Just replaced mine yesterday. Started out just going to sharpen but when I saw how bad they were I went to plan B. Had a spare set I bought from Messicks a few years ago. Big difference. Doable with one person and a good sized impact. Soaked them with penetrating fluid for 20 min before attempting. Took a few minutes to break free and get the keyed bolt to back out from below. All in all once I had the correct sized socket, it took maybe 35 minutes. Very little vibration now and cuts great. Be prepared that sockets this size are 3/4 drive. Would love a larger impact gun but for the amount I would use it, doesn’t make sense to spend the cash. Did a 1/2 to 3/4 adapter which worked. Rural king had what I needed to get it done. I should have done a side by side comparison but one of the old blades was worn over a 1/4 inch more than the other and both were down about a half inch from new