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Drilling 1/2" plate steel

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truckone176

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Oct 7, 2012
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I have a question for you guys. I am finishing up a welding table build and the top is a 1/2" thick piece of plate steel. I need to drill 50 holes 1/2" in diameter for use mounting points for hold-down clamps. I have access to a mag-drill, but I was wondering what you would suggest as far a drill bits, annular cutter, or a hole saw?
 
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mike13u

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1/2" annular cutter bit in the mag drill. It will not get any easier than that. :rocker:

A suggestion...go with a more common hole size like 0.625"+ so you can use clamps and tooling from some of the available fabrication table designers(such as BuildPro and their Stonghand Tools clamping/fixturing system). At least this way you are making a tooling/fixturing investment that you can grow into and expand on even if your table gets beat up down the road.
 
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homebuilt burner

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Use some cutting oil and find a speed where the cutter is cutting not being force through.

Patience, with that many holes you just have to get in a mind set of slow and steady. If you push it your tool will dull and the job gets harder.
 
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bggrnchvy

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Mag drill and annular cutters are a perfect combination.

In my experience the mag drill speed is pretty well set in stone as they have one or two speeds. That means the only thing you can adjust is the feed. Too little and you're going to dull the cutter just as easily as if you push it too hard. Make sure you're giving it adequate amounts of material to eat and plenty of cutting fluid.

Oh, always get the plug out even if it doesn't fall clear by it self. Best way to ensure it I've found is after you finish cutting through, kill the motor power and as it's slowing rapid the cutter back through the hole and it will eject the slug if it hasn't dropped free.



I put about 150 11/16" holes in my shop's A992 beams (more than shown) with the same cutter I used to make 900 holes in some 3/16" A36 box tube. They will last a long time.
 
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Vegaman_Dan

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I don't know, at $250 to get all 50 holes drilled- to me, that's well worth the price as they will be in alignment, done with their equipment, and YOU don't have to stand there all day doing that.

That last part is worth it alone to me.
 
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sqznby

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mike13u said:
1/2" annular cutter bit in the mag drill. It will not get any easier than that. :rocker:

A suggestion...go with a more common hole size like 0.625"+ so you can use clamps and tooling from some of the available fabrication table designers(such as BuildPro and their Stonghand Tools clamping/fixturing system). At least this way you are making a tooling/fixturing investment that you can grow into and expand on even if your table gets beat up down the road.
Click to expand...

This 100%, especially about the size of the holes.
 
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iajonesy

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I agree 100% with " mike13u" go with 5/8" to be able to expand your clamping options. I've never used an annular cutter but everyone who has highly recommends them. If you have the funds, why not have your local shop do the job and you could be doing something productive at home.

Mike
 
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truckone176

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Thanks for the replies, I will go with the 5/8 cutter. This is why I ask here, many good ideas and experience.
 
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bggrnchvy

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Vegaman_Dan said:
I don't know, at $250 to get all 50 holes drilled- to me, that's well worth the price as they will be in alignment, done with their equipment, and YOU don't have to stand there all day doing that.

That last part is worth it alone to me.
Click to expand...

50 holes with an annular cutter and a mag drill is ~3 hours of work including layout at a marginal pace. The cutter in HSS is ~$30.

A hole every 2 minutes is cake, and it's way more monotonous than it is physical tiring as the drill does all the work.
 
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mike13u

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Anyone suggesting a machine shop to a man with a mag drill and 1/2" piece of plate to bore holes through has clearly never used a mag drill and annular cutters. Each hole is 10 seconds max. I'll give you another 20 seconds to pull the ribbons/chips away and move to the next hole. 30-seconds a hole. This job is done in a half hour.
 
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Jazz1

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The mag drill and annular cutters is the way to go. I would not consider farming out any of the fabrication of a welding table. Does not compute!
 
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bodydamage

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I would be more than willing to pay $250 for this, but if it really is as easy as mike13u makes it out to be, then maybe not. Any GOOD videos of exactly how well this works? Maybe I need a mag drill, now. Convince me.
 
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rvieceli

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body damage

Here is a pretty good video reviewing a Milwaukee Mag Drill and their annular cutters.


This one is basically an ad for Drillco stuff but it gives you a good view of what's going on:

 
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Fordman7795

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You have access to a mag drill then its a done deal, use it with an annual cutter. 10 seconds is a bit quick per hole as one person said. No sense in seeing how fast you can do it and possibly break expensive bits in the process. If I didnt have access to a mag drill and was made of money then farming it out for $250 doesnt sound too bad.
 
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2004.5cumminsman

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My hougen mag drill with annular cutters are designed to just hog through the metal. They get dull if you just milk them along. Push them hard and fast with coolant and last a long time! I would go for 5/8" as well but not 50 by any means

The hougen bits I by have a center point and self eject. I am still on my Original bits as they last a long time!
 
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fast85pony

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I just finished drilling my 1/2" top. I couldn't seem to find a 5/8" annular cutter that would work in the conventional chuck that I was using in an ancient Black and Decker mag drill, so I chugged ahead with conventional twist drills. Did a careful layout, center punched, then drilled a 3/8 hole followed by a 5/8 and finished with a small bevel. Yes, with three tool changes per hole and that equipment it took a long time to do 72 holes, but even before I finished I had an opportunity to use it with some Strong Hand inserta clamps and it was a joy - just plug 'em in and go. I did a 4" grid, so can clamp just about anywhere on the table. Enjoy your project!
 
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AndyA

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APEowner said:
I've never used a mag drill. What's the procedure for accurately positioning the cutter?
Click to expand...

Measure, mark, then put in a little divot with a center punch. You can slide the mag drill around until you feel the pin drop in the divot. Then turn on the magnet and drill.
 
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Jim Johnstone

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Re: Drilling 1/2" plate steel

What's it cost to rent a mag drill and how much does the annular cutter cost? Could be cheaper to have a machine shop do it. 50 holes in 1/2" plate would be under an hour including setup and teardown. The issue would be if a given shop had a minimum rate vs strictly hourly.

The other issue could be finding a shop wiling to fit in such a small job.

Sent from my SM-G900W8 using Tapatalk
 
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maverick3316

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Beaumont67 said:
^^ Our local welding shop, charge $5/hole...No thks.


I own a steel fab shop. This makes me realize I am charging wayyyyy to little:sad:.
If you brought it to my shop, with the holes laid out, and center punched, I could drill all the holes in less than an hour with my mag drill. I only charge $65/hour.

$5 per hole seems ridiculous. It sounds like they did not want to be bothered.
Click to expand...
 
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jjgag60

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I just did my 5/8 thick welding table last week. I rented the magdrill for four hours, $54.00. I bought a quality Slugger annular cutter for 5/8 with the additional center piece and their cutting paste for $60.00. I set up my holes in a 6 inch grid pattern and used a center punch to mark the holes incase the cutting paste erased the marks. I had never used the drill and was worried about the speed and how to use it. It was simple. I plugged it in and the magdrill only had one speed. I put the paste on each hole about the size of a dime and started drilling. Everyone recommended once you start the hole don't raise it up and down like you do on a twist drill. Steady pressure until you complete the hole. I used a brush to clean it out each time to make sure no chips could accidently break it. Each hole took me about 3 seconds to drill. Loved it .I started out with 24 holes and ended up with 35 because I was having so much fun. I have now built 6 inserta style clamps using the HF clamps and 4 stops. I am now working on some tubing holders that will hold round stock. I agree move up to the 5/8 holes. good luck
 
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maverick3316

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I just did this in my shop so everyone can see it in action. 5/8" annular cutter, 1/2" plate.


As you can see in the video, it only takes, literally 30 seconds to drill the hole. Thats an old bit as well.

This is by far the best way to drill lots of holes in thick steel.
 
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truckone176

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Well sorry for asking a question to get advice and then get roasted for the question. As for your information, yes I am new to welding and have only made some small items for myself and friends. I do not pretend to be a professional nor do I make anything that would put anyone in harms-way do to my amateur fabrication. However, I have been making furniture and cabinets for years and my shop table has many hold-down clamp holes to make it easier to secure items. As far as spending MY money on my own items, that is my prerogative. I appreciate your response and insight but as far as being on the slightly negative side, I apologize for asking questions and gaining advice and insulting your intelligence sir!
 
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bluebolt

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Truckone176, do what I do with advice. Listen to it, determine if it fits your needs and situation and act accordingly. Don't worry about naysayers, it's your decision.
 
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dr_clyde

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truckone176 said:
Well sorry for asking a question to get advice and then get roasted for the question. As for your information, yes I am new to welding and have only made some small items for myself and friends. I do not pretend to be a professional nor do I make anything that would put anyone in harms-way do to my amateur fabrication. However, I have been making furniture and cabinets for years and my shop table has many hold-down clamp holes to make it easier to secure items. As far as spending MY money on my own items, that is my prerogative. I appreciate your response and insight but as far as being on the slightly negative side, I apologize for asking questions and gaining advice and insulting your intelligence sir!
Click to expand...

Don't get too ruffled. I have holes in my table and absolutely love them. I would recommend 5/8" holes on 12" centers. I used a mag drill and annular cutters.
 
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skipnay

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At least your machine shop will cut them. Mine won't cut any holes into steel unless you bought it from them.I have the annular cutter I just don't have the right drill to drill all those holes. I would like to do maybe like 10 holes. I just haven't yet because I want to be able to fill those holes flush then and not have to worry about stuff falling down them.
 
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gordo9742000

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One of the first things I built was a table with holes for clamps. No regrets. Best thing since auto shade helmets. It works for so much more than welding. Holds parts on weird positions for work. Holds items for bending. Ideas are endless. I say go for it.
 
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