Problem making a cove molding on the TS

[Derek Larson]

This was my first attempt to create any type of cove cut using the TS. So what i did was cut the molding to width approx. 3" then i made four the 45 degree cuts. After i set up my parallelogram thingy and my fence. Everything was working fine except i noticed the first pass over the blade the cove was not in the center, i thought that if I I kept going it would eventually even out. However, after about my 4 pass I realized that it just kept taking more out one sided eventually eliminating one of the 45 degree angles. Now each time I ran the piece over the blade I made sure that only side was kept against the fence, was that my problem should I have been alternating sides to be against the fence, or for each pass should run it a second time with the other side against the fence. Guess I am just a little bit confused as to what I did wrong any suggestions would be appreciated.
Thank you

[Eric Haycraft]

This was my first attempt to create any type of cove cut using the TS. So what i did was cut the molding to width approx. 3" then i made four the 45 degree cuts. After i set up my parallelogram thingy and my fence. Everything was working fine except i noticed the first pass over the blade the cove was not in the center, i thought that if I I kept going it would eventually even out. However, after about my 4 pass I realized that it just kept taking more out one sided eventually eliminating one of the 45 degree angles. Now each time I ran the piece over the blade I made sure that only side was kept against the fence, was that my problem should I have been alternating sides to be against the fence, or for each pass should run it a second time with the other side against the fence. Guess I am just a little bit confused as to what I did wrong any suggestions would be appreciated.
Thank you

My suggestion would be to use wider than required stock and rip it to width after the cove is made. That way if you are a little off in one direction you can correct it. Another option would be to rotate the piece every pass. That will make in imperfect arc, but will be perfectly centered. Finally note that on most saws, the center of the blade changes as the height changes, so when adjusting your parallel guides, make sure the blade is at the final height.