Intermediate sized holes, how to make them (what tool)?

[WobblyHand]

After being a machinist for more then 60 years I like to make things I can’t buy for cheap. Look at my avatar closely. It is made out of one piece solid cube with 3 free floating balls inside cube . The balls are .125 bigger then the entry holes. So they can’t be pressed into cube. And I hand made all the form tools on a bench grinder and lathe. So I tried to warn you of some of the pit falls on making a collet rack.
And I think I am in the right forum.

5C Collet Storage Rack Holds 30 5C Collets Wall/Machine Mount | eBay

This 5C collet storage rack holds 30 5C collets and can be mounted on the wall or machine or set on your work bench or shelf. For easy storage of your 5C collets. Our part # ALL-41280.

www.ebay.com

Jim, not disregarding your advice. Thank you for caring enough to offer it. All the commercial racks I've looked at won't fit in the allocated space. In my shop there is practically zero counter top space, and wall space. My walls are made of rough granite stone and lime mortar. Don't really want to disturb the walls. There is a drawer in my tool bench that will just fit the collets upright. But it requires a custom rack. Space in the drawer is at a premium.

My comment about being in the right forum was addressed to me, not you. Please be assured that I have the greatest respect for you and your experience. Some of us prefer to make things when it's easier to buy, others only do it only when necessary. Me, I'm kind of in the middle. If I can find something that will work and the cost isn't too bad, I buy it. If the cost is high, I look at making it. If the cost of making it is high, I usually re-evaluate if the widget is necessary to have. Sometimes the widget never comes to be. That's how it is in my home shop.

 

[WobblyHand]

I always use a step drill for these kind of holes. The single flute step drills make really close to perfectly round holes. The 2 flute step drills cut faster and still make very nice very round holes. When I get to the step that is the diameter I need I push through to the start of the next step which does a really nice job of deburring the hole. Then I flip the piece over and debur the back of the hole with the same bit.

When I say the one flute bits make really nice round holes I mean I have used a single flute step drill to enlarge the hole of a circular saw blade without adding any measurable runout to the blade.

https://www.amazon.com/Neiko-10194A-Titanium-Drill-Speed/dp/B000FZ2UOY/ref=sr_1_3?dchild=1&keywords=step+drill&qid=1599125733&sr=8-3

I can't phathom getting along without my step drills!!!!

@MikeInOr Might have used a step drill since this plate is aluminum. The Neiko step drills I bought a while back were made of mush. I used one on a light fixture which was made of steel. The edge on the step drill practically melted away and didn't cut. The step drill sort of heated the metal, rather than cutting it. It was an unpleasant experience, especially since this was overhead.

What would you use as a backer for the aluminum if using a step drill? It would have to be rather thick.

 

[WobblyHand]

Being the "cheap old buzzard" that I am, if I don't have the tool necessary for a job, I look around my stash until I find something that sorta-kinda would work. All of this is based on what I am trying to accomplish. I use a lot of sheet steel, both painted and "GalvaLume". And old electrical enclosures. And. . . Electrical enclosures use an 11 Ga back pan. At 0.118, I call it 1/8 "under". Actually 3mm but I still think in fractional inches.

For thin (<1/8") steel, I use a step drill to rough in the starter hole. Then use one of several devices, depending on how I feel at the time. The 30mm / 1-7/32 knock out on a step drill or a 1-7/32 knock out punch. I've used Greenlee's "30mm Slug Buster" for 1/8" stainless. With that material at electrical spacing it leaves a flat finish. I do use a hydraulic punch driver. At my age I'm not as strong as I once was. For aluminum up to 3/16" or so, I will use a hole saw or step drill. Knockout punches can leave internal cracks in the metal when you get into thicker sized material. As would an "Iron Worker".

Then there's drilling a number of small holes in a circle and smoothing up the edge with a file. Or a KO punch. Or. . . If I was in the field, the choices would be much less. It largely depends on the needed accuracy. Just how accurate do you "need" it to be. And how fast. If it's for "profit", it needs to be done yesterday. Which in turn justifies some fancy tooling to do one hole. Or if it's for an idea that may or may not work and time isn't a constraint, drilling a series of holes would do. It all comes down to time VS money VS later use of the tooling. There is a tool for virtually any job, if you look for it. How much do you want to spend?

Yes, I too look around so see if something I already have will do. No punches here, that I know of, unless there's some really old ones my Granddad left me. Maybe I'll fish around the garage to see if there is something there.

My experience with hole saws isn't very good, but that is "free hand", not on a mill. Those coarse teeth (really made for wood) and sheet metal sound like trouble to me. I have drilled metal with a hole saw on a drill press, and nothing bad happened but it was scary. Really didn't like the way it worked. It felt like the setup might break at times. (It didn't, but it was under strain.) And I had trouble removing the annular ring that formed.

Really didn't want to spend much on this, but I'm $28 into it now. The aluminum is a piece of scrap I've been holding onto for the last 20 years or so. Hopefully it's just my time from now on.

 

[WobblyHand]

Have you tried it yet?

I use AC's in the mill (Bridgeport) all the time. I use slow speed and spray coolant. Wouldn't try a hand held drill or even less than a heavy duty drill press. Work needs to be secured!
Get the one you need and add to your collection as needed or buy a set and fill in with more. Once you try you'll like!!

My 2 cents
Aaron

View attachment 335666

Ooh, nice.

No, haven't tried the cutter yet. It won't arrive until end of next week.

 

[MrWhoopee]

The Neiko step drills I bought a while back were made of mush. I used one on a light fixture which was made of steel. The edge on the step drill practically melted away and didn't cut. The step drill sort of heated the metal, rather than cutting it. It was an unpleasant experience, especially since this was overhead.

What would you use as a backer for the aluminum if using a step drill? It would have to be rather thick.

Not familiar with Neiko, but that sounds like a really poor quality step drill (or run way too fast). The step drills I have came from HF or are no-name off eBay. When I bought the first one, I thought they were probably just a gimmick. Not so. I've used them in a mill, lathe, drill press and hand drill and have been very impressed with the smooth cutting action and quality of the hole produced. 1/8 aluminum is a perfect candidate for a step drill. As for a backer, I assume you're talking about support to eliminate flexing. Use a piece of OSB, particle board or plywood. Put it up on blocks if needed for additional clearance.

 

[WobblyHand]

Not familiar with Neiko, but that sounds like a really poor quality step drill (or run way too fast). The step drills I have came from HF or are no-name off eBay. When I bought the first one, I thought they were probably just a gimmick. Not so. I've used them in a mill, lathe, drill press and hand drill and have been very impressed with the smooth cutting action and quality of the hole produced. 1/8 aluminum is a perfect candidate for a step drill. As for a backer, I assume you're talking about support to eliminate flexing. Use a piece of OSB, particle board or plywood. Put it up on blocks if needed for additional clearance.

Probably run too fast, to be honest. When things are sort of falling on you, you tend to rush. Don't remember if the drill was set to Low or not. That's water over the dam. In a nod to HF, their step drills are much better than the Neiko. Surprisingly never had an issue with the HF step drills. Unfortunately my HF set didn't go large enough for what I was trying to do. So I bought the Neiko step drills, which were inexpensive and weren't very good. I tried the Neikos for other things and they didn't stay sharp. Oh well, the perils of cheap tools.

Yes, the backer is to reduce flexing AND stand off from the mill table. I have some old clean plywood which someone was throwing out. The plywood would be perfect for this. The step drills are kind of long. However, this is a moot point since I bought the annular cutter. Blocks of some sort are a good idea to get more standoff from the table, especially with step drills. No matter what, this set up will not be as easy as initially imagined. At this point, not sure how to clamp everything down safely. The work piece is wider than my table slots, but not wider than my table. I can clamp it on 3 edges, don't know what to do for the 4th long edge yet. Have to think about that some more.

 

[ericc]

We had a bunch of idiots trying to drill holes in stainless steel sinks with step drills. They ran them too fast and goofed up one bit for each hole they drilled, then cried about it for the rest of the day. I told the guy to slow down a bit and him and the super looked at me like I was crazy. The super drew me aside and said at this pay grade, the only speed is trigger-all-the-way-down. We ended up bringing in this hotshot team who charged way more. The boss said they had to fly out do do another job on the other side of the state and we'd better buy them a plasma cutter from Everlast. The bonus is that we could keep it. Anyway, we bought the plasma cutter and they did the whole building in 36 hours, then flew out before we could thank them. They left the plasma cutter, dead, in the middle of the floor. Best money we spent, including that Everlast plasma cutter, which paid for itself many times over. The construction manager told me that I had a lot to learn. First, don't tell the wrong guy to slow down. Second, even if that junk Chinese machine doesn't last the week doesn't mean it is not a worthwhile purchase.

There's a lesson in here somewhere, but I'm not sure where.

 

[MikeInOr]

@MikeInOr Might have used a step drill since this plate is aluminum. The Neiko step drills I bought a while back were made of mush. I used one on a light fixture which was made of steel. The edge on the step drill practically melted away and didn't cut. The step drill sort of heated the metal, rather than cutting it. It was an unpleasant experience, especially since this was overhead.

What would you use as a backer for the aluminum if using a step drill? It would have to be rather thick.

I have several step drills and have used them on mild steel plate extensively with great results. I was out of town and needed a step drill for a steel electrical box and picked up this set from Harbor freight. I have used it many times since and it does a great job on steel plate. It does not meet your diameter requirement though which is why I didn't mention it initially. I also Just used this HF bit on 1/8" aluminum plate backing it with only the jaws of the drill press vise. With a squirt of WD40 it ate right through the aluminum plate and left a very nice smooth hole with no warping of the surrounding aluminum. I run step bits on the slowest or next to the slowest speed on my drill press (what ever that is I don't know) for steel or aluminum.

Cobalt Steel Step Drill Bit Set, 2 Pc.

It is Harbor Freight so it isn't the fanciest or have a perfect finish in the flutes but it does it's job quite well!

I have a 25+ year old single flute cobalt Unibit (Made by Irwin I guess) that I remember paying a fortune for at the time. After EXTENSIVE use over the past 25 years it still works great today! There is a single step on my Unibit that doesn't cut as quickly or smoothly as the other steps because I spun it way to fast and over heated just the one step way back when.

 

[WobblyHand]

I have several step drills and have used them on mild steel plate extensively with great results. I was out of town and needed a step drill for a steel electrical box and picked up this set from Harbor freight. I have used it many times since and it does a great job on steel plate. It does not meet your diameter requirement though which is why I didn't mention it initially. I also Just used this HF bit on 1/8" aluminum plate backing it with only the jaws of the drill press vise. With a squirt of WD40 it ate right through the aluminum plate and left a very nice smooth hole with no warping of the surrounding aluminum. I run step bits on the slowest or next to the slowest speed on my drill press (what ever that is I don't know) for steel or aluminum.

Cobalt Steel Step Drill Bit Set, 2 Pc.

It is Harbor Freight so it isn't the fanciest or have a perfect finish in the flutes but it does it's job quite well!

I have a 25+ year old single flute cobalt Unibit (Made by Irwin I guess) that I remember paying a fortune for at the time. After EXTENSIVE use over the past 25 years it still works great today! There is a single step on my Unibit that doesn't cut as quickly or smoothly as the other steps because I spun it way to fast and over heated just the one step way back when.

The cobalt set you linked doesn't look bad at all. Do you know the depth of the steps? It's pretty hard to tell from the photo on their webpage. On the Neiko, the "tiers" aren't round, they are more like polygons. Consequently the 'gold' coating wears off the tips of the polygon and can be seen as silver stripes. Whether being round or polygon actually matters, couldn't say. I do know my Neiko step drill didn't do a good job. Could have been operator error. Might pick up this HF set. Thanks for the link.

 

[MikeInOr]

I tried to measure the actual height of the straight section of the step not including the tapered section and came up with ~.2"


Of course for a 1 3/8" hole the step height doesn't really matter because you can easily push it through a 1/2" of soft metal. For the smaller diameters I have gone in one side until I hit the start of the next step then flipped the piece over and opened the back of the hole up to the diameter I want which almost doubles the height of the step for a clear hole through a piece of flat stock.




When I am worried about how round the hole is I go for the single flute unibit.



The 2 flute design still does very well and produces visually round holes but the extra backing on the single flute does a really nice job of keeping it centered in the hole.