Drilling Lubricant/coolant

KellysEye said:
I used machine oil and as said stop when it starts to smoke. For drilling SS you need cobalt drill bits ordinary metal drills hardly dent it.
Click to expand...

I have machined endless amounts of S/S both in the lathe and Pillar Drill and found HSS tooling quite adequate for use.

The trick is not to have too high a cutting speed and sharp tooling along with a constant pressure of cut. Excessive amounts of heat are usually down to too fast a rotation with little cutting pressure. If you get both right, the excess material will exit the cut in a continual length like a spring.

As said before by others, I also use Rocol Cutting Paste which I purchased for cutting threads in S/S but I have found it quite adequate for drilling. It also has the benefit of being a paste, not a fluid, so creates a pool when heat is present instead of just flying off the drill bit like fluid does.

Lots of lathe work of course requires a continual flow of suds from a suds pump but I don't do that much to warrant it.

Only my experience of course.
 
Last edited:
Posts 4, 16 and 23 have the answer to this one.

I hate it when people gush over one answer to a subjective question, however



I will tell you this

Put a blob of Rocol paste on the end of your todger and you will punch 1in holes through 14SWG stainless with no bother.
 
I am just out of the workshop where I have been making lots of fiddly bits from SS for a 1913 AJS model B veteran motorbike.

As you can imagine, I cant just go out and buy bits for it.

I have been making lots of fastners, fine cycle threads, small diameter hex heads or cheese heads. Some even round or oval-well, round with flats on.

I have a cheapo Clarke lathe/mill, a good heavy pillar drill and a really good grinder/wire wheel.

I only use HS bits for drilling. For S/S, as others have said, slowish speed, plenty of pressure, sharp bits and a little oil. I dont find the type of oil as important as the speed/ pressure/ sharp tools thing.

After boring out a 1/4 BSF nut to make a 3/8 small hex I use hand pressure to turn the lathe chuck with the tap in the headstock. Once through with a starter tap, finish with the plug, just a little oil for lube.

I am fortunate in being able to sharpen drill bits by eye-a skill I picked up when I had to provide workshop tools for dopey mechanics who would not even use the chuck key for the pistol drill!

HS is fine if the pressure, speed and lube is in place.
 
rotrax said:
I am just out of the workshop where I have been making lots of fiddly bits from SS for a 1913 AJS model B veteran motorbike.

As you can imagine, I cant just go out and buy bits for it.

I have been making lots of fastners, fine cycle threads, small diameter hex heads or cheese heads. Some even round or oval-well, round with flats on.

I have a cheapo Clarke lathe/mill, a good heavy pillar drill and a really good grinder/wire wheel.

I only use HS bits for drilling. For S/S, as others have said, slowish speed, plenty of pressure, sharp bits and a little oil. I dont find the type of oil as important as the speed/ pressure/ sharp tools thing.

After boring out a 1/4 BSF nut to make a 3/8 small hex I use hand pressure to turn the lathe chuck with the tap in the headstock. Once through with a starter tap, finish with the plug, just a little oil for lube.

I am fortunate in being able to sharpen drill bits by eye-a skill I picked up when I had to provide workshop tools for dopey mechanics who would not even use the chuck key for the pistol drill!

HS is fine if the pressure, speed and lube is in place.
Click to expand...
Proper!
Stu
 
xeitosaphil said:
I have machined endless amounts of S/S both in the lathe and Pillar Drill and found HSS tooling quite adequate for use.

The trick is not to have too high a cutting speed and sharp tooling along with a constant pressure of cut. Excessive amounts of heat are usually down to too fast a rotation with little cutting pressure. If you get both right, the excess material will exit the cut in a continual length like a spring.

As said before by others, I also use Rocol Cutting Paste which I purchased for cutting threads in S/S but I have found it quite adequate for drilling. It also has the benefit of being a paste, not a fluid, so creates a pool when heat is present instead of just flying off the drill bit like fluid does.

Lots of lathe work of course requires a continual flow of suds from a suds pump but I don't do that much to warrant it.

Only my experience of course.
Click to expand...
I agree in that with a new HS bit I have no problem unless I pilot bore -staight in with a 10mm drill no problem but once pilot bored the 10mm just spins and overheats!
 
ffiill said:
I agree in that with a new HS bit I have no problem unless I pilot bore -staight in with a 10mm drill no problem but once pilot bored the 10mm just spins and overheats!
Click to expand...

Keep the pilot drill small. If you try to go straight in with Ø10, it is more difficult to hit the spot. It is easier with a small drill. For a final diameter of 10 mm, I would pilot no bigger than 5.

I use Tuffcut as a lubricant.

The problem with SS is that it doesn't conduct heat very well and once it starts to become hot, it work hardens and you might as well give up.

Keep it slow, keep it heavy and if it starts to squeal, back off immediately.

We drill thousands of holes in 303, 304 and 316 and never use anything but HSS drills.
 
ffiill said:
I agree in that with a new HS bit I have no problem unless I pilot bore -staight in with a 10mm drill no problem but once pilot bored the 10mm just spins and overheats!
Click to expand...

My experience-purely practical " on the job " experience-leads me to use at least two pilots in S/S when going direct to 10mm from zero.

Probably 5 to 8 to 10.

Thin sheet materials often prove more difficult than a bit of 20mm bar in the lathe.

I always examine the cutting end of the bit closely-even if it looks good I will sometimes touch it up on the wheel.

I think that sheet materials become work hardened during their manufacturing process.

Also, they are harder to clamp firmly in place which can lead to less pressure being applied to stop the work spinning.

It is VERY dangerous to have a piece of sheet S/S spinning around with the bit jammed in it-seen a collegue cut his forearm very badly just drilling an alloy number plate for a motorcycle.

He was the Warranty Clerk- not really a technician though.
 
You must log in or register to reply here.

Share this page

Top