7/08/2008

Gib fitting

This is properly the first problem I've found in this lathe. When I wind the cross slide hand wheel, the cross slide moving with rocking. And this can be easily observe by eyes!

Then I decide to take the cross slide off and see what's wrong.
And this is...

The gib was a bit higher than the dovetail. That means, the cross slide cannot sit down properly on the saddle.
What I am going to do is file the gib down...
Now, the cross slide can sit down properly on the saddle, but when I insert the gib deeper into the space, rocking movement come back again.


When I carefully look at the gib and the dovetail, I find that, the gib is more likely to be less than 55 degree of the dovetail.
Put it deeper into the taper space will press it upward and push up the cross slide again.

Now, I've the handy epoxy putty, put a thin layer on the non-sliding surface of the gib.

Finally, the rocking motion become unseeable.
Of course, I will need to check the cross slide by level or DTI when higher accuracy is needed.

7/07/2008

Lead screw end support bearing

After I've taken out the lead screw, I found that, the end which close to the headstock was directly inserted into a tube.

Without any bushing or bearing support, I can see there has a scrap mark on the inner surface of the tube. And it was definitely a thread scrapped mark!


Luckily, I find a 12x8mm bearing on hand, and...
Turn the lead screw end down to 8mm and bore up the tube to 12mm...

And that's it, you can use what ever spec. of bearing , as long as it is not larger than the tube (0.625 inch), cheap and easy to find for you.