07-02-2019, 04:22 AM
Seeing no-one else seems to be doing anything...
I look like getting a bowhunting trip in soon so I thought i'd better finish the broadheads I made a start on last year. Not sure if I had posted a photo of the ferrules, this was taken last September after the lathe work and the slotting on the mill
I made a prototype blade, figured out a way to make the process repeatable by marking out a set of holes with the DRO and using these with pins to set up on the top edge of the mill vise. The prototype I finished yesterday,
test shooting showed better than acceptable results so I went ahead and made a batch of 5 today.
The DRO is a fantastic addition to the mill, I plotted out all the 3mm holes before cutting the blanks out of a length of RWL34 knife steel. They lined up perfectly to accept the 3mm drill rod pins.
the pins hold the stack in alignment and each edge is milled down to .200 above the corresponding pair of pins
pins swapped from hole to hole and all the edges and the rear slot milled
then off to the surface grinder to take them all down to thickness before marrying them to the ferrules.
The prototype got a double-bevelled edge but I've decided to single-bevel the rest. Did the first one left-handed by mistake.
The weight I was aiming for was 125 grain, I might have to sharpen this one a couple more times. Closer to nominal weight than any commercial broadhead I've ever bought though.
Still got to grind the bevels on two of them. I'll have to make a jig for the SG to get the bevels done more efficiently. More fun than buying them though.
I look like getting a bowhunting trip in soon so I thought i'd better finish the broadheads I made a start on last year. Not sure if I had posted a photo of the ferrules, this was taken last September after the lathe work and the slotting on the mill
I made a prototype blade, figured out a way to make the process repeatable by marking out a set of holes with the DRO and using these with pins to set up on the top edge of the mill vise. The prototype I finished yesterday,
test shooting showed better than acceptable results so I went ahead and made a batch of 5 today.
The DRO is a fantastic addition to the mill, I plotted out all the 3mm holes before cutting the blanks out of a length of RWL34 knife steel. They lined up perfectly to accept the 3mm drill rod pins.
the pins hold the stack in alignment and each edge is milled down to .200 above the corresponding pair of pins
pins swapped from hole to hole and all the edges and the rear slot milled
then off to the surface grinder to take them all down to thickness before marrying them to the ferrules.
The prototype got a double-bevelled edge but I've decided to single-bevel the rest. Did the first one left-handed by mistake.
The weight I was aiming for was 125 grain, I might have to sharpen this one a couple more times. Closer to nominal weight than any commercial broadhead I've ever bought though.
Still got to grind the bevels on two of them. I'll have to make a jig for the SG to get the bevels done more efficiently. More fun than buying them though.
Lathe (n); a machine tool used in the production of milling machine components.
Milling Machine (n); a machine tool used in the production of lathe components.
Milling Machine (n); a machine tool used in the production of lathe components.