thoughts after six months

[Runner4404spd]

yes i made a gib shim. i basically made one for every axis. the shim is the exact shape of the gib including the cut out for the adjustment screw, that way when you move the gib it moves the shim in and out as well. making this mod did wonders for tightening up the machine and then i could use the locks as just locks.

[Cruiser]

Originally Posted by altaic Interesting. I was considering using soft tip set screws, but I thought it probably didn't matter since the screws that IH packages with the machine are standard cup tip. However, I replaced the screws that came with the machine with oval tips. Could that deformation while tightening the side snubs cause the table to move slightly? If you insist on using the snubs, It would be best to use large flat end instead of a ball or cup end. It will dimple the Gib, raise a ridge outside of dimple and push a convex to the other side of Gib which you can see as a localized wear. Repeat, I took mine out Period ! I'm running the Gib's pretty tight, but I'm worried about my x-axis power feed. Any tighter, and the power feed audibly changes-- I've already had one power feed die on me, which Gene@IH kindly and promptly replaced. You don't want to get too tight for sure, Using some moly as described earlier will greatly help it to accept the extra tension of Gib. Oh yes, but it sure feels nicer when most of the slop is eliminated. The one place slop is really a problem for me is in the quill, which is still a real pain. This being a CNC forum, I realize that many people here lock the quill and never unlock it, just using the z-axis. Unfortunately that doesn't work so well for my manual machine :/ Put table in middle of stroke and run an indicator from head or column to end of table, then, go to opposite end of table and give it a moderate push pull and watch indicator. Nice trick! What kind of solvent did you use? Acetone, or perhaps brake cleaner? I've used brake cleaner on a towel immediately followed by an oiled towel (otherwise rust forms lickidy-split) for some engine parts. I used carb and choke spray to clean it, this will deep clean lube from pores allowing micro pockets to hold the molly. I used a piece of leather (old belt) and rubbed it in. I used a lot of molly on leather and rubbed in a stain. This way no need to whip off excess after, just a dose of oil (vactra) and move on to other section. Don't forget to remove Gib and do it to on the slide side. If you see any deformation from screw on side, file off the outy ! Use smooth filing technique ! Keep file clear ! I'm having a bit of trouble visualizing where you shimmed. Was it on the length of the Gib?

The Gib shim fits to the side of the Gib that does not slide against axis side of dove. I found that a thin spray of 3_M 90 helps to hold it in place. Steel shim preferred, and this only allows to gain adjust ability of Gib by its interfering earlier by approximately 1/4" per .009" of shim ? (memory issue) You want the adj screw and Gib at approx 50% of adj'ment stroke. Gibs have a break in cycle that they wear into for fitment. So whenever you feel strong enough, crank the ***** from lock to lock till it time to take a break. The lube you use has a great effect on the perceived friction at the gibs and slides !

[altaic]

Originally Posted by Cruiser If you insist on using the snubs, It would be best to use large flat end instead of a ball or cup end. It will dimple the Gib, raise a ridge outside of dimple and push a convex to the other side of Gib which you can see as a localized wear. Repeat, I took mine out Period !

Is your machine manual? When I make a cut along the y-axis, for instance, it tends to push the table around in the x-axis (and once pulled the piece into the cutter, which really scared the hell out of me) if I don't lock the slide.

Originally Posted by Cruiser Put table in middle of stroke and run an indicator from head or column to end of table, then, go to opposite end of table and give it a moderate push pull and watch indicator.

I measured the slide play once when I first set the machine up and another time a few months later before and after adjusting the gibs. I forget what I'd measured (I wrote it down somewhere around here!), but it was pretty bad (definitely a source of vibration) before I tightened it up. I'll take another measurement soon.

Originally Posted by Cruiser I used carb and choke spray to clean it, this will deep clean lube from pores allowing micro pockets to hold the molly. I used a piece of leather (old belt) and rubbed it in. I used a lot of molly on leather and rubbed in a stain. This way no need to whip off excess after, just a dose of oil (vactra) and move on to other section. Don't forget to remove Gib and do it to on the slide side. If you see any deformation from screw on side, file off the outy ! Use smooth filing technique ! Keep file clear !

I'm really looking forward to trying this out when it warms up a bit. I have to break the mill down and clean it up anyway (unfortunately it may have recently been exposed to some abrasive dust, so this is a must before it's put back into service), so that will be a good time to do it. If only my workshop wasn't stuck in an ice age.

Originally Posted by Cruiser The Gib shim fits to the side of the Gib that does not slide against axis side of dove. I found that a thin spray of 3_M 90 helps to hold it in place. Steel shim preferred, and this only allows to gain adjust ability of Gib by its interfering earlier by approximately 1/4" per .009" of shim ? (memory issue) You want the adj screw and Gib at approx 50% of adj'ment stroke. Gibs have a break in cycle that they wear into for fitment. So whenever you feel strong enough, crank the ***** from lock to lock till it time to take a break. The lube you use has a great effect on the perceived friction at the gibs and slides !

I've got some stainless shimstock that looks to be about the right size-- stainless should be fine, right?

[Shev]

What do you guys think about using way oil with moly? Or should the moly grease thing be done no matter what...

[Cruiser]

Originally Posted by altaic Is your machine manual? When I make a cut along the y-axis, for instance, it tends to push the table around in the x-axis (and once pulled the piece into the cutter, which really scared the hell out of me) if I don't lock the slide. My machine is full CNC and pretty tight ! I measured the slide play once when I first set the machine up and another time a few months later before and after adjusting the gibs. I forget what I'd measured (I wrote it down somewhere around here!), but it was pretty bad (definitely a source of vibration) before I tightened it up. I'll take another measurement soon. You will need to not only service the gibs but also the screw drive and try to take out all the mechanical slop that you can find. There may be adjustments you can make to take out backlash and lost motion. Or disassemble and make some spacers etc. I'm really looking forward to trying this out when it warms up a bit. I have to break the mill down and clean it up anyway (unfortunately it may have recently been exposed to some abrasive dust, so this is a must before it's put back into service), so that will be a good time to do it. If only my workshop wasn't stuck in an ice age. I use Flood coolant to clean and lube machine while its running. It depends on the grit as to how destructive it is going to be. That is also why you use no grease ! only oil ! oil will allow the grit to roll out and it can be wiped away, grease will suck it in. I've got some stainless shim stock that looks to be about the right size-- stainless should be fine, right?

Stainless is perfect ! It is a trial and error for thickness though, you really have to pay attention to where the end of gib is when slipped into position. If when set the head of screw is just into bore it is perfectly set.


MOLY or molybdenum disulfide is very expensive and will make the cost of the oil much more. Just get good oil and a tube of engine assembly lube with moly grease in it. Use a piece of leather to rub it in. After all, it is not the moly in suspension but the moly in the pores of the iron that does the job of fighting friction. Just use some good vactra grade #2, your machine will like it.

If your machine is loose or has a problem, this is the place to ask and we who live here will try to help with it as much as possible.
If it is moving in X when cutting Y then it is going to be a combination of area's to tend to. It has been done, once gibs are set good and tight with proper lube, make up a replacement handle crank that has a longer radius on one side. Keep the short side as is. This will help over come the friction and save arms. An extension can be attached to the existing handle in many ways.
The most amount of slop is in the drive screw assembly, primarily at the NUT and the bearing end of handle. Adjustment and shimming can handle the drive end and making a backlash comp nut can handle that. Lets see some ingenuity here.

[altaic]

Originally Posted by Cruiser My machine is full CNC and pretty tight !

Ah, but a CNC machine usually has zero backlash nuts and the motors hold the table in place. I'm not good enough to operate one handwheel while carefully adjusting the other one to stay still. :/

Originally Posted by Cruiser You will need to not only service the gibs but also the screw drive and try to take out all the mechanical slop that you can find. There may be adjustments you can make to take out backlash and lost motion. Or disassemble and make some spacers etc.

Back when I adjusted the gibs, I also shimmed everything attached to the drive screws to get as much of the slop out as possible and got some cast iron handwheels for a really nice smooth feel (I heartily recommend this upgrade to anyone using the mill manually!).

The only places in the table left with major slop are the nuts, which I'd either planned to replace with a variant of the backlash-free "poor man's roller screw nuts" (as featured in the linear and rotary motion forum) or go with ballscrews and backlash-free ballnuts. I dig the roller screw nuts, but they are a pretty big project. And the ballscrews are expensive, especially considering I don't have a lathe to machine the ends. It'd be great to have slop-free drive screws, but unfortunately I can't currently justify the time or cost. It'd be awesome if someone on this forum was selling the poor man's roller screw nuts fit to our machines.

[Rally]

DO yourselves a favor and modify your toys with a lubing system whether it be hand operated or automatic. A standard way lube works just fine. That alone will give you many more years of service.
Or better yet, get a real Mill. LOL

[Cruiser]

A lubing system has merit if the machine is run 24/7 by idiots that don't know what an oil can looks like. The oil that runs out of the slides is wasted and expensive. It is the retained film which provides the lube and saves the machine. I lube mine manually and have left it for weeks and come back and still had a fine film still where it is needed. I just lay a short shot of oil at each slideway and run the machine into it and run the day, I might give the Z axis periodic oil if I am doing a lot of machining, but it will go many hours without.