Timber Framers Guild Forums Tools Timber Engineering Diminished haunch mortise/ tenon mystery

Hello all. I am currently working on my first frame project a white pine 38x36 western. Two sections complete and on the deck which will be raised shortly. I have been cutting a 1" shoulder on the 8x8 posts with a diminished haunch. The tie beams are 8x10s. I have been cutting the mortise pockets a 1/4" deeper on all mortises. Well it seems that the bottom of the tie beam tenon does have the 1/4" clearance while seven inchs up the tenon it fits with an 1/8 or 1/16 clearance. The tenon is square. It seems the top of the mortise pocket should be taken down a little deeper than the bottom. Is this possible or have I lost it. Thanks for any input. BB

That should not be happening. The only thing that I can think if your tenon is square is that your mortise was not cut to the same depth. Does you shoulder fit with the housing? How are you measuring the clearance?

I agree Mo. The shoulder fits great. The tenon just measures with less clearance on top than the bottom when measuring the mortise pockets top and bottom. I thought maybe with the diminished shoulder cut this could happen for some reason? BB