You may be surprised at how small a circular saw you can use for tenon cheek cuts. Even if it's just over half the depth of the timber, it will be effective. Make four cuts (each side of the tenon, top and bottom). You'll leave a "widow's peak" of uncut wood. If the grain is straight, a light tap with a mallet will usually knock of the waste. Clean it up with a slick. Or use a hand saw to cut the widow's peak. Jim's advice about thin tenons is spot on. CB.
