Yes if you have access to one, the good old Bridgeport is the way. Especially with a rotary table, so you can mill concentric slots for cooling.
Back to the more manageable and accesable to the average guy.
I use various means.
Step drills, very versatile. Get a good quality set. They are in no means self centering but they can be manipulated about after an initial off center mishap. They also have the the advantage of nicely deburing the edges. Use at a steady speed, slowing as the diameter increases. Use a lubricant, WD40 is great for alloy but expensive. Use mehs and some water for this. For steel use a general purpose cutting fluid or general oil. Try it see how it goes and pick your fluid.
Punches. These boys for good ones are fairly expensive. Greenlee is not the only or ultimate manufacturer. Good punches really do do the best job, especially on thinner material. If you are serious about this hobby then buy the best you can only just afford, this goes for any tools. Cheap tools wreck hours of hard work and this will only turn yout off the whole valve amp thing, or any other thing.
Punching holes in thicker material can be achieved by chain drilling around the inner circumference of the hole to be punched.
And lastly, although they can be used for a very good job with skill. The hole saw. These bad boys are hard to master, at the wrong speed especially without cutting fluid they will snatch and tear up your work. When used correctly though, they are extremely effective. Choose these guys well. Bosch and Starret are the ones to go for. The only trouble with hole saws is that they are really not much good cutting at ninety degrees to the job, as is needed for our purpose. No worries thoigh, just lift it every so-often and remove the swarf.
Lastly trepaning tools. No, forget them. At least for this purpose.
Cheers Matt.
Back to the more manageable and accesable to the average guy.
I use various means.
Step drills, very versatile. Get a good quality set. They are in no means self centering but they can be manipulated about after an initial off center mishap. They also have the the advantage of nicely deburing the edges. Use at a steady speed, slowing as the diameter increases. Use a lubricant, WD40 is great for alloy but expensive. Use mehs and some water for this. For steel use a general purpose cutting fluid or general oil. Try it see how it goes and pick your fluid.
Punches. These boys for good ones are fairly expensive. Greenlee is not the only or ultimate manufacturer. Good punches really do do the best job, especially on thinner material. If you are serious about this hobby then buy the best you can only just afford, this goes for any tools. Cheap tools wreck hours of hard work and this will only turn yout off the whole valve amp thing, or any other thing.
Punching holes in thicker material can be achieved by chain drilling around the inner circumference of the hole to be punched.
And lastly, although they can be used for a very good job with skill. The hole saw. These bad boys are hard to master, at the wrong speed especially without cutting fluid they will snatch and tear up your work. When used correctly though, they are extremely effective. Choose these guys well. Bosch and Starret are the ones to go for. The only trouble with hole saws is that they are really not much good cutting at ninety degrees to the job, as is needed for our purpose. No worries thoigh, just lift it every so-often and remove the swarf.
Lastly trepaning tools. No, forget them. At least for this purpose.
Cheers Matt.
I use Unibits for cutting 1/8" aluminum. They work great as long as you lubricate before you cut. I have three: 1/8" to 1/2", 1/2" to 1" and 3/4" to 1-3/8" all with 1/16" steps. Be sure to use the bits with one flute. The bits with two flutes won't cut a round hole. That seems counter-intuitive, but that's from experience.
Unibits will also work for sheet steel, but not nearly as well as Greenlee punches. I have a set with a hydraulic pump, not a screw. That's the way to go.
1) Punches: very expensive and only work on thin metal. You can't punch even 1/6th inch aluminum. Punches are best used for mild steel sheet. For most people step drills have replaced the smaller size punches but for cutting a large 3" hole in very thin sheet punches are the best.
2) Step drill. For working thin aluminum, like on a Hammond chassis even the cheap step drills will do well. But the good $20 drills will cut even stainless steel. A pair of step drills will cut all the holes you need. Step drills work much better than twist drills in sheet. So I used them even for small say 3/8" holes where I have a twist drill.
3) Spade bits. These are cheap wood boring bits. I sounds crazy but they work in thin aluminum if you have a drill press. You need the kind that have points on the outside. These points scribe a circle that gets deeper and finally cuts through. This is the lowest price way to go
4) Hole saws. Get the good "bi-metal" ones. These will cut aluminum plate and even steel that you can't cut with a punch
5) a "fly cutter". This is more crazy than using a spade bit but it's an old standby and works in a drill press for up to about 3.5" holes, maybe 4". I back the metal up with plywood
6) For aluminum only. A router. Use a template made wood. I never use a router freehand. A carbide bit cuts aluminum sheet like butter. This works best for non-round holes for lay-down transformers or IEC power inlet sockets The best way to make a square template is to glue it up from four wood parts.
I mostly agree.
Still. Punching 4mm aluminium is for hero types. At least without initial chain drilling. Or maybe a hydraulic punch or at least one with a thrust race. I agree they are expensive but it is a one off. If you look after them they will outlast you.
Spade bits or Forstner bits, although they seem unlikely, do work well. I have used one with water and occasional sharpening to cut marble!
Fly cutters or trepaning as you say is only really to be done in drill press. It will catch. Slow and steady and the use of a backing block is the way.
Still. Punching 4mm aluminium is for hero types. At least without initial chain drilling. Or maybe a hydraulic punch or at least one with a thrust race. I agree they are expensive but it is a one off. If you look after them they will outlast you.
Spade bits or Forstner bits, although they seem unlikely, do work well. I have used one with water and occasional sharpening to cut marble!
Fly cutters or trepaning as you say is only really to be done in drill press. It will catch. Slow and steady and the use of a backing block is the way.
Lets talk about "Feeds and Speeds" safety and keeping ones eyes working and blood off of the work piece.
Steel (mild) cuts nicely at 125 surface feet per minute. You need to know your drill RPM's and the circumference of the drill bit to calculate SFM. (Or find a chart on the internet.) On a step drill do it for the largest diameter. Aluminum can go to 500 SFM. Stainless 35 is a safe speed. A lubricant is also good. Single weight motor oil works for most steels, kerosene is often used for aluminum. I buy fluids made for this purpose they are sold as cutting fluids and they really do the job.
The best material to machine is brass. It is also more expensive than most.
Always wear gloves and eye protection. I also use hearing protectors. Kevlar gloves have come down in price especially at Grainger. I still have a fully functioning left thumb, much to the surprise of the emergency room doctor. As we both were reviewing it's internal workings I mentioned the gloves took most of the kick! Scars are cool, missing digits are not. So if you are working on small thin parts always use a clamp. The simplest one is a board with a raised edge so the work cannot spin.
My Greenlee punches are sharper than the day I bought them. I use a piece of 400 grit silicon carbide paper placed on a flat surface to sharpen the round ones. You trace a figure 8 five times on each face before every use. Clean them with a dry cloth and then lubricate the treads with a bit of Lubriplate grease, regular moly grease or at the minimum 10 weight brand name motor oil. Also put a dab on the top of the die where the screw turns. The cutting edges should have a thin amount of cutting fluid or motor oil on them. The larger sizes of punches have a thrust bearing to reduce the wasted force in punching. Sometimes it is handy to use it on smaller sizes.
The thickness of what you punch is limited by the clearance of the punch to the die and the amount of pressure available. Hole saws used at the proper speed, with good lubricants and solid clamps will work on even very thick aluminum and at slower speeds steel.
A fly cutter is often called a suicide cutter around here. I do not see them offered for sale where they used to be common. It is possible to use them in a solid drill press. But of course if you have such a drill press adding a table would allow it to be used as a milling machine.
Next step up is a bench punch. Roper Whitney - Quality Sheet Metal Fabrication Equipment I have a similar unit in my shop. With a few gauges it is used for punching holes in sheet metal that already has formed edges. Around here that is mostly wall plates.
On a prebuilt case or chassis you can use a milling machine. Aluminum however is not as nice to mill as steel or brass so you should use a cutting fluid. Pro's would actually use a pump and nozzle to keep the cutting area always flooded with lubricant. It keeps the bit cooler and prevents chips from sticking to the cutting edges.
There are actually bits made for commercial routers to work aluminum. The template mention is mandatory as is a lubricant.
Then there are laser cutters, water jets and my tool of choice the CNC turret press. NIsshinbo - MAP-500 - Punching machine - Used machines and industrial equipment shows a used one (Older than mine) up for sale at a reasonable price.
Steel (mild) cuts nicely at 125 surface feet per minute. You need to know your drill RPM's and the circumference of the drill bit to calculate SFM. (Or find a chart on the internet.) On a step drill do it for the largest diameter. Aluminum can go to 500 SFM. Stainless 35 is a safe speed. A lubricant is also good. Single weight motor oil works for most steels, kerosene is often used for aluminum. I buy fluids made for this purpose they are sold as cutting fluids and they really do the job.
The best material to machine is brass. It is also more expensive than most.
Always wear gloves and eye protection. I also use hearing protectors. Kevlar gloves have come down in price especially at Grainger. I still have a fully functioning left thumb, much to the surprise of the emergency room doctor. As we both were reviewing it's internal workings I mentioned the gloves took most of the kick! Scars are cool, missing digits are not. So if you are working on small thin parts always use a clamp. The simplest one is a board with a raised edge so the work cannot spin.
My Greenlee punches are sharper than the day I bought them. I use a piece of 400 grit silicon carbide paper placed on a flat surface to sharpen the round ones. You trace a figure 8 five times on each face before every use. Clean them with a dry cloth and then lubricate the treads with a bit of Lubriplate grease, regular moly grease or at the minimum 10 weight brand name motor oil. Also put a dab on the top of the die where the screw turns. The cutting edges should have a thin amount of cutting fluid or motor oil on them. The larger sizes of punches have a thrust bearing to reduce the wasted force in punching. Sometimes it is handy to use it on smaller sizes.
The thickness of what you punch is limited by the clearance of the punch to the die and the amount of pressure available. Hole saws used at the proper speed, with good lubricants and solid clamps will work on even very thick aluminum and at slower speeds steel.
A fly cutter is often called a suicide cutter around here. I do not see them offered for sale where they used to be common. It is possible to use them in a solid drill press. But of course if you have such a drill press adding a table would allow it to be used as a milling machine.
Next step up is a bench punch. Roper Whitney - Quality Sheet Metal Fabrication Equipment I have a similar unit in my shop. With a few gauges it is used for punching holes in sheet metal that already has formed edges. Around here that is mostly wall plates.
On a prebuilt case or chassis you can use a milling machine. Aluminum however is not as nice to mill as steel or brass so you should use a cutting fluid. Pro's would actually use a pump and nozzle to keep the cutting area always flooded with lubricant. It keeps the bit cooler and prevents chips from sticking to the cutting edges.
There are actually bits made for commercial routers to work aluminum. The template mention is mandatory as is a lubricant.
Then there are laser cutters, water jets and my tool of choice the CNC turret press. NIsshinbo - MAP-500 - Punching machine - Used machines and industrial equipment shows a used one (Older than mine) up for sale at a reasonable price.
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IME, kerosene worked well as cutting oil, when using a hole saw on Hammond die cast aluminum enclosures.
Does anyone have experience with annular cutters? These "puppies" are, in some ways, a cross between a twist drill and a hole saw and cut a slug. IIRC, they are costly and not for hand drill use.
Does anyone have experience with annular cutters? These "puppies" are, in some ways, a cross between a twist drill and a hole saw and cut a slug. IIRC, they are costly and not for hand drill use.
A caveat when going in for the commonly found punch sets -
unlike Radio chassis punches which cut out the same size hole as
that marked on the punch, the electrician/auto type of
punches cut out a larger hole.
unlike Radio chassis punches which cut out the same size hole as
that marked on the punch, the electrician/auto type of
punches cut out a larger hole.
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