Drill Bits breaking

[radar8756]

I have a Zastava M92PV 7.62 x 39 that I would like to mount a pictany rail on the top (hinged) cover

I have broken 4 drill bits so far - google suggests it may be some type of Tool Steel -

So the question is What Brand of Drill Bit will work - or is there another option

 

[red_zr24x4]

Try a small pilot hole and step up slowly to the correct size

 

[NyleRN]

I bought some Cobalt 3mm bits last week to drill on my AK for the gas block and front sight pins. Bit snapped in half as soon as the bit took one rotation into the barrel. Obviously they're not hardened like they should be

 

[Brandon]

I like my set of Drill Hog bits.
I have managed to break one but I was not using any oil to help keep it cooled or lubed.

Lifetime warranty on them though.

 

[snapping turtle]

Machinist drill bit normally made in Germany and carbide tipped. Wood bits are not going to work. Harbor freight here is not Your friend.

 

[Gingerbeardman]

I broke 4 mounting a scope mount. You'll get it, but whatever they used is tough stuff!

 

[ditcherman]

I too would love to get some recommendations on good bits.
Broke a couple tapping my slide for a dot, found one in a box of parts from machinist auction and it cut through it like butter.

 

[Jaybird1980]

I too would love to get some recommendations on good bits.
Broke a couple tapping my slide for a dot, found one in a box of parts from machinist auction and it cut through it like butter.

Check out Norseman and KnKut.

 

[Lpherr]

Have you tried a center drill?
Look for Cobalt bits. They are good for hardened steel. Use a good drill lube too.

 

[UNCLE HARLEY]

McMaster Carr

 

[ed1838]

I have got spoiled with some bits called dream drills. I can go thru heat treated d-2 with them. they are solid carbide spec ground for hard steel and go thru stainless like its Cold rolled steel.

 

[55fairlane]

If I may offer a spot of help. Now where to start.....

Regardless of what your drilling proper speeds & feeds must be used. Or you will destroy an expensive drill just as fast as a cheap drill. Speeds & feeds charts found via Google.

A harbor freight drill is junk. A hardware store brand is a gamble. 99% of my drills are 35%cobalt & TiN coated, screw machine leanth, I prefer Hertel brand (McMaster Carr) not cheap but well worth the money.

You must center drill & have the work must be ridged (clamp well in vise or fixture).

You must use coolant or lubrication depending on the material you are drilling.

Do I need hold an online class on taping next?

Aaron

Ps...machinist peeve...there is no such thing as a drill bit, you don't want a bit of the drill do you? There are gun drills, jobber leanth, screw machine leanth, aircraft leanth, tre-pan, Carbide tipped, Indexable Carbide tipped, ECT. but no such thing as a drill bit!

 

[KittySlayer]

Ps...machinist peeve...there is no such thing as a drill bit.

What do you mean no such thing?

 

[bwframe]

...

Do I need hold an online class on taping next?

Aaron
...

Your contributions are always followed closely sir. Thank you for them!


.

 

[radar8756]

Priced McMaster-Carr Short-Length Cobalt Steel Titanium Nitride Coated -- 1/8" & #29 ~ $5 each plus 8-32 tap for hardened Steel $14 ... ( maybe get 2 of each bit - just in case )

--- Shipping $10 seems excessive --- any places in NWI that sell the McMaster-Carr brand ?

 

[blain]

What do you mean no such thing?

View attachment 256720

Maybe he's talking about twist drills.

 

[2tonic]

Once you get your drills, get yourself some Tap Magic (cutting fluid). A drop or two will do ya.

 

[55fairlane]

Once you get your drills, get yourself some Tap Magic (cutting fluid). A drop or two will do ya.

Tap magic is a good cutting fluid for most things and it is safe on aluminum as it does not contain 1,1,1, trichloroethane

 

[DoggyDaddy]

Ps...machinist peeve...there is no such thing as a drill bit, you don't want a bit of the drill do you? There are gun drills, jobber leanth, screw machine leanth, aircraft leanth, tre-pan, Carbide tipped, Indexable Carbide tipped, ECT. but no such thing as a drill bit!

Spelling nazi peeve... there is no such thing as "leanth".

leanth​

Not English​

Leanth has no English definition. It may be misspelled.

Leanth vs Volume - What's the difference?

As a noun volume is a unit of three-dimensional measure of space that comprises a length, a width and a height it is measured in units of cubic centimeters in metric, cubic inches or cubic feet in english measurement....

wikidiff.com

 

[55fairlane]

I became a tool make, because "can you spell" was not in the mechanically inclined test.
And after 32 plus years, I have quite caring if I can spell.....lol.....