cutting and boring aluminum

Cue Crazy

Cue Crazy

AzB Silver Member
Silver Member
I'm hoping for some good opinions from some of the people here with machining experience. Does'nt have to only come from cuemakers, I'm open for info and opinions from anyone with experience machining aluminum alloy type materials.

First, what is the cheapest, but best route to go when chopping aluminum to lenth? I'm not talking about the thin stuff, but either plate aluminum or stuff like some 80/20 t-slot I need to cut. I figure a chopsaw will cut nice and square, but trying to decide on what blade to get. At first I thought, and abraisive blade maybe, but then I thought that It may just load up, and could be dangerous, so I did alittle research, and found that some people use a carbide tipped non-ferrous blade with a high tooth count. Wondering If others here aggree, and would be even better If I could find a reasonably priced blade that works well, because some of them can run quite a bit of money, and I'm just using this to chop stuff to lenth, so I'm not looking to make a huge investment if that's posible.

My other question, has to do with boring holes say 1" or larger into flat plates. Years ago I had a machinist friend of mine give me a tip for making the plates identical, He told me that he drilled, tapped, and screwed the 2 plates together before machining them. If someone was to do this, and then wanted to drill/bore both plates with 1" or larger holes at the same time, then what would be the prefered method? What tool should they use, and what's the precedure? I have a small mill with a R8 collet system to do this on, and I'm wondering If I should buy a R8 boring head to do this, or if there is a better or less cost effective method I can use?

Pretty basic questions I guess, and I may have answered some of them My own , but figured there could always be things I'm not aware of, and hoped maybe some of You guys can help with advice that may save me a few bucks or a even possibly a trip to the hospital to have carbide and aluminum removed from My person;) .:)

Thanks, Greg
 
cutting aluminum

Hi Greg: I will attempt to help (of course subject to criticism by the pundits).

It all depends on the accuracy of the cut you are try to achieve. If the piece is going to be machined later, or if you just want to hack off a piece, your bandsaw will probably do the trick with your standard blade, use a little light oil.
I have cut 1 1/2 bar stock (6061-T6) with my band saw and also with my chop saw using a carbide chop saw blade. Again cut slow and use a little oil. A machine shop would use a wet cut-off saw with a blade designed for this or a band saw with a blade designed for cutting aluminum or even a shear.

If you just want a 1" hole then mount your piece FIRMLY to your mill and drill with a 1" bit. Pre-drill a 1/4" or so pilot hole
Don't forget the oil. If you want a precision hole bore it with a boring bar. Fastening the two pieces together works all the time and super glue works some of the time.

Hope this helps.

Bob Flynn
 
Greg,

I second the Bandsaw. I cut all my metal bars to length with a Jet Horizontal metal cutting bandsaw. Then machine to size.

As far as the hole. It all depends on how accurate you need it to be. I would probably lean towards drilling .500 to .625 through, then .9375, and then ream. But, these are all tools I have in the chest. If you already have a boring bar then great.

Good luck,

Troy
 
Some general information about machining aluminum:

It sticks to tooling unlike steel does. For this reason you have to take certain precautions. First, a lubricant does wonders to keep the aluminum chips from sticking to the tooling. Oil works fine, as does WD-40 if that is all you have lying around. Use a lubricant for cutting with saw blades, drilling, and milling. Turning on the lathe doesn't really need oil because you are only cutting with one edge and the chips are free to fly away. For bandsaw blades you can use a wax style lubricant that comes in a push tube, or wd40, or oil.

When selecting tooling for aluminum, again the key is that aluminum sticks. So you have to choose tooling that has large gullets so the chips have room to escape before sticking and getting trapped. For milling this means using a 2 flute endmill instead of a 4 flute end mill as you would for steel. For sawing this means using a blade with large gullets between the teeth. A woodworking type bandsaw blade is better for aluminum than a very fine blade you would use on steel. And you can use a woodworking chop saw to cut aluminum to length. They have blades specifically for nonferrous metals that are the same price as woodworking blades. The grind on the teeth is not as angled (side rake) as woodworking blades so the edge stays sharp longer.



For your hole cutting question, you can use a boring bar, but it is very slow. You have to drill a through hole first, then switch to the boring bar. And you cant take huge cuts in one pass. So if you had multiple holes to make that each required several adjustments of the boring bar, you would be there for a long time. A boring bar is generally used when you need a very high level of accuracy (.001 to .005) and the hole has to be straight. It also requires a good amount of skill to get a hole within a very tight tolerance using one.

A drill is the fastest way to remove material. You can get a cheap set of large diameter drills by increments of 1/16ths. The most important thing about drilling is to drill in steps going from small diameter to large diameter. You will save your tooling, save time, and get a much better hole. The reason for this is drills do not cut well in their web area. This is the center part of the drill that is tapered from shank of drill to tip of drill. If you were to cut a drill bit in half and sharpen it, it would not cut as well as a full length drill because the web is larger in that area due to its taper. Anyway, my point is always step drill. For a 1 inch hole, you might want to progress with center drill>1/8>1/4>1/2>3/4>15/16>1. The last step is smaller to give you a finish pass. Make sure to pull the drill out on a regular basis to clear the chips. ANd you MUST use a lubricant when drilling aluminum.

Another way to make a hole is with an endmill. This can be very useful on something like 80/20 that has a channel in it where you might not be able to start a center drill. You can make your hole in one step with an endmill. Make sure you buy a center cutting endmill for plunge cuts (holes). A non-center cutting endmill can not be used for plunge cuts.

Another option is a hole saw. I've never done this personally in metal, but I believe they are designed to cut nonferrous metal as well as wood. You can go right to your final size using a hole saw (in fact you must due to their design).

So there you have several different ways to make holes. It really depends on what you are doing, how accurate you need to be, how much time you have, what your skill level is, and what tools you currently have or are willing to buy. Hope I was of some help to you.
 
Thanks for the input Guys, I have to admitt I was aware of many of the options available, have used some of them, and I purposely left out how accurate they need to be, so I would get many different answers, and more detail, as what has happened. Sorry I didn't mean to keep anyone guessing, but I have several type holes to drill, some less accurate then others, but would like a nice finish to the bore just the same. The most accurate will probably be 1" and under, so some of that range I have covered already, But do need to setup with drill and reamer for the 1" if I go that way. I see that I can get larger then that, and some have a reduced shank that would work for My larger holes, but in doing that I'm purchasing a seperate drill and reamer for each size I need, Add step drilling into the ratio, and that's more large drills I'll need for the inbetween sizes, so that's why the thought of getting a boring head comes in, although I guess I would need several sizes of those also, and drills to open the holes up. I'm trying to give Myself the best range of diameters with a clean bore, for the least cost, is about the best way I can explain It I suppose, but like I mentioned the ones that need to be dead straight and most accurate would be 1" and under, so drill and reamers may be sutable for those sizes.

I do need to stock this little mill with more tooling though, so always picking up small lots of stuff when I find a deal. Have a set of collets, some various size end mills, some 2 flute drills, and that sort of thing that I use with It already, and have the tooling for the lathes that I can cross use, but I'm really lagging in stuff that makes a larger hole, and It's starting to come into play for me in some of what I'm working on. A hole saw may work for the stuff that doesn't need to be deadnuts, If I can find one that works well with aluminum, not sure about the finish it would leave, but I guess I could take a drum sander to it If need be. I mostly only use those on thin stuff, the only thick stuff I use those on is wood or soft materials.
The thing is I may have a need for dead nuts large holes also to mount bearings or whatever, so I keep going back to a boringhead in My thinking, and trying to think ahead. On the lathe I can really control how clean and accurate a hole is with a boring bar, and if I don't have a certain drill and/or reamer that I need on hand, the boring bar really comes in handy. I want clean cuts, but want to stretch My dollar to give the most options in the 1" to 2" range too.


On the chopsaw, I guess, I'm looking for clean, square cuts without milling the ends to clean them up. My understanding from some of what I've read, and through some personal experiences is if cutting on a bandsaw, that It's hard to get a perfectly square cut. Also I may have a need for some mitered cuts, Pluss It seems easier to setup to cut one time, as opposed to second operations, even if I have to go slower. I guess on that one, I'm looking for a suitable blade for a chopsaw.



All good info, and I really apprietiate You guys taking the time to reply. It really helps back up My own thoughts, and opened me Up to few things that may make My decisions easier.:)

Greg
 
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If you are making holes for large OD bearings, I think a boring bar is the only way to go. Sounds like you are making some sort of headstock if you need accurate holes for bearings in two plates at exactly the same position. A project like that deserves the extra time and effort of a boring bar. Large diameter reamers will quickly get expensive as well. A reamer following a drill bit is also not guaranteed to be a straight hole. When drilling holes with multiple drills/reamers, "a hole will follow a hole". This means that if the first drill wanders a bit, the next drill bit will follow the inaccurate hole, as will the reamer. You don't get that with a boring bar, and will generally get extremely straight and round holes. THe worse condition for a boring bar can be an interrupted cut. And of course you have to account for the flex in the boring bar when approaching your final hole size.

At work we build fixtures with 80/20 from time to time and use a woodworking chop saw to cut the material to length. I'll see what blade it has and let you know. It cuts quite well and no secondary operation is needed to improve the cut.

If you are making holes for bearings you will probably want a press fit, and you will need a way to accurately measures the hole and the bearing diameter. Calipers are not the best tool for this task. A micrometer will be much more accurate. For measuring the ID of the bore, get a set of telescoping gages that you can then measure with the micrometer.

You mentioned you have a small mill. Does it have a power down feed? If not, how about a manual down feed wheel? You will definitely want to use the feed or wheel when boring. Moving the quill with the lever normally used will not give you as much control over the feed of the hole.
 
iusedtoberich said:
If you are making holes for large OD bearings, I think a boring bar is the only way to go. Sounds like you are making some sort of headstock if you need accurate holes for bearings in two plates at exactly the same position. A project like that deserves the extra time and effort of a boring bar. Large diameter reamers will quickly get expensive as well. A reamer following a drill bit is also not guaranteed to be a straight hole. When drilling holes with multiple drills/reamers, "a hole will follow a hole". This means that if the first drill wanders a bit, the next drill bit will follow the inaccurate hole, as will the reamer. You don't get that with a boring bar, and will generally get extremely straight and round holes. THe worse condition for a boring bar can be an interrupted cut. And of course you have to account for the flex in the boring bar when approaching your final hole size.

These have been My experiences too, so That's where alot of My thinking is coming from. It's really important to center drill the hole accurately, before stepping up, and even then things can sometimes get out of line down the road. I'm pretty good with a boring bar on a lathe, and can usually bump the diameter in to perfect size depending on how snug I want the fit, not sure how easily that ability will transfer over to boring on the mill though, and I already know through experiences on the lathes that metals are less forgiving when trying to get a good fit, as opposed to wood or composites.

At work we build fixtures with 80/20 from time to time and use a woodworking chop saw to cut the material to length. I'll see what blade it has and let you know. It cuts quite well and no secondary operation is needed to improve the cut.

I read somewhere about someone using a woodworking chopsaw to cut the stuff, and was wondering if I could use one instead of a metal chopsaw if I clamped the pieces down well before cutting them. Will a mitersaw cut mitered corners into this stuff? Wonder If A sliding compound saw would work too. I would be very interested in the type of blade If You are able to find that out. I've found some links with a few suggestions on them, but still trying to gather all the info I can about blades that have actually been in use cutting the 80/20. From what I read the cuts are clean, and square when cut that way, so That's why I'm leaning towards that method instead of a bandsaw, that and the secondary operations part being illiminated at the same time.

If you are making holes for bearings you will probably want a press fit, and you will need a way to accurately measures the hole and the bearing diameter. Calipers are not the best tool for this task. A micrometer will be much more accurate. For measuring the ID of the bore, get a set of telescoping gages that you can then measure with the micrometer.


I just received a set of old NSK dial calipers that I won on ebay for between $3 & $4, after shipping It was like 9 bucks. Didn't really need them, as I have others but they turned out to be in good condition, and couldn't turn them down for that price. They are still in the original case too. Anyway the reason I mention those is because on the dial It says Japan & underneath It says "Micrometer". You Know I use to mistakenly call them that years ago, and was even corrected a few times for using that term. I just thought that was funny when I saw It actually written on the face of these calipers. I guess the term mostly refers to the actual measurement, more then the type of tool.:confused: I do believe I know the type You are refering to though, The ones that look like a "C" clamp, Correct? Atleast that's the type I know refered to as a micrometer, but then what do I know:D . Thanks for the headsup on that stuff.

You mentioned you have a small mill. Does it have a power down feed? If not, how about a manual down feed wheel? You will definitely want to use the feed or wheel when boring. Moving the quill with the lever normally used will not give you as much control over the feed of the hole.
Click to expand...

Are You refering to the "Z" axis? If so, no power downfeed, just the large spoked handwheel, but It does have a smaller hand dial, or really just a big round knob, for Micro downfeed, by hand ofcourse. The larger spoked wheel locks down, so You can use the Micro feed instead. It's just a harbor freights type minimill, only Mine is a Cummings. Basically the same thing, probably imported By Seig like the little lathes. Until I move from here It's all I have the extra room for right now. I plan to upgrade to a large mill first thing when I have the extra space though. I've let too many deals pass by, due to not having the space. It's been decent for utility type stuff, but may not be up to snuff for a boring head, not really sure until I try. It does have a R8 collet spindle though, and they make boring heads for It. I heard a long time ago that some bridgeport type mandrels will work too, but some may need modifying as they are a bit longer or something. It's been a while so not sure what the deal was with that, but they are both R8's I believe.


Thanks For the info I really do apprietiate the sharing of thoughts, Greg
 
Kerosene

When I was working in the Machine shop, we used Kerosene.. Cuts cleaner than oil and easier to clean up.. Sometimes we used "Rapid Tap" made by ?? I forget.. :confused:
Watch out for the long chips.. And might want to Lessen the cutting edge so it will not bite into the Munimula,
(Aluminum spelt backwards:D )..
 
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CueCaps said:
When I was working in the Machine shop, we used Kerosene.. Cuts cleaner than oil and easier to clean up.. Sometimes we used "Rapid Tap" made by ?? I forget.. :confused:
Watch out for the long chips.. And might want to Lessen the cutting edge so it will not bite into the Munimula,
(Aluminum spelt backwards:D )..
Click to expand...



Thanks, Yeah Oil makes sweeping chips a royal PITA.

What is a rapid tap?

Are You talking about something like one of those tap-O-matic units, or whatever they are called, or is It something else?

Speaking of that, I need one of those tapping units. I've seen them, but never used one. I have just been using a tap handle with a piloted hole drilled in the back, and mounting a pointed center in the mill spindle. As I tap I have to lower & raise the Z axis to keep them aligned. Not perfect, but It gets me closer then just straight up hand tapping them does. I both drill and tap one hole at a time though, so I don't have to mess with trying to re-align the spindle with the holes to tap each one of them. There's better ways I'm sure.


Greg
 
Greg,
If you're seriously looking for a tapping head, I have one that I'm not using. I'll get all the particulars when I go to the shop today. They retail for $400/600, depending on model & capacity. I'd take 1/2 that or less from you. I'll have a pic when I come back. KJ
 
Rapid Tap

Sorry, I didn't mention it. Rapit Tap is a clear cutting fluid.. Helps cutting the metal , diplacing the heat and lubing for a more cleaner cut.. Aluminum loves to Gaul (Spelling??)
Forgot to mention, Kerosene is Flamable. I know you know,but, I still gotta mention it, so all can be safe. As we all know that #1 Rule in a Machine Shop..
" SAFETY FIRST"..:)
 
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CueCaps said:
Sorry, I didn't mention it. Rapit Tap is a clear cutting fluid.. Helps cutting the metal , diplacing the heat and lubing for a more cleaner cut.. Aluminum loves to Gaul (Spelling??)
Forgot to mention, Kerosene is Flamable. I know you know,but, I still gotta mention it, so all can be safe. As we all know that #1 Rule in a Machine Shop..
" SAFETY FIRST"..:)
Click to expand...
Rapid Tap is a great product that you can find some information on this page...
http://www.relton.com/cutfluid2003.html#nrt
Personally I have been using Tap Magic for tapping and cutting....
http://www.tapmagic.com/

Both are available at McMaster-Carr which I use for a source of tools and information when I need to research something...
http://www.mcmaster.com/

Great info in this thread...
Myron
 
CueCaps said:
Sorry, I didn't mention it. Rapit Tap is a clear cutting fluid.. Helps cutting the metal , diplacing the heat and lubing for a more cleaner cut.. Aluminum loves to Gaul (Spelling??)
Forgot to mention, Kerosene is Flamable. I know you know,but, I still gotta mention it, so all can be safe. As we all know that #1 Rule in a Machine Shop..
" SAFETY FIRST"..:)
Click to expand...




Thanks, Now that You mention the fluid part, I think I remember someone mentioning the stuff before. I haven't personally used It Myself though.

Yes Sir, I'm well aware that kerosene is very flamable, We use to use It to help start pit fires with when I was young, but It still should be mentioned for anyone else that may read this.;)
 
KJ Cues said:
Greg,
If you're seriously looking for a tapping head, I have one that I'm not using. I'll get all the particulars when I go to the shop today. They retail for $400/600, depending on model & capacity. I'd take 1/2 that or less from you. I'll have a pic when I come back. KJ
Click to expand...



KJ, I sent ya a PM.
 
alpine9430 said:
Rapid Tap is a great product that you can find some information on this page...
http://www.relton.com/cutfluid2003.html#nrt
Personally I have been using Tap Magic for tapping and cutting....
http://www.tapmagic.com/

Both are available at McMaster-Carr which I use for a source of tools and information when I need to research something...
http://www.mcmaster.com/

Great info in this thread...
Myron
Click to expand...




The can that the tap magic comes in reminds Me of the old 3in1 oil cans. I have some 3in1 that I use for various purposes. It comes in plastic bottles now days. I'm assuming these cutting fluids work better though. I read on the one link for rapid tap that they have anti weld properties. Looks like different fluids for different metals though.

Thanks for the info,

Greg
 
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