minimizing tearout..

[dan moran]

quick question- prolly been posted before, but im having a bit of a tearout problem trying to flush trim some lazy curves in red oak 1x via a template.

im using a 1/2" shank bosch trimmer w/a 1.5" flute on a 2.25 HP dewalt router. the guy was working just fine--ive had the bit since april and used it on some cedar 2x4(quite a bit of cuts on a pergola project), treated 2x4 (a deck with rounded rail caps), some poplar 1x(matching an arc- about 3 ft of cut), and finally some oak 1x (about 12 linear feet of arc-1/2 of my current project) .and then it started ripping the hell out of last batch of arcs i was trying to cut, i tried slowing the router down and speeding it up - nothing good.

im wondering if i may just have worn the bit out? does the amount of use i described sound like a lifetime of one of these jobbies?

i rough cut the curves to about 1/16" (maybe a little more) over with a jigsaw.. was that too much??

like i said, its worked before but now its turning my stock into firewood.

anyone?

[pat warner]

Cutter is wasted alright, but too small in diameter even if new.
Look at cutters starting at 3/4" cutting diameter. Skinny bits like yours always tearout, especially in tight turns taking at or near full thickness cuts.
Most trimming should be done in stages and that is not practical with bearing guided cutters.

[dan moran]

i was kinda thinking that the cutter went south..

i guess ill head out ISO a newer- bigger one.

thanks alot..

[Jack Ganssle]

Great advice from Pat.

Infinity is today listing 3/4" bits on overstock for $8 each, about half the regular price. I just ordered one.

Jack

[Richard M. Wolfe]

I'll chime in to agree with Pat also. I used the skinny flush trim bits for a long time. They were cheap and I'm cheap so it seemed a good match . I finally broke down and got a 3/4" flush trim bit and it makes a huge difference.

[Lee Schierer]

It may not be the bits fault. The tear out may be the result of poor grain orientation. Try another piece of wood or try climb cutting. If you climb cut take light cuts and have a firm grip on your router.

You can also apply masking tape over the cut area before cutting and the tape will help prevent tearout. When removing the tape pull the tape toward the trimmed edge not away from it.

[dan moran]

i went over to rockler and picked up an amana flush trim bit (30701 or something).. and woah, the 3/4 diameter cutter made all the difference in the world...

i was even able to salvage one of the pieces that were messed up by the other cutter...

i used the tip about climb cutting to knock down some of the thicker sections left by the jigsaw as well..

thanks all around..