[2_many_hobbies]

I have a Taig Micro Lathe and am attempting to make a few small nozzles for one of my projects out of 6mm 304 stainless threaded rod.

I need to put a 5/64 bit 1-3/4" deep concentrically but I have not even managed to create a single bloody chip! I have tried many speeds and feeds with both HSS and Titanium 135deg drill bits but not a single one will bite. I also tried a #3 center drill and that went in a tiny bit but then much have work hardened the rod.

I live in canada and only have the box stores nearby, I can order bits online but will need a place with reasonable shipping.

Does anybody know how the heck I can accomplish this? I need to make 10 of these things...

[wizard]

I have a Taig Micro Lathe and am attempting to make a few small nozzles for one of my projects out of 6mm 304 stainless threaded rod.

304 is generally for welding. In general stainless is "difficult" (the polite word) to machine.

I need to put a 5/64 bit 1-3/4" deep concentrically but I have not even managed to create a single bloody chip!

That sounds like stainless. You mentioned threaded rod, here I'm worried that the threads where rolled in which case might have work hardened the stainless a bit before you even started.

The first thing you need for stainless is high quality drill bits. After that you need to machine with far lower surface speeds than you would for mild steel. Combine that with an aggressive feed.

I have tried many speeds and feeds with both HSS and Titanium 135deg drill bits but not a single one will bite. I also tried a #3 center drill and that went in a tiny bit but then much have work hardened the rod.

Actually I've had bad results with center drills in stainless as they seem to harden the steel far to fast no matter how I use them. I attribute that to the way the ones I've used where ground. Even if you do get a proper start with the center drill, you still leave a hard spot that the drill then has to pierce.

I live in canada and only have the box stores nearby, I can order bits online but will need a place with reasonable shipping.

That sucks.

Does anybody know how the heck I can accomplish this? I need to make 10 of these things...

Here are some suggestions, not all of which may fit your needs.

1. Try 303 if 304 isn't really required.
2. Avoid using all thread as it may already be harder than plain 304 rod.
3. Anneal the all thread.
4. Buy good quality tooling.
5. Consider using a drill bushing to start the drill.
6. Consider plain rod and thread externally afterward.
7. As above but with 303.
8. Try single flute carbide drills.
9. Don't baby the drilling feed rate. If the drill bit rubs on the stainless you immediately have a hard spot and a ruined drill bit.
10. Related to the above always use a sharp drill bit.
11. Once the work piece is hard you won't be able to penetrate the hard area with normal HSS drills. Trying to do so just ruins more drill bits. You can try drilling from the opposite end and break through the hard spot that way. That is if you can get the machine to drill the material in the first place.

By the way I have no confidence in home center tooling.

[hydropro]

Good quality 135deg Cobalt drill bits and slow spindle speeds work best for me when drilling stainless steel. Good luck

[ohbuckley]

I find a quicker spindle speed works with the small drills I was putting a 2mm hole in 304 today. 2000 rpm and about .015 mm pr. It takes time but I did 25 holes 37 do try using a shorter drill first then the longer drill. I find a spot drill 6mm is better than a cnt drill.

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