Best method to drill hundreds of holes

[Lis2323]

I can not find rotobroach or annular cutters in 5/8 that will go through 3".

Rotabroaches won’t cut that deep. . You will have to go to a true annular cutter with Weldon shank designed for a mag drill or use with an adapter for drill press or mill. 3” DOC cutters ARE available

Plus not all mag drills will allow 3” depth of cut. A lot are only 2”DOC capacity.

If you use a Rotabroach you could drill a 3/16 pilot hole all the way through both walls and drill each side separately to 5/8”.

[Reebz]

Thank you less. I did find some Mag drill that would drill deep enough but not in that 5/8 size. I will continue to hunt Tuesday.

[BrooklynBravest]

Truthfully you shouldn’t drill it from one side regardless.

Your hole is unlikely to be spot on on the opposing side. If you pilot drilled both sides and the bit was able to catch the bottom pilot then it would work but in my experience it never lines up where you hoped it would free drilling through tube.

I sell a product that uses two 1.5” tube posts and they’re drilled on all 4 sides with a good amount of holes. Before I began outsourcing them, I made a template out of 1/4” flat stock that I lined up to edges and then used a transfer punch to do all my layout on that side very quickly.

I actually made one template and labeled the marks for which side of the tube they were meant for. You don’t want to use under 3/16” for your template because the transfer punch may not have enough of a guide from being slightly off measurement.

If you’re very active business wise and see a real future in this venture, I would almost consider a Bendtech Dragon which would allow you to make these with the press of a button. Mind you it’s gonna run you $20,000 so i know it’s a bit of a crazy suggestion.

The other option is outsourcing but unless you buy in pretty good bulk it is not going to be practical.

[Woznme]

I find 5/8" x 2" rota broaches a bit delicate. I tend to break em after about 25 holes and good German ones too. Longer ones would be worse. Maybe I'm ham fisted or something. Ordinary length one I've drilled over 500 holes and not broken it yet. I'd be looking for another way like what Lis2323 suggests.
What about a plasma table if it's on going work?

[MetalMan23]

A properly sharpened bit, a split point, and the correct drill press speed, and you will not have any issues,

I would say you want a 400 rpm or so for a 5/8 hole in mild steel.

Do you know how to sharpen bits by hand? Or do you have a drill doctor?

[MetalMan23]

My experience is bits walk when they hit the other/unpunched side.

This is a common problem that I deal with

[MetalMan23]

I do cable rail posts all the time, which require accurate drilling, I build a center punch jig, which is made from a 1/4x2 flatbar, with pieces of steel welded on all sides to keep it centered on the 2x2 tubing that I drill, the holes in the jig are just big enough to let the center punch fit through, doesn't take long to clamp the jig on, center punch all the holes, and move on to the next piece.

[Reebz]

I did talk to a guy about laser cutting
them. it would kill my profit.

[Reebz]

Metal man I was thinking of making that exact jig. I sharpen my bites by hand, the drill doctor never worked great for me. With all the gyms closed in Ohio I'm making lots of squat racks. If it was like before the virus I really don't mind. Thanks again

[tapwelder]

I find 5/8" x 2" rota broaches a bit delicate. I tend to break em after about 25 holes and good German ones too. Longer ones would be worse. Maybe I'm ham fisted or something. Ordinary length one I've drilled over 500 holes and not broken it yet. I'd be looking for another way like what Lis2323 suggests.
What about a plasma table if it's on going work?

I have had this issue with 5/8 and 1/2 inch annular cutters.

Reebz

If you go annular cutter make sure the slug clears before drilling the opposite side, sometimes they do not self eject. I think that contributes do damaged bits, since it will spin without cutting.

Hmmm, For folk using annular cutters in a drill press, how do you remove the slug? Spent seem like a choice for a lot of holes, since they are made to self eject using the mag drill spring?

[Reebz]

I am going to look for a used mag drill. I do see a need for one.

[Lis2323]

Hmmm, For folk using annular cutters in a drill press, how do you remove the slug? Spent seem like a choice for a lot of holes, since they are made to self eject using the mag drill spring?

The Weldon shank adapter I use is spring loaded for slug ejection.

[MinnesotaDave]

I did talk to a guy about laser cutting
them. it would kill my profit.

Laser cutting is cheap when the order is large. Small jobs are expensive and not worth having it done.

When I priced it out, it was per 1,000 parts and made great sense to have them do it.

...I didn't get that job, or the next 2 jobs either. They went to big guys in town (one is a great friend of mine).

The guy who collected all the bids is also a very good friend.
He said my bids were always in the middle - so for large orders, laser must be in the right cost category.

Some great guys on here advised me on those bids

[BrooklynBravest]

I am going to look for a used mag drill. I do see a need for one.

Something worth noting, mag drills don’t stick great under 1/4” thick material.

If you’re cutting 1/8” wall tube for gym equipment, do not use too much down pressure I have had the tool dislodge and violently toss itself. They have tremendous torque for a little drill.

[Reebz]

Dave J
That is the issue, If i new i was going to make 4 squat racks a month for 6 months I would order it laser cut. But I'm small potatoes (barely above hobby status lol). I can't have stock inventory sitting for a year that is expensive.

Firehouse
I will have the mag drill on the welding table (5/8 thick) and use it like a drill press. At least thats what I have pictured

[tapwelder]

The mag drill will need a stand. Otherwise. you may not be able to reach center the bit on the material. Also, the thicker the mounting surface the better the holding power. You can also clamp the drill. If you still gotta drill slow the don't use a mag drill, it will get expensive with bit replacement and time.

Drill press with rotobroach might be a better option? Cause even with 3 inched cutter, depth might be compromised, if material has to sit below the mag drill.

[Lis2323]

I agree with tapwelder. Using it for drilling square tube as you planned you could save money using a DP with adapter and annular cutters. Unless you anticipated other immediate uses for the mag drill of course.

[BrooklynBravest]

The mag drill will need a stand. Otherwise. you may not be able to reach center the bit on the material. Also, the thicker the mounting surface the better the holding power. You can also clamp the drill. If you still gotta drill slow the don't use a mag drill, it will get expensive with bit replacement and time.

Drill press with rotobroach might be a better option? Cause even with 3 inched cutter, depth might be compromised, if material has to sit below the mag drill.

Id absolutely make a transfer punch layout template in that case.

[Reebz]

Agree. I can not find annular cutters in 5/8 that will go 3".

[Lis2323]

I guess rigidity can’t be maintained for that DOC with the smaller diameters.

[BrooklynBravest]

Agree. I can not find annular cutters in 5/8 that will go 3".

You should be drilling it from both sides. Crazy not to. No matter what method you use short of a plunge cut on a good mill, you’ll never have accurate alignment.

Quality = more referrals.

If i bought a rack and noticed the alignment was off I’d be annoyed.

Another issue with drilling both sides with an annular cutter the slug may not eject at end of first side and then you’ll be unable to drill the bottom.

The rotobroach is still the best choice and cheapest by far.

[Lis2323]

Id absolutely make a transfer punch layout template in that case.

It looks like you will be making quite a few racks in the near future so you may as well spend a few bucks and and have the template laser cut for accuracy.

[M J D]

It looks like you will be making quite a few racks in the near future so you may as well spend a few bucks and and have the template laser cut for accuracy.

I would skip the transfer punch thing and go right to a setup that allows you to use drill bushings.

[Reebz]

Brooklyn
I'm kind of slow. We may be saying the same thing. I scribe a mark every two inches, center punch the steel. Then I drill a 1/4 pilot hole with a long drill bite from Mcmaster carr. It goes through the top and bottom,both sides. I then take an ordinary twist bit in 5/8 drill the top. Move down the length of tube down then flip it and do the back side. Its slow but accurate.
Like this: https://www.mrmtool.com/Hougen-12220...saAvM9EALw_wcB


Liss2323
That is a great idea, I was thinking of making it myself. But getting a laser cut templete might be the way to go. Get it so it slips over the 3x3 and or 2x3 tube like a saddle. Punch, slide, punch repeat.

MJD
I have never heard of a drill bushing. I will look into that. Thank you

Thanks guys

[Lis2323]

Brooklyn
I'm kind of slow. We may be saying the same thing. I scribe a mark every two inches, center punch the steel. Then I drill a 1/4 pilot hole with a long drill bite from Mcmaster carr. It goes through the top and bottom,both sides. I then take an ordinary twist bit in 5/8 drill the top. Move down the length of tube down then flip it and do the back side. Its slow but accurate.
Like this: https://www.mrmtool.com/Hougen-12220...saAvM9EALw_wcB


Liss2323
That is a great idea, I was thinking of making it myself. But getting a laser cut templete might be the way to go. Get it so it slips over the 3x3 and or 2x3 tube like a saddle. Punch, slide, punch repeat.

MJD
I have never heard of a drill bushing. I will look into that. Thank you

Thanks guys

Maybe look into drill bushings first. Then you may laser cut the template to accommodate it.