I’ve tried brand new drill bits and cobalt bits and I’m having no luck whatsoever… it does absolutely nothing. 😢😢😫😫😫 wtf so annoying.

 

I know nothing about this operation, why it is being done, but it sounds to me like you are drilling into some very hard material.

In general....
a... When drilling hard material, you MUST drill at a very low rpm. High speed burns up drill bits, so go very slow speed. The bigger diameter the drill, the slower you go. ( same goes for your sawzall blades, run the sawzall on low speed when cutting steel, high speed for wood, this will give a very long blade life, go to fast with steel, and your blade turns blue from heat and the teeth wear or break off.
b...Use coolant, water is good, or a cutting oil is better usually, but you got to keep the liquid flowing while drilling. motor oil is not cutting oil.
c... Drill a small diameter pilot hole first.
d. some times the surface is hard, but the interior is soft, so if you can, grinding away the top layer may expose softer material for drilling.
e. heating the material to really hot, then slow cooling can soften the steel, making it easier to cut
f. use of a carbide drill $$$$ is often required when the material is hard, cobalt drills are not the same as carbide., cobalt is not as hard as carbide
g. Drill tip geometry must be correct, if the tip is not sharpened correctly it wont cut it. A bud of mine bought a set of red chinese harbor freight drills. I was helping him on the project, using the drills, and they didnt cut even soft steel. I took a look at the tips, being a former machinist I saw right away that the tips were ground incorrectly, every drill in the new set had a negative rake on the tip, meaning the cutting edge was not contacting the work piece, those drills just spun around, getting hotter and hotter from friction until they actually softened (see e. above)

So slow way down in rpm, try a good drill with correct tip geometry (plenty of info on the interweb on what a good drill tip shall look like), use cutting oil. if you need carbide, and you are not trying to get a perfect hole, a cheaper carbide concrete drill bit can be used rather than a solid carbide drill. since only the cutting edge is carbide, these are much cheaper than solid carbide You need a special grinding wheel to regrind the carbide tips, as standard wheels wont cut them.

good luck!

ps what are you doing this for?

 

He is doing the hack-n-tap rear driveshaft setup. You chop some of the rear output shaft off, then drill a hole in the center, then use a tap to cut threads in it, then bolt on an output flange. It eliminates the slip yoke without doing the SYE conversion.

As said above, slow and steady with cutting oil. And use the drill bit guide you can buy to make this job easier. Have a helper be the lube guy so you dont have to stop constantly. It is hard to drill things and keep them lubed right when it's a sideways operation.

 

it’s for a 1993 xj Cherokee 231 transfer case.

 

Sounds like youl have a real sye in junk drill bits before to long

 

I did mine last year. It was not difficult, although it was intimidating when you cut off that tail section.

I cut it off with my angle grinder with a cutoff wheel. I started the engine, put it in 1st gear, and let the tail shaft spin and I proceeded to attack it with the grinder. Doing it via this method generates a very nice, clean, square cut. It looks like a machine did it. Actually, it is kinda hard to screw up when doing it this way. Just keep the wheel cutting at a 90 degree angle to the tail shaft.

For those who may have trouble drilling it, it is my belief that shafts such as this are case-hardened, and it is my belief that "case hardened" means that the outermost "layer" of metal is really hard, but once you are beyond that, it was not difficult drilling but it was not the softest steel ever. I used the drill guide from Iron Rock Offroad. It isn't necessary to have, but just increases the ease and confidence factor of getting a hole drilled in there right. This hole does not need to be machine perfect, but you must try to get it perfect and not be lazy about it. So, when cutting off the tail section, it exposes softer metal.

The scary part was tapping the threads. It took much more force to do it than I was comfortable exerting, but that could very well be because my tap was dull. We all know what happens when taps break off in stuff. If you do not know, you don't want to find out.

As another poster commented, some people just go *****-out with their drill bits and that's a good way to kill a drill bit. Keeping the speed down can go a long ways towards extending the life of a drill bit. Lubrication to keep it cool helps a lot as well.

I also RTV sealed the splines to prevent them from rusting together. Once splines rust together.... yeah. Not fun. You people in the desert have it made.