Here's another source for long tools: https://www.endmilldiscount.com/end-...s-175-185.asp#

Don't remember where, but I bought some 8 or 10" length tools several years ago. Amazingly cheap for the size. Something-something Mold Supply?. Relieved the shanks myself on a bench grinder. Ugly, slow, and hot, but aluminum oxide wheels will cut it. Later found another place that sold reduced shank tools for the same price or less. Don't have any links to either :-(

I'd also section that if at all possible. But not by 3d profiling thin pieces and stacking them for a finished part. Stack square cut pieces with an offset, and then knock the corners off. Wood props were laminated anyway.

I came up with a work around for multiple roughing passes in v-carve. The molds I was doing would have been cutting air for a week before getting to any material using a roughing cycle, which assumes a solid block.

I made a series of finish passes starting with 'larger diameter' cutters and used tool length offset to raise the height above bottom. And set the control (mach 3) to ignore tool change. We didn't have a toolchanger anyway.

As an example using a 1/2" ball endmill.

T1: Dia 1.5, TL +.5
T2: Dia 1.0, TL, +.25
T3: Dia .625, TL +.063
T4: Dia .5, TL 0

I set it up working backwards. Set the tool length (depth) for T4. In MDI, G91 (incremental), G00 Z.063. Set TL T3. G00 Z.187, TL 2, etc. It's not correct in terms of tool comp, as you're not getting the actual radius comp anywhere but at the tip and side. But it's good enough for roughing and semi finishing. The last pass fixes it all.