Drill Press RPM for steel

[chaffe]

As a machinist for the past twelve years experience tells you what speed to run drills at, not a book. No one situation is the same.
In my experience 380 is far too fast for even a 1/2" in steel, it will drill but will not last as long as a reduced speed. 1" holes will need between 120 to 200 rpm depending on many factors. thanks

 

[LD1]

As a machinist for the past twelve years experience tells you what speed to run drills at, not a book. No one situation is the same.
In my experience 380 is far too fast for even a 1/2" in steel, it will drill but will not last as long as a reduced speed. 1" holes will need between 120 to 200 rpm depending on many factors. thanks

Agreed:thumbsup:

Running 400RPM with a 1" bit (by the book) is obsurd. Unless you really like sharpening bits every 1/4" of hole drilled:confused2:

 

[sal64]

As a machinist for the past twelve years experience tells you what speed to run drills at, not a book. No one situation is the same.
In my experience 380 is far too fast for even a 1/2" in steel, it will drill but will not last as long as a reduced speed. 1" holes will need between 120 to 200 rpm depending on many factors. thanks

ive been machinist for years also and totaly agree with every situation is different, i realy dont no the speed i drill at, i look at it by eye, and most of my drill presses dont have rpm gages the only time i no the speed im running is on the cnc.i also think 380 is to fast.

 

[Iplayfarmer]

Even if 380 is slow enough for you today it likely won't be slow enough as you expand your horizons into new projects. Hole saws need a lot slower speed. Larger drill bits need slower speeds. Different materials do better with slower speeds.

 

[k0ua]

many people make a jack shaft and reduce the speed on shop drill press more than the factory settings,

on large holes that is to fast IMO, but on small holes it will work fine, keep some coolant on the bit,

I have never have over heated a bit using this press,

Hey that thing looks pretty useful! I would not mind having one of those
James K0UA

 

[SandburRanch]

Those book formulas are sure enough guide lines and not etched in stone. But get the most out of a machine that it was designed for or you are wasting time.

I'm surprised there are any machines still around in the USA running half speed. Industry is interested in production so they moved to China.

If you "by the seat of your pants" half speeders worked for Henry Ford you would be going home with a full lunch pail. Why? Because he would have fired you before lunch time.:laughing:

 

[BHD]

[I have never have over heated a bit using this press,

How about the motor. Does it ever overheat.[/QUOTE]


really it is not bad to use at all, and in some instances it is easer to and less fatiguing to use than a electric drill, there is a nut that puts the down pressure on the bit and if you do not get carried away it is simple easy and fast, helps to have polite hole pre drilled, tho,

 

[Iplayfarmer]

...helps to have polite hole pre drilled, tho,

Those polite holes are so nice. They always say please and thank you.

Sorry, I just couldn't resist giving you crap over that one.

Seriously, though; one of those hand drills would be VERY handy. I wonder if a guy could still buy one somewhere.

 

[grsthegreat]

Hay... i happen to like my Drill doctor. its saved me many times over its cost in drill bits. If i had a professional shop, than things might be different. Then again, i was introduced to the drill doctor by a machinest that worked at Boeing.

 

[easygo]

Those polite holes are so nice. They always say please and thank you.

That is hilarious!!!! :thumbsup::thumbsup::thumbsup:


Thanks to all of you for your advice and I got some good laughs. Now I drill three holes for every one that has to be larger then 3/4"

1 Drill 1/4 polite hole
2 Put in the 3/4 hole saw
3 1" step bit to enlarge hole

This method works in mild steel up to 1/2" maximum thickness. It's a real pain and I can't rely on the exact placing of the holes due to the inaccuracy using the hole saw. It works for making tractor attachments but just barely.