[4]

Compound gib issue

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#1
20180718_150727_resized.jpg 20180718_150708_resized.jpg

Here is a shot of the end of the compound. The compound doesn't slide smoothly and it appears that it is because the set screws force the gib to ride all the way up in the slot and the edge of the dovetail digs into the gib, as seen in the other pic. Should it ride that high up? The problem is that the set screw dimples are already at the top edge of the gib and keep it held at the top of the slot. Do I just need a new gib? Is the roughly 1/16" space between the two pieces of the compound normal?

Thanks.
 

T Bredehoft

Active User
H-M Supporter - Gold Member ($25)
Joined
Dec 27, 2014
Messages
2,722
Likes
2,096
#2
The "slots" for the set screws should allow the gib to be central in its' slot, neither top or bottom. Possilby yours has worn to the point it is not longer functional. They were made to be replaceable.
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#3
Looking some more, it looks like part of the issue is that the set screws are so high in the slot that when you start tightening them they skew the gib to a more vertical position making it rub on the edge or corner of the dovetail. It seems that it should ride lower so that it can't skew in the slot and the flat faces ride against each other. I have new ones on order but the one for the coumpound and the one for the slide are the same in the Sears system, even though they aren't but I may be able to make them work.
 
Last edited:

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#4
Yes, the roughly 1/16" vertical clearance is normal. The compound slide is supported vertically by the bottom of the slide resting on the two lower flats of the dovetail. And the gib should not touch the right lower flat.

My guess would be that either there is a "dinged" spot on the top right nearly sharp edge of the male dovetail on the swivel, or one of the gib screws is catching on the edge of its flat bottomed hole/slot instead of seating in the hole against the flat bottom.

The proper/safe way to install the gib is with the compound swivel and compound slide removed from the pintle on the cross slide and inverted on your work bench. In that position, the gib's beveled top surface rests on the slide, instead of the bottom bevel wanting to rest against the swivel, which will try to happen if you try to install the gib with the swivel sitting on the pintle as in your photo.

I have some new steel (Clausing went to plastic in the mid 1970's) gibs. However, aside from the line of wear (that won't much matter after you find and fix the problem), there probably isn't any reason to replace the one that you have.
 

markba633csi

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Apr 30, 2015
Messages
2,961
Likes
1,535
#5
Hi Dan I have the same lathe, mine is a little stiff too, but usable. Check the gib strip for bends and rough spots, maybe polishing with some garnet paper and re-greasing (or oiling)would help. I'm planning to replace mine with either bronze or brass eventually. I put a brass one in my 6" and it's considerably smoother. It will wear faster I'm sure, but to me it's an equitable trade.
mark
 

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#6
I was writing my last while you were writing. You did not show what the back side of you existing gib looks like. But your use of the term "dimple" makes me wonder whether your gib is original or not. The steel gibs should have what amounts to a flat bottomed slot that starts shallow and finishes deeper, or a flat bottom hole cut at a 30 degree angle with the deeper side nearest the top of the gib. Only the carriage gib has countersunk "dimples".

The reason that the current compound and cross slide gibs are the same part number is that you install them and then cut off the part that sticks out. I don't think that anyone here who has made the change back to steel gibs would recommend that you try to use the plastic ones.

Show us a photo of the other side of your existing gib.
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#7
Here is a pic with the gib installed. You can see how it gets skewed to a more vertical position and rubs on the corner. 20180718_162333_resized_1.jpg
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#8
20180718_160607.jpg
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#9
I was writing my last while you were writing. You did not show what the back side of you existing gib looks like. But your use of the term "dimple" makes me wonder whether your gib is original or not. The steel gibs should have what amounts to a flat bottomed slot that starts shallow and finishes deeper, or a flat bottom hole cut at a 30 degree angle with the deeper side nearest the top of the gib. Only the carriage gib has countersunk "dimples".

The reason that the current compound and cross slide gibs are the same part number is that you install them and then cut off the part that sticks out. I don't think that anyone here who has made the change back to steel gibs would recommend that you try to use the plastic ones.

Show us a photo of the other side of your existing gib.
Here is a pic.
 

Attachments

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#10
Yes, I see the gap. Are the bottoms of the three holes still flat and at a 30 degree angle to the surface that they are cut in?

Pull the three gib screws and confirm that the ends are flat, not rounded. If they are rounded, use the side of a grinder wheel to flat them. You might want to make a quicky holder by taking a piece of aluminum round stock and drilling and tapping a hole in the end. You can do that without the compound being assembled. Just don't make it too deep or you might screw the screw into it and not be able to get it out. Run the screw in no more than about five turns and tighten the nut to hold it.
 

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#11
We doubled again.
 

Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Joined
Feb 1, 2018
Messages
410
Likes
405
#12
How about rotating the compound 20 degree's so we can see where the set screws are located to the gib. It's possible the factory screwed up and drilled the holes to high in the casting. You may have to drill and tap new holes lower down so it hits in the middle. Many times lathes have a pin the diameter of the hole and approx 1/2" long in front of the set screw and the end that pushes against the gib are rounded so the gib will rotate and fit the angle of the way. How about taking it apart too and show us all of the compound top and bottom so I can advise you on the ways. Is it an Asian made machine? If we knew the brand name and model number we might be able to find a drawing online and not have to guess. As the title says I am a professional machine rebuilder and will do my best to help you.
 
Last edited:

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#13
The set screw holes are about 7/32 from the bottom surface. It looks like they are too high because the gib dimples are at the top of the gib. The gib dimples are kind of jacked up. The set screws have flat bottoms.
 

Attachments

Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Joined
Feb 1, 2018
Messages
410
Likes
405
#14
you need to let me see the piece apart or turned 20 degrees' so I can see where the tapped holes are coming thru the other side and see the nuts on the outside. looks like you need to drill tap smaller screws lower and as I said use round headed pins in front of the sets screws. Did you buy it new or used and it was like that ?

Here is a Greezly that is on here and it has pins in the gib.
https://www.hobby-machinist.com/thr...t-compound-mod.67600/#lg=thread-67600&slide=7
 

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#15
Richard,

I don't know why it is painted red instead of gray but it's an Atlas or Atlas-Craftsman 12" Commercial. If you go back to his first photo on Post #7, you can pretty clearly see the rear gib screw and jam nut. The gib screws are supposed the be flat on the front ends and the flat-bottom holes or slots cut at 30 deg into the side of the gib should be flat bottomed. It is difficult to tell from the photo of the gib what the condition of the bottom of the holes actually is.

Dan, the factory drawing for the 10-304 Gib is in Downloads but you don't have access to Downloads. If you wish, PM me your email address and I will send it to you for comparison to your existing gib.
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#16
Whoever owned my machine was not kind to it. The cross slide and compound are red, the saddle white, tailstock yellow and the rest is flaking grey. Broken screws, missing cross slide gib, broken levers. Will be interesting to see how well it cuts once I fix a few things.
 

Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Joined
Feb 1, 2018
Messages
410
Likes
405
#17
OK. I found this on you tube. I know Nelson doesn't like us to link to them but you can cut and paste this to the search box.

"shop tips Craftsman 12" Commercial lathe compound".

It appears the gib that are in the show are at top tpp and I was mistaken about the pins. It only had dog point set screws. Post 9 showing the gib it looks like the center hole is buggered up and the gib was to low when the gib screw was installed and it had to have been over tightened to bugger the gin up. So best to file the buggered gib and as the YT show says is aligned with a ice pic and look in with a flash light. If the gib is factory then the adjustment on the flat spots on back of gib should pressure the gib in center.

Try this and then let us know. Rich
 

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#18
As I wrote earlier, removing the compound from the cross slide and inverting it on the work bench is a trivial exercise and prevents damaging the angled holes. Unfortunately doing that isn't practical with the cross slide gib but there is no excuse not to do it for the compound.
 

wa5cab

Downloads Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Dec 25, 2011
Messages
4,344
Likes
1,069
#19
Dan,

Does your machine still have the nameplate affixed to the right end of the bed? If so, please give the Model and Serial Number. If it doesn't still have its nameplate, does it have on it anywhere either a plate or a decal that says either Atlas or Craftsman?
 

Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Joined
Feb 1, 2018
Messages
410
Likes
405
#20
Yes I also advise people not familiar with install to flip it over in a vise. GMTA. :)
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#22
Dan,

Does your machine still have the nameplate affixed to the right end of the bed? If so, please give the Model and Serial Number. If it doesn't still have its nameplate, does it have on it anywhere either a plate or a decal that says either Atlas or Craftsman?
 

Attachments

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#23
Got my new gibs from Craftsman. Didn't realize they would be plastic. Oh well. Good enough for now.
 

Winegrower

H-M Supporter - Silver Member
H-M Supporter - Silver Member ($10)
Joined
Jul 29, 2014
Messages
149
Likes
133
#24
Just to complicate, my Logan had a compound that was sticky in places that messing with gib screws couldn’t fix. I set it up carefully in the mill and took a very light skim cut with a dovetail cutter. Stoned the gib a bit, and now it works well.
 

Winegrower

H-M Supporter - Silver Member
H-M Supporter - Silver Member ($10)
Joined
Jul 29, 2014
Messages
149
Likes
133
#25
Oh, sorry...I made light cuts on each side to insure they were parallel. Duh.
 

Richard King 2

Master Machine Tool Rebuilder & Instructor
H-M Supporter - Commercial Member
Joined
Feb 1, 2018
Messages
410
Likes
405
#26
Remember those gibs are made to be "Fit" and you can't just install them and trust they will work. a few more pictures of them would help now.
 

DiscoDan

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jul 16, 2018
Messages
238
Likes
115
#27
Richard, were you referring to Winegrower's comments or to my plastic gib post? I put the new plastic gibs in the cross slide and compound and adjusted and they seem to be working well.
 
[6]
[5] [7]
Top