You can get them in carbide for the 155mm planers and jointers
by Makita, but a Google search for 170mm makes it look like
perhaps they aren't made. If the part is made, it has a Makita
part number. Knowing that number will get you closer.

 

Yeah, I have the Makita part number for the HSS knives:

7931864 or 793186-4

They just come in high-speed steel (HSS). I was hoping someone would know how to source some carbide-tipped ones.

Maybe I can have a machine shop make a cutterhead for a helix-type knife set. Sounds like I have some fabrication work ahead of me… maybe this will be reason enough to buy a small CNC mill. HA!

 

You might sell the 1806 and get an 1805.

I've had both an 1805 and and Ryobi which is very similar
and takes the same blades. Hitachi probably made a 155mm
format planer. I suspect Makita introduced the 170mm
planer because their patents on the 155mm format planers
expired and the Chinese started making them willy nilly.

 

It's a nice thought, but I like the 1806. I'd much rather spend my money on more HSS knives than buying an 1805 to replace my 1806.

I know Byrd makes shelix head for a 6" Makita jointer. I wonder what they'd charge to extend that or cut down an 8" to fit the 1806.

 

The carbide blades for Makita format jointers and hand
planers are machined from solid tungsten carbide. A
local saw shop may be able to to it for you as it's not
that different from making a moulder knife. Expect
sticker shock.

 

The Makita 1806B certainly is a beast!