I have a few questions on preheat treat

[zaco519]

I am making a 6 inch blade knife. 1/8 inch thick stock. O1. scandi grind.
1) how thin should i leave the edge. I ground it all the way so I should take materiel off the edge to make it more blunt, right?
2) I cut a rectangle out of the center of the handle. Do I need to sand the rectangle sides to 120 grit to prevent cracking when HTing.
3) Any suggested guides for hand sanding the blade horizontally. How do I know when to switch grit.
4)what grit should i sand the scandi edge to.

I read the thumb nailed guide for beginners but I want more details on this type of stuff. There is not to much info that I found on sanding before HTing so this is why I am asking.
please post links.

thank you

 

[Stacy E. Apelt - Bladesmith]

Curves are better than 90° angles when they can be avoided.

The edge can be anywhere between .01" and .03" , depending on the steel type, and the HT method. For O-1 and a non-oven HT, I would say .020" will be OK.

400 grit pre-HT

I don't see any need to sand horizontally before HT if you go to 400 grit.
If you are referring to switching directions between grits, you change grits when you can't see the previous grits marks any more.