MadModder

The Shop => Tools => Topic started by: ScrapMaker on October 03, 2009, 11:03:37 AM

Title: Bad Vibrations
Post by: ScrapMaker on October 03, 2009, 11:03:37 AM
Afternoon all,
Up until now I've been mainly using on the lathe, and just using the milling machine for drilling tapping etc.
I've got a project now, where I am having to mill the edge of a piece of 1/4" mild steel.
I've got it in the vice, with about 1/4" of material above the jaws, everything is snugged down tight but yet
I'm getting awful vibrations. I'm only trying to remove twenty thou at a time, but even reducing the depth of cut has little effect.
I've been using a 5/8" end mill, in an er32 holder. I've also tried a little hogger, in a 3/4" end mill holder.
Both seem to result in the same amount of vibration.
I've checked the tram, and its within a thou both ways.
Its beginning to do my head in, as i cant carry on with the part.
Any ideas?

Matt
Title: Re: Bad Vibrations
Post by: Darren on October 03, 2009, 11:14:04 AM
Are you sure it's mild steel and not something harder?

Have you nipped the gibs up?

Title: Re: Bad Vibrations
Post by: Darren on October 03, 2009, 11:14:38 AM
What is the rpm of the spindle?
Title: Re: Bad Vibrations
Post by: Stilldrillin on October 03, 2009, 12:48:20 PM
Are you milling with the material central to the cutter? Only the 1 leading corner will be in contact at a time......

Moving over to one side will allow 2 corners to cut at once.....  :thumbup:

David D
Title: Re: Bad Vibrations
Post by: CrewCab on October 03, 2009, 01:30:14 PM
What sort of Mill is it Matt?
CC
Title: Re: Bad Vibrations
Post by: bogstandard on October 03, 2009, 01:38:47 PM
Are you trying to run with a rather extended quill? Mill/drills don't really like over extended quills.

Get the head down as much as you can, and get as much of the quill buried in the head, and make sure the quill lock and head tightening bolts are locked up. If cutting in the X axis, make sure you lock the Y axis gib up, or vice versa.

As suggested before, make sure the cutter isn't central to the job. If you are cutting right to left, ensure the cutter is more to the far side than to yourself, otherwise you are putting yourself into a climb milling situation, a situation you need to avoid like the plague. If cutting left to right, the cutter should be more towards yourself.


Bogs
Title: Re: Bad Vibrations
Post by: chuck foster on October 03, 2009, 03:59:43 PM
you might want to check and see if the spindle has end play...............when i got my mill new from busy bee the end play on the spindle was about .030"  :bugeye:

after i tightened up the end play it made a huge difference in the finish on my material. :)

just a thought, keep us posted on your progress.

chuck  :wave: