Author Topic: Grizzly G9249 Lathe Improvements and DRO install  (Read 9000 times)

Offline propforward

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #60 on: April 10, 2022, 11:49:50 PM »
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!  :lolb: 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.

Stuart

Forging ahead regardless.

Offline propforward

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #61 on: April 23, 2022, 04:35:38 PM »
Well now. This is not for the feint of heart................. >:D

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.  :ThumbsUp: :ThumbsUp: :ThumbsUp:
« Last Edit: April 23, 2022, 06:37:10 PM by propforward »
Stuart

Forging ahead regardless.

Online Kim

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #62 on: April 23, 2022, 04:49:25 PM »
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

Offline propforward

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #63 on: April 23, 2022, 04:59:46 PM »
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.
Stuart

Forging ahead regardless.

Offline crueby

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #64 on: April 23, 2022, 06:34:29 PM »
 :whoohoo:   So much more fun when the tools do what they should!   :ThumbsUp:

Offline Admiral_dk

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #65 on: April 23, 2022, 10:04:52 PM »
Quote
:whoohoo:   So much more fun when the tools do what they should!   :ThumbsUp:

Double Amen to that statement  :praise2:    :cheers:

Per

Offline propforward

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Re: Grizzly G9249 Lathe Improvements and DRO install
« Reply #66 on: April 23, 2022, 10:44:27 PM »
Heck yes! Its 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.
Stuart

Forging ahead regardless.

 

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