[screenzzzz]

G'morning all
I'm looking to drill 5/64" holes into 3/8" thin wall stainless steel tubing, I picked up a couple of DeWalt Titanium Split Point bits. The way I have it set up is with the bit all the way up in the chuck so only about an inch is coming out of it. I need advice on the best type of bit for the job as mine are basically just polishing the surface.
Thanks
Gary

[djr76]

On stainless, I usually go with Precision Twist cobalted screw machine drills. 30-60 sfm, .004 per rev. 2000 rpm is a good starting point, keep it feeding and use oil for lube.

[NodecoMachine]

.004 IPR on a 5/64" drill is not s good idea. I would definitely stay away from all dewalt drills as well.

Decent brand cobalt screw machine drill with 40sfm and about .0013 IPR will get you a bunch of holes.

[screenzzzz]

Thanks guys
Urgh, what is IPR and 40sfm? Also, I can find out the hard way and spend bucks n time so, Any brand names I should follow?
Thank you

[NodecoMachine]

Are u doing this with a machine or hand drill?

[screenzzzz]

Actually mate I'm using a lil ol Dremel 4000 on a 220 work station with an attached vise. I thought it would be good for a small hole on thin wall ss tube O.D 3/8"

[NodecoMachine]

Ok.

SFM = surface feet per minute
Spindle speed = (SFM*3.82)/tool diameter
Using 40sfm u would get 1959rpm for a .078 dia drill

IPR=Inches per revolution
IPM=IPR*spindle speed
Using .0014 IPR you get 2.7 IPM

So run at 1959 RPM at 2.7 IPM.

NOW, something is telling me your not using a spot drill to get this hole started. You MUST use something to keep the drill from wondering down either side of the tube. Unless you were ABSOLUTEY dead nuts center on the tube, that flimsy little drill will just deflect away and probably snap.

As for drill selection... You should be fine with dewalt brand drills if you plan on just drilling 1 hole. If you are doing a lot of holes step it up to a metalworking brand drill. I prefer YG1 brand drills myself. You can get them pretty cheap at suncoasttools.com or in eBay.

[screenzzzz]

Wow Nodeco, thanks for the heads up mate, I've got the basic but gotta give this one some more thought. Being really really new at this this and to be totally honest, I originally thought it was place the bit in the chuck and position the ss tube and drill. So, I really do appreciate the education.
Have a g'night mate