[Mecanix]

Hello machine-builder experts. Got my weekend scheduled in the hobby shop and planning to machine new gibs for a benchtop lathe.

Long story short; I've had the bedways of my benchtop lathe reground and while disassembling the kit I've found out the gibs are made of steel while the ways are made of cast iron. That doesn't exactly look right to me and so I'm looking for an alternative material to get new gibs machined from so to prevent excessive wear on the freshly grounded ways.

Tempting to get those machined out of aluminum however I doubt those won't stick when lapped.

What's the best material to use for that purpose?

Thanks

[metalmayhem]

If you can wear the slides out then I'd say that by then you'll have made so many parts or you'll be old enough to retire the machine and/or yourself .

steel gibs on steel cast produces a self lubricating effect which will actually reduce the risk of wear vs other materials . I've seen war era heavily used lathes that had the screws worn to an hour glass shape and the slides were fully intact . Typically gibs are made from what they are because it is the best material to use . If it's from china then everything is questionable , but thats throw away stuff anyhow

Aluminum is a sticky and soft material and is probably the worst material to use for gibs . Aluminum can also get grit embedded into it and cause premature wear . I've seen numerous hobby guys make them out of brass which in my opinion is another terrible material because brass is very abrasive

[Mecanix]

All fair points and knowledge sharing, much appreciated for that. I'll keep those steel gibs in that case.

Throwing away my perfectly fine Chinese import lathe and finding democratically-correct mined biden iron for a better version of it will be challenging! </sarcasm>

[awerby]

I never heard that brass was abrasive, especially when sliding against ferrous metals, which are harder. It's one metal that can be machined without lubrication, and it's easy on tooling. Are you saying that it can pick up abrasive particles and abrade things, or that it's abrasive in itself? The former seems plausible, the latter not so much.

[metalmayhem]

Throwing away my perfectly fine Chinese import lathe and finding democratically-correct mined biden iron for a better version of it will be challenging! </sarcasm>

Not suggesting you throw it away but like a hyundia pony there's a point to tossing them rather than rebuild them . I have a couple chinese lathes and almost half dozen chinese mills , I view them as disposable tools
The problem with chinese machines is a guy really doesn't know what they are really built from . I've drilled or attempted to drill holes in those castings and hit sand an what were probably stones

Awerbry , brass is abrasive . Gibs would be made from oilite above anything if a softer material would be better

[peteeng]

heres some thoughts - Peter
https://www.detroitedge.com/machine-...%20deformation.

[joeavaerage]

Hi,
my goto answer is nickel-aluminum-bronze. One of its uses is as a worm gear, it gets hard and wear resistant as a result of a 'wiping' type stress.

Craig

[Mecanix]

heres some thoughts - Peter
https://www.detroitedge.com/machine-...%20deformation.

Guys, that's awesome. Sweet knowledge based forum packed with talents, got to be said. Learning everyday, and grateful for the link-up from a machine-builder (thx, Peter).

Craig seems to have The Ultimate Fits-All Solution with this "nickel-aluminum-bronze". Where on earth do I source this stuff from though, jeez.

Edit: Unbelievable. UNS C63000 is listed as one in my material supplier database. Worth a try? In all honesty I recognize the advantage and understand the reason steel is used in far more rigid machine-tools, but on an imported cast iron mini-lathe... my alarm sensors are triggering with this hard steel-on-butter here.

[joeavaerage]

Hi,
here in New Zealand I go to Kormax:

https://www.kormax.com/material/630-...AaAvnxEALw_wcB

Craig

[joeavaerage]

Hi,
another place to go is Fraser's, It about 2km from here, more for large quantities but a bewildering range:

https://www.awfraser.co.nz/Alloy-Finder

Craig

[awerby]

Metalmayhem - have you got a source for this assertion about the abrasiveness of brass? Oilite's fine, but brass is commonly used in bushings and other applications where an abrasive material wouldn't work. I checked around to see if I could come up with any support for your view, but came up empty. Brass is softer than bronze, and wears away more quickly, but that's because of the abrasiveness of the materials rubbing against it. Here's something that compares brass, bronze and oilite bushings - nothing about the alleged abrasiveness of brass, though: https://bushingmfg.com/brass-bushing...how-to-choose/

[metalmayhem]

Awerby take what I say for what it is worth to you and I mean no offense by that . Yes it is used for bushings but wear from much harder materials is mostly due to factors other than abrasion . Iron castings aren't much higher in rockwell than yellow brass when they are harder , and unlike brass their makeup varies as does their hardness . Aside from being littered with sand and who knows what these chinese casting are soft , and under a hardness test I wouldn't be surprised if they are softer than brass .

The way I look at it is that if the materials used for manual lathes and mills haven't changed in all these years then there is a solid reason for it

[Mecanix]

these chinese casting are soft , and under a hardness test I wouldn't be surprised if they are softer than brass .

I can carve my name on mine with my fingernail. Never tried (lol) but sure feels that way. Stupidly accurate over the whole bed though, aligned in all planes (5um), but that's the thing about it - if you want to preserve this fun you must babysit this tool like no other. So far added way-covers to keep it surgically clean, 4x oilers with an oil pump wetting (flushing?) this with ISO60 each and every 3000mm of travel, and now dealing with the "friction-vs-wear" gibs nightmare.

Got a few stocks of C63000 (Ni-Al-Bronze) on order as per Craig's recommendation. Should get me started.

[metalmayhem]

I've found all of my chinese machines feel soft , that is until I try to drill into them and hit something hard . That one is definitely a lot more solid looking than mine . I cnc'd mine to , I noticed a slight consistent taper on my parts but , the stick out is a bit extreme so it's likely deflection and is easy enough to program it in . Otherwise once they are warmed up they hold up within a few tenth and are pretty reliable .

They have specific jobs they will do til their deaths , pretty much goes for all my machines that do production (my first old mills have been retired) . I suppose thats where the disposable tool is stuck in my head , even my tormachs will eventually find themselves at the scrapper .

The bronze should work out for you and I hope it does , I'll be interested to see how it works out

[Mecanix]

The bronze should work out for you and I hope it does , I'll be interested to see how it works out

That's one of those you know, rewards are so much greater psychologically than mechanically I'll update regardless.

Interestingly enough I've spoken with someone locally who has similar range tools and he swears by POM (delrin) made gibs for those softies. Considered the 'consumable' idea, quite brilliant in fact, however I'm aware that thermal expansion of those engineering composites ain't exactly pleasant to deal with, and so ditched the idea.

You should consider having your cnc'ed surface grinded. Effortless job for one who knows what he/she's doing, the bed is so light to handle. One day job and the results are simply miraculous, can't recommend it enough.

[metalmayhem]

mine are only 7x14 lathes . They are so cheap to buy that getting a local grinder to grind them would cost the same if not more than the lathes cost . Plus they work as they are so no grinding needed .
I did take them apart and deburr and do some polishing though when I bought them . If I do any work to them I'll modify them to use linear slide which I already have on hand , and I am considering it . As I mentioned , I get a few tenths taper which I just modify the program to compensate . 5/8 aluminum with no end support being machined down to 1/2" with a stick out of 3.5 inches is going to be prone to some issues on the best of machines , at least the taper is consistent since my parts need to be within .0005"

[Mecanix]

Cheap?! haha you're joking right? I swear the amount of man-hours that goes into those things just so to have them make a part within tolerance is mindblowing. Not to mention the time spent dialing them to where it's possible to get half-repeatability out of them. Guess mine's worth $1.5mil in that context, considering the time spent on that retrofit alone anyway - pretty sure yours the same tune. All in all; NEVER AGAIN, cheap or not, this lathe travels suspended-on-oil from now on and never again directly on the bedways anymore. Bronze...

Waiting for the industry to engineer Maglev Ways & Air Bearing lathes for an upgrade. Although I like your idea about linear rails too! Pls update if you ever go that route.

[peteeng]

Hi Mechanix- There are many lathes that use air bearings and linear drives are becoming popular. Hiwin sell linear drives if you want to make a maglev anything. Hydraulic ways are also used on very large big mills and lathes. As they are stiffer than air bearings. I started designing a little router with air bearings once but linears are so cheap I gave that idea up...Peter

New Way Air Bearings - Frictionless Motion™

[Mecanix]

Hiwin sell linear drives if you want to make a maglev anything.

Wait, what? Magnetic Levitation railing/ways for machine-tools is already a thing? Honestly I was making a joke about it (maglev), are you saying this exist already?

[peteeng]

Hi Mec - Not quite but linear motors exist so you just have to add the maglev yourself... Peter

https://youtu.be/H8fMRO9tuws