Drilling for an answer- annular cutter vs drill bit

[little_sparky]

hello all,

now i know that this question has probably been asked before, maybe not, i dunno there is 7000 discussions here so im asking again.

I need to drill a 16mm or 5/8 inch hole in 16mm steel plate. Simple hey? The catch is i need to drill about 700 of them. So how should i go about it? Its for a fixture welding table much like the build pro ones and i have access to a mill with a DRO so i will set it out on that, i just need to know what cutting tool to use.

here are the options
1) HSS or Cobalt drill bit
2) Annular or broach cutter
3) please specify.

I originally thought an annular cutter but when talking to my school teacher he said "your drilling holes so use a drill bit". My concern is how long the drill bit will last, althought it may be a bit more accurate than the annular cutter. My teacher also thought that annular cutters are slow. Ive never used an annular cutter only drill bits and they arnt exactly that efficient. Please leave your opinions it would be greatly appreciated

 

[ovrrdrive]

The wiki doesn't seem to have anything bad to say about annular cutting bits...

https://en.wikipedia.org/wiki/Annular_cutter

 

[Matt Irvine]

We use annular cutters plenty on mag drills at work, I don't know about small sizes, but in bigger stuff they could probably cut drilling time in half, if not quarters. Generally stay sharper longer too, but you cannot regrind them by hand when dull

 

[Whitworth]

5/8" is not a big hole, so I would use a drill bit. Depending on the horse power of your mill, of course, but you shouldn't have any problem drilling the hole in one operation. I would recommend a "screw machine" length drill bit to minimize any deflection or walking of the drill bit. Use a cutting lube (Moly Dee is best) and buy several bits.

 

[little_sparky]

trust me, the mill we have will have enough horses in it, 5hp both vertically and horizontally with 1200mm of travel. no bragging im just excited haha

 

[metalmanbryan]

mag drill only way to go 5/8 annular bit is probably 30-50 $ you can rent mag drill 50 a day bit will drill 700 holes with lube buy name brand bit not ebay cheapo

 

[Doug Arthurs]

run what you have. If you already have a 5/8 bit run it. If you don't then annular cutters are great. I have used them in my mill and my mag drill.

 

[fnieto]

Like mentioned, go with what you have. Just to clear up the accuracy of annular cutters, they will cut a very accurate hole but your set up will need to be secure to prevent breakage.
Slow PRM's and plenty of lubricant. Not sure why your instructor indicated differently.

I use them on Mag dill, Mills and lathes.
Imagine step drilling to this diameter with conventional methods. This 1-13/16" hole was done in 4-6 min.

 

[Strouty]

I would absolutely go annular cutter, the only trouble is if you don't have the proper adapter for the mill the slugs may come out tough on that small of a bit. The mag drill has a spring loaded center pin that pops the slugs as you raise the bit. They make them for mills, but they are about $200.

 

[DBendr]

HSS drill bit. Pilot with 1/4" first and finish it up with the size required.
2 bits of each will handle that.No need in getting crazy.Keep it slow. Keep it cool(lubed)

 

[sk farmer]

no question, annular cutter and mag drill. look at the picture above. with a drill bit, you need to remove so much material. using an annular cutter you only remove the outside material leaving a nice clean hole and a slug that is the inner part of the hole. the only real advantage to a drill bit is depth of cut. annular cutters are most often 1 or 2 inch deep cut and your depth falls well within that range.

punching holes on plate with a mag drill and annular cutter is fun. using a drill bit *****.

upon rereading your question, i see that you have access to a mill. my advice still stands. set up the annular cutter in the mill and have at. the annular cutter will be much more secure because of it's shorter length and more secure attachment. the longer bit and chuck are much less solid.

 

[Strouty]

HSS drill bit. Pilot with 1/4" first and finish it up with the size required.
2 bits of each will handle that.No need in getting crazy.Keep it slow. Keep it cool(lubed)

The amount of time that it would add to the project is huge compared to the cost of the equipment purchased.

 

[woody 73]

I have used drill bits all my life but...If I had a mill or a mag drill it would be annular bits all the way and I would never look back!

Drill bits are slow, messy, time consuming and break easy plus you need to stop sometimes and hit them on the bench grinder. Instead of cussing when I step on the spiral droppings I would much rather step on flat round discs but that is just me.

 

[sk farmer]

I have used drill bits all my life but...If I had a mill or a mag drill it would be annular bits all the way and I would never look back!

Drill bits are slow, messy, time consuming and break easy plus you need to stop sometimes and hit them on the bench grinder. Instead of cussing when I step on the spiral droppings I would much rather step on flat round discs but that is just me.

you desribe me quite well. i invested in a mag drill and good assortment of annular cutters a few years ago.


i have used very good drill bits in hand drills and drill presses. i would take a crappy mag drill and annular cutters over drill bits in anything 1/2 inch and up any day of the week. especially if i had 700 of them to do.

 

[Whitworth]

On my puny drill press I could easily drill the described hole in well under ten seconds with a HSS twist drill. I see no need for annular cutters, unless spending xtra money is called for.
The OP has access to a mill, constantly re-positioning a magnetic drill press for 700 holes would take an eternity.

To OP, you described the project as a fixturing table, are the holes to be tapped as well ?

 

[dr_clyde]

For holes this size, it depends on what machine is running it. If you're doing this in a manual mill or mag drill, annular cutter wins. If you are doing this on a machining center, I'd use a screw machine length twist drill.

I have drilled many 5/8" holes in thick plate with an annular cutter. They work great. No pilot needed, better quality hole and better cutter life. They still make a mess though. Long stringy chips as opposed to small spirals.

 

[larry_g]

It sounds to me like your in school, correct? So who is paying for the the cutters you or the school? That would influence my answer. The school is probably set with some 5/8" drill bits and no hurry to get the job out whereas a 'for profit' shop wants it out the door in the most efficient manner. So think about the cost per hole from just a point of tooling and ignore the labor cost. That is just as big a part of the teachers answer as anything. As a teacher he should be explaining this facet of the job himself. If you were my student I would have you do a cost per hole analysis comparing a drill bit to a annular cutter with both materials and labor cost.

lg
no neat sig line

 

[zkling]

700? I'd seriously check into a water jet.

 

[cannondalejoe]

I second the water jet idea... I have been sending a lot of work to a guy in North Carolina who has both water jets and laser cutters. If I had to guess he would do that kind of job in about 30 minutes for $100 ( assuming you provide the material ), and his machines have been proven to hold about +/- .005".

 

[sk farmer]

it appears the kid is in school working on a project. i think the whole idea is to do as much of the work in house as possible and i doubt sending the project out for water jet or laser cutting is in the cards. if all you have is hand drill and a drill bit then that is all you have. in reality there must be access to at least a mill and possibly a mag drill as he talks about both access to a mill and having an annular cutter.


i am just guessing but it sounds like the op is working on a personal project at school for grade and is expected to do as much of the work in house as he is able to do. since the mill is already there and also an annular cutter. he is pretty well equipped for the job. what we need is more info. we don't know what the hole pattern is and we don't know if 700 holes go in in 1 item, 7 items, 70 items or 700 items.

i stand by my opinion, there is no way i want to do 700 holes with anything less than an annular cutter if there is already one at hand, whether it is with a mill or mag drill. as far as mess, there will be lots of swarf no matter what method he uses.

 

[Strouty]

When I read this originally I did not get that the OP was a student. I think 700 holes with a mill and drill bit would be a great learning experience for sure.

 

[sk farmer]

it pays to read. i just went back and read it again. it appears they are building a welding fixture table. i built a small welding bench very similar a few years ago. not 700 holes but a good bunch of them. mag drill and annular cutter all the way. scribe out the holes, center punch, line up the pin of the annular cutter in the punch mark, turn on the magnet, punch the hole and move to the next one. don't forget the cutting fluid.

 

[larry_g]

When I read this originally I did not get that the OP was a student. I think 700 holes with a mill and drill bit would be a great learning experience for sure.

This line in the OP

My teacher also thought that annular cutters are slow.

kinda led me in the student direction...

lg
no neat sig line

 

[Strouty]

When I first read it, I thought he was talking about advice he had gotten about the use of them, I see now it looks more like a current student. Call it morning fog, or maybe I was just all ready into my rebuttal in my head.

 

[little_sparky]

Like mentioned, go with what you have. Just to clear up the accuracy of annular cutters, they will cut a very accurate hole but your set up will need to be secure to prevent breakage.
Slow PRM's and plenty of lubricant. Not sure why your instructor indicated differently.

I use them on Mag dill, Mills and lathes.
Imagine step drilling to this diameter with conventional methods. This 1-13/16" hole was done in 4-6 min.

How did you put the annular cutter in the tailstock?

 

[dr_clyde]

Most annular cutters have a 3/4" shank and will fit fine in a large Jacobs Superchuck.

 

[little_sparky]

Sorry about the confusion all! Yes I am a student and the fixture table will be made up of 8, 950x150x16mm mild steel plates. If any of you add that up I think its 456 holes, but i will also have side plates and homemade fixturing tools like riser blocks and so on. I am currently planning on using a 50mm grid pattern but i may opt to use 75mm or 100mm to reduce the amount of holes. Water Jet cutting is actually on the cards, just depends on price. Not sure what its worth in Australia.

 

[Strouty]

Thanks for the update, I was wondering where you were located. If the teacher wants you to learn, there is no better way than repetition.

 

[little_sparky]

Thanks for the update, I was wondering where you were located. If the teacher wants you to learn, there is no better way than repetition.

From Down under, northern victoria

 

[zkling]

Sorry about the confusion all! Yes I am a student and the fixture table will be made up of 8, 950x150x16mm mild steel plates. If any of you add that up I think its 456 holes, but i will also have side plates and homemade fixturing tools like riser blocks and so on. I am currently planning on using a 50mm grid pattern but i may opt to use 75mm or 100mm to reduce the amount of holes. Water Jet cutting is actually on the cards, just depends on price. Not sure what its worth in Australia.

How did you add up dimensions to get a total number of holes without knowing the number of holes per piece? : Again I say, a CNC table of some sort is the way to go for this.

 

[Mohawk Dave]

Hougen makes all kinds of adapters so you can run an adapter chuck in your mill.

Annular cutter is the ONLY way to go. Gotta be crazy to use a twist drill for 700 holes.

 

[zkling]

Hougen makes all kinds of adapters so you can run an adapter chuck in your mill.

Annular cutter is the ONLY way to go. Gotta be crazy to use a twist drill for 700 holes.

Disagree, the sucky part is fixturing and feeding a cutter 700 times. Now if he wanted to build a self feed fixtured air spindle that would be an option, but that would be a project in and of itself.

 

[little_sparky]

How did you add up dimensions to get a total number of holes without knowing the number of holes per piece? : Again I say, a CNC table of some sort is the way to go for this.

I have current plans that has a 50mm grid pattern. But I am considering changing that to 75mm or 100mm to reduce the amount of holes. The '700' number is not 100% accurate, its just to give a guestimate and show you all that im not drilling half a dozen holes because id do that with whatever i had. Its just so you consider that number when you recommend a cutter. get me?

 

[sk farmer]

Sorry about the confusion all! Yes I am a student and the fixture table will be made up of 8, 950x150x16mm mild steel plates. If any of you add that up I think its 456 holes, but i will also have side plates and homemade fixturing tools like riser blocks and so on. I am currently planning on using a 50mm grid pattern but i may opt to use 75mm or 100mm to reduce the amount of holes. Water Jet cutting is actually on the cards, just depends on price. Not sure what its worth in Australia.

something sound fishy. you start out wanting to know whether to use a drill or annular cutter as you have no experience and your teacher wants you to drill and annular cutters are too expensive.

now all of sudden you are serious about water jetting depending on price.i may be overly cautious but may we be getting trolled?

 

[uart]

I've never used annular cutters or had to drill so many holes, so I was following this thread to learn something.

One thing I was wondering, roughly how many of these holes (5/8" in 5/8" plate) would you expect to drill before having to retool or resharpen:

1. with good quality HSS drill bits.
2. with annular cutters.

Can anyone hazard a guess. Just curious.

 

[A_Pmech]

Don't make this more complicated than it needs to be. 700 holes is not a lot, it's a day's work if you set it up properly. We do a job here that is 800+ holes in similar material located, drilled, chamfered and tapped in about a day and a half using a drill press and Bridgeport.

I suggest you stack your plates 4-up and drill with an HSS twist drill using coolant. Spend the time to properly locate each start with a center drill so the big drill makes it though straight.

 

[Strouty]

Of course you would think that 700 holes is not a lot!

 

[gte718p]

A days worth of drilling is a lot to me. Even if it is only 480 holes, that is requires setup and drilling a hole every minute for an entire 8 hour work day. If he can do 4 plates at a time you still have to setup and drill a hole every 4 minutes. That is going to be close with slow feed speeds. Center drilling adds another step and additional time. Also hope he has power feeds on both the axes and the quill.

My time and my overhead would make sending it out to laser or water jet very very appealing. Two hours of someone else's time of 8 of mine. Not even a question.

 

[Mohawk Dave]

I've never used annular cutters or had to drill so many holes, so I was following this thread to learn something.

One thing I was wondering, roughly how many of these holes (5/8" in 5/8" plate) would you expect to drill before having to retool or resharpen:

1. with good quality HSS drill bits.
2. with annular cutters.

Can anyone hazard a guess. Just curious.

I'm definitely not an expert and don't do a million holes. But the old timer I have bought mag drills and cutters from is always bitchin that when the youngsters come on the job they don't use cutting fluid and smoke the cutters.

He says his cutters will last damn near forever. I don't know how many holes that equates to. ??? He's drill construction material, so no hardened steel or titanium, but I would "assume" several" hundred holes when kept cool....

Anybody have a more educated response?

 

[DekeT]

Anyone ever slipped one of these into your drill press? They hold cutters.

http://www.victornet.com/alphabetic/Annular-Cutter-Holders/1861.html