Go to Oregon's web site and drop in your mowers model numbers.
That should bring up whatever blades Oregon makes for your mower along with the complete dimensions including the hole diameter ,
OR
Drop your model number into Exmarks web page then note the blade numbers
Being a commercial mower there will be a few on them.
Drop those numbers into Stens, Rotary or Prime Line web page for their aftermarket alternatives.
All of them give the full dimensions of the blade
For some reason Oregon has taken the good cross refference to OEM part numbers off their public site .
