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Tapered gib adjustment - cross feed - ct1440G

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middle.road

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Two cups of coffee and a whole bunch of searching later, I'm giving in and posting.
I'm having trouble adjusting/reinstalling the tapered gib on the crossfeed.
The manual for this puppy has no detail to it at all.

One of the Fathead screws was missing so I fabbed a replacement. I have that at the dial end and the original at the far end.
Thick end of the taper is at the dial end. -Have I at least got that right?

Gib does have a slight bow to it.

When cranking back towards the dial from center the gib is escaping the screw at the far end.

What the devil is the procedure for setting one of these?
I searched and found a bunch on mills but nada on crossfeed.


I am, by gosh going to make some chips today (maybe...) with a bunch of help.

Thanks,
_Dan
 

LEEQ

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What do your pieces look like? Is there a screw at each end of the gib? Is a screw head supposed to be captured in a groove on the gib like a Bridgeport gib? I would say if you have a tapered gib and assemble it to where the two tapers are opposite each other you have that much right. I also wouldn't sweat a little bow in the gib just yet, get the thing trapped in right and see how it works. I know you know, but a pic would help us see what you're working with. Good luck
 

12bolts

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Im not familiar with your lathe Dan, but tapered gibs are secured by the retaining screw at each end. Are you sure the thicker end is at the correct end? Whilst the key is parallelogram in section they can also be trapezoidal shaped so maybe you have the thick end at the correct end but need to rotate (twist) the key 180* to get the correct orientation?
A pic would help

Cheers Phil
 

middle.road

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Thanks all for taking some time on this.

Been monkeying with it on and off all day. Sorry I didn't post picts earlier.
The manual for this model is worthless, I did however find a manual for a Grizzley G0709 which is spot on. (Page 61)

Had to re-remake the missing screw.
The upper one is the first one I used, not enough bearing surface. The bottom one is version II
P1050998r.jpg
-=-
The wear on the bottom is rather heavy on the left side (upper). Any sign of scraping is just about gone.
I don't think that this poor beast ever saw any lube during it's use.
P1050996r.jpg
-=-
Following the instructions in the Grizzly manual, I got it close, .001" slop at mid travel position, .004" slop at 3/4 travel, but now the gib is starting to protrude at the dial end and is limiting the travel.
There is a thread from 2013 that shows something similar to mine. When I reassemble I'll get some actual picts of mine.
So I think I'm going to have to mill back this notch. I'm going to sleep on it tonight and see what you guys suggest.
When I do take it to 3/4 distance the gib still escapes the screw at the far end still. Is there too much bow?

P1050995r.jpg
-=-
P1050999r.jpg

P1050998r.jpg P1050996r.jpg P1050995r.jpg P1050999r.jpg
 

chuckorlando

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The gib should move with the table or cross slide or what have you. It should not be able to flex that I know of. It also should not be sticking out. Could you slot it so it captures the bolt head like a bridgeport?
 

12bolts

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Dan,
I understand what your saying about the gib escaping but I just cant fathom how it can do this if its installed in a dovetail correctly?
There shouldnt be enough travel, or slop for that matter, for the key to be able to get out of its slot. Can you show some pics of it installed but escaping?

Cheers Phil
 

LEEQ

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Something that caught my eye is the three screws in the cross slide that look like gib screws for a straight gib. They would bear in dimples in the gib trapping it in place and setting it under tension. I haven't seen that on a tapered gib. (doesn't mean it doesn't exist) I have seen a tapered gib trapped between a screw at either end. Also a notched tapered gib that your adjustment screw rides in. (Bridgeport style) I look forward to your next round of pictures. Someone will get this figured out:)) Say, did you try swapping ends or measuring gibs and ways to make sure your taper is in right?
 

middle.road

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Something that caught my eye is the three screws in the cross slide that look like gib screws for a straight gib. They would bear in dimples in the gib trapping it in place and setting it under tension. I haven't seen that on a tapered gib. (doesn't mean it doesn't exist) I have seen a tapered gib trapped between a screw at either end. Also a notched tapered gib that your adjustment screw rides in. (Bridgeport style) I look forward to your next round of pictures. Someone will get this figured out:)) Say, did you try swapping ends or measuring gibs and ways to make sure your taper is in right?
Not quite, nos. 2 & 3 were added by yours truly while the pieces and parts of the compound along with the gib were soaking in solvent back in May.
I added two #10-32 while I had the slide off before I realized the gib was tapered. They're just window decoration now.
The single m6 was mangled and while I had it in the mill chasing the threads I put in the two #10's.

The gib has a very visible taper to it. And of course I didn't measure it before I put it back in this round. It'll be coming out probably tomorrow.

- - - Updated - - -

Latest pictures this fine rainy day.

Gib protruding with retaining screw removed, there's about .001" of play at this point:-
P1060005r.jpgP1060008r.jpg

P1060010r.jpgP1060011r.jpg

Position of compound where/when the gib starts to come away from the rear retaining screw:-
P1060013r.jpg

And to top it off while I was taking these picts, I went to rotate the compound and one of the nuts is jamming so it's only moving about 15°. *SIGH*
Just how many times does one have to remove the cross slide...? hehe

_Dan

P1060005r.jpg P1060008r.jpg P1060010r.jpg P1060011r.jpg P1060013r.jpg
 

LEEQ

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I think at least once more to swap gib ends and see how it looks/behaves then. You might be able to remove the screw and drive it out with a piece of brass without tearing it down though.
 

chuckorlando

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If it has a noticeable taper I would think you could measure the gap front and back on the cross slide ways and know whats what. When I tighten the gibs I run it in, run the table out and back, then run it in some more. I would keep the back screw loose when doing. When your on the way back it will want to pull the gib in. But I still dont see how that little over hang can flex enough to jump the keeper. I mean if the gib does indeed stick out like that, why not put a big washer in front of the step?
 

middle.road

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I tried to reverse it a few days ago during reassembly, and it wouldn't go at all.
As it is currently installed I can run the cross slide out off the screw, slide it a bit more and remove the gib from the dial end.
It doesn't go when reversed.
Just went out and took it apart, should be able to do this with my eyes closed soon...
Pull out a hunk of granite, slapped the gib on it, and I do believe I have a messed up gib on my hands.
It's bent/bowed in both directions, side to side (which shows in the picts) and up to down (which didn't show well) in the last third of the gib, the narrow end.

P1060016r.jpg

P1060021r.jpg

P1060027r.jpg
Dimensions of the gib across the ground flats:
P1060024r.jpg
I measured the female dovetail in the cross slide with 1/2" pins, Dial End: 1.590" | Far End: 1.485"
The male portion on the slide is straight.

P1060027r.jpg P1060024r.jpg P1060021r.jpg P1060016r.jpg
 

chuckorlando

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That puppy is tweaked. Well that could be all your issues right there. I would thin it would start acting like a spring once it starts being compressed and not sitting in how it should
 

middle.road

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I should have checked the gib over when I first took it out. Stupid move.
I'm not sure I have the touch to work this piece back to where it should be...

- Update -

Got it! Clamped it up on a large piece of bar stock spacers under each end, anchored with a clamp at one end and softly held down at the other.
Slowly applied pressure at the worse point until it was just past lining up with the straightedge. Removed it and walaa :-
(I thought for sure I'd end up cracking it...)

P1060028r.jpg | P1060035r.jpg
__ ...and re-re-re-reassembled :
P1060038r.jpg

P1060035r.jpg P1060028r.jpg P1060038r.jpg
 
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