![]() The best way to understand the cutting speed is to draw a large circle on a sheet of paper. ![]() It seems to just be easing along effortlessly until you hit it with coolant and it sizzles and smokes like crazy.The correct cutting speed is important to achieve good work results and minimize tool wear. Even drill bits over 2" diameter don't load the motor up, no matter how fast you run it. ![]() If you don't get the speed set right on that one, it will fry a drill bit or snap off a lathe tool before you can blink. I didn't realize the importance of correct cutting speed until I got that big 25hp Pacemaker lathe at the museum. Horizontal drilling assists the chips in getting out, but a vertical spindle drill press relies on the flutes to clear the hole. ![]() It's only a matter of time until it pushes out a wad of metal that jams between the walls of the hole and the flutes of the bit. A grainy slow speed crumble will pack in the grooves. An endless ribbon will flow right out of the flutes. A drill bit is just two opposed lathe tools with chip guides (the flutes) built in. At the proper speed, the chip is an endless ribbon. Too slow and the drill is pushing metal out instead of cutting cleanly. Cutting coolant combined with the correct speed will DRAMATICALLY improve the finish of your work and will make your bits last ten times longer between sharpenings (or replacements, whichever you choose). Assuming you start with a sharp tool, it will produce a progressively smoother finish with increased speed until the cutting edge breaks down due to heat and the bit burns up on the edges. Surface finish is directly related to speed, all things being equal. The closer you can get it to ideal, the better. Why is the exact speed so important? Too fast and you burn the bit up. The great benefit of this lower speed on your lathe is that it multiplies torque to the point that it will cut without slipping the belt or loading the motor. You said 1/8-3/8 so that means about 2000-700rpms for steel or a little faster for cast iron. Better yet would be variable speed and an accurate tachometer. Using those speeds, it will drill from about 5/8" down to under 1/16" holes in steel at the proper speed, and I can select a speed that will be very close to ideal for all sizes in between. I have a Harbor Freight 16 speed press that will go from 340-4770rpms. More important than absolute speed is the range of speeds. The motor supplied with the drill press (unless it's about 5hp) won't run a bit that big in aluminum a common workshop press probably won't even pull a 3/4" two-flute bit in steel unless you step-drill by 32nds. That same speed is good for about a 3 1/2" bit in aluminum. Sounds like a lot of money to add variable speed, but this would add a lot of capability to one of these drill presses and might be worth it for someone who drills a lot of holes in different sizes and materials.Ģ00rpms will drill a 3/4"-7/8" hole in steel. Might cost around $150-$200 for a new motor/VFD package. Torque from a low-speed can be regained by running on the slowest speed available on the belt system. Most VFD will allow a range of speeds from very slow to two times the motor speed (0-3500 maybe). These VFD/3-phase systems can be driven from 220V single phase, and some will even run on 110v. If matching speed to material and bit size is important, it might be very easy to pick up a VFD/3-phase motor package to mount in place of the 110v single phase motor. I'm sure there are a lot of similar brands with similar features. I don't know the speeds off the top of my head but I'd guess the lowest would be in the 180 rpm range. They are around $160, 16 speeds, MT3 spindle, etc. These are imports sold through TSC (Tractor Supply Company). Find a good one and you'll not likely ever regret it.Ī pain in the a$$ tool gets to remind you every time you use it - a good tool lets you focus at the job at hand.įriends of mine have had good luck with "Clarke" brand drill presses. I see that industrial drill presses are often sold for CHEAP at used tool dealers - especially the bigger ones. At least in my case that was the way it normally goes (before my Electro Mechano. More cutting tools are ruined by going too fast rathger than too slow. Surely it's not all encompassing, but the thing that I liek the most about it is it's ability to go SLOW not fast. I absolutely LOVE my Electro Mechano - drill press - it's quite versatile - slow enough for 4" hole saws and fast enough for 1/16" diameter drills. The Real Industrial models are likely to have a two speed gearbox with a LOW end and a HIGH end. When in reality we are more likely to be served better with slower running models. The few imported "sum flung dung" varieties I've seen all seem to want to impress the potential users with HOW FAST they'll run. Drill Presses tend to be rather "get what you pay for items"
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |