Heavy drillin

[bfullmer]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

 

[Ark68SS]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkillS

Slower speed, both bit speed and feed speed, sharp bit, lubrication, pilot hole, and patience.
BillL

 

[Jim.ME]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

I've drilled 1" holes in 1" material with a homeowner grade craftsman drill press, using the same guidelines as Ark68SS just posted.

 

[Janicholson]

4 Stages (center punch and locate, then:
Drill 3/16 through using cutting oil, or antifreeze!
Drill that to 1/2" (lubricated/cooled as above
Drill 3/4" lubed
Drill 1" Lubed
All bits must be nice and sharp. all feed rates steady and moderately aggressive.
Control feed pressure on breakthrough. Jim

 

[Ray,IN]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

Belt slipping is an indication of an under-sized belt for the pulley system. The belt must never bottom out in the pulleys, and be as wide as the top of the V in the pulley or a bit wider if a new belt.
JTo get by with your present setup do as Janicholson said with the exception of aggressive press pressure, that can easily cause the bit to grab and lock, which can have bad consequences; and perhaps a bit of belt dressing will help too; but take care, pulleys and fingers don't like each other, when they fight fingers always lose..

 

[DanielW]

4 Stages (center punch and locate, then:
Drill 3/16 through using cutting oil, or antifreeze!
Drill that to 1/2" (lubricated/cooled as above
Drill 3/4" lubed
Drill 1" Lubed
All bits must be nice and sharp. all feed rates steady and moderately aggressive.
Control feed pressure on breakthrough. Jim

Hmmm, Janicholaon is usually spot-on it all advice and probably the sharpest contributor on here. But I'll have to disagree with him on this one. Most machinists will tell you that stepping up drill sizes is very, very, very poor practice. Punch with a center punch ground to the correct angle. Drill pilot hole with a bit just large enough to clear the lands of the full-sized bit you're using. Then drill through with the full-sized bit. Keep surface speed between 100 and 150 fpm (or slower) if you're worried about it, lots of cutting fluid/coolant and good pressure. Too little pressure and too high speed are common causes of bits wearing out: you need it to cut, not slip. Stepping up bit-by-bit will not be advantageous in any way and only serve to burn out the intermediate drill bits. A 1" hole in 1" plate should be no problem for even the smallest/cheapest drill press. I'd think the first steps to try would be more coolant and slowing down the speed as much as possible (smallest sheave diameter possible on the motor, largest on the quill). And keep the wprkpiece clamped tight. Chatter is death to any tooling.

 

[stevieb49829]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

I just drilled a couple of 7/8 holes through 1" bar stock for a new drawbar. My old Craftsman benchtop with a 1/2" chuck has been modified with a center reduction pulley. It is complicated to change belts and flip the motor pulley over, but it slows it down to a crawl. Then I can concentrate on good sharp cutting edges on the bits, and oil to keep the bit cool. I piloted the 7/8 hole with a 5/16 and it worked really well. I tried without the pilot and it was too slow and created too much heat. steve

 

[zuhnc]

When I drill that size hole, I use a hole saw. Either bi-metal or carbide toothed. Slow speed and lots of appropriate lubricant, such as thread cutting oil or something specifically designed for metal cutting. No WD-40, transmission fluid, hydraulic fluid, etc. None of those help with clearing the teeth of metal chips or cooling. Moderate pressure; let the tool to the cutting! zuhnc

 

[NDIHC]

I somehow lost the drawbar from my Hydro 70. I took it off because it was in the way to mount my Mohawk mower. I laid the drawbar on the mower deck but it must have vibrated off at some point. I made a new drawbar from a beam from a plow. I drilled a 3/8 inch hole to start and then drilled a 1 inch hole with my cheap Tool Shop drill press from Menards. Had to use the slowest speed possible and a lot of lube, but it drilled with no problem. Maybe the plow beam was soft metal? Been using it for close to 20 years without any problems.

 

[Charles in Aus.]

A little molasses on the belt will stop slipping . The belt might also be glazed if it has slipped a lot . A new belt will help as well .

 

[Loosehandle]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

Speed needs to be 350 rpm or less

 

[Russ from MN]

Hmmm, Janicholaon is usually spot-on it all advice and probably the sharpest contributor on here. But I'll have to disagree with him on this one. Most machinists will tell you that stepping up drill sizes is very, very, very poor practice. Punch with a center punch ground to the correct angle. Drill pilot hole with a bit just large enough to clear the lands of the full-sized bit you're using. Then drill through with the full-sized bit. Keep surface speed between 100 and 150 fpm (or slower) if you're worried about it, lots of cutting fluid/coolant and good pressure. Too little pressure and too high speed are common causes of bits wearing out: you need it to cut, not slip. Stepping up bit-by-bit will not be advantageous in any way and only serve to burn out the intermediate drill bits. A 1" hole in 1" plate should be no problem for even the smallest/cheapest drill press. I'd think the first steps to try would be more coolant and slowing down the speed as much as possible (smallest sheave diameter possible on the motor, largest on the quill). And keep the wprkpiece clamped tight. Chatter is death to any tooling.

I too don't agree with step drilling, I was taught to drill the pilot hole slightly larger than the thickness of the drill web, and have at it. If the pilot hole is too small you may drill oversize if the drill has been improperly sharpened. We were spoiled in the paper mill we had a Carlton radial drill press, with power feed, it was a wonderful machine if you understood how to run it.

 

[bfullmer]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

Would a mag drill work better

 

[DoubleO7]

Use more intermediate drill bits.

Would a mag drill work better

What are you drilling? One or many? Purpose of hole?

 

[rustred]

Hmmm, Janicholaon is usually spot-on it all advice and probably the sharpest contributor on here. But I'll have to disagree with him on this one. Most machinists will tell you that stepping up drill sizes is very, very, very poor practice. Punch with a center punch ground to the correct angle. Drill pilot hole with a bit just large enough to clear the lands of the full-sized bit you're using. Then drill through with the full-sized bit. Keep surface speed between 100 and 150 fpm (or slower) if you're worried about it, lots of cutting fluid/coolant and good pressure. Too little pressure and too high speed are common causes of bits wearing out: you need it to cut, not slip. Stepping up bit-by-bit will not be advantageous in any way and only serve to burn out the intermediate drill bits. A 1" hole in 1" plate should be no problem for even the smallest/cheapest drill press. I'd think the first steps to try would be more coolant and slowing down the speed as much as possible (smallest sheave diameter possible on the motor, largest on the quill). And keep the wprkpiece clamped tight. Chatter is death to any tooling.

agree,i have drilled 1 inch holes in steel, and its just as you say. use only 1 pilot hole the size to match the drill bit being used. plus i would be checking the belt to make sure its the proper belt . and use rapid tap oil. them cuttings should be curling out .

 

[stdsch40]

A good quality hole saw (Milwakiee, Lenox) for larger than 1/2" works just fine. I use old motor oil as lubricant and to clear the chips. Lower cost than a 1" twist drill. I've drilled plenty of 1", 1 1/4, 1 1/2" holes through thick steel and cast iron no problem. I use a floor mount drill press at low speed.

 

[Blackhole49]

Bought what i thought was a good size drill press from Grizzly that stated 1 1/4 capacity but belt slips no matter how tight when hard drilling -/ what do I need to drill 1 inch hole in 1 inch thick steel with out it stalling a. Bridgeport seems overkill

It may be overkill, but it sure does make short work of those jobs.

 

[Texgasser1]

Gear head drill press or Bridgeport. I have never used a belt driven drill press that would not slip with anything over 3/4.

 

[504]

Slugger drill bit. you don't remove near as much material to make an 1 inch hole.

 

[Janicholson]

agree, I have drilled 1 inch holes in steel, and its just as you say. use only 1 pilot hole the size to match the drill bit being used. plus i would be checking the belt to make sure its the proper belt . and use rapid tap oil. them cuttings should be curling out .

I agree. If using a gear head drill press and solid fixturing that would sure be the correct method. His issue is lack of applied torque to the apparatus. I was giving him a way to make it happen. Jim