Does saw chain need Hook? 

I'm not really sure. I went through heaps of carlton 404 semi over the years and it's extremely easy to make that 85-90 side plate on it due to the height and shape of the tooth. The file just sits in there at the right height. I have heard it's been discontinued as well and it's a shame. I loved the 404 semi and the 3/8 full chisel has a fantastic side plate profile for square filing. It has the thinnest top plate of all the chains I have used. We can still get some of the old stuff here but from what I can tell no more is being imported and possibly not manufactured. I miss the old Windsor chains and still have a bunch of the speed tip bars. The 1 in this video is a D009, 404, 063 speed tip.

@@SawChainTheories Now I think that someone preparing the document simply made a mistake and replaced 8 with 6. Of course, this value of 60-65 is duplicated many times in the document. On the other hand, at the moment Stihl tells you to get a side plate angle of 60° for RS in the USG chart. That is, according to Stihl, 60° is sufficient (and required)... At least they are consistent with this lack of recommendation to use the down angle.

@@elpolaco7654 In the latest carlton catalogue that I can find there is 325 chain that they recommend 60 side plate on. It looks identical to Oregon 20/21/22 LPX. I made an attempt to copy the Stihl RS grind the other day. On the Chinese Oregon grinder I have I had to come in at 50/30/10 and profile the wheel to match. The flat part of the wheel had to come down to about the bottom of the top plate to match the shape they put on there from the factory.

@@SawChainTheories Wait a minute. Are we talking about the same angle now? In the current catalog (2020) on their website, the .325 K1/2/3L(X) chains (others too) have a side plate angle of 85-90° listed. With that said, they don't recommend to use a down angle with them. Of course, the head tilt angle or the cutting angle has not changed for Carlton and remains 60°, unlike Oregon, where it is 55° generally. 50/30/10 and lowering the wheel this way sounds very reasonable. 50° agrees with Stihl's recommendation for the USG.

@@elpolaco7654 You are correct, just looked at it and I thought they had changed the recommendation for the LX. Looking at the pictures of it in the catalogue, there's no way that it has a 85-90 degree side plate like they are recommending.