I have a JET 16 Mill Drill that I am pretty happy with, even though it is NOT a knee mill and I know it's limitations.. My question is very simple. When run a fly cutter from right to left.. I get just a very hint of a cut on the trailing edge of the cutter, which would indicate the quill is out of tram with the table. However, when I mill from left to right, it does the same thing. Is this an indication of the bearings being loose?? Or worn out??
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[How-To] Mill Drill question
- Thread starter ZouchaR
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I think what you're seeing is pretty much normal for a fly cutter. Here's a link to a video using a Tormach CNC mill with one of their Super fly cutters. Note about half way through the video the cutter is leaving marks on the work piece.
www.cnccookbook.com
If you read through the article it explains how to grind a face mill cutter and how to identify if your head is out of tram
Fly Cutter: Ultimate Surface Finish Rewards [Complete Guide]
Love a great surface finish? Use a fly cutter with our expert advice, tips, feeds & Speeds, and how to make or choose the best fly cutter.
If you read through the article it explains how to grind a face mill cutter and how to identify if your head is out of tram
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It sounds like it might be the tool deflecting, moving up on the leading edge where it is taking a heavier cut, then springing back down as it swings into the cut area, taking a few more thousandths off. I have encountered this phenomenon on my mill and that's how I reasoned it out.
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Pretty normal, there's always a bit of spring pass as Ed mentioned
-Mark
-Mark
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If your fly cutter does not scratch (the part being milled) on the back side then the head is not in tram.
It does.. just barely.. like it isn't even cutting.... but enough that it leaves a very faint mark.. and this was in copper...
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Bearings generally make noise when they fail.
"Loose" bearings would show up as tool deflection with even a small endmill.
And finally, what you're seeing sounds normal to me.
Many images and videos you see have been recorded in such a way as to indicate a "better" finish than what it looks like in person. Flycutting finishes look awesome in pictures, but in my short time, I have very seldom been in awe in person. It's more like a "gasket ready" finish to me.
"Loose" bearings would show up as tool deflection with even a small endmill.
And finally, what you're seeing sounds normal to me.
Many images and videos you see have been recorded in such a way as to indicate a "better" finish than what it looks like in person. Flycutting finishes look awesome in pictures, but in my short time, I have very seldom been in awe in person. It's more like a "gasket ready" finish to me.
This is what I'm looking for.
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When facing with an end mill or fly cutter, the tool is deflected slightly by cutting pressure. This causes the back of the tool to lift up slightly. As the tool exits the cut, the pressure is relieved and the back of the tool can drop back down, leaving tooling marks on the work. Loose bearings can accentuate this pattern. A perfectly trammed machine will show a mirror image of the left to right pass in a right to left pass.
Old timer would sometimes purposely set their head slightly out of tram and only face in one direction to eliminate the back of the facing tool from making contact.
Old timer would sometimes purposely set their head slightly out of tram and only face in one direction to eliminate the back of the facing tool from making contact.