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Sherline Mill Saddle Movement Beyond Backlash

jhmiii

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Apr 24, 2016
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#1
I have a manual Sherline mill and recently I have been having a lot of problems whenever the endmill starts to cut past the end of a part. The cutter starts dropping down and digs deeper into the work piece. Sounds like backlash, so I loosen the set screw, raise the motor, push down on the handwheel collar, and tighten the set screw. I still have a lot of free play in the vertical movement. Then I notice that the entire saddle and lead screw can move up or down about 1/8"! That is the gap between the collar and the top of the column thrust when the handwheel collar has been set as low as it will go.

Is there another adjustment that I need to make? Is the column thrust worn out?

Appreciate any and all advice.

John
 

mikey

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Dec 20, 2012
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#2
I have a manual Sherline mill and recently I have been having a lot of problems whenever the endmill starts to cut past the end of a part. The cutter starts dropping down and digs deeper into the work piece. Sounds like backlash, so I loosen the set screw, raise the motor, push down on the handwheel collar, and tighten the set screw. I still have a lot of free play in the vertical movement. Then I notice that the entire saddle and lead screw can move up or down about 1/8"! That is the gap between the collar and the top of the column thrust when the handwheel collar has been set as low as it will go.

Is there another adjustment that I need to make? Is the column thrust worn out?

Appreciate any and all advice.

John
John, you say that this is a "recent" problem. That suggests something is either worn or out of adjustment, and it can be a number of things. I would first look at this:

http://www.sherline.com/pages/tips/tip31.htm

If you don't have the 4017Z (Imperial) Z-axis Backlash Adjustment Upgrade then I suggest you consider it. It can take most of the backlash out of the Z-axis. If you do have this and have set it properly then the other thing to try is to set your depth of cut be going below your desired setting and then backing up to it; this takes the backlash out of the leadscrew/nut and prevents that digging in issue.
 

chips&more

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#3
Since the handle is held on with a set screw. The set screw can put a nasty burr onto the feed screw shaft. So, make sure the handle moves freely “all the way” up and down on its shaft. If you have a burr(s), then simply and carefully stone/file it away. Then try adjusting your backlash. I also see on fleabay “Sherline dial washers” that might also help with the backlash adjustment… Good Luck, Dave.
 

jhmiii

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Apr 24, 2016
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#4
Dave, thanks for the encouragement. You are spot on. In fact there was a burr almost completely around the shaft preventing the collar from dropping all the way. I carefully filed the shaft smooth. Now the backlash is down to about 3-4 thou.

Mikey, thanks for the advice on "backing up" to the desired depth of cut. I will definitely try it out to minimize even the few thou I now have. I have ordered the backlash adjustment upgrade and look forward to using it. When installing it I will also try to figure out why the small ball used as a detent no longer holds the stop sufficiently in the open position. My current work-around is to hold the stop open when raising the saddle. Makes milling a chore.

Sincerely appreciate the feedback. Still learning!

John
 

mikey

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#5
Mikey, thanks for the advice on "backing up" to the desired depth of cut. I will definitely try it out to minimize even the few thou I now have. I have ordered the backlash adjustment upgrade and look forward to using it. When installing it I will also try to figure out why the small ball used as a detent no longer holds the stop sufficiently in the open position. My current work-around is to hold the stop open when raising the saddle. Makes milling a chore.
Yup, had the same problem with the ball detent thing. After changing to the upgraded nut, no more issues. It actually deals with almost all the backlash but I still back up to my new depth of cut to get rid of whatever little backlash remains. Hope this gets it done for you.
 
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