Finally got Logan/ MW 2136 Home

I don't think shims are going to be of any use for your situation. As has been said, adjust the 2 nuts at the handle to take out as much slop as you can without making it hard to turn. As for the cross slide screw... take the screw out and turn the nut on it all the way up the length checking the fit in different areas as you go. It's obviously going to have some wear on it but if it's fairly consistent your nut is probably causing most of the backlash. Honestly 0.060 isn't going to stop you from making good parts. As long as you keep your gib snugged up and always take up the slack before starting your cut it shouldn't be an issue. I advocate making some chips with a machine and getting to know it before throwing a bunch of money at it.
 
I agree with Chuck K.
And we may able to find you some affordable acme thread and make a nut. If that's what is needed.
One step at a time.
First get her leveled in plane.

Daryl
MN
 
I guess that I was thinking about a different badge. I keep an eye on more than a dozen fora, and the last time someone had this problem, the adjustment wasn't made by differential adjustment of a nut between the crank and the bushing that the dial runs on. Must not have been a Logan. The Atlas machines have a nut that holds the crank on the screw and a nut between the crank and the dial bushing. And end float adjustments are made by loosening the crank nut, adjusting the 2nd nut, tightening the crank nut, and turning the crank to check the end float. Repeat until force required to turn the crank becomes noticeable. If you can't get the thumb nut that holds the dial loose, that shouldn't affect whether or not you can adjust the end float. The dial lock should be independent of that because the screw in the dial is used to zero the dial whenever you need to, independent of where the crank is.

It sounds like your machine has the end float adjustment nut, but if you ever do need small shims, I usually get them from McMaster. RAF Parts is another possibility. But I usually default to McMaster because they have so many other things.
 
If you can't get the thumb nut that holds the dial loose, that shouldn't affect whether or not you can adjust the end float. The dial lock should be independent of that because the screw in the dial is used to zero the dial whenever you need to, independent of where the crank is.
We are not talking about a "thumb nut", we are talking about a set screw in the graduated dial that holds the dial firm to the crossfeed or compound screw. Tightening the adjustment nut against the dial will do nothing, if the set screw is not loose so the dial can move on the cross feed screw to remove the slack.

Below is a diagram from a Logan 200, but all of the smaller and earlier Logan mfg lathes (I believe) were pretty much the same. Basically with set screw 0431 loosened and tightening the nut behind the handle, you are reducing the distance between the graduated dial (171) and the gear on the inside (190). Logan used the dial (171) and the gear (190) as thrust surfaces against 172. Too tight and the assembly will be too difficult to turn, too loose and more slop, float, endplay you will have.

Compound screw is similar. No gear, but has a slight flange on the acme screw.

I was always going to retrofit a bearing on either side of 172 to allow the components to be pretty snug and still turn.
Capture.JPG
 
Hopefully there is a brass slug under that set screw to protect the shaft.
 
Chuck -
I have never seen one listed in parts diagrams or on the two older model lathes I have messed with (not counting the new one). I would have to think all the early 9"-11" were probably pretty much the same. Not sure off the top of my head when they switched to a different (larger) dial design ... 1800 - 1900 series?
 
I would put one in regardless. Without it the shaft gets all scored up. I like to adjust those so they are tight enough to turn along with the handle but still free enough that you can zero it at any time. Once the set screw has bitten into the shaft a few times it's all but impossible to have it turn smoothly when you want to adjust it to zero.
 
I agree on the brass or lead plug.

Over the past few years, I have looked at a lot of lathe and mill assembly drawings and these is the first ones that I recall seeing where the cross feed screw thrust was taken against the dia and its set screw. Every other one I recall seeing had a bushing or shoulder bushing that the dial ran on. So that when taking heavy cuts, the reaction thrust wasn't taken against the dial (with the friction component trying to turn the dial).

But to get back to the original question about backlash in the cross feed screw (and ignoring the fact that there is no reason to let that backlash actually affect the accuracy of the work). I don't recall a case where part of the backlash wasn't due to excessive feed screw end float.
 
That was a good write up Daryl, I had not see that one before.

After reading it, I realized that the idea I had for the thrust bearings in the carriage came from another of Bob's articles.
 
Back
Top