensive stuff from the local lumber yard, not the big box store stuff, and does measure a true 3/4" thick). For that reason screws are also out. A biscuit joiner is an option, but that would expose the end grain on half the pieces. Still, If I arrange the butt joints properly, I can probably hide most of the end grain from casual glances. I haven't even begun to think about trim on the front.

What I have in the garage at home is a "contractors" table saw which I don't like. It's my contractor brother-in-law's third (or fourth) string saw. Its main advantage is its small size and light weight. It lacks a square (Ray only ever uses a table saw for ripping, so generally discards or loses the squares) and it's difficult to get the rip fence set parallel to the blade. Adding a dado blade to it would definitely be putting lipstick on a pig.

I do know a router table would make this easy peasy, but as I indicated, I simply don't use the router enough to justify it (I'm not a woodworker, I would rather spend excess money on my bikes )

I'll poke around a bit more for router bearing options or different sized rabbeting bits. Something will work.