Gauging interest: anyone else want to get in on some high quality X4 Z feed gibs?

[MadMax]

I'll be getting some high quality gibs made for me because I found the Z feed gib to be quite poorly made. Their poor quality is quite sub par in comparison with the rest of the machine build. I've looked at two of them now (one replacement) and found them both to be well out of plane and not very smooth. My first one even had severe ding marks on the surface presented to the vertical way so I suspect that the parts are being dumped into a common box and roughly handled so they're damaging each other.

I'm going to stick my neck out (because the current gib hurts my eyes) and get a couple accurately custom ground for me. I can put on some marking blue to see what kind of contact I get before committing to a short run.

Are other X4 users interested in upgrading to higher quality vertical feed gibs? I took my machinist out for coffee to talk the job over and it would probably cost me around $150 to do a short run of gibs (around 25 gibs) ground in O-1 steel. I plan to use unhardened stock so as to reduce wear to the ways (gibs are replaceable, ways are not).

I'm not asking for any significant commitment. Just a shout out from those interested in better quality gibs to preserve their Z ways and maybe even improve performance a bit (lower friction, less wear, maybe even less clearance).

I think I should have my own gibs made in a couple weeks so I can do the contact assessment (prussian blue etc) and see if we're able to make good parts. After that, maybe 3wks before I have deliverable gibs for other X4 users.

Any takers?

[Martin Long]

I would be interested if you don't mind posting one to Australia???

Marts

[iGG1e]

Any idea how/if the X4 Gibbs differ from the older SX3 based machine?

[ataxy]

the problem you will get i think is that most of those machine a matched together so the gibbs that fit perfect on one machine might not on another

[Journey_Man]

I bought some Sintered Bronze Bars awhile back with intentions of making Gibbs for my Lathe but havent really needed to. Maybe you could use some on your Mill...It is Oil Impregnated Bronze and Things would stay Oily and the wear factor would be on the Bronze side and not the Cast ways.. 01 will chew cast iron up in a short while...I think The Bronze would be the deal...
Here Is a Link to the Bars..https://sdp-si.com/eStore/
Bob

[MadMax]

Thanks for the material suggestion Bob!

I'm not sure if matching is an issue or not. I've only got one mill for me to gauge to determine the taper angle. Keith at Syil Canada got me an engineering drawing of Syil's gib, but both of the gibs I've got don't fit my machine right (not enough adjustment) so I have to assume the worst and gauge my taper myself. The gibs are more or less to spec (not GD&T specs on planarity though) so I have to assume that my machine is out of spec.

Perhaps I can gauge my own machine and see if the taper is at least at the spec'd angle. I'm hoping to get some help from other X4 users to see if the taper angle is consistent between machines.

I'm pretty sure that gibs are not matched to machines. They're so badly made that I can't see anyone going through the trouble of blueing them to check for contact area.

Martin Long: No problems posting parts to Australia

iGG1e: Sorry I have no information on the X3 mills. I note that they are a significantly different build so I kind of doubt that they have similar gibs.

[Martin Long]

I served my apprenticeship with a machine tool company in UK, the company manufactured Milling machines and Gear Planners.
The gibs were always machined to the dimensions provided by the fitter, who measured to largest and smallest gap in the slideways with slip gauges, the machinist then machined the taper to suit. The gib was then returned to the fitter who scraped the sliding face to ensure the gip made contact along it's total length. The final operation was to cut the oil groove in a "W" or "V" pattern along the full length ensuring not to break out at the ends, an oil hole was then drilled from the top end to meet a second hole at 90deg into the root of the oil groove
Each gib was was manufactured to suit each specific machine.
Hope this gives a little insight for those who need it!!

Martin

[MadMax]

Hi Martin,

I appreciate the craftsmanship put into a custom fitted machine. I've been looking into way scraping techniques and realizing that machine fitting is a deep technology that is easy to overlook.

However if you've looked at a stock X4 gib, you'll probably accept that almost anything that is ground with a precise angle setup would be miles better than the original part which is well out of plane and covered with what appear to be manual bench grinder marks as well as a rash of dings from bad part handling practices.

I do have a plan for seeing if I could make reasonable replacement gibs. I first plan to guage my own machine's slide way with straight ground rods to measure the gap at both ends and points in the middle. I'm not ever sure if the slide ways are straight at this point. If they're not straight then it's all over and there isn't much reason to make custom ground gibs because scraping an internal slide way dovetail to make them both planar and to a 60deg angle is well out of reach. I think indicator blue on the rods and slide ways should be a good way to test degree of straightness in the ways because the rods would contact both critical faces of the slide way if they are made to a straight taper.

If the slide ways are at least straight (consistent taper) then I'll get my own gibs made to match my machine's taper and see if indicator blue shows good contact.

If all that works out, I hope to enlist the help of a distributor or other X4 users to gauge their machines to see how consistent the slide ways are from machine to machine. If they're all over the place I think the project gets dumped because it would be uneconomical for us to get my machinist to have to make gibs to match machines, especially if need some back and forth fitting.

My plan isn't to provide parts to the same standard of a part fitted by a skilled machine fitter. That would put a lot of cost and effort into improving only one aspect of a machine which would not be commensurately good in many other aspects. My hope is to replace a single part which is currently really really badly made and bring it up to the class of quality of the rest of the machine which is pretty good for an economical CNC machine.

[iGG1e]

A good insight into how it's done properly Martin, thanks.

I may just be sceptical by nature, but I doubt the same applies with the cheaper Asian mills. Speaking only for my mill, the gibb was right at the end of its travel straight out of the factory. I’m contemplating getting a standard replacement to see if that fits any better, or can be made to. If it doesn’t, at least it’ll be some form of template to work off.

[MadMax]

Hi iGG1e: Are you able to crank your vertical gib down far enough to clamp the ways? Do you mind removing your Z gib and taking a look at it? If I just got into a bit of bad luck and got two bad gibs by chance (maybe dragged out of a reject bin?) then I'll ditch my project and just make gibs for myself. If there are a lot more users out there with crap gibs then I might invest in a bit of jig production to help other X4 users get good gibs.

My gib also came fully cranked down. I tried to adjust them to get the X direction play out. I chucked a dial indicator and found that I was getting over 0.010" of X direction play when the travel lifted on and off the airspring. I couldn't bring myself to bother tramming the upright post to the XY slides with so much play in the head so I'm working on the Z axis gib first. Once that's done right, I'll move onto tramming the upright to make it perpendicular to the XY plane, then move onto tramming the mill head spindle to the XY plane.

[extrapilot]

Guys
No special insight here-
I have an SX3, and found the same problem- stock Z gib literally looked like someone hand filed it from bar stock. And, as with the experience here, it was cranked down at its limit and still had not locked the head; I had to insert some shim stock just to determine if the angle was close (it wasnt)...

I ordered a replacement gib, and though it was cleaner, it was still pretty bad. My thinking is that this new replacement is the 'stock' that the assemblers use, which is then hand filed to suit the machine. I think you all know that these machines are so out of tolerance that nearly everything is tweaked. Anyway, just suggesting that the angles in question here may be unpractical to batch-run. What might make more sense is to determine a standardized way to measure for an appropriate gib, and then send that spreadsheet over as a collective order. That is- if the difference is really just angle and face offset, maybe the grinder could setup a fixture to make that easier to dial in. Maybe run 2-3 for each in the group so you have a spare or two, and make it worth the setup cost? Id be in for a few- assuming the SX3 is similar.

Best
Rob

[iGG1e]

MadMax, I took the opportunity to measure up the gibb the last time I had the head assembly off. Somewhere I've got a SolidWorks model of it. As standard the adjustment wasn't enough to stop the head from lifting under for example spot drilling. It was actually difficult to tell anything was wrong from a static condition, but under a run condition it was possible to see the movement.

I decided to mill the lower notch in the gibb to allow it travel further. I had to put a spacer on the top screw to allow it to keep pressure on the top of the gibb as it would just bottom out on the thread travel. It is a lot better than it was, but it's obviously not as good as it should be.