Lock miter router bit on quarter sawn white oak
I am starting to build a mission style (Stickley) table with quarter sawn white oak. Each square leg is to be made with four pieces of oak, mitered so that a quarter sawn face will show on each of the four sides. I was planning to use a lock miter router bit to create the miters, but the knife edge of the miter (the edge that will be half of one of the corners of each leg) chips out. The chipping seems slight but is highly visible when the joint is assembled. The router bit is new. The wood is 6% to 8% moisture content. I am using a Porter-Cable 7518 (3.25 hp) router in a router table. I don’t think I am feeding the stock too fast. I have tried making one or two preliminary cuts and then a very light final pass, but it always chips on each pass.
What am I doing wrong? Or is there a better way?
Thank you.
Replies
Chip Out
Not sure why it would do that. Have you tried it on some scrap pine or poplar ?
Maybe mill mitered ends and run a spline instead of the lock bit ?
SA
Start thicker
Mill the boards thicker to start with (say 1/16) then after everything is assembled and glued take a pass on the jointer of equal depth (1/16) on each face of the leg. This removes any chipping, glue stains and brings the leg to final size.
Rich
You might just skip the router bit and just cut the edge on the table saw and glue it up. I have done that for posts where I wanted four sides to all have face grain and it worked just fine. I think you will get a joint that will glue up just fine and have plenty of strength with out the fussy router bit. Of course you already have the bit so that is a challenge.
Good luck and let us know how it works out.
Reducing tearout when routing edge
Quarter sawn material is considerably more prone to tearout that flat sawn oak when you're routing the edge. With the lock mitre bit, you're ending up with a knife edge, where there's very little material left to prevent separating the rings. If you have a stock feeder, the tearout can be reduced if not eliminated by doing a "climb cut" where the cutter will be entering the edge surface of the wood and cutting into the board rather than cutting into end grain. Climb cutting should only be done with the use of a stock feeder and never attempted holding the pieces by hand. If you don't have a stock feeder, I'd go with the approach of routing the edge on thicker stock leaving some body backing up the cut profile then using a jointer or plane to remove the excess material as suggested in another response. I typically run the assembled legs through a drum sander to get a sharp finished edge as the edge often gets a few dings during the assembly process.
Charlie, No clue about lock miter bits, I would rip miters on table saw and use masking tape to do miter folds.
There is no need IMO for any spline or lock miter joint, Titebond 2 will be plenty strong.
I like to lat my mitered pieces face down edge to edge then run masking tape the length of each joint then strips of tape approx every inch perpendicular to the joints. When done taping flip over apply glue /fold / and check for square apply tape.
No need for fancy tape , I buy the cheapest 3m stuff at the borg ... Stock prep is the key with miter folds.
tom
I also have had issues with QSawn oak chipping on the router table. Found that by chaning the speed of the router i could reduce the problem.
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