Milling Hardwoods such as White Oak and Chestnut

[Bill Adamsen]

Can I use a 20° corrugated knife (5/16ths) shaper knife (4" diameter head, 1-1/4" spindle) to cut hardwoods like air-dried White oak? I have read 12° is preferred for hardwoods. My shaper has four speeds including 4000 and 6000 rpm, giving a tip speed range (depending on cutter tip diameter) somewhere between about 40 and 65 m/s. I'm looking at corrugated head/knife combinations and just trying to better understand versatility.

[Mel Fulks]

You can,Bill. I've worked in architectural millwork for a long time and I don't think I've ever seen a 12 degree head in any
shop. Always wanted to try one because I've read the same reccomendation you have read. I can say M2 or T1 steel gives
a better finish than the cheap "similar to M2" steel you get by default.

[Peter Quinn]

My head is 20 degrees, most places I've worked were too. I think its a more generic once angle fits all, if you want to run at max feed rates and do very large volume investing in a head with two angles or the particular on that maximizes the species you are in might make sense, but for generally shop use I've not found it necessary. I run most knives around 6000K in a 4" corrugated head with up to 1" projection, bit slower on big stuff. I'm guessing you can tweak the variables to maximize knife life but you wont see much change in surface quality until the runs get really long. Use the best steel you can afford for the job at hand.

[Mark Bolton]

Do you already own a 20 degree head? If not and your considering a purchase why not buy a dual hook head? I have 3 12/20 heads here in the shop but only occasionally use the 12 degree.