2" long+ router bit for HDU

Good afternoon all, (and to the half of you digging out of snow right now, my condolences...)

Does anyone have a recommendation for a 1/4" cutting tool to contour cut HDU foam that is 2" thick or more?

We have a bit from Onsrud (2 flt low helix for foam, per their catalog) that simply does not leave a clean edge when contour cutting foam....it looks as if the bit itself is vibrating slightly as it cuts (even for final passes when shaving off minuscule amounts of material)

We've verified that this happens with duplicate bits, in different collets. We have a 1.5" 0-flt spiral that works perfectly, but it only is 1.5".
Anything longer requires a 3/8" or 1/2" dia. tool.

- Keith Watkins
Sign Solutions


Very Active Member
I have a 3" CEL from hartlauer bits. It was crazy spendy but works great and I only use it for foam work.



I used a local company for my bits good price and they hold up better then gerber bits