Tool Talk
Machinist Forum => Machinist => Topic started by: Mike H on March 11, 2021, 10:26:16 AM
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I have been working on an ASO (Anvil Shaped Object)
Angle Iron with a 3/4" steel plate welded to it
Know that the face should probably be thicker;
but the 3/4" is what I could get a-hold of.
Tried the other day to drill some holes for the corners
of a Hardy Hole layout. The bits I have (Fractional Twist Drill BigBox Store)
were not even making it. Does this suggest the steel used for face is hardened?
Was able to use same bit/s to drill holes in the bottom of the angle iron
for mounting ASO to a base with relatively no problem.
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Sounds like it. Or at least high-carbon steel. You can get drill bits designed to drill tough materials - even my local hardware store has them.
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Choosing and using the optimum drill speed and feed rate with cutting fluid is the way to go.
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Choosing and using the optimum drill speed and feed rate with cutting fluid is the way to go.
I agree. It's also much easier if you drill through first with a smaller bit, and then follow up with the size you want the hole to be. 3/16-inch is a good starter hole diameter. (5mm)
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In most home shop situations, (and a great many professional shops), a good grade of HSS drill bit 3/4 dia would do well at only 250 RPMs. You need a stable feed, cutting/coolant, and patience. As noted above, especially in a non-professional situation, taking three steps up to 3/4 could make life easier, say 5/16, 1/2, then 3/4.
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Sounds like good advice from all. Thanks
Have been informed on follow-up that the
plate is hardened steel.