Found a trick for drilling rivet holes in steel frame

[belfert]

I've been drilling tons of holes in my steel frame for skinning over my windows.  Each hole seemed like it took forever to drill.  I figured I would be drilling holes until next summer as slow as it was going.

Normal advice is to drill steel at a slow speed.  I accidently set one drill to high speed and it drilled the hole in less than HALF the time!  I started drilling all of the holes at high speed and my skinning project is moving much faster!  I am also getting chips of steel now instead of just steel dust.

Now, if it wasn't so darned hot, I could get this project back on track.  I do want to install roof A/C in the next week or so, but no use running the A/C without the sides covered.  It will still be a week or two before the hottest part of the summer is over.

Brian Elfert

[Stan]

Figure on 100 feet per minute cutting mild steel. Calculate the circumference of the bit in feet and divide by two (a bit has two cutting flutes) times the RPM of the drill.  A few caculations will give you sme idea of how fast to run your drill with different size bits.

[Hartley]

Run them until just shy of smoking or turning blue.

Some drill bits are better than others, I found that the Jobber bits made in cobalt steel work best for me
and if I do hit a tough spot in the stainless I keep a spray can of Kroil handy. ( cools the bit and metal ).
I have used the other stuff that comes in a small can which is used for thread cutting and machine tools
but can't remember the name of it.

Doesn't matter how many inches per second a drill bit chews a hole unless you are programming a CNC machine.

Just the right speed.. The right amount of pressure and no-wiggling the drill..
of course drilling through a weld area in stainless will test your patience but it can be done...

[Stan]

Dr Dave: snip "Run them until just shy of smoking or turning blue." snip

I think you have found the ideal speed from a lot of experience drilling holes.  For an inexperienced person that  is the equivalent of 'tighten the bolt until it breaks and then back off a quarter turn'. If you don't have some ballpark idea of the correct speed before you start, you either ruin a drill bit or make very slow progress as Brian as learned.

This is another of the subjects that keep coming up on the BBs. Doing a search on this board or on BNO board will bring up a lot of good info.

[DrivingMissLazy]

Hey Stan, you are no longer a newbie. Congratulations.

I really think it is worth the money to ruin a couple of bits by experimenting a bit with speed and pressure. Nothing worse on a bit than running it with too little pressure in my opinion.

Dr Dave: snip "Run them until just shy of smoking or turning blue." snip

I think you have found the ideal speed from a lot of experience drilling holes.  For an inexperienced person that  is the equivalent of 'tighten the bolt until it breaks and then back off a quarter turn'. If you don't have some ballpark idea of the correct speed before you start, you either ruin a drill bit or make very slow progress as Brian as learned.

This is another of the subjects that keep coming up on the BBs. Doing a search on this board or on BNO board will bring up a lot of good info.

[belfert]

This is another of the subjects that keep coming up on the BBs. Doing a search on this board or on BNO board will bring up a lot of good info.

All of the research I did before starting to drill holes said to run the drill at a slow speed.  I found doing the opposite and running them fast drills the hole much faster.  I don't think the bits are being damaged as they aren't turning blue and they are still plenty sharp after 30 or 40 holes.

Brian elfert

[Hartley]

Brian,
Sounds like you found the magic touch...

I usually break a bit now long before it's dull. ( I am impatient and tend to drill in wierd places anyway ).
( seems that I can find places where the hardened stainless is covered by soft aluminum )

If you are getting more than 20 holes on a bit, It's a good Day !!