Joseph Gwinn wrote:

performing cutoffs, and using
a 0.5x0.5" HSS tool (versus 0.25x0.25), everything was peachy until I
tried to take a cut 4" from the chuck in a mild steel bar 1-3/8" in
diameter.

What!? You are making cutoffs with 12 x 12 mm bits!?
You don't have to wonder if there is chatter, noise and vibration. 4mm wide
for a 50mm deep cut is OK, but the bit has do be *considerably* higher.
My HSS-blade is 2,7 mm wide and 11mm high. Good for 40mm (diam.) cutoffs.
The carbide inserts blade is 32mm high and the width is 3mm. That is OK for
100mm diameter cutoffs.
Get real tools.

Considering the leaded (supposedly) steel with a weld. Can't be, can't weld
leaded steel. It makes bubbles while welding.


Nick
--
The lowcost-DRO:
http://www.yadro.de