MadModder
The Shop => Tools => Topic started by: quantumeer on May 25, 2014, 06:06:10 PM
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I have always just crossed my fingers and "gently" hit the drawbar on my X1 mill to remove things from the MT2 socket. Sometimes while doing it, I have pondered the unused screw thread inside the top of the spindle...
(http://www.ytlab.myzen.co.uk/machining/drawbar/spindlethread.jpg)
Presumably, the unknown designer intended this M12 x 1 thread to help discourage people from hammering on the bearings; sadly the supplied drawbar makes no use of it. So today I made the simplest possible mod to bring it into use. Since the business end of the drawbar is M10 x 1.5, engaging the top with the M12 thread gives us a differential screw of effective pitch 0.5 mm, captive at the top.
The new part is a 20 mm sleeve, M12 x 1 outside, 10 mm clear inside, shown here with the drawbar...
(http://www.ytlab.myzen.co.uk/machining/drawbar/drawbar1.jpg)
Here it is stuck on the drawbar with high strength retainer.
(http://www.ytlab.myzen.co.uk/machining/drawbar/drawbar2.jpg)
In use, the drawbar protrudes a few mm from the top of the spindle. After screwing the collet loosely into position, a turn at the top pulls it in, or pushes it out.
(http://www.ytlab.myzen.co.uk/machining/drawbar/drawbar3.jpg)
The mill can now relax when I pick up the hammer.
Mark
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That's a very nice quick easy mod. :thumbup: Another guy did this on his VMC but had to thread the spindle and make a new draw bar. Why the Chinese don't make all their draw bars self extracting I'll never know...
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Hi Mark,
Now I really like that mod. Saves bashing the drawbar and rattling the bearings.
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Great idea Mark, only trouble is that my mill is an X2 = no internal thread in top of spindle. Glad it works for you though. Think some use tapered wedges to extract collet holders etc. I am still giving judicious taps or not so judicious taps to the top of the draw bar.
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My X1 does not have the thread in the top of the spindle so I cannot immediately implement this idea. However, I really like the idea and I may bore out and thread the inside of the spindle. Thanks for the idea.
Mike
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My X1 does not have the thread in the top of the spindle so I cannot immediately implement this idea. However, I really like the idea and I may bore out and thread the inside of the spindle. Thanks for the idea.
Mike
Have a look here to see how this guy did it. It's about 3/4 of the way down the page by "Ralph".
http://modeleng.proboards.com/thread/5804/mill
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So it seems I got lucky with that particular version, very nice. It came from Chester some years ago.
Mark
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Hi,
I have an Axminster micro mill - same chinese clone (I think) as the X1. The first time I fitted my new milling chuck it stuck fast! I realised that I needed to push the MT2 taper apart and that hitting the drawbar with a hammer wasn't going to move it. Eventually, I bit the bullet and tapped the top of the spindle (M12, I think) to allow my use of a bolt as a means of applying pressure to the stuck chuck, through a short drawbar. If I recall correctly, I had to drill out the existing hole a millimetre or two. I used a pistol drill to do the drilling and took it steady with the tap to get it all square.
I guess what I'm trying to get across is that my spindle was not hardened at the top end and so even if you don't already have a tapped spindle, you could do it yourself.
I did manage to get the chuck out, but managed to dramatically distort the 3/8" steel drawbar in the process, however, that was easily replaced by some studding, whereas new bearings would be somewhat harder and more expensive to do!
Regards Tom