Problem- Chamfer mill

[CNCMike]

Hi guys,
We are currently looking into doing a job that requires a 60 deg. angle to be machined on the end of 1 1/4" dia. and 1 1/2" dia. cold rolled bar stock. We have done small quantities on a manual lathe, but the customer is talking much larger quantities now.

Our idea to speed up the job was to machine soft jaws and run numerous parts at a time in our CNC mill (we don't have a CNC lathe). We purchased a "face angle shank" mill from MSC for our test runs, but got mixed results. We are able to do the job, but we get quite a bit of chatter. There is only 0.75" of material protruding out of the jaws and we have varied the speeds, feeds and cut depths. We have a feeling it may be the tool causing the issues as it is a straight flute light weight mill (HSS).

Does anyone have any ideas on a more robust tool capable of machining steel? Is there a better tool other than a "face angle shank" mill for the job? Thanks for any suggestions.

Mike

[Geof]

I don't have any suggestions regarding the chatter but do have a suggestion about using the mill as a lathe.

This has been discussed a few times and some people are doing it quite successfully. If your parts are short enough to hold in a vise they should be short enough to put in a tool holder; maybe a large collet holder.

With two holders one could be loaded with a part out of the machine while one is being machined; unloading and reloading the machine would be a matters of seconds.

[fuzzyracing1967]

You may have better luck with a indexable tool,we have a few jobs that are cold rolled ,cast iron or 4140,and they work fine.They have two .5 square possative rake tools on the cutter witch is about 2" dia with 1.25 shank,nice and solid.That said are you saying your just looking to put a chamfer on end of part? What kind of lathe (engine-turret)?

[Delw]

geof's idea works pretty good.
but you should still be able to chamfer mill the part in a decent cnc mill I have done if for years. indexable is the best way to go and you really need to have the largest shank size avail. cause if your running a 1/2 or smaller shank size and trying to get a .250 depth it wont fly.
also shorten up that tool in the holder to were it is just sticking out enough to do the job.

BTW what kinda mill and taper holders as this make a huge dfference in the rigidty, you may have to take less of a cut ie more pass's

in all honesty if its just a chamfer I wouldnt waste mill time I would use a large emergency collet and put them in the lathe it takes a whopping 5-10 seconds at best. if you dont have a collet nose for your lathe and only a chuck then a mill would be faster.

[DareBee]

You can also buy (or make) a cutter that is like a countersink only inverted and do this job in a drill press, lathe or mill with a one shot drilling operation. 6 0r 8 flutes would be really quick.

[dertsap]

kennametal has a good 2 flt 60 deg chamfermill , it will mill the angle dead nuts and quickly

[CNCMike]

Thank you for the suggestions. It looks like we are going to try a carbide/indexable tool and hope for better results. The mill we are using is a 40 taper.

Mike

[Andre' B]

I have always liked these.
http://www.abtoolsinc.com/ChamferHog...hamferHogs.htm

They have a multiflute version, but somtimes due to the larger diameter and cutting speed limits you can make more cuts per second with the single flute.