End millfor HDPE

For these reasons, you want to make sure your 1/4" down cutter is made right & built to last. That's why these are made above industry standards and 100% tungsten carbide.

Sometimes you need you need 1/4 radius chamfer around the outer which save time on the rotor table. Not sure how long it will stay sharp only time and usage tell.

DowncutEnd MillAluminum

The 1/4" down-cutting bit (a.k.a. down bit, down cut bit, downcut bit) is the workhorse of CNC router bits! You will almost always make this the first on your machine. Why?

Carbide is what professional metal machinists use to make complex items like car engines. It stays sharp 50x longer than conventional CNC router bits.

I had very good results with the bit. It is longer than the bit I replaced it with which is handy for deeper cuts. One thing I noticed was that when I used it for a clearing cut on an inlay where the mill just spot faced a small area it leaves a raised dome in the middle due to the clearance grind on the end of the bit. I went back and flattened the domes prior to gluing in the inlay to make sure they seated correctly. So far I've been very happy with the quality of cut and the service from IDC.

CompressionEnd Mill

With straight flutes the load builds up almost instantaneously, making the end mills prone to self excited chatter. With helix angles, chip load is applied to the entire flute length in a progressive siding action similar to that of a snowplow with its blade angled off to one side. This makes the cutting forces much more constant with less chance for chatter. End mills with a higher helix also tend to produce much better work piece finishes. The 50° and higher helix angles significantly reduce side loading on the mill making it possible to periphery mill thin wall sections with much less deflection.

Standard end mills are offered with helix angles as low as 15° to as high as 60° angles. General-purpose end mills are generally around 30°. Any increase in the helix angle increases the effective shearing action thus reducing cutting forces and the amount of heat generated during the milling process. Chip ejection is also improved. Lower helix angle end mills are used on more difficult to machine materials where maximum edge strength and rigidity are important.

A third reason is, most CNC routers are set up for 1/4" bits, so it is the reasonable go-to for your work. This is why it is standard practice to have two 1/4" down-cutting router bits in the rack.

The 1/4" down bit, the workhorse of CNC router bits! This will be your first go-to bit with your CNC router. You will want to make sure it's a good one.