Flush Trimming bit

[Ed Gibbons]

Looking forward a recommendation for a flush trimming bit.

[Jim Becker]

There are so many possible solutions here with many different sizes and configurations...it may be helpful it you are more detailed about what you want to use the flush trim tooling for so folks can make recommendations that fit your need.

[Charlie Jones]

As Jim said,there are many types but you can’t go wrong with the Whiteside brand.

[Jamie Buxton]

Do you want the kind with a bearing on the bottom or the kind with a bearing on the top?

[Bill Dufour]

Shaper? bore?
Bill D

[Thomas McCurnin]

Free hand? Router table? Bearing location? These three options usually dictate whether the bit is upcut or downcut.

[Patrick Varley]

Agree with others, that there are so many options it depends what you're doing. Probably why I have so many variations. That being said, I've found a combo top/bottom bearing bit gives you a lot of flexibility.

If you're going to be doing a lot of pattern routing (especially in hardwoods), could be worth looking at something like the Whiteside "Ultimate Flush Trim" line which have compression spirals and top and/or bottom bearings. Not cheap, though.

https://www.whitesiderouterbits.com/collections/ultimate-flush-trim-bits

[Ed Gibbons]

I will be using a hand held router. I made a template out of 3/4 ply that I will place against a 3/4 piece of walnut.

[Jim Becker]

I will be using a hand held router. I made a template out of 3/4 ply that I will place against a 3/4 piece of walnut.
In that case, a top-bearing (if you want the template on top) or a bottom bearing (if you want the template on the bottom) of your preferred brand of tooling will work just fine. As to diameter, if you need tight curves you need a tool that's smaller in diameter. If it's all larger, gentler curves, you can go with a heavier tool which will also chatter less. I agree with Patrick that an additional consideration is expected finish quality and some of the newer tools with spirals, etc., can really kick things up, although many of them are largely intended for table use. A shearing cut format at least can help with quality...check the description carefully. Many Freud bits have a shearing action as a feature, for example.

[Paul F Franklin]

I will second Patrick's recommendation of the Whiteside ultimate flush trim bit; it works beautifully. The compression feature cuts both the top and bottom edges of the work cleanly, and the spiral action reduces tearout when the grain direction changes, as it often does when pattern routing. It has top and bottom bearings so the template can be on top or on the bottom. It is expensive however, so if this is a one time thing, there are other decent options. Another consideration with the compression bit is for it to work as designed, the work piece has to be roughly centered on the cutting area of the bit. This is usually only an issue if the work piece is thin because you would have to use a thick template. A 3/4 work piece and a 3/4 template would not be a problem. Finally, that bit is 1/2" shaft, so you need a router that can handle that.

[Jim Dwight]

I usually order bits from MLCS. I have used Whiteside and I think they are a little better but for most of what I do MLCS bits are plenty good enough.

Cutting 3/4 walnut is hard duty for a router, regardless of HP or bit. I would cut most of the waste away with a bandsaw or jigsaw and only use the router to remove the last 1/8th or so. If you do that, a simple straight flush trim bit should work fine. Be careful with grain direction as well as bit rotation. Either can cause the bit to try and grab too much possibly dislodging the template or taking a chunk out of the walnut. Trimming most of the waste away helps a lot. The larger the diameter of the bit the faster the cutter is moving. Big bits cut quickly but are more prone to grabbing.

I made 10 chairs last year mainly out of cherry. The back legs are about 1 1/8th thick and were routed to shape using a plywood template on my router table. The router table has a 15A Porter Cable motor - so plenty of power. I've done something like you seem to be describing. I trimmed with my bandsaw as I recommend. I still got a few instances of chipout which I managed to sand out. If you even touch end grain BE VERY CAREFUL. Probably best to sand end grain and skip the router. If you do that should work well but make sure the bit is sharp and be careful about the grain direction.

[Dwayne Watt]

I second MCLS but only their Katana bits. They seem equivalent to Whiteside to me. The standard MCLS bits seem not as sharp as the Katana. Whiteside are top shelf.
Even if you are doing a one time project, solid router bits are a must. That $20-30 saved on a lesser bit looks pretty pointless when you chip out or burn that perfect piece of wood because the bit did not start or stay sharp.

[Christian Hawkshaw]

I have had pretty good luck with whiteside compression bits. https://www.whitesiderouterbits.com/products/udft5152 is what I am currently using for many applications.