Drilling hole question for metalworkers?

[Gavin Allan]

I need to drill four 3/8" holes through two 3/16" extruded steel pieces to fix my brush hog. What is the chance I can do this with a hand (power) drill? Doesn't need to be pretty or dead nuts straight- I am mainly concerned this could take me all day. Think I can do it, or should I look for an alternative way to repair it? I know it could be done easily on a drill press or Bridgeport- I just have no experience drilling larger holes in steel by hand. I know all about cutting fluids and cutting speeds- which for this one should be about 850 rpm (max).



Thanks.

 

[Todd Z]

I say just do it in step sizes or start with a step bit, they work well....



I think you can do by hand.....



OR mail it to me and i will drill in the press......



Got any place local that has a press and could just drill for you for a few bucks?



Todd Z

 

[Mark K 2]

No problem with a hand drill. Just drill a 1/8 inch pilot hole first. Go slow and be ready for the 3/8 inch bit to grab just before it pops through the steel.

 

[Gavin Allan]

It is on a couple of large pieces of a brush hog- I don't want to disassemble it that much to use a press. I am thinking I can do it OK too- just wanted a little reassurance, I guess.



Thanks

 

[Johnny O]

Pilot hole and either buy a really good drill bit (i.e. expensive) or two or three cheap ones.

 

[Todd Z]

Yeah then step it up, even 2 sizes inbetween, Slow and steady...



Good luck !!



Todd Z

 

[Richard L]

Most Step drills are only good for up to 1/8" thick metal, however if you have access to both sides, you can easily drill the 1/8" through one side and finish the rest from the other side. The nice part of the Step Drill (also called Uni-bit) is that the next step can be used to slightly deburr or campher the sharp edges of the drilled hole.



Anyway, if you don't want to by a Step Dril or you don't have access to drill from both sides you can do it with conventional twist drills. Just start with a small hole and progressively enlarge the hole with larger bits until you get to the size you need. A 3/8 inch hole could be drilled starting with a 1/8" bit and progressing through a 1/4" and finally the 3/8" bit.



If you have a Harbor Freight store near you, they sell some cheap Titanium coated (gold colored) drill bits that really work great and stay sharp through a lot of drilling in steel and aluminum. I used them in my shop when I was making LeverLift products for Sport Tracs



...Rich

 

[Gavin Allan]

Got 'er done easily with twist drills. Did a 3/16" pilot and then the 3/8". Took me probably all of 10 minutes to drill four holes through two pieces of 0.250 stock. Guess I got my panties in a wad over nothing! I could have drilled all day the way it went through!



Stuck some Grade 8 fine thread bolts coated with Locktite and tightened down with a Grade 8 locknut. Should be good to mow forever now!



Thanks.