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Deep hole drilling in Titanium

Gos

Aluminum
Joined
Oct 14, 2008
Location
Western Washington
Greetings,
I'm looking at a job that requires some deep hole drilling in grade 5 titanium. I've never done that, and have always been just fine with that. Any suggestions for a specific drill design that can pull this off without that wonderful "SNAP" sound? I'm drilling clearance holes to be reamed out to a finish ream of 6.5mm for temperature probes in a block. Shallow holes are around 1/2" deep, deep holes 8"!
Of course we don't have anything like EDM so if I bid on this, it's a manual milling and lathe show.
Thanks in advance.
 

Terry Keeley

Stainless
Joined
Oct 18, 2005
Location
Toronto, Canada eh!
I did some 1/16" holes 4" deep a while back (65D) and they came out straight to less than 0.010".
Started with a carbide stub drill, then jobber length and finally 6" aircraft length, these worked great:
Lots of pecking and coolant to clear the chips are your friends, I indicated all drills in to 0.001" or less.
I didn't have any luck with reaming and went with a carbide drill that cut right on size.
 

implmex

Titanium
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Hi Gos:
I'm with Terry Keeley on this technique.
The only thing I'd change is to substitute RapidTap versus coolant. (personal preference)
The only thing I'd add is to keep the speed slow and drill in small pecks.
Pecks like 0.025" and clear the chips after every peck.
I agree with Terry that reaming is an iffy thing.

A tactic I use is to bore a guide hole at the start of my deep holes so the drill effectively has a guide bushing.
I try for no more than 0.0005" of clearance with the drill I intend to use.
This is not a drilled hole, it's a single point bored hole so it's straight, round, and to diameter.
I try to go in around 3 diameters or more.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 

trevj

Titanium
Joined
May 17, 2005
Location
Interior British Columbia
All my experience drilling or turning Ti., has been that you start with a sharp tool, and keep the cutting pressure on it, and if you hear a squeak louder than a mouse fart, you pull the tool and make it sharp again, because cutting through the combined mess of Ti. fused to molten tool steel of any kind, is a mugs game! Ie: it sucks, and wastes a lot of otherwise productive time re-sharpening, or changing out, tooling.
 

boslab

Titanium
Joined
Jan 6, 2007
Location
wales.uk
We had 12” deep holes (400!) in a beryllium copper mould for thermocouples ( continuous caster moult thermal monitoring system) we got skf in as sanvick weren’t bothered, they came up with a drill that was stepped and fast helix, it worked a treat ( the tip looked like the dewalt reduced tip drills) they could guarantee depth but there was a bit of wander, tolerable
It was peck peck peck withdraw pressure flush with a probe tube, slow job but you didn’t want to break a drill in a 29 ton casting costing well over 1million pounds
Mark
 








 
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