Drilling Nuts for Safety Wire

[donpearsall]

I have gone through many 1/16" and 3/32" drills trying to drill safety wire holes in M8 nuts. I have used HSS, Titanium, and cobalt drills and they either break or get dull part of the way through. I even bought a drill jig just for this, but that is no help. The drills barely touch the stainless steel nuts, and go dull part of the way though softer nuts. It seems that all the nuts I have have some hardness to them.

Anyone have tips? What about using the safety wire washers where they lock the nuts and bolts then have tabs that are safety wired? I have also looked for sources for pre-drilled nuts but can't find any.

Thanks
Don

[kiwi belly tank]

Self locking nuts or blue Locktite.
  Sid.

[Koncretekid]

Buy a 1/8" or 3/16" 2 fluted end mill, carbide if possible, and hold the nut in a vise with one flat horizontal. Use the end mill to mill a small partial flat (like a smile) where you want the drill bit to enter.  But before you drill, it is best to turn the nut over and mill a small flat on the opposite side where the drill bit will exit.  Now you have a flat for the drill bit to enter and a flat for the drill bit to exit.  Then use a small center drill to just make a point where you want the drill to start.  Then you drill the hole using the 1/16" bit . . .or two.  Easy-peasy - - only takes about 5 minutes to drill each nut!

The best alternative is to go onto one of the aircraft suppliers websites to find pre-drilled nuts, but small ones may be hard to find, and I don't know about metric nuts.

Tom

[revolutionary]

yeah, depending on the quantities, it may be easier and cheaper to check with Aircraft Spruce or Mcmaster Carr to just buy them.

[Vinsky]

McMaster Carr has slotted M8 nuts. https://www.mcmaster.com/#slotted-nuts/=14mtuw4

[WOODY@DDLLC]

http://www.landracing.com/forum/index.php/topic,14960.msg295820.html#msg295820

[wobblywalrus]

It takes a slow drill rotation rpm and a lot of pressure to cut the typical stainless steel.  You need to be aggressive.  Norseman drills are what I use.  They are mad in the USA.

[noboD]

Slow speed fast feed lots of black oil is the rule with SS. Use screw machine cobalt, no center drill needed.

[Sumner]

Probably wouldn't work for the nuts, but for flat SS stock I take the plasma cutter and blow a hole through first and then use the cheap HF nitrite coated bits and enlarge the hole 1/64" at a time up to the desired size.  Works well for me,

Sumner

[GH]

Sumner, it's good to hear that
you're still kicking....

[RGV]

Not sure of the quality of these but might be worth a try after you have put the flats on the nut.

https://www.ebay.com.au/itm/2mm-Cutting-Dia-1-8-Straight-Shank-PCB-CNC-Jewelry-Engraving-Drill-Bits-4-Pcs/301977502422?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D52946%26meid%3D3b987c5ef21744ee943cf7ecd8c09c11%26pid%3D100010%26rk%3D10%26rkt%3D12%26sd%3D253253359540%26itm%3D301977502422&_trksid=p2047675.c100010.m2109

Dave

[RansomT]

It takes a slow drill rotation rpm and a lot of pressure to cut the typical stainless steel.  You need to be aggressive.  Norseman drills are what I use.  They are mad in the USA.

Sorry I'm late to the party!  Been a little "out of it" for awhile.

The only thing I would add to this is to use elmers wood glue as lube, don't have to be as agressive.  (top secret trick)

[tauruck]

Self locking nuts or blue Locktite.
  Sid.

Yup, Blue Locktite.