Anyone tried a spiral cutter in an overhead pin router?

Hi guys,

I'm thinking of putting together some kind of framework to use my router as an overhead pin router but has anyone used a spiral cutter in anything like this? Any warnings against doing this? And would I need a down or up cut bit?

Cheers,
Phil

I use 1/8th two flute spirals in my OH pin router all the time for profile cutting. Not sure if I'd use a large one though!

I have a big Wadkin LS and no probs whatsoever up to 5/8 diameter and provided you go up to 1/2 inch and your router has a bit of power and well secured then you should be ok. Great bit about spirals is they are touching the work all the time so the cut is consistant and smooth whereas a 1 / 2 or even 4 flute cutter is out of contact for 2 or 4 parts of it's revolution. Downcut is fine if feeding in from an edge but can burn on a plunge. Upcut is good on a plunge but tends to leave top edge a bit furry. There are upcut/downcut spirals which leave both sides clean and a few companies such as Trend and Titman do a 1/4 Spiral with a bottom bearing fitted for pattern work. Spirals can be resharpend but you do lose diameter against the pin so always worth speacifying the required regrind size such as 1/2inch (12.7mm) down to 12mm then by using a 12mm pin your back on track.

I try to only use spiral down cut bits in my pin router. I have 1/8"-1/2" bits and they have really nice quality cut.