I used a borrowed Woodmizer blade sharpener. There is nothing special about blade sharpeners. I bought an older model Woodmizer type, that did not have the feed advance mechanism. Very soon, I will be making that part, so I will have an automatic sharpener. You can find Videos on Youtube.
The nice thing about the Woodmizer is, it's sturdy and stable. Ones like the Dyno charger and others, need to be clamped down or they shake as the thing runs. I would do some searches on Ebay or other forum classifieds. Many people are going to the newer type wheel sharpeners, and are selling the older models. Can't think of the types that use the new wheel shape? getting old
There is a way to build one from scratch, if you are the tinkering type. Use a radiator fan motor and a windshield wiper motor. Then, make the wheel motor mount, so it can be angled to give from 4° to 12° for whatever you want to set the tooth angle to. Then, make a cam, so that wheel motor goes up and down. Use Heim Joints for all swiveling connections. Then, set the windshield wiper motor, so it shoves a blade against the tooth gullet, and make that blade adjustable, so, as the wheel drops down, it wipes the leading edge of the tooth, then, as it reaches near bottom stroke, the wiper motor starts shoving the blade away from the wheel, as the wheel starts back up, barely wiping the tooth, and finally, clears the tooth. Then, here comes the next tooth, to repeat the process. Make everything speed adjustable. Include water cooling, so you don't burn tooth tips.
I did a post on how to set up the cam, on an earlier thread, started by Sawmill Squaw. She bought a Cooks Cat Claw, and I explained how to shape the cam and her husband was very impressed at her sharpening skills. She turned out sharper blades than manufacturers.
My Son and I did the sinker logs in Florida. We made an oversized Woodmizer and cut many table slabs that were 36" wide with natural edges. Made some nice money with them, so, keep wide table slabs in mind as you saw larger logs.