HELP! NEEDED G0704 Mill X-Axis Gib DOES NOT FIT

A

angelfj1

Active User
Registered
Joined
Jan 20, 2013
Messages
112
OK I know you're out there - all you Grizzly G0704 Mill owners. I'm more than a bit embarassed but I must be doing something wrong.

I have completely disassembled the mill to clean and adjust everything. I reassembled the X-Y saddle onto the base, adjusted for backlash, inserted the Y-axis gib, and the saddle glides back and forth very nicely. No such luck with the table. When trying to put the table onto the saddle, I can't completely insert the X-axis gib. The X-axis gib is approximately 7 inches long which is the "X" dimension of the saddle. I can insert the first 5.5 inches and then the table, gib and saddle seize up. This is not by lack of gentle persuasion. In fact, at one point, I tried to tap the end of the gib with a small brass drift. Bad idea! The gib got jammed between the table and saddle and would not budge. I eventually had to use a piece of brass rod to drive it out from the opposite end. I hope I'm doing this the correct way. First I engage the table into the saddle dovetails, center the table on the saddle and then insert the narrow end of the gib from right to left.

Just to clarify, at this point both X-axis gib adjustment screws are out and the X-axis leadscrew has not yet been installed.

I really can't proceed until I get this problem solved.

Thanks in advance.

Frank
 
I know this isn't much help, but I'm pretty sure that when I removed and reassembled my table that the x-axis gib slid right out and right back in without any issues. I know I took great pains to make sure that I was sliding in back in in exactly the same orientation that it came out. Maybe you managed to flip it end for end or top to bottom? It sounds like the procedure you're using to put it together is the same way I did it, table centered and sliding the gib in from the right (when facing the front of the machine). I would try installing it in all four possible orientations to see if any work any better, just to check whether you managed to flip it while it was out...

Good luck getting it back together!
 
kizmit99 said:
I know this isn't much help, but I'm pretty sure that when I removed and reassembled my table that the x-axis gib slid right out and right back in without any issues. I know I took great pains to make sure that I was sliding in back in in exactly the same orientation that it came out. Maybe you managed to flip it end for end or top to bottom? It sounds like the procedure you're using to put it together is the same way I did it, table centered and sliding the gib in from the right (when facing the front of the machine). I would try installing it in all four possible orientations to see if any work any better, just to check whether you managed to flip it while it was out...

Good luck getting it back together!
Click to expand...

kizmit99, thanks for your reply and suggestion. I will try this, but I think I may have already. I know that gibs don't grow! There must be something that I have done or haven't done that is preventing the gib from sliding in place.

Thanks again,

Frank
 
I thought of one more thing - I don't recall whether or not there were brass pins that lock down screws actually tightened against the gib itself, but I suspect there were (I have a vague memory of them falling out when I removed my table). If so, it's possible that one of them slipped deeper into the hole, instead of falling out and it's now blocking the gib from being reinserted. Good luck.
 
That's a good point kizmet99. I''ve seen that before; the screws contact little pins that in turn contact the gib. This prevents the screws from deforming the gib but could be a problem at reassembly. It might be a good idea to pull the table and verify that nothing is in the screw holes.
 
I'll have to look at mine, but I'm pretty sure that the gib adjustment screw for the table in on the right side (facing the machine), so the gib should go in from the right. Make sure the locks are completely out of the way and that the table is seated on the dovetail properly. Unless there is something in the way, the gib should go in relatively easy. Take it apart and make sure there is nothing out of place like the gib locks - I'd remove them entirely and install them after the gib is back in place.
 
hi Frank
I had a problem with the 704 build I did for baconbits here, I must have mixed up where each gib came from. I kept swapping them around until I found the original locations. I think it was x and z but I'm not sure now. also make sure the drain hole in the table is facing back and not forward. It took me quite a while to figure it out. the hand scraped side goes against the dovetail. do not tighten just snug the adjustment screws until you figure out where they go. the screws can bind the gib and make it seems like it fits when it's wrong. the gib adjustment screws are too small and will cock the head of the screw wedging the gib
each gib was hand fit to it's position and scraped to fit correctly.
steve
 
jumps4 said:
hi Frank
I had a problem with the 704 build I did for baconbits here, I must have mixed up where each gib came from. I kept swapping them around until I found the original locations. I think it was x and z but I'm not sure now. also make sure the drain hole in the table is facing back and not forward. It took me quite a while to figure it out. the hand scraped side goes against the dovetail. do not tighten just snug the adjustment screws until you figure out where they go. the screws can bind the gib and make it seems like it fits when it's wrong. the gib adjustment screws are too small and will cock the head of the screw wedging the gib
each gib was hand fit to it's position and scraped to fit correctly.
steve
Click to expand...


UPDATE!

Thanks to everyone who responded here and also to Dan Kemp (Hoss) if you read this. I did in fact have the X and Y-axis gibs mixed up. However, in the final analysis it didn't matter because the problem followed the bad gib. The X-gib was not flat and straightening it is not easy. I took the easy way out and used a motor powered flat polishing wheel to wear away a few thousanths from both sides of the gib. I eventually had to remove about 10 thousanths before I got an acceptable fit. I also ordered a new gib (they're cheap). For anyone like me who has a way to get parts mixed up see the photo below showing the three gibs and their approximate overall length. Xand Y ony differ by an eigth of an inch so it's easy to mix them up. Now with X & Y finished I'll get started with Z. Stay tuned for more updates.

DSC07427.JPG

DSC07432.JPG

DSC07427.JPG DSC07432.JPG
 
I took Richard King's scraping class in December and he showed us how to straighten a gib. You wouldn't have had to remove any metal from it. We all think of cast iron as brittle, but it will bend and can be straightened as Richard showed us in the class. To straighten it, put it on a surface plate (or any reasonably flat surface if you don't own one) and put a feeler gage under it to determine the two points it's resting on, and mark those points with a magic marker. Put the largest feeler gage you can fit in the gap to see how bent it is. That tells you how much you need to bend it. Mark the highest spot with the magic marker. Now take the gib to a sturdy bench (preferably metal because you'll be using a dial indicator) and rest the two outer marked points on blocks. Put a clamp next to the high point. Put the dial indicator's point on the high point of the gib and zero it. Tighten the clamp until the indicator has moved about twice the distance of the gap you measured with the feeler gage. Release the clamp and see how much the gib returns to its previous dimension. Hopefully it will have moved toward straightness a few thousandths. Repeat the process making the feeler gage go a little farther down than before. Release and see how much more you need to go. Keep repeating the process until the gib is within 0.002" of flatness. He would then scrape it to flatness. In your situation, I'd just accept the 0.002 of bend and install it.
 
RWL said:
I took Richard King's scraping class in December and he showed us how to straighten a gib. You wouldn't have had to remove any metal from it. We all think of cast iron as brittle, but it will bend and can be straightened as Richard showed us in the class. To straighten it, put it on a surface plate (or any reasonably flat surface if you don't own one) and put a feeler gage under it to determine the two points it's resting on, and mark those points with a magic marker. Put the largest feeler gage you can fit in the gap to see how bent it is. That tells you how much you need to bend it. Mark the highest spot with the magic marker. Now take the gib to a sturdy bench (preferably metal because you'll be using a dial indicator) and rest the two outer marked points on blocks. Put a clamp next to the high point. Put the dial indicator's point on the high point of the gib and zero it. Tighten the clamp until the indicator has moved about twice the distance of the gap you measured with the feeler gage. Release the clamp and see how much the gib returns to its previous dimension. Hopefully it will have moved toward straightness a few thousandths. Repeat the process making the feeler gage go a little farther down than before. Release and see how much more you need to go. Keep repeating the process until the gib is within 0.002" of flatness. He would then scrape it to flatness. In your situation, I'd just accept the 0.002 of bend and install it.
Click to expand...

RWL, thanks. This is very interesting. Who is Richard King? Is this an on-line course?

Best regards,

Frank
 
You must log in or register to reply here.
Back
Top