Flush trim bits ...

[Chet]

Submitted on the old forum by bushwacked

So I don't do much router/flush trim bitting so I'm curious ... Why the different thicknesses? Do they do anything different? Minus the height which is obvious what does having a fatter flush trim bit get you? Longer life? 

Follow up posts

1) Many times, it just depends on some corners that you need to get into. If I were doing a lot of straight flat flush trimming, I would think the larger bit would have an easier time staying cool and therefor last longer.

2) Yeah, if you have a pattern with a tight inside radius, you would use a smaller od bit.

3) Also there is a height difference, the two on top are shorter then the two on the bottom. Another thing that is nice about these is they have a bearing on top and bottom.

4) I was just reading about these bits on Infinity's website and in the long haul of a hobbyist's shop they all would be nice to have. The shorter ones can handle up to 5/4 stock and the taller ones can handle up to 8/4. They recommend using the larger diameter bits in your router table only. The larger diameter bits because of their large diameters have a higher angle of attack which would be helpful in highly figured woods and also patterns with reversing grain. The smaller diameter bits along with the above mentioned use in a tight radius they are also good for trimming veneer and laminates.

Hope this helps.

5) I thought i would add to this very old discussion. I purchased one of the Mega Flush trim bits, I got the 3/4 diameter X 2 inch length. I have been using it quite a bit on my current project and it has been more then worth the money. One of the cleanest looking cuts I have seen. The finished surface is like you went over it with your smoothing hand plane. Shame of it is some of the places I used it won't show in the final product.

6) Thanks for the update Chet! I've been on the fence a bit with these bits!

7) good to know if I am ever in the market that it wont be a waste of money