best drill material for drilling hardened high strength steel??
best drill material for drilling hardened high strength steel??
(OP)
We are using a manual drilling process for reworking items.The material being drilled is a hardened high strength steel. The bit sizes are 4.1mm and 6.7mm and made of carbide. We are using an air drill with no lubrication.
Currently we can drill only 1 or at the most 2 holes before the bit is dull. Any suggestions on drill materials and or coatings??
Currently we can drill only 1 or at the most 2 holes before the bit is dull. Any suggestions on drill materials and or coatings??





RE: best drill material for drilling hardened high strength steel??
My first step would be to introduce a drill press into the process.
Second I would get with one of the larger carbide drill manufacturers and present your problems, like materials, hardness, etc.
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
Don
Kansas City
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
Tungsten carbide is actually tungsten carbide grains cemented in a binder. The binder is usually cobalt.
Use the finest grain, highest cobalt % drill you can find. If you can find drills with a little Vanadium and chrome in the binder as well that could help.
Otherwise I’d find a really good tool shop and get the drills reground regularly.
You might also check the drill design.
Tom
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
RE: best drill material for drilling hardened high strength steel??
How did you make the holes during the first pass?
Can you give some hardness numbers?
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
Here is a suggestion, use a small hole saw / trepan tool slightly larger than the rivet. Cut the whole rivet out and replace the pop rivet with another fastener.
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
http://www.bamanufacturing.com/sp_series.html
RE: best drill material for drilling hardened high strength steel??
A critical component is the edge prep of the drills you are using. In hardened materials you can apply a Conicity EMG edge prep and actually push the drill harder than before. Although a hand held air drill is not the ideal operating condition you can still do better in the tool life department. You must make sure that your feedrate exceeds the size of the edge prep, otherwise it will rub and basically work harden your material and dull the drill.
RE: best drill material for drilling hardened high strength steel??
Search for "black drill" on this page:
http://www.astralloy.com/print/rolman.asp
Mike Halloran
Pembroke Pines, FL, USA
RE: best drill material for drilling hardened high strength steel??
Have you considered driving the old rivet out?
I would first punch it with a cheap center punch and then a pin punch. Cheap center punch because the point will likely not be hard enough to damage the base metal but would get the rivet body moving. It should also form a bit of a cup to guide the pin punch. Similar set up used for splitting roller chain and chain saw chain. Cheap enough to try.
Griffy
RE: best drill material for drilling hardened high strength steel??
RE: best drill material for drilling hardened high strength steel??
We can help,
Steve Roberts