What are good drill press safety rules?
There’s a long list but I would say pay careful attention to these two rules specifically applicable to drill presses and no other machinery:Drill presses are notoriously top heavy - mine weighs 163 pounds and 100+ pounds of it are in the top 8 inches and its six feet tall with a 12″ wide base. It will tip over very easily and could do some serious damage and hurt someone, esp a child. Bolt it to a wider base, or bolt it to the floor or table. Seriously.Use a fence, or brace your workpiece against the column to the right or clamp it really firmly to the table. This is most important for metal workpieces rather than wood, The mistake most rookie drill press users make is to have the piece long end pointing to the right and drill into it (bigger bits are worse). The bit, when breaking through the bottom will grab and spin that workpiece in a big circle. Serious stomach and chest lacerations can occur when that 1/2 horsepower motor grabs that sharp piece of metal and rips it across you. Solution: Start with the piece braced against the column to the right side of the workpiece so when it tries to spin, it pins it against the steel column.and then the usual about keep long hair, clothes, loose jewelry, fingers and body parts and stuff out of the sharp and/or rotating parts, use of appropriated guards, electrical safety and eye protection. Also the bit and drilled parts might be quite hot to the touch after drilling.
What is meant by this 'Drilling capacity of the drill machine?
Its the diameter of the hole. All hand held and particularly cordless drills are graded by stating the drilling capacity in specific materials by the maximum drilling diameters of the drill bits that can drill through masonary(concrete), steel and wood. So typically you might see something like this stated for a general purpose cordless drill: Drilling capacity is: Mild steel: 10 mm, Wood: 25 mm, Masonry: 12 mm (by the way 16mm =0.629", which is about 5/8")
How do I determine the torque required for my drill press design to drill through a certain material (steels etc) and are there catalogs you know of to assist in this decision?
You can figure it out by reading the torque specs if you like, but most drill presses (and mills) are rated by bit size in steel. That really ought to tell you what you need to know.Or are you asking how to set up a drill press for the job in hand? The rule of thumb is the bigger the bit, the slower the speed and the greater the pressure. Many drill presses have a plate on the side showing speeds to use for different bit sizes, and a google search — try “feeds for speeds” — will find more.In general, though, I sneak up on it empirically. I set the machine according to the chart, lean on the handle, and watch the chips. If the chips are too big or too small, I speed up or slow down accordingly. Heck, I don’t even watch any more, I can feel the bit cutting through the handle on the quill.
If I drill a hole, why must the speed of drilling machine be faster for smaller hole but slower for bigger hole?
When using a high speed steel tool such as a typical drill bit to cut steel there is an optimum speed. If the tool moves through the work too slowly it doesn’t cut well. If it moves too fast it overheats and damages the cutting edge.If you look at a twist drill tip you can see that ir has a pair of cutting edges shaped a bit like little plows. If the drill size is one inch (a pretty big drill) then the outside corner of each cutting edge moves 3.14 inches for each full turn of the bit. This is because of the formula we learned in elementary school pi times the diameter of a circle gives its circumference. If our one inch drill turns at 100 rpm the cutting edge moves at 314 inches per minute. A 1/8 inch drills cutting edges will be moving at only about 39 inches per minute.In real practice, for a 1 inch drill bit cutting steel, 350 rpm would be a good speed. For a 1/8 inch drill you would want to use 2800 rpm.Here’s a drilling speed chart from Wood Magazine, I do recommend this publication for home woodworkers.http://images.meredith.com/wood/...
If I drill a hole with bit diameter “x”, what is the diameter of the resultant hole? How is the bit diameter related to the actual drilled hole size? I'm sure the latter is slightly larger, but by how much?
The short practical answer to your question is to finish your hole with a reamer. Reamers should be run with plenty of lubricant and much slower than drills. You may even want to size your mating cylinders according to available reamer sizes. For example - dowel pins present a common case where precise press fits and slip fits are desired. Dowel pins are sold in standard sizes with tight prescribed tolerances. Reamers are commonly available that are sized specifically to produce press fits and slip fits for particular dowel pin sizes.If you are in the U.S. McMaster-Carr is a good source for drills, reamers etc.If you don't have a reamer at hand but need to make an accurate hole - first use a drill one or two sizes below the final size you want. Then go back and drill with your final size drill. This is called drill reaming and can usually get a hole to within a few thousandths of an inch of the nominal final drill size.If you are not using a drill press or a mill or lathe, you may consider building yourself some kind of guide block with a drill bushing which can help you guide in your drill perpendicular to the surface of your plate - more so than drilling by hand anyway.
What drill should I use to make holes in rocks for jewelry?
As for dremels , just get a 120 volt one. That way you can just plug it in the wall when you want to use it. If you get a battery powered one you have to leave it on the charger and then one day it will stop working. You know how batt operated stuff is. http://search.yahoo.com/search?p=drillin... http://www.making-jewelry-now.com/drilli... I talking about the 300 or the 4000 that are in the link below. They are corded and variable speed. You may be able to find them without the accesories for less.$ It looks like the cordless ones are not variable speed. http://www.google.com/search?sourceid=na...
Why do woodworkers recommend owning a drill press?
Because whenever you need to drill a hole, it needs to be perfectly straight. Either up and down, perpendicular to the surface or straight into end grain.Dowels being used as connecting pins need to mate properly with the opposing hole, and won’t unless the hole is perfectly perpendicular to the surface.Drilling shelf pins is another reason, although that can also be accomplished with a jig and a cordless drill.It’s not just regular twist bits either to think of.Forstner bits are used for drilling the holes needed for modern door hinges. Again, if that’s not perfectly perpendicular to the surface, your hinges and therefore your cabinet doors will be all wonky.There’s also circle cut-out jigs that can only be used with drill presses. Handy for cutting out circles smaller than 6″ diameter.I think there’s many dozens of other uses, but I’ll let someone else have a stab at listing them. Door hinges and shelf-pin holes are the two big ones if you’re doing kitchen cabinetry.
Plug welding holes then drill and tap them?
It depends on the diameter of the hole and how deep it is. I have done that at work a couple times and made it work but here is some problems you might run into 1. When you heat metal up to melting point, all the carbon in the surrounding are rushes to the weld making it stronger and harder. This will affect all the surrounding material as well because now you have different carbon levels in your part so in the future cracks may start to appear in the part( could be months or years) 2. Machining through welded material sucks balls. just turn your RPM down 1/3 of what your were previously running. tapping it is even worse. taps break very easily. i don't know how you plan on tapping them but i would do it by hand. a tap-o-matic would just mess it all up. 3. depending in the part you are making the surface of the part may have to be machined again to compensate for the part expanding, contracting, warping, etc. P.S. in case you didn't know the formula for calculating RPM on a lathe, mill, or drill press is CS X 4 divide by the diameter of the tool. The CS stands for cutting speed which you will have to get a chart that says the cutting speeds for different materials. i happen to remember that the cutting speed for 1020 steel is 100. so 100 x 4 = 400. now lets say its a .187 drill bit. so you would go 400 divide by .187 giving you 2139. and bam you have the maximum rpm for that material.