# Quick Tip: Drawbar Alignment Collar



## Ray C (May 20, 2014)

So, the other day, I had the CNC spinning at 3000 RPM and noticed a little vibration that wasn't there before.  Oh Oh...  What's up with that?  Took a short while to realize the drawbar was not sitting straight in the spindle tube -this happens from time to time randomly...  What to do?  Easy!  Check it out.

I noticed the spindle bore up at the top (near the splines) is chamfered a good bit and both of my machines are like that.  Well, here's the fix.   A piece of drops volunteered itself and it's just a little collar with a tapered nub that fits in the chamfer.  The bore was chosen to match the diameter of the threaded part of the drawbar as closely as possible.  I'm not supplying dimensions for this as folks with brands of mills other than mine may be different -and you might not even have a chamfered bore up there so, you might need to touch that up a little bit.

Pics are self explanatory...  The solution works very well -and no more high speed vibration.






Ray


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## samthedog (May 20, 2014)

Simple, practical and does what it says it will on the tin! I like it.

Paul.


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## Jamespvill (May 20, 2014)

Good idea! I know what I'll be making tomorrow. I used to have some vibration issues with flycutting at max speed. I just don't run it all the way up now, seems to solve my problem.


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## Ray C (May 20, 2014)

One thing to note here that I just thought of...  If you do very deep drilling, you'll want to make that collar a diameter small enough so the spindle shaft can go all the way down.  I never drill that deep so, I'm not going to change my collar but you folks might want to make the collar the same diameter as the flange nut.  I happened to pick a piece out of the bucket and used it and that's what diameter it happened to be...


Ray


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