I'm assuming your 3/16 holes are multiple entry holes for the wire feeds. In copper I've had success with TiAlN coated solid carbide drills with peck depth @ 55% of dia and SFM around 150 (no more). You'll be fine with the 1/4 aluminum, as long as you sandwich it from the top as well, if you don't sandwich, forget the whole thing. Guhring also sells some beauties called GT100 (high helix) drills that love terrible situations.
-ernie ----- Original Message ----- From: Larry Jacobs <[EMAIL PROTECTED]> Sent: Monday, December 03, 2001 2:39:47 PM To: SMARTCAM <[EMAIL PROTECTED]> Subject: [mfg-smartcam] Drilling stacked plates > I have an application involving stacked brass plates (10" x 16" -- .030 thick -- stacked 30 to 50) for our EDM. > > 1" extra stock is allowed for clamping purposes around the perimeter and 1/4 alumimun plate is used underneath for rigid support. Drill size is 3/16". > > Any suggestions as to maximum thickness of plates, special drill points (Bickford, double angle),or > procedure (pecking as opposed to straight through) to keep holes straight (within +/-.005) and minimize chips and burrs? > > Thanks, > Larry J ====================================================================== To find out more about this mailing list including how to unsubscribe, send the message "info mfg-smartcam" to [EMAIL PROTECTED] ======================================================================
