Freud Adjustable Tongue & Groove bits

Joea,

There is nothing wrong with a "cheapo" table if it fits your needs. The following is from Wood Magazine about router speed:

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Routers with variable-speed motors run between 8,000 and 26,000 rpm. More important than speed at the bit shank, though, is a bit's rim speed, the velocity of the cutter at the farthest point from the center of the shank. For example, a 1⁄2 "-diameter bit spinning at 10,000 rpm runs almost 15 mph at the tip of the cutter. Increase the speed to 25,000 rpm and the bit's rim is traveling at 37 mph. Now take a 3"-diameter raised-panel bit. At 10,000 rpm the rim travels nearly 90 mph, but at 25,000 rpm the rim speed would capture the pole at any NASCAR race: 223 mph!

Speeds greater than 100 mph put excessive stress on bits, especially those with 1⁄4 " shanks, and increase vibration. In addition, cutting performance suffers, as shown below, when speed exceeds the optimum level. Routing at a too-fast speed causes tear-out and burn marks on the workpiece and dulls bits faster. Routing with the speed set too slow leads to choppy, rough, or rippled cuts.

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I use the Frued adjustable bits for rail and stile. The bits make a lot of noise so wear hearing protection. If you are getting excessive vibration from the whole router table then screw some boards on the bottom of the router table and then clamp it down. You should be clamping it down anyway. With the table being rather lightweight, a spinning large bit and depending on your feed rate you have a lot of moving parts to cause problems.

If the bits are not loosening the screw that holds the cutters together then it is just the combination of your router table vibration, router speed and router bit rotation.

Run some material through and check it out to see if you are too fast, too slow, or just right by looking at the finished piece. Using a 1`.5" spinning bit I would set the router speed to about half speed. Every router runs at different speeds. After running a test through then increase or decrease the speed a little. Since most people run 1/8" to 3" bits, the 1/8" runs at top speed and the 3" at lowest speed then it makes sense that 1.5" half speed + or - a few RPM.

One rule of thumb is that you never remove more material in one pass than your router bit cutter diameter. So in your case the tongue is 1/4" wide and maybe a 1/2" deep. So only remove 1/4" depth at a time by moving your fence and making multiple passes. So be sure to mark each board with the top so you always run it the same way. It is almost impossible to get a board perfectly centered and if you run one side up on the first pass then turn it over on the second pass you will have a grove that is bigger than 1/4" and an uneven bottom.

To set up the fence use a straight edge on the bearing and line up the fence with the bearing. Then mark your table and move the fence forward and make a pass on all material. Then move the fence back once or twice till you get to the marked line or just use the straight edge to line up the bearing and fence.

This will make a better outcome then trying to run it all at once for the full depth.

Also look at the grain direction. Some wood like oak are very easy to chip out. It is like petting a cat. If you pet from head to tail the fur is smooth and the cat purrs. If you pet the cat tail to head the fur is ruffled and the cat tries to scratch you. So look at grain direction and try to cut down hill, when you cut up hill you get tearout, chipout and generally rough finish.

Good luck and let us know what worked and what did not work.

joea said:

Table?

Ok. just a typical cheapo "sears" table top, 925479 with short legs and a fence. While I was getting the number and some pictures, on a wild hare came up to me and whispered "try slowing it down some more". Dummy bunny. It got worse. So, being a bright feller, I sped it up, bit by bit, so to speak, and it smoothed out perfectly. It now inspires a wee bit of confidence. And certainly cuts easier.

No idea if it is some "sweet spot" for the bit, the router, or the combination. But, it is what it is.

Click to expand...

you to adsorb this information..

.

Thanks for all the advice. Much more than expected, especially this time of year.

The table - I recently screwed it down to a couple 2x3 to make it easier to clamp to a table, rather than use the "ears" on the leg bottoms. I'll take a closer look at how that may have affected things. But it may be simpler to remove the router from the table as Stick486 suggested and test things again.

I do tend to agree that if it vibrates at some speeds, it is probably not the bit, but then we have all known the car tire, or driveshaft, etc that was "out of balance" at some speeds and not others.

Overnight I had the revelation that maybe my whole approach to the project is ill advised. Since this is the Router forum I won't get into that too deep. But I need to build a removable "panel" to close off an interior crawl space in a "split level" room. To sorta match an already finished wainscotted area the panels are to be bevel 1x6 cedar, set into 1x (x) cedar perimeter boards. Since I needed to allow possible future easy access to the crawl space I need to make these "panels" attached probably be decorative screws, instead of nailing or trim screwing them directly. However, I'm finding my effort to tongue and groove this to be a bit of a bad dream. The router vibration aside, the lumber I have access to, seems to develop a slight "bow" in the narrow (cross grain) direction, when cut to size, no matter how carefully I select full boards at the yard. That makes getting a good tongue a bit difficult. Test assembly of prototypes has proven difficult as even with a slight bow pieces tend to split. Given all that I am thinking of going with biscuits and pocket screws, maybe even "loose", not glued.

Well, I guess I went too far with the off topic part, if there is a more appropriate place to get into that, let me know.

Plane ''B''...
splines...
hold up on the biscuits....

Plan ''C''...
straighten the boards...
use your router as a joiner...

you never did say what make of router you have...

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Router is Craftsman 320.17542 "2-hp, 11 amp", variable speed. Not used that much.

Do you just not like biscuits? Seems for what I am doing the biscuits are a "kinda spline" and a lot simpler to accomplish.

The pics may convey better what I am attempting. One is of a slightly bowed board, the other is of a rough up of the panel, from scraps.

The older Sears steel tables were only made to fit Sears routers which were almost always made by Ryobi (315.xxxxx). The tops were thin steel that had dimpled holes punched in them so the regular base plate screws would sit slightly countersunk. You had to sit them on a level surface or they would warp. I've seen who makes 320 models before but I can't remember who it is and search for Sears manufacturer codes don't usually list that prefix. Sears, like Porter Cable, is notorious for using poor quality bearings which is why we are suggesting testing to see. The bottom bearing is one of the prime causes for the vibration you experienced and it's better to replace it before it goes if that's the problem. The heavy bit would cause the problem to show up sooner that small bits would and it could smooth out at certain speeds.

Maybe Stick can verify this but I think Freud spin tests their bits before they go out to make sure they aren't out of balance. Freud does make some crappy cheap bits that are painted black instead of red and those might cause problems.

For your panel: you normally don't glue the boards in. You have grain going in two directions and gluing the boards in can cause them to crack or push the frame apart. Long grain doesn't move much with seasonal humidity changes but the cross grain does so the cross grain has to be able to freely swell and shrink and you normally leave about 1/4" of freeplay from side to side but if you are in the season where they are most likely already swelled up then you might want to reduce that some. There are things that can be done to keep the panel from rattling (as in the case of a cupboard door) but it doesn't sound like that door will get used much so that probably isn't an issue.