I picked up one of these knockoffs recently. The two holes drilled on either side of the tip are sharp enough inside to cut. I thionk the manufacturer klnows it because they come with a tiny bit of sand paper. I can't really reach the problem to fix it. So two questions: Anybody have suggestions for smoothing an inside edge thaty is hard to reach? Are the originals like this? Dasa
Deburring tool would work well I would think. I would imagine you don't have one though. Sand paper wrapped up in a small diameter drum. Then stick it through the hole from the outside, tip at an angle to make contact with the inside sharp edge. Then rotate about the axis through the length of the drum with your fingers to sand away the corner. Or move it in and out of the hole to accomplish the same thing while working around the holes circumference. And the real HT are rounded on the inside edges of the vent holes and end slot.
If you have a rotary tool (like a Dremel), you can use a cotter pin to hold a piece of sandpaper and smooth the inside (and outside) edge of each hole by sanding around at an angle. See the technique described in this article (it depicts how to smooth a bore which is a bit different than what you are doing, but the principle of how to use the rotary tool with a cotter pin as abrasive holder is the same).
You could grab a set of these which should help : https://www.amazon.com/Piece-Precision-Needle-File-Set/dp/B006N3EPKE/ref=asc_df_B006N3EPKE