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1 1/2 hole in aluminum

bkervaski

Hellloooooooo!
Testing
All,

I need to drill a 1 1/2 inch hole in an aluminum sheet. The largest step drills I can find go up to 1 3/8.

I found an annular bit but they won't fit in my drill press which has a 3/4 shank limit.

I thought "hole cutter" but looking at those teeth I wasn't sure how that would turn out.

Thoughts?
 
I have drilled lots of holes in aluminum with a hole saw - have to clean up the edges a bit when done but does an acceptable job. A fly cutter is cleaner. In both cases be sure to clamp the material tightly, and best results are with a drill press.
 
I've used a hole saw at a slow speed with good success. Try to use a drill press if you can & clamp material down good. Also use some lubricant like Boelube or kerosene.

Sam
 
Fly-cutter in the drill press. Works well as long as you respect it.

FC53-Large.jpg
 
Fly-cutter in the drill press. Works well as long as you respect it.

Didn't know such a thing even existed, nice! And Cleveland has it.

Thanks! Any notes on usage? (what did you mean by "respect it")
 
Didn't know such a thing even existed, nice! And Cleveland has it.

Thanks! Any notes on usage? (what did you mean by "respect it")

It's a dangerous tool -- a whirling knife that will show no mercy to the careless. You want the material being cut tightly clamped to the drill press table, no loose clothing, body parts well clear until the drill press stops.
 
Thanks! Any notes on usage? (what did you mean by "respect it")

This thing is notorious for grabbing the work and spinning it around--------DO NOT hand hold the work piece. Use a vise or clamps to hold the work to the drill press table.

Also, not a good idea to use a hand held drill.

I suggest you practice on scrap until you get used to how it works.

Lastly, the cutting bit as shown in the photo will leave a taper in the hole------you will need to reverse the bit (if the cutting rake will allow), or be sure you plunge deep enough to clean up the inner face of the hole.
 
How thick is the sheet you are cutting? The taper Mike mentioned is really only an issue with say .063 and thicker. Also you might could just reverse the cutting blade to avoid it completely.
 
Fly-cutter in the drill press. Works well as long as you respect it.

FC53-Large.jpg

My, how times have changed....
Back in the day.... when people actually had to build an RV (vs just put some parts together;)), This was the standard tool for cutting all of the lightning holes in wing and empenage ribs and many other parts.
Yea, that's right. All parts were solid with no openings (or pre-punched rivet holes).
 
If the hole doesn't have to be a perfect circle, make the biggest hole you can and enlarge it with a sander in your die grinder.

drillholesanddrum.jpg


Works pretty well if you can mark the circle first with a Sharpie -

51gNREXzauL.jpg


I've been doing this to create 2 inch holes for air ducting in my -10 bulkhead after fuselage assembly.

It's safer than the circle cutter and can be done free hand without a drill press. :)
 
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1.5" hole in alum sheet

The Rotacut annular cutters by Hougen are great for thin sheet stock.
Cutter goes on mandrel/arbor and will fit in 1/2" chuck.
Much cleaner hole than hole saw, great if you need precision hole.
Clamping in drill press or mill is essential for that size cutter.
 
Yep, I've cut quite a few holes using flycutters. Including holes for additional instruments in completed panels in flying a/c.

The cautions are legit; be careful. But as strange as it may sound, there are situations where controlling one can be easier with a variable speed hand drill than in a drill press. You need to turn these slowly, and be able to disengage from the work instantly if the tool grabs the work. With a drill press, you can't stop the tool quickly, you're limited in how slow you can turn it, and if it 'grabs' the work, you can't disengage unless the work is held perfectly all around on the table. With a quality variable speed drill, you can run the tool so slowly that you watch the blade move around the circle it's cutting. If it grabs the work, simply release the trigger. You still need to secure the work, of course.

It takes a bit longer, but is actually more controllable; at least in my experience.

To the OP, do practice on scrap. If you need perfect holes, get some shaft stock the same diameter as the center drill. Drill the center hole in the work with a slightly smaller bit, so you get an interference fit on the shaft stock. Use the shaft stock to replace the drill bit in the cutter. This will give much tighter tolerances on the final hole (the flutes on the center drill bit tend to wallow out the guide hole as you cut, otherwise).

Charlie
 
I didnt catch what thickness of material youre holing out, but that makes a difference on what method you choose. For thin stuff up to .032 and onsie-twosie holes, I just go old school with drilling holes around the periphery and perfecting it with a half round file. I have three steam gauges with tight spacing in a sub panel and I've remade that sub three times now (changes along the way), all old school filing and very sweet fitting. It does work.
 
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For that size hole, I use one of the Lenox annular hole saws. I've cut many holes with them. My drill press goes down to 500 rpm and I use that.

I use some plywood under the part, and pre-drill the center of the hole in the part and in the plywood to 1/4". Then I use a 1/4" pilot (really a bolt with the head and threads cut off) instead of the normal drill. This helps give a good hole.

If necessary, I use a drum sander to finish off the circumference of the holes.

All very easy and quick and quite reliable - safe, too. And the local hardware store carries the hole saws, so I can do the job soon after I find that I need to.

Dave
 
Yep, I've cut quite a few holes using flycutters. Including holes for additional instruments in completed panels in flying a/c.

The cautions are legit; be careful. But as strange as it may sound, there are situations where controlling one can be easier with a variable speed hand drill than in a drill press. You need to turn these slowly, and be able to disengage from the work instantly if the tool grabs the work. With a drill press, you can't stop the tool quickly, you're limited in how slow you can turn it, and if it 'grabs' the work, you can't disengage unless the work is held perfectly all around on the table. With a quality variable speed drill, you can run the tool so slowly that you watch the blade move around the circle it's cutting. If it grabs the work, simply release the trigger. You still need to secure the work, of course.

It takes a bit longer, but is actually more controllable; at least in my experience.

To the OP, do practice on scrap. If you need perfect holes, get some shaft stock the same diameter as the center drill. Drill the center hole in the work with a slightly smaller bit, so you get an interference fit on the shaft stock. Use the shaft stock to replace the drill bit in the cutter. This will give much tighter tolerances on the final hole (the flutes on the center drill bit tend to wallow out the guide hole as you cut, otherwise).

Charlie

All very good information..... I did exactly this process when I needed to cut a 1.5 inch hole in my rear baffle for heat muff air. Used a battery drill motor and a 90 deg. adapter. Place the cutting tool so the taper is on the inside and will taper cut the scrap.... it will then leave a nice square edge on the hole. Start off so slow that you see the cutting tip just etch the surface. As you see the line appear, you can tilt the drill to keep the bit in continues contact. You will be pleased at how easy it is to do.

The fly cutter can be purchased at any hardware store.

BTW.... the 1.5 scat to the heat muff did provide a very good flow of air and temperature of the air was greatly increased.
 
hole saw

I have used a hole saw to drill out a plug from 3/4 plywood and then bolted this plug to the part (firewall) and then this plug is the guide with the center drill bit removed from the hole saw also had a piece of plywood on the backside held on by the same bolt holding the guide plug
 
Check out Travers tool on the web. Look at piloted hole cutters. I used one with a 1 1/4 inch cutter to make some of my gage holes for my dash. They have some that are much cleaner than the big box store hole saws. I would post a picture if it was not so hard to do on this site.
 
My, how times have changed....
Back in the day.... when people actually had to build an RV (vs just put some parts together;)), This was the standard tool for cutting all of the lightening holes in wing and empennage ribs and many other parts.
Yea, that's right. All parts were solid with no openings (or pre-punched rivet holes).

I used to call these things the widowmaker...hahaha hated using those things
...but did on many occasions
 
Amazing community.

A local RV-9 builder tested and cut a sample with a hole saw and dropped it off on my doorstep last night.

You just can't buy this kind of support.

Thank You! (you know who you are) :D :D :D
 
Learned my lesson with a fly cutter years ago, they are just plain dangerous. Harbor freight sells several size punch kits that work well on aluminum and also SS firewalls. Cheap, 20-30 bucks.
 
HIGHLY RECOMMEND A FOOT SWITCH WHEN USING THE DRILL PRESS! Approx. $35.00 and may save your hand if or WHEN something grabs. Your foot becomes the third hand that can turn off the drill press if needed.
 
All,

I need to drill a 1 1/2 inch hole in an aluminum sheet. The largest step drills I can find go up to 1 3/8.

I found an annular bit but they won't fit in my drill press which has a 3/4 shank limit.

I thought "hole cutter" but looking at those teeth I wasn't sure how that would turn out.

Thoughts?

depending on the thickness of the material, a hole punch at Harbor freight should work nicely and rather inexpensive. I have cut many holes with it in the past and worked out great.
 
I guess this is all academic now since bkervaski already got his hole cut, but clearly the hole punches (we used to call them chassis punches) are the way to go. A lot of EAA chapters own a set. You can buy large ones for the instrument panel, too.
 
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