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The
turned end on this shaft is too large in diameter for the small ball
bearing to fit. I need to machine 650 pieces so the bearing fits.
Precision ground shafting would spec at 0.1872” plus 0 minus 0.0002”.
This isn’t achievable with a lathe operation. My goal is to shoot for
0.1862” plus 0 minus 0.002” But as long as the bearing fits and isn’t too
loose we will be happy!
The trick is that I do
not have a CNC lathe so I will be setting up the old CNC knee mill as a
lathe! (machining center is down for control
upgrade)
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Click
here to watch a video of this operation!
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20160714_101724
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I rounded up some NMTB
TG100 collet holders and 3/8 collets off eBay from tools4umachinists. I
selected the TG100 series because of the collet length and the amount of
clamping surface in contact with the leadscrew.
I used the factory screw
in threaded stop to create a dead length stop for the leadscrew.
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20160714_091323
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This was the only
wrench (2 ¼”) that I could find to fit the nut!
3 reasons I didn’t
buy it:
1: too big
2: too heavy
3: too expensive
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20160714_095054
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I did find a ¾” drive socket with ½” adapter
that I purchased for $15.00 but this still wasn’t ideal!
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collet
wrench-2
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07/18/16 4:34:19 PM
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I decided to
design my own wrench and printed it in the SLS 3d printer!
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collet wrench-3
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07/18/16 4:34:58 PM
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Perforations were intended to help reduce warpage in the
sls process and some generous corner radii to make it comfortable to use.
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20160714_095225
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SAMSUNG-SGH-I337
07/14/16 9:52:24 AM
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A pretty sizeable wrench even
when placed next to my size 13!
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20160714_095017
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SAMSUNG-SGH-I337
07/14/16 9:50:17 AM
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20160714_095024
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SAMSUNG-SGH-I337
07/14/16 9:50:24 AM
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20160714_095033
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SAMSUNG-SGH-I337
07/14/16 9:50:33 AM
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20160714_150310
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SAMSUNG-SGH-I337
07/14/16 3:03:10 PM
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20160718_165516
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Here is the old YCI Supermax mill
with aging centroid M50 control. We purchased this mill new in 1990 or so and its been a
good accurate machine! It doesn’t get much use anymore opting for the
fully enclosed Atrump B5AC machining center with the Centroid M400
control. The Machining center is down while we upgrade the old M400
contorl to the current level control offered by Centroid. We will be
using the latest Yaskawa servo drives and motors which will improve
performance considerably.
But until its finished, I’m having to
gete by with the old mill!
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20160718_150948
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SAMSUNG-SGH-I337
07/18/16 3:09:48 PM
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It’s a somewhat time consuming
process to remove the tool holder from the spindle and change parts, but
it’s a doable process which holding tolerances quite nicely and running
without any problems so far!
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20160718_165422
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SAMSUNG-SGH-I337
07/18/16 4:54:22 PM
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Here are a series of consecutive shots showing the
turning process.
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20160718_165433
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SAMSUNG-SGH-I337
07/18/16 4:54:32 PM
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20160718_165437
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SAMSUNG-SGH-I337
07/18/16 4:54:37 PM
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20160718_165440
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SAMSUNG-SGH-I337
07/18/16 4:54:40 PM
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20160718_165444
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SAMSUNG-SGH-I337
07/18/16 4:54:44 PM
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20160718_165453
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SAMSUNG-SGH-I337
07/18/16 4:54:53 PM
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20160719_104836
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SAMSUNG-SGH-I337
07/19/16 10:48:36 AM
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This is un machined shaft #155 that the bearing won’t
fit on.
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20160719_105704
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SAMSUNG-SGH-I337
07/19/16 10:57:04 AM
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#155 after machining with the
bearing on the newly turned shaft and the mic showing about 0.0008 removed.
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20160719_105103
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SAMSUNG-SGH-I337
07/19/16 10:51:03 AM
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Shaft #156 un
machined at 0.18705”
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20160719_105313
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SAMSUNG-SGH-I337
07/19/16 10:53:13 AM
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Shaft #156 machined at 0.18575”
While this shaft is oversized by
about 0.00055” from my target dimension of 0.1862” the bearing slides on
with little resistance so I’m calling it a keeper!
The reality is while the mic is
reading out to 5 decimal places, it’s not practical to work in this range
without better measurement tools and a controlled environment.
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20160719_105532
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SAMSUNG-SGH-I337
07/19/16 10:55:32 AM
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Shaft #157 un
machined at 0.18700”
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20160719_105512
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SAMSUNG-SGH-I337
07/19/16 10:55:12 AM
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Shaft #156 machined at 0.18630”
I won’t be arguing with this one
either!
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33070626 leadscrew rack
1
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I needed some sort of rack to hold the shafts after I
machined them to keep things neat and orderly. Hopefully we can just
leave them in the racks without the need to re bag them individually
which will take about the same amount of time as the machining process!
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33070626
leadscrew rack 2
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07/18/16 4:36:16 PM
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Bottom of the tray showing the recessed
rubber foot mounting locations.
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20160718_150955
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SAMSUNG-SGH-I337
07/18/16 3:09:55 PM
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Here is the FDM printed parts tray!
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20160718_150714
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SAMSUNG-SGH-I337
07/18/16 3:07:13 PM
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First 200 parts off the machine!
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20160718_150904
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SAMSUNG-SGH-I337
07/18/16 3:09:04 PM
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A nice artsy shot of the first 200!
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