Apr 14, 2013 at 10:27 am #1301713
I was given a sheet of 1/8" aluminum (don't know the make up) and I am using it for snow saws.
The problem is when trying to drill the teeth for the saw I can't get the 3/8" drill bit to fully penetrate the saw blade. It worked on the first couple of holes but then the bit of the drill press would bind and stop turning. I changed bits and the other bit did far worst.
Is there a special bit for some aluminum's? I didn't have this trouble with the last saws I made (more than a few years ago).Apr 14, 2013 at 11:39 am #1976492
sharp bits, slow speed, slow feed, use a cutting fluid. Most aluminum is easy to drill holes in.Apr 14, 2013 at 12:19 pm #1976504
@retiredjerryLocale: Oregon and Washington
Clamp piece of wood on both sides, drill through wood, through aluminum?
That's good for sheet metalApr 14, 2013 at 12:21 pm #1976505
@filsingerLocale: Pacific Northwest
Your drill chuck spindle may be lose in your drill press. Most are easy to fix. Check out this video on YouTube for procedures.Apr 14, 2013 at 2:35 pm #1976545
@ewolinLocale: Hampton Roads, Virginia
There are special bits for drilling sheet metal, the end of the bit is almost perpendicular to the shaft of the bit, very shallow cutting angle. They almost look like an end mill. Sometimes machinist make them out of regular bits. If you have a lot of drilling you might look for them, otherwise clamp well, oil, slow feed, as others have mentioned.Apr 14, 2013 at 2:42 pm #1976549
If you said you were having trouble drilling high tensile steel I could understand it, but aluminium, of any sort?????
I think you must have a problem with either the chuck jamming open or the pulley belt slipping. Even a dull drill bit should go through.
Question: does the drill spindle also stop, or does the bit slip in the chuck?
CheersApr 14, 2013 at 5:35 pm #1976615
…Apr 14, 2013 at 6:18 pm #1976632
@jamesdmarcoLocale: Finger Lakes
I suspect your drill press is not running correctly, as others have said, if the bit is up and just stopping.
If you have a mill press, often the chuck will use a morse taper, #1 or #2. On occasion, this may get a bit rusty, especially if it has been unused for a while. Clean and reseat it. They, the male/female seats, *should* be fairly bright with no oil on them (well, maybe a light rustproofing film.)
This *can* slip even if the motor and pully's are functioning normally. You may need to clean the rust and reseat it. I didn't see where this was mentioned.
Aluminum is a very sticky metal. Often, it will build up around a less than perfectly sharp bit. The heat will actually fuse shavings to the sides of the bit making the bit VERY difficult to penetrate to any depth. The metal will expand with heat, then contract around the bit, rather like a vise. Normally these are both symptoms of a dull bit and/or too high of a turning speed. Slower is often better. Pressure can do this, too. Really a bit of an art.
The first 1/4" may be worn a little and the upper portions are still the correct diameter, also. This has happened with bits that have been resharpened 8-9 times, too. With deeper cuts, you end up cutting a LOT of metal. Old belts sometimes develop a glaze and slip very easily. Take it off and try scrubbing it with some alcohol and a fine wire brush. It might need replacing if it is really bad and has notches in it. It's very hard to regulate speed and pressure with a bad belt/inconsistent belt pressure. Check the tension, while I am thinking about it. Aluminum should cut easily but it has some quirks. Like brass, it will often dimple around a hole slightly anyway. (Brass is not quite as sticky, though.)
Oil, or, cutting fluid (often soda water) will help, but was mentioned.
Not real complicated, the splined shaft should not be dropping below the seat, of course. And the motor should spin. Not much else to go wrong and freeze up.Apr 15, 2013 at 9:20 am #1976805
Thanks for all the info. Roger, I too was surprised that The drill had trouble, never did this before.
I'm using a Delta
Here is what the belt looks like (I tried it at 2400 RPM, 3100 RPM, 1750 RPM) the belt is about 10 years with very minimal use
Here are the drill bits I used
Here is what I'm trying to drill, see the one with the elongated hole, that is what the last two did also. Could it be that I'm trying to drill a 2/3 hole in the side of the blade and the bit is just binding?Apr 15, 2013 at 10:20 am #1976836
I think you may have identified the problem; trying to drill a partial hole at the edge.
I'd be tempted to drill complete holes and then trim (guillotine) the edge off to get the partial holes you want. It will waste a bit of metal…
How are you clamping the workpiece? It looks like it's drifting, because I don't see those big bits moving much (although they're pretty long).Apr 15, 2013 at 10:45 am #1976848
Thanks Kevin, I am free handing it (no clamps- trying to save time).
Any Ideas on how to do it with out drilling a full hole? I don't want to make the blades to narrowApr 15, 2013 at 11:27 am #1976867
You're going to have to clamp for sure otherwise you'll get too much chattering and vibration free hand. I'm not sure but I'd assume you'd also have to lower the rpm as much as possible (similar to milling operations).Apr 15, 2013 at 1:15 pm #1976908
@cadyakLocale: southwest georgia
that is probably the issue.
If you have enough of the metal left to try it again you can move your hole over until it clears the edge and then cut the metal through the hole. I use that technique to get this type of top edge on my stainless steel wood stoves.Apr 15, 2013 at 5:16 pm #1976982
Fine drill press, OK drill bits. Although stub drill bits would be better.
WRONG place to drill hole however. I would never attempt to drill a hole that close to the edge of sheet metal. It WILL go wrong. The tapered point on the drill means it relies on having metal ALL around it to stay centred. If the drill bit is unsupported on one side the metal will walk.
You have two ways to do this. The first is to drill the row of holes with about 5 mm of untouched metal left on the outside edge of the saw. Then, with all holes made, you cut off the excess along the edge. A good guillotine is best for this, but tin snips can be used. So the blank you start with has to be wider than you want.
The second method uses a square-ended 2-flute slot drill or milling cutter. This lets you 'drill' right on the edge. However, for this you MUST have the job firmly clamped down for every hole. Even so, it is a bit of a chancy business, and is not recommended.
I suggest you start again. Make the blank over-size. Fix a guide to the table for the back of the saw to press against. Drill all holes, then cut off the XS.
CheersApr 15, 2013 at 5:27 pm #1976987
@b-g-2-2Locale: Silicon Valley
I'm not trying to break up a perfectly good MYOG project, but I guess you know that these aluminum snow saws are commercially available. The teeth even have an alternating crosscut pattern. With the MYOG version, I think you will end up with rip pattern teeth, even if it works.
–B.G.–Apr 15, 2013 at 5:34 pm #1976996
W I S N E R !Participant
You might also try clamping the aluminum between two ~1/2" pieces of plywood. The wood can help keep everything aligned, your bit from slipping over the edge, and prevent the metal from deforming in the process.Apr 15, 2013 at 5:59 pm #1977003
@retiredjerryLocale: Oregon and Washington
Take a piece of wood on both sides and clamp it all together. Then drill through wood, metal, wood. The wood will keep the drill centered. Doesn't matter you're on edge of metal.
(This may or may not work)
oh – Craig beat me to it – except I mentioned it above too : )Apr 15, 2013 at 7:16 pm #1977037
@scfhomeLocale: Chocorua NH, USA
The top one looks very dull and worn at the point, and the only ones I've ever seen that look like the bottom one were for wood, not metal.
Try a fresh HSS bit.
You can also get HSS Forstner bits in 3/8 that might work better in this application.
The work should also be tightly clamped to wood underneath, and you'll have to move the underlayment a little and reclamp for each hole to there is solid wood underneath each time.Apr 15, 2013 at 9:16 pm #1977116
Sometimes I get too close to the problem.
Hunt around and find a cheap hole punch for sheet metal. This WILL work just fine at the edge of sheet metal. eBay is the obvious place to go. Try
'1 Ton Aviation Power Punch Kit Sheet Metal Hole Puncher Compound Leverage Tool'
as a perfect example – but note limited hole size, up to 9/32".
Q-max punches also wortk very well.
Do NOT try to use a punch designed for paper! It will not work.
CheersApr 15, 2013 at 10:17 pm #1977142
Roger, will the unit you recommended punch through 1/8" aluminum?
That looks a lot easier then clamping wood on both sides for each hole x 12 holes per saw x 4 saws.
I figured out that on my old saws I made I did drill first then cut. I was in to big a hurry this time, free piece of metal and trying to get as many out of the sheet as I could.
Bob, I have used the "commercial" saws and they are a nice toys- they are way too small to make a correct sized block for igloos, you need at least an 18" blade. There is only one on the market now that I've seen that come close and at $55, I'll stay with my MYOG. Plus with the Scouts as the main users, I need something that I don't have to keep an eye on while in use.Apr 15, 2013 at 10:32 pm #1977145
@b-g-2-2Locale: Silicon Valley
"Bob, I have used the "commercial" saws and they are a nice toys- they are way too small to make a correct sized block for igloos, you need at least an 18" blade. There is only one on the market now that I've seen that come close and at $55, I'll stay with my MYOG. Plus with the Scouts as the main users, I need something that I don't have to keep an eye on while in use."
You are somewhat correct. The Life-Link saw that I have is 21.5 inches long, and its cost was about $45. It works good and lasts a long time. Maybe your snow is different from California snow.
–B.G.–Apr 15, 2013 at 11:38 pm #1977161
> 1/8" aluminum?
1/16" is OK, but I think 1/8" Al would be really stressing the poor thing. Eh, you could try – with long handles on the punch. Could be damaging to the punch though.
Next option – rather like hard work, but it works.
Drill small holes where you want them, while staying just INside the edge.
Then use large rat-tail file to open each one out. You would need to clamp the metal between planks.
Next option – yeah, many ways to skin the cat.
Drill small holes inside edge as above.
Clamp metal to drill press table and open hole with some sort of cone cutter. Or a wood burr. Repeat N times.
Note: clamping down for this method is crucial. You don't want spinning 1/8" aluminium sheet to take your hand off.
CheersApr 16, 2013 at 5:37 am #1977196
@jamesdmarcoLocale: Finger Lakes
Yeah, a drill bit only cuts in one direction. It will grab the corner and pull it into the but on an edge cut…hence an extreme bind. Even clamping the thing down won't help a lot. This is more or less the action of the metal and has little to do with the drill press.
You could reduce the distance from the edge to 180 degrees or less, ie, a semicircle. This will put as much or more metal supporting the the cut as is being cut away, but, this may not work too well for a snow saw.
I think you may be going about this a little wrongly. The drill press is probably not the tool you want to use for cutting aluminum. Rather, I would use a router for the task at hand. Generally a wood bit will cut through aluminum, but I would suggest using a good carbide router bit. I believe a regular dovetail jig with half inch fingers and spacing will work producing the squared ended rounded bottom profile you are looking for. A square 1/2" bit, rather than a dovetail bit, will work. Make sure you wear goggles and gloves. Hot, sharp metal shavings are nothing to fool with.
Cutting the actual teeth is a bit of a chore, but can be accomplished with files. Again, aluminum is "sticky", so it may gum up the files. Keep a wire brush handy for cleaning them.Apr 17, 2013 at 12:16 pm #1977700
I didn't read all these replies, but I'm going to reply anyway.
That piloted cobalt drill you have should be fine, can't comment on the other one, but as mentioned, the issue is edge drilling. You simply can't do that with twist drills.
A bi-metal hole saw, or an annular cutter would work, but it's *much* easier to just drill holes in a line, and then cut through them for this particular task.
It's also important to clamp, and back your work. It'll produce better results, less warp and damage to your work piece, and keep you from cutting your fingers off with a spinning helicopter of aluminum. Luckily, it's a tiny drill press. If you tried to do this with either of my mills or my big Powermatic Floor drill by hand, you'd have been in the hospital.
Drills are made for boring semi-round holes in one axis only. Not half moons, not step milling, nothing else.
As James mentioned, you could *easily* do this task with your work clamped vertically in a vise, and using a *quality* round file, get much better results, in probably half the time.Apr 17, 2013 at 3:02 pm #1977759
@fluffinreach-comLocale: no. california
Roger C is exactly correctly stunned at thethought of trying to drill something so soft, so near the edge. it's just a recipe for misery.
twist drills and thin material are an iffy combination in all cases regardless. the beast of the twist drill is not something that scales up and up and up very sweetly. yes, i have used them almost 4" across, but it is not pretty.
by the time you get to 3/8" at home, you are well into the range of them being not-that-great.
yes, i know.. they work. i build things for a living. but they are not always the most elagent tool.
helpful hints for folks look;n to make big holes in thin stuff.
the "clamp it between wood (or plastic) technique" works well, and has been mentioned.
for the more annoying tasks, you can employ a step drill, known as a uni-bit, and it can often successfully auger neat holes up to perhaps maybe an inch or so in very thin stuff. you may have to clamp that as well, but then you are getting into shearable thicknesses.
as for Tad's delimma :
get more aluminium, make it twice as wide as you want, drill down the middle, split it in 2, and you now have a nice pair of saw blades.
also, the cutting speed of alloy is quite high. you can in some cases spin the drill to astromnomical speeds with success.
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