Router Bit or Endmill

[cncneo1]

I have been using a router bit until now. I am planning to use an endmill to cut a pattern on FAGOR 5 axix cnc machine. I would like to know is there any technical difference between an endmill and a router bit?

Thanks.

[mxtras]

The flutes of router bits are usually straight and produce no shear. End mills typically have helical flutes and will produce a smoother surface in most wood that I have cut, which is not all that much.

If using a straight tool, I use end mills.

Scott

[chad123]

Not necessarily. Most of the bits from woodworking stores seem to be the straight flute brazed carbide type, I have found that these do not work well in my cnc router.

I have found that carbide 2 flute end mills work pretty well in wood when you get the feeds and speeds ironed out.

If you really want the best to rip through wood then take a look here. All kinds of great stuff...

https://www.onsrud.com/

chad

[ger21]

Spiral router bits have different geometry and bigger flutes than metal cutting endmills. I've never used endmills, but I believe that router bits should allow for much higher cutting speeds. Router bits are also a bit more expensive. Another supplier of high quality router bits is www.vortextool.com

[fatal-exception]

Endmillls are designed for lower speeds with proper chip evacuation. If you use them in your router with speeds in the 10K+ range, they will just burn. End mills require a 'real' and consistent cut. Strait flute carbide router bits don't need a real cut and will still stay sharp. (this is my opinion)

One of my workers asked recently how often I used to change my 1/2" carbide 2 flute cutter when I made stuff with a bosch router and templates. Got me thinking...'never' was my reply, one tool worked for more than a year, with excessive use. It's now in a glass shrouded case. Now I replace 1/4" endmills every 10 pieces. If I don't, the pieces aren't the right size. Some times up to 10 thou too small on internal cavities. One carbide 1/4" cutter I had lasted an incredible 60 pieces! I would pay big for tools like that! It's next to the 1/2" router bit.

If you are using the endmills with cnc, you can increase your feed quite a bit, and it will also be very quiet. Keep in mind that the faster the feed, the higher the upward force to your table and clamps. Make sure they can handle the upward force without moving lateraly. Experiment first.

In most cases, I would rather use an endmill over a router bit.

Paul

[Clockwork]

I had a need to cut a 2" deep pocket in hardwood on my CNC router. Couldn't find a suitable router bit so I purchased a 4-flute solid carbide spiral mill bit (1/4").

The geometry of the mill bit flutes didn't eject waste fast enough when cutting a path .2" deep/pass. The result was some chatter in the bit during the cut. The chatter was minimized by reducing the depth/pass to .1"

This only happened on enclosed paths. There was no chatter on cuts where one side was open allowing better wast removal.

[awerby]

The trouble we've been having with helical-flute endmills is that they tend to hook the wood and pull themselves out of the collet, with disastrous results for the piece we're working on. Carbide doesn't give the collet much to grip on, and high-speed tooling doesn't use the notch and set-screw system that the toolholders in mills can have. I've ordered some straight-flute cutters made specially to see if they work any better; I'll keep you posted...

Andrew Werby
www.computersculpture.com

[mxtras]

Originally Posted by Clockwork ..so I purchased a 4-flute solid carbide spiral mill bit (1/4").

I think you would be hapier with a two flute EM. What you have there is meant for finishing and does not have very deep flutes as you know. A 2 flute EM would do better for you.

Scott

[Clockwork]

Scott

Thanks for the insight. It makes sense now.

[jolafson]

Well, if i may add to this, we run only wood (except for when making fixtures) and we use 3 flute, up spiral router bits, in both solid wood and particle board etc... It really depends on what you're looking for in a cut. If you can, use a hogging or roughing bit for the first material removal operation. Be sure to leave 40 thou or so on the perimeter (x,y axis) and then use a straight flute bit to go back over and put a "finishing" pass on the part. A rougher with serrated flutes can FLY through alot of wood fast, very quietly, and with much less cutting force pulling on the part. Check out www.amanatool.com, they don't sell direct, but look through their CNC tooling stuff. Also, if you can use a bigger bit, the better off you'll be. Especially for roughing. You can rough it with a larger tool, then finish it with a smaller tool. Hope that gives you some new ideas to think of "outside" the normal thoughts

[Haydn]

If you need clean edges on the top surface of your wood then use a down spiral wood router bit. This sends the chips down into the cutting channel and hence leaves a clean top edge with no breakout. An upcut spiral bit will through the chips up so feed rates can often go up but the top edge will feather. Upcut spirals require firm work holding as they try to lift the part (just like an endmill). Down cut spirals can cause compaction of the chips at the bottom of the cut which reduces performance. Get round this by creating an ofset of your part and then stepping in for a finish cut, you should get a very clean cut that way. The geometry of end mills and spiral wood router bits are different, but I do use carbide end mills occasionally for cutting wood without too much problem. Straight fluted wood bits are ok when new but a spiral bit is far superior as the cutting edge is constantly in contact with the part, and the shear cutting action eliminates tearing out and bruising on end grain.

[jolafson]

All very good information for the guys Haydn. I didn't mention the up/down spiral tendencies.