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Sherline backlash

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bfk

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#1
My Sherline 5400 mill was more than 20 years old when it came home with me. The previous owner used it quite a bit, I was told by his son. Mostly for clock making and repairing.
I noticed that the backlash varies depending on the position the lead screw.
I took everything apart and cleaned it. Adjusting the backlash device (the old one with the little metal pointer) on both X and Y axes, the backlash (for left-right) is either good at the left and sloppy at the right, or good at the right and almost immovable at the left. My only thought is that the previous owner did all his work toward one end of the table and that part of the lead screw is worn. This is based on knowledge of basic mechanics and near-total ignorance of milling machines.
Any ideas from the more knowledgeable out there would be appreciated.
Cheers,
Brian
 

chips&more

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#2
Welcome! It is impossible to get all of the backlash out of a standard mechanical machine. Your Sherline is no different, maybe even a little more prone to have more than it should. If used and or worn, then even more backlash. I would just use the machine, enjoy it. Learn its idiosyncrasies, in doing so, that will give you an additional skill! And be safe…Dave.
 

Asm109

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#3
Your trouble shooting sounds spot on. Lead screw wear. I would call up Sherline and get a price on a new lead screw and nut.
Other thing to check first would be wear in the ways from one end to the other.
 

kvt

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#4
Ok, The site list parts and prices for them, I would look at a new screw, and a new set of backlash nuts. The new ones are better but you will have to drill and tap or send your piec in to have it done by them. Another option for the new parts is Ebay, every once and a while you can get them on sale from either place.
Also the sherline can be quite accurate once you figure out all the little things. There are several on this site with them.
O h and welcome to the site. stick around and have some fun. People here are willing to help get you some answers.
 

mikey

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#5
My Sherline 5400 mill was more than 20 years old when it came home with me. The previous owner used it quite a bit, I was told by his son. Mostly for clock making and repairing.
I noticed that the backlash varies depending on the position the lead screw.
I took everything apart and cleaned it. Adjusting the backlash device (the old one with the little metal pointer) on both X and Y axes, the backlash (for left-right) is either good at the left and sloppy at the right, or good at the right and almost immovable at the left. My only thought is that the previous owner did all his work toward one end of the table and that part of the lead screw is worn. This is based on knowledge of basic mechanics and near-total ignorance of milling machines.
Any ideas from the more knowledgeable out there would be appreciated.
Cheers,
Brian
Brian, I also own a 5400 that is now about 25 years old. Good machine. You should know that a Sherline leadscrew is a precision screw. The brass nuts are more likely to wear out than the screw itself, although wear in the screw can happen. When the nuts wear, there is usually play at all positions; not just at one end or the other. I have some suggestions to try:
  • Adjust the gibs. There should be smooth movement without play in the table. If the gibs are loose, the table can bind.
  • Adjust the handwheels. There should be a set screw in the hand wheel hub. Loosen it, the turn the hand wheel 90 degrees and push in while tightening the set screw. Don't go crazy with the torque. The hand wheel hub that houses the thread for the screw is only aluminum. This should help.
  • Then adjust the backlash nuts (CW on the x-axis, CCW on the y-axis). You only need to snug these things. Excessive torque will cause binding. A Sherline table moves with almost no effort when things are right. Normal amount of backlash is in the range of 0.003-0.005".
Try this and see what happens. If you cannot get things adjusted then you may need to replace the brass backlash nuts. There is an upgrade version of these things, I believe. Contact Sherline and ask.
 

bfk

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#6
Thanks, everyone. I should have a chance to fiddle some more at the weekend, and will report back.
 

bfk

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#7
A combination of things were in play:-
1. The hand wheel was not pushed in tight before being tightened, so there was some slop there.
2. The little pointer on the old-fashioned backlash adjustment was actually bent so it wasn't holding the backlash nut in place.
3. The operator didn't understand the importance of numbers 1&2. He understands more now.

Backlash is down to about .004, which I'll consider a win. Thanks a bunch to all.

I also realized that I put this in the wrong group, I meant to put it in the Sherline group, but it put it here in error, if a moderator sees this and would like to move it that would be nice.
 

mikey

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#8
Nice, you got it in the middle of the range. This amount of backlash in the table is not a big deal so you done good! :)
 
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