fly cutter

[dan_nelson]

I need to remove alot of material fast. cutting pink foam. pocketing out 40x27 area .250 deep. how big of a fly cutter can I SAFELY spin? do you have a supplier in mind?

[rww]

I use a 2 1/2" bottom cutter from magnate.net

http://www.magnate.net/index.cfm?event=showProductGroup&theID=136

[steve_g]

Also from the magnate web site is this suggested speed chart...

SG

[gerryv]

Having used fly cutters on milling machines, I'd not use one of that type on a much higher speed spindle or router. They're not balanced and some just have a small screw and no other "stop" holding the removable bit in place.

[billp]

I'm going to presume that since they seem to MAKE these bits for wood cutting that they will be just fine...In fact even if those speeds they suggest are a bit "off" there's plenty of room to slow down your bit to 10,000 rpm and use them with little concern.
This is something that comes up at almost EVERY Camp, when I ask people what size bit they are using to surface their tables with, and a surprisingly large number of people are using bits UNDER 1" to do the job ! That's the reason many of these people rarely DO surface their tables, it takes SO long with such a small diameter bit!
Do the math- a 1" bit means at LEAST 48 passes in the "X" axis" , while a 2.5" bit means less than 20 passes...Time= $$$$$, and smaller bits leave MANY more "ridges" that need to be dealt with.
I'd like to see one of these bits in the starter set myself...it would probably mean more people would keep their tables in better condition...

[Rob Gunn]

Dan, A true "Fly Cutter" has only one cutting bit and is not balanced. I tried one on my router when I first got my ShopBot and it was a bad bad bad deal. I couldn't hit the stop bottom quick enough! What you want to use is any "shell cutter" that is balanced.

[myxpykalix]

I've used this bit for years in a 1.25" and 2" size with no issues in a router
http://www.magnate.net/index.cfm?event=showProductGroup&theID=136

[bob_reda]

I've used this bit for years in a 1.25" and 2" size with no issues in a router
http://www.magnate.net/index.cfm?event=showProductGroup&theID=136
Just got one of those that is 1.5. did the table at 6ips with no problem. Probably being a little conservative with the speed, could probably set it at 8ips taking off .03" at a time.

Bob

[gerryv]

Dan,
The danger is in how we tend to generalize the term "fly cutter." As Robb correctly points out a true fly cutter is not balanced and has only one cutting bit - typically being an outboard cutter. These are made for much lower speed metal milling machines. The picture Jack posted is the safe kind of surfacing tool. The ones shown below are NOT considered safe in a high speed router or spindle and some are just downright dangerous used that way because some fellows will hang the cutting bit way out like an outrigger. If it doesn't scare the s#%t out of you or fly apart it will likely damage your bearings.

[gene]

I use the same cutter that Jack posted a photo of to do my top . I cut .03 depth at 12ips. no problems. Happy,Happy,Happy.

[feinddj]

I just purchased a 2.5 inch spoil board cutter from Vortex. has a label on it not to exceed 12000 rpm. ran it at 10000 to surface off a slab of avocado, left a beautiful surface in next to no time. It has inserts so when it dulls I just move the inserts.
David