Well, I’ve read a lot of archives about modified planers and especially the modified Clark Hitachi Planer. However, I purchased the Hitachi P20SBK with the assumption that this was the same or similar to Clark’s version. I’ve modified (beveled) the shoes and adjusted the blades for a deeper cut. I am not concerned with the exhaust at this point (I can live without it). What I need to know is how to modify the depth adjustment. The way it is right now does not allow for on-the-fly adjustments. VERY stiff. There is a foam pad in between the shoe that may help loosen it up if removed, but I don’t think that will solve the lack of swing in the adjustment (1/4 turn is like 1/64 inch up to 1/32 at half crank). Anyone have any ideas on modifying the depth control to mimic a Clark. ps: I borrowed the pic off e-bay, but mine is just about identical. 
I have a stock planer and a Clark modified, and I think it’s worth the extra cash to buy one from Clark foam, it’s a world of difference and alot of input went into it.So it’s worth the extra $100 or so dollars unless you like to mess with those type things. http://www.soulsurfertv.com
Try putting in a lighter spring…not to light though or the adjustment will move on you. Also put some high grade grease on the threads after buffing them on a wire wheel. This will smooth things up. No way to modify “throw” without new parts or rethreading both pieces. I tried that with a Harbor Freight knock off and it was sketchy. I just use mine with the small increment. Keeps me out of trouble. Krokus