Most of the time that I've ever used a flush trim router bit has been to
trim a melamine edge or something like that, I'm in the process of building
an oak dining room table and chairs.

Decided to build the chairs by using a template to bandsaw the blank and
then flush trim to shape. Needed 8 legs and fortunately I cut 9.

Took the first blank and using a 1/2" shank 3/4 x 1 1/2 flush trim in the
router table proceeded to trim. Much to my surprise, actually scared the
hell out of me, as I was trimming down the slender part of the leg, the bit
dug in and split the leg along the vertical grain.

Seems I didn't pay enough attention to how close to the line I made the
bandsaw cut. Got a little sloppy and some of the cuts were over 3/8" deep.

Needless to say I went back over the blanks and cut much closer to the line.
No problems after that.

Vic

--
There are 10 kinds of people - those who understand binary and those who
don't

I do the same ops with a shaper with a 2 5/8" trim cutter.

Yes, the less material to remove the better cut and less chance of
chip out
Yes do a climb cut of difficult section or at the exiting end
Yes, create a fixture with a zero clearance exit if possible to stop
blow out

Shapers can also be reversed (the motor and the cutter) so you can cut
with the grain at both ends. Kind of a lot a work to do. Especially in
my case since I trashed my reversing switch during a refurbishment
process and I hve to actually switch wire to revere the motor.

I have found that in some cases I became so carfeul and experienced
with my bandsaw cut that I didn't need to actually do the trim. Just
sanded.

On a router you might look into a spiral cutter. Actually even more
dangerous in some regards (they like to grab) but cleaner slicing
removal of material because you always have a cutter in the material
instead of the bang bang of a straight cutter.


On Nov 3, 8:38*am, "Vic Baron" wrote:
Most of the time that I've ever used a flush trim router bit has been to
trim a melamine edge or something like that, I'm in the process of building
an oak dining room table and chairs.

Decided to build the chairs by using a template to bandsaw the blank and
then *flush trim to shape. Needed 8 legs and fortunately I cut 9.

Took the first blank and using a 1/2" shank 3/4 x 1 1/2 flush trim in the
router table proceeded to trim. Much to my surprise, actually scared the
hell out of me, as I was trimming down the slender part of the leg, the bit
dug in and split the leg along the vertical grain.

Seems I didn't pay enough attention to how close to the line I made the
bandsaw cut. Got a little sloppy and some of the cuts were over 3/8" deep..

Needless to say I went back over the blanks and cut much closer to the line.
No problems after that.

Vic

--
There are 10 kinds of people - those who understand binary and those who
don't

"Climbing cuts" (going the wrong way with your macrouter) are pretty
safe if you are careful, don't take too much off at one time, and are
experienced in doing it.

I don't mind doing it, but as Leon cautioned, it can be very
dangerous. A 2 1/4 horse router doesn't seem to powerful until it had
a handful of your project.

If I were going to suggest something to the less experienced, I would
suggest this one, or its relatives:

http://tinyurl.com/ydaogqq

They have the family on this page, at the bottom, about the last 6 - 7
bits. They are called "flush trim plunge" bits.

http://www.toolstoday.com/c-416-flus...uter-bits.aspx

Look carefully at the bit. You can take off tiny amounts at a time by
adjusting the depth of your cut, making sure the bearing rides on your
template.

This differs from the normal flush cut bits that don't let you choose
how deep you cut, which in turn makes the bit take a big bite. But
note as well that for a 1/2" collet router head, you can get a 1 1/4"
depth plunge at a very reasonable price of about $20. That should
easily cover a 1" thick piece of stock.

Or you could index your template, flip it over, and cut from the other
side and get about 2+ inches form the bit.

I use the bottom bearing flush cut bits for laminate work, but for
pattern work/woodwork I always pick the top ride bearing style. You
have a lot more control and you can adjust your cut/bite on the fly by
eye if you want. It is safer and easier for me.

Of course, YMMV....

Robert