rail/stile router bit and panel thickness

[Dennis Jarchow]

I am making a bar and am running all of the rails and stiles on my router table with a new Amana one piece rail and stile bit. I ran all of the rail cuts today and found that the 1/4" cherry/MDF panel won't actually fit in the slot. Now before you all yell at me, I did check a short cut of the slot maybe an inch or so on a scrap board and one corner of the panel before I ran all the rail cuts and it fit, albeit pretty. I tried it again today and see it was spreading the slot open but since it was the end of the board, it worked. I have never had an issue with these mdf panels fitting rails and stiles I have cut with other rail/stile bits.

I measured the slot, tongue, and the panel and got the following measurements:

Tongue: .233" (Amana specs this as 15/64/.233")
Slot: .238" (Amana doesn't spec this) but on another rail/stile bit set I had handy the slot cutter measured .249"
Panel: .242"

I called Amana and they said they only had the dimension of the tongue, not the slot but nothing had changed on the bit, and the one he measured was .239". So they said nothing they could do for me.

I suppose I could rerun the all the rail cuts and lower the bit 5-10 thousandths or so and rerun all of the rail cuts. Another option is to try to sand the edge of the panel or the inside of the slot.

Any other suggestions? Thanks for any help.

[Mitch schiffer]

I have a freud set that has a adjustable t&g. This is the one I have https://www.woodworkingshop.com/prod...RoChz8QAvD_BwE

[Mel Fulks]

First thing I would do is just run them again. Never check fit with a narrow piece , that’s like bull fighting a two day old bull ! Lot of times
materials just close up a little and have to be re-run. Try it, then ,if it still won’t fit you will have to adjust router.

[Myles Moran]

If the back of the panels won't be visible, I'd run a raised panel back cutter and raise it until they fit. I'm not sure what effect this would have on the MDF panels, but I'd guess you could seal them up to prevent issue (I'm sure someone here knows far more than me on this material).

Alternatively if you have a way to cut a loose tenon (domino or router jig) you could reroute the slots to fit and put a loose tenon in to make up for extra gap in the tongue and groove.

[George Bokros]

If you have not run them twice I would do so. I find that helps many times.

[Dennis Jarchow]

Thanks for everyone's replies. I ended up running the stick cuts twice, once at the right height and then again with bit lowered about 6 thousandths. This gave me a slot that fit my cherry/mdf plywood. The downside of this is that the tongue is a bit loose but not so loose that it shouldn't glue up OK. What confuses me is what type of center panel material Amana is expecting. The cutter leaves a slot.238". Mdf plywood is usually right around .25" (mine was .242") so that is too thick. Veneer core plywood is usually 5mm-5.5mm which would be really loose in the slot. The listed size is about 6mm but I have never seen any US plywood come in that thickness. I checked an old jig I made out of 1/4" baltic birch and that was closer to 6mm but still would have been too big for the slot. I am sure I am missing something since Freud's similar bit has the same sizing.

[Mitch schiffer]

The veneer mdf plywood I buy locally is typically .205 to .215 I am typically running a 5.5 mm groove with a freeborn shaper cutter. I almost always get a decent fit on the center panel. I do have a 1/4" cutter for Baltic birch since that i believe is sold as 6 mm.