Drilling large holes thought thick plate?

[Atlascycle]

Get a 3/4" Step drill if using a hand drill, go slow as the steps start to get larger and use lots of cutting fluid.


Jason

 

[comedyman809]

Yes, the hole saw is the way to fly for one off projects of this type, I use a battery drill, sometimes even water but usually a few drops of Tap Magic or Rapid Tap. A few drops every 1/8 of thickness. I have drilled the 3/8 in as little as 35 seconds but those 3/4 thru 2 half inch green plates took about 5 minutes a piece with break, done in place. I recall it took maybe half an hour to drill 4 sets of holes and one battery change.

im jealous of your drill...!!!!

 

[Adam@theHoffmanGroup]

if you want them to be fairly true, use a hole saw, if it's not a big deal, use a drill bit. Either way is no big deal. I drilled 20 holes through 3/4" plate with one 5/8" holesaw.

I used to drill 5/8" hole through truck frames all day long when I was building dump trucks. I would never use a hole saw. I always made three passes 1/4" first 7/16" next then a 5/8" tapered reamer. did the same for 3/4" and 7/8" holes. you have to use the big 7/8" chuck riding drill to do it though. just go slow and use a ton of lube

 

[sberry]

I agree, if I was drilling frames all day I would come up with something better.

 

[caper]

Just did 62 5/8" holes in a truck frame a few months ago.Used our standard "hillbilly magdrill".Consists of two guys,a heavyduty drill,a short length of chain and a pipe.Center punch where you want the hole,rap the chain around the frame,slide the pipe through the rear handle of the drill and hook the chain with it so your using the leverage to push on the drill.One guy works the drill and the other works the pipe.Takes teamwork and communication but you can drill a 5/8" hole through a double frame in less than a minute.We have a large old Jet drill that spins way to fast for that big of a bit but with the leverage available because of the pipe the drill just grabs metal and cuts as fast as it will go.You can stall the drill depending on how hard you lean on the pipe.62 holes,one Walter drill bit and it's still cutting fine.Amazing to watch a 5/8 bit just taking a frame out in a steady spiral of metal.

 

[nissan_crawler]

I used to drill 5/8" hole through truck frames all day long when I was building dump trucks. I would never use a hole saw. I always made three passes 1/4" first 7/16" next then a 5/8" tapered reamer. did the same for 3/4" and 7/8" holes. you have to use the big 7/8" chuck riding drill to do it though. just go slow and use a ton of lube

No argument there, but there's a huge difference between a reamer and a drill bit.

We're talking buying one hole saw, or two bits and a reamer. For production use, you'll get no argument from me on the reamer. However, for a home user, I think the holesaw is a better bet, especially when it might get screwed up.

We're talking a $40 reamer that could get screwed up, vs. a $13 holesaw.

 

[OldToolMan]

if you are in no.cal. i have milwakee mag.base drill larry

 

[123Go]

Thanks guys, I'll try a lenox hole saw I know their blades are tough.

 

[gte718p]

I would just use a good quality 3/4 inch drill bit and looooooooooow speed.

If you do go with the hole saw, a cool trick is to take a chunk of 2x4 or scrap wood and run the hole saw through it on the drill press, or extremely carefully by hand. Clamp the 2x4 to your work surface you want to drill through and you get straight holes every time. If the wood block is large you need air to blow out the chips.

In any case slow and cutting oil are your friends.

And in closing because this is the internet, the only correct way to do this is a water jet, anything else is a hack job.

 

[bodydamage]

How is WD as a lube for something like this?

 

[Richard D]

WD 40 is not really a lube but will work in a pinch. Anything that will cool it down is better than nothing. I have even used Pam cooking spray!

 

[gte718p]

How is WD as a lube for something like this?

WD-40 is about useless on steel. Works surprisingly well on aluminum though, but that is a different mechanism. ATF or motor oil will work in a pinch. It only takes a few drops every minute or two. A cutting oil is best, but anything will do.

 

[Techie1961]

Thanks guys, I'll try a lenox hole saw I know their blades are tough.

It took you five years to decide?

 

[csp]

It took you five years to decide?

The person you quoted isn't the one who originally asked the question. Not sure why they had to reply like that to someone elses thread though.

 

[RogueFab]

Just get a reduction kit to slow down your drill press, and then run a hole saw, or go in a couple of steps up to your size. Drilling at about 50 RPM is the ticket when you only have .5 hp or so.

https://www.roguefab.com/category.php?category=DPRKS