I’ve been 3D printing for years but am totally new to CNC, so apologies if this is a dumb question 
Is there anyway to cut deeper than 3/16" deep with a 1/16" endmill? I’m trying to cut a small gear out of 1/4" thick aluminum and I can’t find any 1/16" endmill with a cutting depth of more than 3/16". The simulations in Carbide Create show that using an endmill of larger diameter will result in the gear teeth losing their shape. I saw posts that say you can cut deeper than the flute of the bit if the shank is the same diameter as the cutting diameter but all of the 1/16" endmills that I can find have a 1/8" shank diameter so that doesn’t look like an option.
I’m thinking that maybe I could add registration holes to the part and flip it to cut it from both sides but that seems like a lot of extra work. Is there a better solution I’m missing?
You would need a 1/16" endmill w/ a 3/8" (or longer) cutting flute length — that would be a very fragile thing. I think the Precise Bits folks sell such, or check Harvey or Garr Tools.
Two sided cutting would be a work-around, but will be challenging.
Gears are tough, that’s for sure. What a milling machine does is use an indexing jig, which holds a cylindrical piece in place horizontally to the bed, then runs cutters across the length of the round bar to cut one groove. The rod is then turned a precise angle around, and a new groove is cut.
I don’t know if an index jig for CNCs exists. It might be possible to rig a 4th axis accessory to be operated manually to do the same thing.
One possibility would be to make a series of gears in thinner stock, with registration holes on the radius between the center hole and the cogs. If you’re careful with the tolerances to make them tight, you ought to be able to rivet the gear parts together through the registration holes. You’d probably want to mill both sides of your stock really flat first, and you’d want to make sure the cogs are deburred carefully to keep from getting more backlash in the gear system than you want.
Did you mean to say 3/16" instead of 3/8"?
You only need a cut height of 1/4" to cut from 1/4" stock.
Yes, queue first foot in mouth 
Yes the cut depth on the endmill is only 3/16" hence I can’t get to the 1/4" depth I’d like to cut to.
So something like this one would work well.
You should find plenty of two flute versions. Just take light cuts and leave stock for a light finish pass.
Thanks for all of the replies! I figured that they didn’t make the cutting depth longer than 3/16" on a 1/16" endmill for a reason. It makes sense that it would be too fragile.
I’m making a parallel gripper mechanism where some of the linkages end in a partial gear so a 4th axis accessory or indexing jig probably wouldn’t work for that. Stacking a couple of 1/8" gears together with registration sounds like it might be a good approach! I also might try making a custom 3d printed jig to hold and align the part so I can mill it from both the top and bottom.
If you have the time, you can cut using a larger endmill (like a 1/8") to remove most of the material, followed by a contour path with the 1/16" to clean up the areas where the 1/8" wouldn’t reach. Much less stress on the 1/16" that way.
Thanks for the links @Ensalaco and @neilferreri those look like exactly what I was after! I’m still new to the endmill sourcing game.
Hi
Never really tried this but- Another solution may be do us an ER collet and a 1/16 bit this way
I got an er11 collet and chuck holder on Amazon
For my Mikita router also bought an 8 mm collet to fit the Mikita Cut chuck holder down so that I can use drill bits up to 8 mm
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