Spiral Flush Cut Router Bits

[rgand]

Since I now have a router that will take 1/2" shank bits, I'll be looking at some new ones. Nothing new for this body but for the next one, I want to make cutting things out as clean and easy as possible.

Does anyone have experience with the spiral flush-cut router bits? I can get one that will cut the whole body in one pass but these things are costly.

How well do they work and are they worth the cost?

 

[Cagey]

I haven't really needed one in the past, but have looked into them to find out why I would want one. The biggest advantage is they tend to slice, rather than shave the wood. So, you end up with a cleaner face on the cut and less vibration in the tool.

The downsides would be that they tend to either "grab" the work, pulling it up or down depending on whether it's an up-cut or down-cut spiral, or in the case of hand-held routers, to possibly cause you to lose control of the motor. I would expect the larger the cut you're making, the more pronounced the effect would be.

Another downside you already know - they're pricey. They're usually solid carbide vs. carbide-tipped like straight bits.

Finally, you might have a waste control problem that could limit your sightlines, particularly with a hand-held router and an up-cut bit, as it'll tend to throw chips up into the collet area.

I think those bits are designed more for industrial automation, like CNC machines or those floor-standing pin routers you see in some of the guitar factory videos, rather than DIY guys like us with portable powered hand tools.

 

[rgand]

Thanks, that saves me a pile. I'll look for a standard shave cut one. I think I can get one that will do the whole body in one swipe also. They're a whole lot less expensive, too. I'll find one that isn't too costly but not cheapo-wait-30-days-while-we-send-it-over-in-a-container level.

I appreciate the information.

 

[Cagey]

Even on the big machines, they don't try to cut the body out in one fell swoop. That's a lotta wood to tear off in one bite, especially hardwood. You'll likely burn it - a lot. Maybe more than it would be practical to sand clear. Even going slow, trying to take that much wood all at once is gonna heat the bit up real fast. It will almost certainly be faster and cleaner to make two passes at it. It would be better to use a top-bearing flush cutter with the template to get halfway down, flip the body, and use a bottom-bearing flush cutter to follow the top cut and get the bottom half.

 

[rgand]

Even on the big machines, they don't try to cut the body out in one fell swoop. That's a lotta wood to tear off in one bite, especially hardwood. You'll likely burn it - a lot. Maybe more than it would be practical to sand clear. Even going slow, trying to take that much wood all at once is gonna heat the bit up real fast. It will almost certainly be faster and cleaner to make two passes at it. It would be better to use a top-bearing flush cutter with the template to get halfway down, flip the body, and use a bottom-bearing flush cutter to follow the top cut and get the bottom half.

Well, that's good. I already have both of those with a 1" length although not with 1/2" shanks. When I replace them, I'll certainly get them with that in mind. Again, thanks for the great direction.

 

[Cagey]

If you're already planning to replace those bits, why wait? Some nice, new, sharp carbide flutes and a 1/2" shank will make clean cuts on what amounts to about a 5' run that will be irregularly-shaped and therefore difficult to sand for finish prep. Not trying to eat your entire annual tool budget on one project, but this will  be a demanding cut.

And speaking of spending time/money, a lot  more time is spent in setup for a cut and cleanup afterward than on the cut itself. You might want to consider making two or even three bodies at once. Won't take much longer than making one, and you can use the proceeds from selling the extra(s) to cover your tool costs plus some. Maybe get that oscillating spindle sander you know  you're going to want... :laughing7:

Thanks to our friends in China whose factory workers aren't saddled with $250K mortgages and $35K cars, you can have one of those lovelies new for your very own for in the $100 range. Gets a lotta work done accurately and quickly. Hint: get the Wen unit sold here.

 

[rgand]

You know you're just tempting a tool junkie, don't you? :icon_biggrin:

 

[Cagey]

Yes, but I'm a shameless tool junkie myself, so it cancels out. You're free to use your best judgement while rationalizing just how silly it would be to not have those tools. I mean, in this case they're all free after the first job, so how good can they be? :laughing7:

 

[rgand]

Uh, huh. The drawback is I was going to start routing tomorrow and new bits would delay that. But...

We'll see. :glasses10:

 

[Cagey]

Too bad there's not a Lowe's or Menard's or someplace like that near you. Only problem with those places is you wouldn't get to wait or pay shipping or send your dollars to another jurisdiction.

 

[rgand]

There's a Lowes in Gilroy but that means going to get the bits or staying home and just getting to work. Can't get there today, unfortunately.