Grizzly G9249 Lathe Improvements and DRO install

[propforward]

I now have a plan for finishing up the gib that I bought from Grizzly. I've been doing a bit of research and looking at what others have done. Based on some test cuts on cast iron, I think I can get a good part by milling the gib to size. After that I can try my hand at scraping if I really need to, but I think I can at least get a better part than is in the cross slide now.

So to do it, I am going to glue the gib to a flat plate using toughened superglue. I'm not a fan of using glue to fixture things, but at the end of the day if it holds the part then so be it.

So I started off by skimming a steel bar. This bar is yet another piece of nice steel that was literally being thrown away. I'd like to go on about what a disgrace that is, but it ended up being thrown away in the back of my truck with me getting it for free, so WIN!

Got a few piccies here - nothing exciting really. I tried skimming it dry. Then I tried using a bit of cutting oil to improve matters.




It worked better in the vice.





This worked well enough, but I decided that since I have flood coolant available, I would use that.





This worked great, but at the high rpm's I was trying the coolant went EVERYWHERE!  Benefit of a separate shoppe I suppose. I had to rush around and get some makeshift splash guards in place.

However, net result is a nice flat bar - like .0005" flat, so I think this will be a good start for what I am going to try next.



The idea is to mount the old gib next to the new gib, so I can get the bar angled properly, and touch off on both new and old gibs and see how much to machine back.

That part is still to come.

[propforward]

Well now. This is not for the feint of heart.................

What I have done here is not how you are SUPPOSED to make a gib, but I decided that I surely cannot make a worse gib than was supplied with the lathe in the first place, ergo any improvement I make must surely be an improvement, even if it is not as good as it should be.

So - I got some of the toughest superglue I could find, and I glued the new gib (rear) and the old gib (front) on my flattened steel bar.



I used the old gib as a reference to angle the bar until both gibs were presented at the right angle. Note - I only used the "good" end of the old gib, as the thinner end is not flat or true in any way shape or form.

I then installed a brand new carbide end mill, run at the highest rpm I could, and proceeded to skim off the .060" inches of extra material on the new gib. I ascertained that dimension by using a test indicator and touching off on both gibs in multiple spots. I actually measured .063" but decided to play it safe, since I have extra length on the new gib.





This worked like a charm. Now I know that gibs are supposed to be ground and then hand scraped, but I'm well happy with the achieved finish.



So I test fit it - and it was looking good. I marked it front and back, and cut off the excess using a bandsaw - but playing it safe (ie cut it long) and did some more test fits. After trimming off a little more, I set up my little tool grinding post to steady the gib and ground a notch for the front adjusting screw, and reinstalled the gib.

Here is the handwheel end - as you can see there is still room to trim a little more, but no need, this is fine.



Net result..................

It absolutely works! I now have an even drag of the cross slide over its whole range, and when I grab it and try and move it there is no change in reading on the DRO, whereas with the original gib I could move the DRO several thousands quite easily, and the cross slide always felt loose and slack (it was).

So - I don't doubt that the gib is not properly seated in normal precision lathe terms, but it's a heck of a lot better than it was. I'm very excited, and now I'm going to turn some test parts and see how it performs. 

[Kim]

Looks great to me, Stuart!  And proper lathe etiquette or not, the results speak for themselves!  Congrats on successfully completing something new and different!

Kim

[propforward]

Thanks Kim! I just made an attempt at taking .0005" off a piece of aluminum and slap me sideways if it didn't work. Never been able to reliably do that before. Noticeable improvement in surface finish as well, which I ascribe to reduced chatter.

What a great day - I'm over the moon with this.

[crueby]

    So much more fun when the tools do what they should!   

[Admiral_dk]

   So much more fun when the tools do what they should!   

Double Amen to that statement     

Per

[propforward]

Heck yes! It’s a game changer. A lot of frustration with this lathe went away today. It took me a silly amount of time to figure out what was wrong, but I got there eventually.