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Questions about router bits and end mills

old_iron

Aluminum
Joined
Aug 18, 2004
Location
Forest, VA, USA
Hello All,

I recently picked up a lot of tooling for my mill and as I was looking through it I found some of what looked to be end mills that were made by Unsrud. I used to work in the woodworking field and remembered them as tooling maker and shaper and router manufactuerers. I assume these are router bits instead of end mills but can't visually see any difference between a real end mill and these. They are ground exactly the same.

Is there any difference?

Thanks,
Troy
 
Old_Iron = Ferrous Antiquos

Are we related??

Onsrud did/does make woodworking routers, and those are probably spiral upcut bits to get the chips out in a hurry. My guess is they are not exactly the same as for metal-cutting end mills, (deeper gullet, more acute cutting edge angle) but I think they would work pretty well in aluminum in a regular mill.

I was at an auction where an Onsrub overarm router in perfect working order went for $100 bucks, just because is was a big dog and too heavy for the home-shoppers to deal with !
 
Lacking the correct ball end mill, on several occasions I've used single flute HSS router bits of the right radius on aluminum - worked OK.

edited to add: but they didn't work as well as a ball end mill.
 
Ferrous,

Not sure if we are related or not but it looks like we have the same disease. Cast Iron in our blood!!

I looked at these bits from every angle and they are made exactly like a regular HSS end mill. I guess I can try them out and see what happens. Should work OK in alum.

Thanks for the replies guys!
 
i have a carbide 1/8 radiuos round over router bit with a ball bearing guide on it that i use all the time to radious alluminum plates, its held up great. i also have a hss endmill that i ground the end down to make a pilot and pressed on a ball bearind that had the same od as the endmill, i originaly made it cause i had to cut out some mold imperfections on some plastic parts so i put it in the mill and just manualy ran the part along the cutter, it worked great, i later used it in a router to trim laminate and it worked great for that too
 
So is the general idea that router bits are "ok" to use with metals? I mean a good quality carbide router bit, used on 6061 aluminum at best? I repeatedly have people shooting this idea down as crazy. (hell i know i am, but not my ideas ;) )

Nick
 
on aluminum they should work great, i even know people who work aluminum using a router with standard router bits and have excelent results, so i would think that if they hold up good at 20,000 rpm in a router then they should be great at the speeds most mills can put out, now i dont know if i would go buying router bits rather than endmills, but i think for the form cutters they are a great deal, and of course any ya get cheap or free i would definatly run
 
Bear in mind that the shanks of router bits do not have to be as rigid as an end mill. Some router bit shanks are not hardened and will bend under the side loads of cutting metal. I speak from unhappy experience :eek:
 
I once did a run of about 100 parts while waiting for a stamping tool that used an ordinary hand held router with a simple hardwood template to cut an odd shaped hole in a 6061 t6 aluminum extrusion, about, .080 thick. worked well but noisy as hell! Did simular things with better set ups, but ordinary straight bits, worked well enough in a pinch.
 
So, how would one go about calculating RPM/feed for a router bit?

Since I have no clue about a router bits geometry, i would probably try to measure that, then calculate RPM and feed from SFM at the largest diameter, and given material. Sound reasonable?

Nick
 
there a different geometry so i dont know how feeds would work, but rpm i would think i would use the same as an ordinary carbide cutter, probably a little less feed tho cause they often have a more positive rake for cutting wood. rpm ya would most likely have to do largely by eye and ear tho since often with there smaller shanks they arnt as rigid as a form cutter is
 
Thanks for all the replies guys. I tried them on some aluminum and they seem to work fine. Haven't tried them on anything else....yet
Thanks again!
 
The company I work for has made thousands of solid carbide wood routers for private label accounts like Onsrud. They are essentially end mills with a higher radial rake angle, radial relief angle and radial clearance angle. Axial features are pretty close to standard. I've seen them used a lot in aluminum and with any kind of reasonable speed/feed combo should work OK.
 
A friend of mine - builder of front engine fuel dragsters and driver of same back in the day - relieves Ford flathead V8 blocks with a bolted down pattern/guide, router and carbide router cutters.

Looks as good as anything else done to the old flatmotors.
Doesn't seem to hurt the cutters either.
 








 
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