Mini Lathe Crossfeed Nightmare

O.K. Trial and error is the order of the day here I guess. I will continue to try to get it right. I have so far failed due to frustration and defeat. And I will continue to try and find a better way.
 
sounds as if the nut is to high, or to low, of really crooked. move cross lside all the way back toward you. loosen all three bolts. play with the center grub screw to try and get the nut in the same axis as the leadscrew, and LIGHTLY snug up the two socket head cap screws. i bet shims would work equally well, but take more time. the nut is brass with small threads so not much torque can be or need sot be applied. also loosen the lead screw mounting block and see if it helps to move it around a little. it has some play on the mounting bolts.
 
Did you ever get this sorted out? It sounds to me like you have a Speedway 7x10 style lathe like mine, purchased in 2003, and there is a specific process to adjusting that nut. I can post the info if you would like. I have also recently read on one of the forums about an easy upgrade to how this nut adjusts, which only involves drilling a small depression in the place of the center "dimple" on the top of the nut, and then replacing all 3 screws.

You may notice the heads of the outermost of the 3 screws will actually move in their holes. This design is meant to have this nut "floating" in its location, but it lends to allowing end play in the screw mechanism, which can allow your cross feed to move when it needs to be stationary. The upgrade I mentioned is reported to have removed pretty much all the end play. I have not tried it yet, but I plan to do so eventually. Between keeping the cross feed gibs adjusted and adjusting that brass nut, I've been using my lathe this way for 10 years.

I also use the digital crank readouts the are sold by LMS, if those are what you mean. Aside from the way the batteries are mounted being very poorly done (they can short the circuit board if pushed in too far) I find them to be accurate, but you do have to allow for the end play in the screws. So just like using the manual rings on the cranks, you back away a turn or two, then crank back in to make the change in adjustment.

Happy to help if I can. :)
 
If you search for 7x12 spindle bearing swap on this site you will find in that thread these problems where discussed .
you have two areas to look at the nut and spindle backlash. The nut mod in also on my web site, See bottom of this page.

Brian.
 
No I have not worked on it at all. I have become obsessed, with getting my cnc gantry router rebuilt and adding a 3d printer head to it as an interchangeable accessory. But, I did have a look at your pages Brian and I must ask, how did you determine how thick, what looks to be a shim under your split nut is? This does address my nightmares though. I must put in a shim, if only to satisfy myself, so I can lock down the nut. My ultimate goal is to get it so it don't want to creep back to its old condition, and I think your solution will do the trick. Now, with that said, what can you add about maybe permanently securing a shim in the sweet spot under the nut? Any thoughts on that?:nuts:
 
If you don't have a manual, you might go to Little Machine Shop and read their lathe guide. It gives a clear description of Adjusting your lathe including that nut. I'm not saying don't mod it, but you might want to try to adjust it first.
 
Oh yes I have the manual, I just want to make it fool proof. I'm sick of having to re adjust it time and again. When it gets above freezing in my garage, I have plans to replace that pesky screw with an acme lead and anti backlash nut once and for all. Until then I have to collect all the suggestions and comments on this so I can weigh the options. Thanks
 
Go to groups.yahoo.com/group/7x12minilathe/ for a wealth of info on minilathe lore. Join the forum and ask members for help. You will be inundated with advice.:))
speedre9 said:
This is a tale of woe. I got me a mini lathe from Grizzly sometime around 1998, I was excited. After experimenting and noodling I wanted to improve it, so this is where the nightmare began. The first thing I bought were the inch lead screw and nut offered by Micro Mark. That went well but it was for only the X and Y axis. I managed. Then came the Digital readouts for the cross feed. I installed them as instructed, it did not work as advertised. I never got an accurate reading, so I removed it and re installed it as instructed again, and then, again, three times total, still not correct. By that time it was to late to return it for refund or replacement. So long story short here's what I'm left with. A cross feed screw that binds and is now somehow 0.010" - 0.018" too long, plus it seems to rock on the ways when adjusted. Has anyone come up with a method of replacing this miasma of inaccurate and ungainly parts. I want to change the screw and the sucky nut arrangement:panic: to something more normal. Would someone want to start a dialog with me to explore this issue? I could really use some help with this.
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