Drill Press RPM for steel

[R W]

How about the motor. Does it ever overheat.

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,[/QUOTE]

With a good quality drill bit & a pilot hole they are easier than a hand held electric
for 1/2" and over.

 

[R W]

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.

Try Ebay.

 

[JB4310]

Is there any way to slow the electric motors down?

Like a dimmer for a light, or would that reduce the motors power?

JB

 

[grsthegreat]

Is there any way to slow the electric motors down?

Like a dimmer for a light, or would that reduce the motors power?

JB

yes..and no. For single phase motors you can use a motor speed control unit. I have one on my bench grinder. problem you HAVE to remember to have it fully on when you start up the motor..or you could cause some damage. Ive never seen anyone put one on a drill press...but i dont see why it wouldnt work. and O a dimmer switch wont work, the motor speed control needs to be sized to the drills amperage.

my drillpress has like 16 speeds so it has never been an issue.

3 phase motors can use a frequency drive....these are used all the time for large motors.

 

[Iplayfarmer]

Is there any way to slow the electric motors down?

Like a dimmer for a light, or would that reduce the motors power?

JB

This ought to do it... Router Speed Control

I'm sure there are options available from other suppliers besides Harbor Freight.

 

[JB4310]

yes..and no. For single phase motors you can use a motor speed control unit. I have one on my bench grinder. problem you HAVE to remember to have it fully on when you start up the motor..or you could cause some damage. Ive never seen anyone put one on a drill press...but i dont see why it wouldnt work. and O a dimmer switch wont work, the motor speed control needs to be sized to the drills amperage.

my drillpress has like 16 speeds so it has never been an issue.

3 phase motors can use a frequency drive....these are used all the time for large motors.

I knew it was not the same as a dimmer, but the same concept.

Do you lose power with a motor speed control, and where do you get them?

My taiwan drill pres has multi speeds but the slowest is ~600 rpm's and I know exactly what these guys are talking about, too fast for larger holes in thicker steel. I have to bring those jobs to my buddies machine shop, he's got some crazy old school machines.

He slows the drill press way way down for me to drill my holes.

JB

 

[SPYDERLK]

********************************************************
You better believe it will work so buy it if the price is reasonable. Those don't come around for sale very often. I wouldn't be without one.

RPM is determined by cutting speeds of various materials and those recommendations are all over the place depending on who's chart is being used.

For mild steel 90 feet / minute was once popular but I see now 100 ft./ min. is being used and even higher.

In the link below is the old formula that don't need no stinken pie to figure RPM.
Simply multiply the material cutting speed X 4 and divide that by your drill bit diameter. Using 100 ft./ min. cutting speed you can readily see your 1" HSS bit can be rotated 400 rpm. A coolant fluid or cutting oil for cutting (NOT LUBRICATING OIL) is always recommended.

Safety Tip - always clamp your work securely to the press table via vise, C-clamps etc.

Machine Shop 2 - Lathe Cutting Speeds - RPM Calculations

HA! Under what conditions. Achieving acceptable performance at that rpm at that size would require a rigid, positive feed/rev, forced coolant setup. Not someting youll achieve by hand.
larry

 

[grsthegreat]

heres what my little old Delta has..and its about 10 years old. Model is still made..

 

[JB4310]

This ought to do it... Router Speed Control

I'm sure there are options available from other suppliers besides Harbor Freight.

Wow! seems to easy. Any reason that wouldn't work for a drill press?

JB

 

[grsthegreat]

My only concern with a speed control, is its going to reduce the torque and power of the motor also. If a simple dial control would /could control a drill press they would be using these instead of a series of pulleys.....just to save $$$

when i slow down the speed of my grinder, its way easier to bind up the disk during grinding...less POWER. so if you did this to a drill press, it might not be able to actually drill thru the steel????

 

[Iplayfarmer]

heres what my little old Delta has..and its about 10 years old. Model is still made..

My drill press has two sets of numbers, one for 60hz power supply and one for 50 hz. power supply. The numbers on yours correspond to my 50 hz. I wonder if your old Delta speeds are based on a 50 hz. power supply. It would be interesting to find out.

My only concern with a speed control, is its going to reduce the torque and power of the motor also. If a simple dial control would /could control a drill press they would be using these instead of a series of pulleys.....just to save $$$

when i slow down the speed of my grinder, its way easier to bind up the disk during grinding...less POWER. so if you did this to a drill press, it might not be able to actually drill thru the steel????

I think you're right about cutting the power of the motor when you reduce the speed. I think a router speed control would be good for reducing the speed from 600 to 400 or something like that, but won't work well for reducing the speed more than about half of the the nominal speed of the machine.

 

[grsthegreat]

My drill press has two sets of numbers, one for 60hz power supply and one for 50 hz. power supply. The numbers on yours correspond to my 50 hz. I wonder if your old Delta speeds are based on a 50 hz. power supply. It would be interesting to find out.


.

\weird..mine has a 60hz plate on the motor. nothing else stating 50HZ.

 

[wawajake]

Now I know why when I drill steel , my bits don't last long.(and I just use some old 10w30 in the hole)

I use whatever speed the drill press was left at last time I played with the belts and pulleys. I always thought fast was better , but then I do more woodwork than steel !
I learned a lot from this thread, I am guilty as charged and will mend my ways for steel ....I will set pulleys to slowest speed and buy some cutting oil !!! And maybe I will save some time no longer spending time in hardware store buying more bits.

thanks folks

 

[grsthegreat]

Now I know why when I drill steel , my bits don't last long.(and I just use some old 10w30 in the hole)

I use whatever speed the drill press was left at last time I played with the belts and pulleys. I always thought fast was better , but then I do more woodwork than steel !
I learned a lot from this thread, I am guilty as charged and will mend my ways for steel ....I will set pulleys to slowest speed and buy some cutting oil !!! And maybe I will save some time no longer spending time in hardware store buying more bits.

thanks folks

then buy a "drill doctor" and sharpen the old bits. that machine is AMAZING.

 

[sparc]

This ought to do it... Router Speed Control

I'm sure there are options available from other suppliers besides Harbor Freight.

These are made to work with universal motors which are series wound; many of which can be operated from either AC or DC. These are the types of motors used in portable power tools.

I don't believe a router speed control will work on a motor with capacitor start, which is a type of split-phase induction motor and commonly found in stationary power tools like table saws, band saws, and drill presses.

 

[sparc]

I am guilty as charged and will mend my ways for steel

Bit speed is just as important when drilling in other materials such as wood.

I use Rapid-Tap when drilling steels and get good results. It does not leave an oily mess but its not cheap. A pint can will run you around $5 to $7.

 

[BobRip]

This ought to do it... Router Speed Control

I'm sure there are options available from other suppliers besides Harbor Freight.

This is not for use with induction motors. That is what most if not all drill presses use. So do NOT use this on your drill press. It may work, but you risk damage to it and the drill press.

 

[Wyobuckaroo]

My best two pieces of are...........

ALWAYS buy quality high speed steel drills.
Like Cleveland brand or other good name brand like you will find available on Granger, MSC, or other machine shop accessory web sites. Hardware store drill are not going to last well enough to even justify the lesser price.........

Use the formula............
For most mild steels......... 300 divided by the diameter of the drill.
This will give you a ball park starting RPM to run the drill at.

For larger drills. Drill a pilot hole for the drill. The pilot hole should be the diameter of the center part of the drill (web) This lets the drill cut the whole width of the cutting edge. This will help keep the hole true to size, neat and clean.

Use a cutting lube........ NOT old motor oil...........

Good luck