Hello. I have a Dremel tool. I am thinking of getting the drill press accessory and/or the routing accessory. Is it practical to use the Dremel Drill press combo for light milling with the appropriate tools? ie such things as grubbing out brass channel for loco frames. thank you. John Hudson.
Thanks very much for your replies and advice. John hudson.
Thanks very much for your replies; most helpful. John Hudson.
I agree with your conclusion that the Dremel in a drill press does not make a good milling machine; however, I would argue that most of the tasks it is designed for involve side thrust. You could argue whether its design is adequate for its primary purpose, but the Dremel tool is not a drill, it is a rotary tool that can function as a drill. I would be interested to know how the design of a drill press or a milling machine compares to the Dremel. I'm also not so sure I believe this stuff about side thrust- I know it is standard lore in machine tool world, but wonder whether in the real world the bearing surface alignments of the two types of tools are that different.
I bought a Dremel drill press thinking it would be kinda neat to get more precise drilling. There's so much slop in it I can do just as well by hand.
JP
I'm want to avoid the use of the term 'Dremel. These are properly hand 'motor tools'. The Dremel is a fine and popular version, but far from the only one. This also include most of the 'flexible shaft' machines. On the much larger end, you also move up to the so called 'die grinders' (air and electric) ... the same fundamental type of tool. On the smaller end, you have the various 'dental' type hand tools (mostly air powered). I'm NOT criticizing the motor tool, but pointing out it's limitations. ALL things have limitations, and you can always push your luck.
The bearings in such a motor tool may not be much different in design than those in a milling machine, but the SIZE of them are sure different. As are the bearing mountings (quill, etc.), arrangement, and the machine spindle. The main spindle of a motor tool would flex under the cutting load of even a small mill. Flex means 'wind up', deflection, and 'chatter'. Even a tiny benchtop 'micro mill' machine will have a spindle and bearings MANY times the size of those in any motor tool (perhaps an inch or more in diameter). My little benchtop milling machine has a spindle about two inches in diameter at it's smallest point, and bearings considerably larger than auto wheel bearings. It's still a SMALL mill.
In the common motor tool all this is mounted in a plastic case ... there goes any hope of rigidity. Of course, these are HAND tools, so no rigidity is even possible for their intended purpose. It's NOT a design fault ... the motor tool is FINE for what it's for.
Motor tools also have inadequate provision for mounting the cutters for milling. Chucks are near useless, as they will not grip the hardened shanks of milling cutters. The tiny motor tool collets may grip to SOME extent, but are too feeble, and NOT dependable. Even far larger and stronger collets (like R8) can have trouble gripping a mill adequately. There's not much joy in having a cutter pull out of a collet under load, and dig into the work. If you're still fully functional after, and haven't wrecked the machine, you're doing pretty well. End mill holders are the proper low cost solution, but they won't fit in any motor tool, and in few drill presses.
As for side thrust, it will cause a taper-shanked toolholder or chuck to work loose in it's socket in the spindle (hence the need for a drawbar). This is one of the biggest problems with trying to use a drillpress as a milling machine, even for light work. You also have to observe a big cutter, or the structure of a big milling machine flex under the load of the cutter to appreciate the forces involved. Or worse, have the machine throw a big piece of metal across the room when something digs in, slips, breaks, or is not properly fastened down. Cutting metal, especially rapidly, takes a lot of force and power. Things flex and 'wind up'. Learning to control such forces by machine design and proper technique is what the game is all about. You can't get rid of these forces, you have to control them.
And, yes, all is relative to machine size. Nobody expects a 'micro mill' to remove vast sums of metal per hour like a big production mill can. But it can out 'chew' a motor tool by a factor of hundreds, and maintain something like precision while doing so.
You can minimize many of these problems by taking VERY light cuts. But then you've also minimized much of the advantage you'd have with a proper milling machine.
Dan Mitchell ==========
JP wrote:
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