Mill bits in router?

[Rick Potter]

The new WoodSmith mag has an article on using a 5/16 metal working mill cutter to cut mortises to fit Festool Dominoes. It looks pretty neato, but is it safe to use a metal cutter at router speeds?

I would like to try it.

Thanks

[Bruce Page]

I've done it many times with good results. But, in my experience, metal working end mills will not last as long as their wood cutting counterparts because of the different cutter geometry, relief angles, etc.

[Lee Schierer]

I've used end mills to do cuts using a router, where I needed a longer reach than I could get with a router bit. I had no problems and it gave a good cut.

[Tony Pisano]

I used to use endmills in machine shop when doing little wood projects and they always seemed to work fine. I agree about geometries being tailored to the materials being cut. Steel cutting endmills were different than those for aluminum. On a similar topic, I was ordering some router bits this week. I needed something with an inch long cutting surface. The site I was at that sold Amana brand had router bits and cnc router bits. Does anyony know the difference? The only thing I could think of would be higher feed rates?

[Brian Gumpper]

Sure it was a metal working end mill and not a spiral router bit for wood? I don't know how you would tell them apart by the picture unless they said they were for metalworking.

As others said, they are different but work. Also, carbide is different for metal which could be another reason they dull faster in wood.

[Doug Hepler]

Rick,

I will echo earlier responses. When I needed a 9/16" spiral bit for my router, an end mill was all that I could find. I have used it a few times and it seems completely OK. Since you are unfamiliar territory, go over the specs carefully. For example, some end mills plunge and some do not.

Doug

[Chris Fournier]

It works for sure but the cutter is not designed to move the wood chip volume from the cut so they tend to run hotter than woodworking cutters. I do it all the time.

[John TenEyck]

I've been using end mills in my MiniMax mortiser and also in my horizontal router mortiser. The MM runs at something around 5K rpm, and I turn my router down to maybe 10K rpm. I mostly use 3 flute spiral upcut bits, center cutting obviously, and they cut very smoothly and seem to last a long time. As was mentioned, you can get some really long end mills. I try to keep the length as short as possible but for deep mortises like needed in an entry door end mills are usually your best and cheapest.

John

[Rick Potter]

Thanks guys, I just rechecked the article in WS issue 230, and it is talking about 'spiral end mill bits used in metalworking'. Four flutes and they used a 1/2" to 5/16 (8mm) collet adapter. This apparently fits the 8MM domino.

The article is about a simple wood mortising jig made to use with Dominoes.

I think I will give it a try.

[John TenEyck]

Rick, there are plenty of simple jigs you can make for cutting mortises with a router. Even just a side fence works for many of them. But if you want to build something with a tremendous amount of flexibility, accuracy, speed, and safety, you might consider making a copy of my horizontal router mortiser. https://sites.google.com/site/jteneyckwoodworker/current-projects/horizontal-router-mortiser

John

[Rick Potter]

John,

Your mortiser setup has been on my list for a looong time. It is a favorite dream of mine. It's one of those someday items that I should have built before I started the three year kitchen project, which is part of the 11 year addition/remodel project. Not when I am almost done. I still plan to build it, when I have time to play.

Getting slow in my old age.

[Bill Dufour]

use as few flutes as possible. I think two is the lowest count. This gives more room for chips to get out of the way. An endmill for Aluminum or plastic is probably best for wood as it will have more backrake and a sharper shear angle.
Bill

[Ray Newman]

I also use end mills in my routers. While once looking for a specific sized end mill, I noticed some end mills have a 3/8" shank. On a whim I bought a 3/8" collet for my Porter-Cable routers. Do not know if other manufacturers have a 3/8" router collet or if one is still available from Porter-Cable, but it might be worthwhile to try find one in case you ever need an end mill that is only available in 3/8" shank.

[Rick Potter]

I will keep my eye out for that. I do happen to have a 3/8 collet for my PC routers. It's on a Castle pocket hole machine I don't use anymore.