Router bit width question.

[Stobe]

Quick question.  When choosing a straight, flush trim bit (pattern cutting), how much does the width of the bit affect things?

I found 3 different bits, all 1" tall, but two of them were 1/4" shafts with widths of 1/2" and 3/4", and the big one was a 1/2" shaft with 1 1/8" width.

For cutting 3/4" MDF, is any one of these better than the others?  My first guess was that the bigger ones would handle the cutting better, and the smaller one would handle corners better.  Is this close to true?

Thanks!
-Stobe

[lordtodd75]

First thing, make sure you get the correct shaft size to fit your collet. Most people have a 1/4" collet. I am no expert on this but judging from my experience, I would get the smaller (1/2") bit. It will cut easier due to less surface area and will be less likely to burn the bit. You might want to do multiple passes as well, 3/4" mdf is not going to be easy to get through all at once. What exactly are you planning on cutting?

[lordtodd75]

Oh and I forgot to mention the dust. Make sure you wear a mask as MDF dust is toxic and there will be A LOT of it when you use a router.

[Stobe]

I've cut and sanded one side of my project, and I traced it to the 2nd side.  I used a jig saw to cut to about 1/8" from the trace line.  Now I have the 2 sides clamped together and I want to just pattern cut with my router.

By multiple passes, you mean cut down perhaps 3/8" for the first pass, and then get the rest with the 2nd pass?

Thanks,
Stobe

[flyguy1821]

I hope your router bit has a bearing either on the top or bottom.  If it does then it really doesn't matter the width of the bit.  I prefer a smaller 1/2 -3/4 width bit for flush trim.  A wider bit with a bearing is meant to cut a wider rabbit or groove into the wood.  If you router is capable, get the 1/2 inch shank, they are typically for heavier use.  Unfortunately, they are usually more expensive.

[kelemvor]

I'd go with the largest shaft you can fit in your router as long as the size of the actual bit won't mean you can't get a certain corner size or something.

My router takes 1/4 and 1/2 and I've had 1/4" bits literally snap in half beacuse they were weak.  Now I always buy the 1/2" size and get quality bits and not the ones you get 10 bits for $5....

[Grauwulf]

I've cut and sanded one side of my project, and I traced it to the 2nd side.  I used a jig saw to cut to about 1/8" from the trace line.  Now I have the 2 sides clamped together and I want to just pattern cut with my router.

By multiple passes, you mean cut down perhaps 3/8" for the first pass, and then get the rest with the 2nd pass?

Thanks,
Stobe

You will be fine to take off the remaining waste in just one pass.

[flyguy1821]

If you are only 1/8 inch from your trace line the single pass like Grauwulf said is sufficient.  Typically the material and a greater then 1/4 - 1/2 inch needs a double pass with a flush trim bit.  Nice thing about using the flush trim bits and routers, you finish with an exact copy of the template.

[Stobe]

Thanks to everyone for all the input.  It worked fine for me in one pass.

-Stobe