Rf31 ‘climbing’ downhill in z during y travel

M

mbmcewen

H-M Supporter - Gold Member
H-M Supporter Gold Member
Granted, I am taking a heavy cut and im sure that is what is doing it but still I cant think how or why

Im getting a sloped depth of cut… about 1/16” DEEPER from one end of a 5” pass to the other. This is in y axis travel.

Movement must be in the head as im not seeing any movement in the quill.

Is this a common issue with these round column mills?

Thanks!
 
Heavy cuts when side milling can result in end mill pullout due to the helical nature of the cutting edge. This is common when using collets. An end mill holder rather than a collet and an end mill with a Weldon shank will prevent this if end mill is positioned so the set screw engages at the top of the flat.
 
RJSakowski said:
Heavy cuts when side milling can result in end mill pullout due to the helical nature of the cutting edge. This is common when using collets. An end mill holder rather than a collet and an end mill with a Weldon shank will prevent this if end mill is positioned so the set screw engages at the top of the flat.
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I bet this is the culprit exactly. I am using a helical endmill in r8 collet. Makes sense and good to know. Thank you
 
If you keep going it will come all the way out and fling itself across your shop....

John
 
Yep happened to me. Luckily didn't have to scrap the part so it was a cheap lesson.
The only change to my procedure was to really gronk on the collet draw-bar, hasn't happened since.

I imagine there could be such a thing as over-tightening, but I don't have a spindle-lock so I'm just grabbing the big belt pulley with one hand while tightening. No way that'll ever over-tighten it. On that day when I had the inadvertent plunging, it was clearly under-tightened.

None of my end mills have notches for a Weldon type holder, and none are big enough to need them. And I wouldn't want one anyway, uses up Z space and slows down tool changes. These are the opinions of an untrained amateur though so pay me no mind.
 
This is one of the advantages of collet chucks like the Osborn Titanic I and II and Clarkson Autolock collet chucks that take threaded shank end mills.

Vertex, and then other Taiwanese manufacturers (and subsequently of course, other Chinese manufacturers) also made copies of the Osborne collet chuck system and called it 'Pozilock'.

I have an ER32 collet chuck and it's obviously versatile but I love my Osborn Titanic II, it's part of British machining heritage, and it's a good solid system too.
 
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