New Guy Here With A Few Questions

[mzvarner]

Hi there

I recently purchased a used Central Machine 7x10 lathe. I did some basic research before making the purchase, but it was not 100% in depth so now I come to you with a few questions.

First, I need some assistance with gearing. This lathe did not come with any extra gearing so I can adjust for threading. Are all the gears in there I just need to reconfigure them? As is, I am not able to use the power feed in general turning purposes because it moves too quickly. If I am missing gears can I buy the metal gear replacement kit from LMS as a replacement and prevention of trashing the plastic gears?

Next, I had to replace the cross slide screw and nut as the brass one stripped and trashed the screw. I have done multiple adjustments but still have about .001 of play. I also have about the same amount of play in the cross slide and cannot get rid of it after adjusting gibs either.

Thanks for all the help. This forum has been a lot of help so far. I tried to include pics of my first completed project too

 

[kd4gij]

I have never ran one. But .001 is really good.

 

[mzvarner]

I'm sorry. I sent that from my phone and did not notice the correction. I will edit the original post when I retake the measurement.

 

[Redbird]

I have the grizzly 7x12 and it came with change gears, I see the 7x12 HF seems to come with change gear also. The HF 7x10 I do not no. Change gear set can be purchased from LMS for 35.00 dollars, think it is 9 or 10 gears. If you only have 0.001 play with cross screw that is great. mine right now which I have done nothing to is around 0.030" play

 

[Baithog]

You need a set of change gears for that lathe. See if the seller has them collecting dust somewhere. Backlash of .001 is good. My 10X22 lathe recommends not going under .001 and my mill recommends .003 to ..006 as a minimum. You have to have clearance for the screw to turn. You can live with a lot of backlash in a manual machine. The gib problem may take some fiddling. The gibs in those little machines are often warped and/or poorly fitted. It you can take a cut without chatter, then make a few simple things so that you will get some experience with how well it will work. You will probably find that you want a larger better built machine in the future.

 

[mzvarner]

I don't know if this play is the same as backlash. My understanding of backlash is a few thousandths of play when you reverse direction of travel on the various handwheels. If that is correct then I have .005 of backlash on the cross slide and compound.

The issue I have is if you grasp the cross slide or compound they both shift along their respective dove tail some amount (I need to use feeler gauges to re verify the amount). This issue has been a big problem at times when trying to face or turn harder materials like 1081 steel. I get a large amount of chatter. And can see both slides pulsate at times because of the looseness. I will double check the adjustments of the gibs and cross slide nut screws. Anything else I should check?

Hope I am using proper terminology so I can convey they issue correctly?

 

[higgite]

I don't know if this play is the same as backlash. My understanding of backlash is a few thousandths of play when you reverse direction of travel on the various handwheels. If that is correct then I have .005 of backlash on the cross slide and compound.

The issue I have is if you grasp the cross slide or compound they both shift along their respective dove tail some amount (I need to use feeler gauges to re verify the amount).

The movement that you are seeing along the longitudinal axis of the slide is backlash. If you turn the cross slide handwheel clockwise, the slide will move away from you after the backlash is taken out in that direction. Now if you stop and push on the slide with your hands, it will move further away from you by the amount of backlash present between the leadscrew and the nut. You have just taken the backlash out in the reverse direction by moving the slide instead of turning the leadscrew. If you again turn the handwheel clockwise, it will turn by the amount of backlash before the slide begins to move again.

I think your chatter problem is most likely a matter of gib adjustment.

Tom

 

[kvt]

What I would do is use an indicator to see how much. turn your hand wheel one direction till you cross slide starts to move, then set up your indicator and bring your slide to a point on the indicator, then note where your hand wheel is. Now turn your hand wheel the opposite direction until the indicator just starts to move. Now note where you are on the hand wheel scale. Then figure out how much your hand wheel moved without moving the cross slide.
Another thing to do is have the cross slide going on direction and lock the hand wheel. Then with the dial indicator set up push the cross slide back the other direction and see how much it moves. A lot more accurate than using a feeler gauge.