I have been searching for a large rouer bit to use on eps the same as what they use on the cnc machines however the only one i have found one is on Shapers Australia website and is very expensif and allso out of stock so looking for alternatives.
Charlie, I wonder if an end-mill style ball nose would get you started for less money. Will you be cutting from both sides? Could you reduce the length of cut?
I have a 1/2" x 8" monster bit from Frogtools http://www.3dcutting.com/solutions/frogtools.html Cost a bit. Does a nice job and allows a very deep cut on the rails. Used it for cutting boards out of blocks of foam. Too much waste that way, so built a hold-down for hot wired blanks.
I have a 5/16 dia. Typhoon Ball Nose Burr that I got from a wood shop (Carba-tec) that looks like a mini version of the big burrs sold by Shapers. You can get Typhoon bits many places. Cost ~$40 and does a great job, but it’s only 2" long so can’t go too deep (your blank can’t be too thick). Still my go-to bit but I sometimes have to hack off excess blank manually around the tail during a cut. Love to find the same bit in a bigger size.
Someone on Sways a while back tried to gather interest in a bulk buy of custom burrs, but I don’t think he got enough takers.
I hear that you can resharpen regular drill bits into a ball end and use it for foam, but I’m waiting for someone to show me how (and worried about spinning a bit rated at a few hundred rpm at a ten thousand rpm!).
I’ve cut 1" deep in EPS @9000-11000rpm with no problems. Keep the bit moving pretty quick to prevent burning (stringers are another beast, LOL). I forget the inches per minute. Somewhere around 60, i.e. tail to nose in under a minute.
Cheers many thanks for all the leads every one i will look into the frogtools a little more they look to have some monsters! The Burrs look very similar to the sayburr tooth bits i linked to so may be worth giving one a shot any way it will just mean cutting multiple passes or something.
are you using the flat end and not the bull nose? the frong tools are prity pricey so will have to deside if its worth it, i may start with a cheap one and see how it goes.
Always bull nose. Fits curves better. But if you want keyhole cuts and insets then square end is better.
Start with a cheap bit. I tweaked a few bits crashing into things, etc. The Saburr and Typhoon are good options.
Of yes, I also have a bit called a “wood miner” for use with a grinder up to about 10000rpm. It’s a cylinder shape burr type bit about 3/4" dia. 4" long. I put a cut-off bolt in the back so I could router mount it. You can get wood miners from woodcraft stores ~$30.