View Full Version : Will this end-mill plunge?

25-02-2013, 03:48 PM
I got 5 end mills from eBay - 6mm Straight Shank 3mm End Mill Bit for Aluminum Iron | eBay (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290822586616&ssPageName=ADME:L:OC:GB:3160)

However they don't seem to have any teeth that go all the way to the centre of the cutter. I expected that 1 of the 3 teeth would do. Does this mean it can't plunge? Why does it have this rather deep slit on the cutting end?

They call it a slot drill so I took that to mean it will plunge.



25-02-2013, 06:49 PM
Without the flute extending to the centre it will not plunge and even if it did I would avoid plunging on a router as it puts a substantial force on the gantry, leading to reasonably large tool deflection. Does the hole in the end go all the way through? If so its purpose may be for flood coolant.

25-02-2013, 07:46 PM
No, it doesn't go all the way, though interestingly there is a similar recess on the other end but it is only a few mm deep.

Poo, I'll have to send 'em back.

Anyone know of a well priced 3mm cutter with 6mm shank and about 12mm depth of cut?

25-02-2013, 08:26 PM
I mostly work with mild steel, so always buy slot drills rather than end mills. I get them from Warco as they supplied my machine and seem to be competitively priced on tooling. I've had the slightly cheaper cutters from eBay and they don't seem to last as long.


25-02-2013, 10:20 PM
These look good :)

5 X 3mm Spiral Double Flute HSS Milling Cutter CNC Bits High Quality | eBay (http://www.ebay.co.uk/itm/5-X-3mm-Spiral-Double-Flute-HSS-Milling-Cutter-CNC-Bits-High-Quality-/140548875992?pt=UK_Home_Garden_PowerTools_SM&hash=item20b95da6d8)

However before I found that I found some new old stock and bought those.


25-02-2013, 11:12 PM
Why do you need them to plunge if you don't mind me asking? Reason for the question is that I have read that it is always better to ramp down into the substrate rather than plunge.

26-02-2013, 12:06 AM
I often find it convenient to put 3mm holes in stuff and it's a pain to change bits. Also the standard pocket and contour commands in Dolphin don't ramp the Z.

26-02-2013, 12:15 AM
Would it not be possible to use 3mm carbide end mills with a 3.172 shank and an adaptor if you dont have a 3.172 adaptor? these cutters will plunge and are very cheap. I use them quite often although I mostly use 0.5mm - 2.0mm. G.

26-02-2013, 12:50 AM
I can use them, but I prefer a 6mm shank so I don't need to spend time changing the collet in the chuck.

26-02-2013, 12:21 PM
Sorry, the 2nd time I used the word adaptor it should have read collet. You could still use the cutters with a 6mm adaptor without changing the collet. These cutters are seriously cheap and very good and I cut material up 15mm thick and could go to 18mm, but using the 3.172 cutter. G.

26-02-2013, 03:40 PM
Would you be able to link to an adaptor? I've not seen any. I presume it is just a kind of sheath that makes the shank larger? It would be good to have.

Also, I should have said above that when I plunge the Z axis I only do so in wood and plastics.