Miniature End Mills

A drill chuck? Who uses a drill chuck with an endmill? That would be a big no. I'm probably going to start using ER chucks and collets. :)
 
For high RPM on aluminum, wood and other materials I rigged a porter-cable router to the side of my international hobbies mill. I use after-market higher precision collets in it. It works well as long as I don't get too aggressive with the cuts. It does reduce the effective X travel by about 8" though because it is offset. I have drilled holes with 0.020" mills and do shallow engraving with 0.050" mills successfully. By successful, I mean that I might only break one mill or so getting things set up for a few CNC runs.
 
I've considered using a Dotco die grinder or pencil grinder for small hole drilling. The Dotco collets are precision with low run out.
Not sure if I would use end mills. Too much run out using a router. Sounds like it works for you. Awesome.
 
A side note, I make my screw slots with my shaper. Just measure the slot your matching if your making a replacement part and grind a piece of cobalt to that sze and use the "one tooth hacksaw". Pretty slots that look factory made! A quick spin to polish the burrs away and a touch with the cold blue,(that works a lot better warm) and install it. Piece of cake. Who can afford all the sizes of jewelers saws?
 
A slot saw will work for many screw slots, especially for those without a shaper.
I can live with a tiny radius, which can be cleaned up with a file. You do the best you can with what you have :)
 
I have a Kress high speed electric spindle piggy backed on my Syil X4+. It is a German made precision die grinder designed to be used as a spindle. Both metric and imperial sized collets available. Tormach carries them for around $400, but I found (through a lot of searching and backtracking) a supplier in Holland that had 110V 60Hz models (most exporters only carried the 22V 50Hz units) for less than 1/2 the price. I forget the exact figures from the run-out tests I made when I first got it (3 or 4 years ago), but it was negligible even for micro endmills.
 
Cactus Farmer said:
A side note, I make my screw slots with my shaper. Just measure the slot your matching if your making a replacement part and grind a piece of cobalt to that sze and use the "one tooth hacksaw". Pretty slots that look factory made! A quick spin to polish the burrs away and a touch with the cold blue,(that works a lot better warm) and install it. Piece of cake. Who can afford all the sizes of jewelers saws?
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Regarding sizes of jewelers slotting saws. I have a modest selection or various thickness's, and I stack them to get the desired width. I have wondered though if this is considered good practice?

David
 
I just skimmed through the reading. And yes, all is true. BUT, it should also be mentioned that the machine doing the work should be of equal caliber. It is essential IMHO that the machine have the feel/sensitivity of the cut being made. IE: like putting a 1/32” end mill cutter in a Bridgeport. You will not be able to feel the cutting action. Hence, cannot tell chip load or anything else to do the job correctly. All you will do is break those tiny end mill cutters. Especially the Carbide ones! The machine should have a rigid velvet smooth table motion with the least amount of mass. I have been doing micro machining for decades and as far as spindle speeds? I cannot say that anything higher than 4K rpm is meaningful. I totally get the cutting speed thing. It’s just that in my shop all is happy at ~4K or less…Dave
 
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David S said:
Regarding sizes of jewelers slotting saws. I have a modest selection or various thickness's, and I stack them to get the desired width. I have wondered though if this is considered good practice?

David
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I think since they have no "set" to the teeth it would be OK. That said, I bet you cry when they get dull. With my one tooth set up ,I just take it to the grinder and sharpen it!
 
I do quite a bit of small work in general and have successfully used small, (down to .025') end mills on brass, steel and slightly larger, (.050") on machinable tungsten. The I find the mini rougher cutters work well when doing cuts with depth equal or greater to the diameter of the cutter and it seems 4 flute cutters lower the chip load. A good cutting fluid helps as does the use of a brush or judicious use of compressed air to keep the chips clear of the cut always helps.
 
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