What Is This Metal?

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69ZNut

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My made in china lathe started leaking oil like a sieve. On the back of headstock I noticed the shaft that drives the back gear could move easily with just one finger and oil oozed out.

Drained the oil and found the sump had 1/2” of casting sand and cosmoline sludge in the bottom. All the gears were stained cosmoline brown.
I removed the Tri-Gear-Shaft then the bushing and discovered the 15mm shaft bushing was taper machined to 15.1mm and they force fit a 14mm oil seal onto the 15mm shaft that cut deeply into it.
The machine has about 200 run hours on it. I bought new taper bearings for the spindle.

I am writing because I have no idea what these Chinese bushing are made of???

They all need replaced. They have a polished Aluminum or bright steel in appearance with no porosity like one would see in sintered bronze.

All the headstock bushings are very magnetic but do not retain any residual magnetism once the magnet is removed.

I helped a friend replace the rear axle bushings on his Craftsman lawn tractor 2 years ago. When extracted the old bushing fell on the concrete and it rolled rapidly toward my magnetic parts tray and stuck to it. It too has the same silvery appearance?

China discontinued this machine. Grizzly makes a similar 3in1 but ordering parts hoping they would fit gets expensive. I’d rather fix it myself the American way then send another dollar across the mud puddle to them.

I already redesigned the bushings, seal placement and Tri-Gear-Shaft design in CAD. Now I just need to know what this metal is.

What could this bushing material be made of?

Also is 4140 hot or cold rolled good for a new shaft to made from?
IMG_3790 copy.jpg
 

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petertha

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I haven't used aluminum bronze myself, but that might possibly be it because its a more silvery color? I've made bushings from 660 bronze & they have turned out well. The norm in many offshore machines is to run rotating shafting inside a drilled (reamed if you are lucky) cast iron holes. Sometimes with a lubrication oil gallery of you are luckier still. Its not a good way to do things. Here I'm talking secondary shafting like apron gear shafts, power feed rod journals or leadscrew bearing blocks. You headstock definitely needs a bushing of some sort.

OLM sells various kinds of bronze, both in solid or hollow. I tend to buy solid because the price is similar & you can remove a slug with an annulur cutter & still have a smaller leftover to make something with.
http://www.onlinemetals.com/merchant.cfm?id=850&step=2&top_cat=850
http://www.onlinemetals.com/merchant.cfm?id=760&step=2&top_cat=850
 

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10K Pete

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I'm with petertha on this one. Make 'em out of 660 bronze (or similar) and you can't go wrong.

Pete
 

petertha

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The other experience I'll pass on is bronze can be quite 'grabby' with large diameter conventional drills, so beware. If you dub the edge angle a bit, like what is called for drilling brass & similar alloys, they cut much better & mitigates planting them in the hole.
 

Anatol

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its not babbitt metal is it? There are different compositions, some mostly tin, some mostly lead, most with a little copper. (I'm not an expert).
 

Charles Lamont

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It appears to be a steel shell, which is likely to have (or to once have had) some sort of lining, such as white metal (babbit), ptfe, or bronze. They are probably a stock item (somewhere). If you want to make your own replacements, I too would go with bronze ( a leaded, cast bronze, ideally).

I think it is probably still the case that new Chinese machinery should be dismantled on receipt, thoroughly cleaned out, deburred, the parts fitted, and then reassembled, lubricated and adjusted before any use. I certainly found this to be the case with a recently bought rotary table, which would not budge until I fettled it properly.
 

Cogsy

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'fettle'. Never seen it used in a sentence. charming.
Once upon a time, for a brief period, I was employed as a 'fettler' and used to fettle all night (I was working night shift). Not a fun job where I worked and was glad to be promoted to a pickler and finally a dipper after a short while, although occasionally I had to help the jiggers out too.
 

Anatol

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Once upon a time, for a brief period, I was employed as a 'fettler' and used to fettle all night (I was working night shift). Not a fun job where I worked and was glad to be promoted to a pickler and finally a dipper after a short while, although occasionally I had to help the jiggers out too.
"used to fettle all night"
Me too, whenI was younger, never got paid for it though. ;)
 

redhunter350

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A good quality bearing bronze - phosphor bronze -would be best, but from my experience do not use Aluminium bronze ! It is not suitable a bearing material , I once made some bushes for a vintage 2-stroke engine, it seized in about 10 seconds, tried with more clearance and it did the same -- reverted to Phos bronze and it ran for years afterwards.
 

Mark Duquette

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Did you check to see the hardness of the bushing? It is possible that the material is full hard 52100 which is common to off shore countries. Full hard bushings require good lubrication to function.
 

Wizard69

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A couple of points here.

If you are running shafts in plain bushings then ideally the shafts will be hard in those areas. That is you run hard shafts in soft bushings. Not knowing the specifics of the shaft involved I'm not sure if pre hardened materials would work for you here.

As for bushings id go with the lowest common solution here which would be oilite bushings. They are cheap and easy to find. Easy to rework too if you can't find one of the exact dimensions needed.

Beyond oilite there are numerous high performance synthetic bearings out there that may or may not work. These would still be plain bearings.

You should also consider rolling element bearings like needle bearings. Needle bearings need to run on a hard shaft or a hard bushing on the shaft. However if the bores are the right size in the casting housing you maybe able to go this route.

The ultimate solution would be ball bearings but this would force fairly extensive reworking of the shaft and likely the housing. The advantage here is far lower friction and no need for a hard shaft.
 
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DJP

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I recall that one of Bazmak's lathe purchases came with drawers full of bushings. I like the idea of replacing an unknown bushing with oilite bushings and if necessary buy a dozen. Adding an oil reservoir to keep it constantly wet would also be prudent.
 

bazmak

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I agree with DJP.Any oilite/bronze bush with adequate lubrication will be good with our type of work/usage
Myford fitted a front bronze bushe to the 7 series headstock.People who have changed to roller bearings sometimes experienced
chatter coming thru on th workpiece.Good quality taper roller bearings were ok
 

colby15642

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Your Chi-Com lathe bushings are almost without doubt cast zinc (pot metal). Any free-machining bronze or brass should work well for the replacements, including porous sintered stock. Aluminum bronze, which is not silvery in color is not particularly easy to machine.

I suggest 12L14 leaded steel for the shaft. It is strong, relatively inexpensive, and super-easy to obtain a good surface finish. Your lightly-loaded application does not require a hardened shaft. The original shaft is likely just plain old 1018 cold-rolled steel. If you prefer more of a machining challenge, buy an inexpensive piece of unhardened drill rod already ground to the correct size.

When it's all over, consider buying a used vintage South Bend lathe on eBay to keep it from being parted-out... Your Chi-Com lathe will still be useful for gritty grinding operations or as a classy door-stop!
 

colby15642

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Oops! I should have read a couple of the details more carefully. If your Chi-Com bushings are magnetic, they are sintered iron. Cheaper to manufacture than zinc bushings and reasonably long lasting if oiled, but a little hard on steel journals.
 

alchr

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I would go with the sintered iron too. It is very common on cheap low power electric motors, fans etc.. they are impossible to recoil, I r3plac3 th3m with Oilite!
Chi-Com machinery sucks.
 

Mike1

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No wonder, Fettled is a late Middle English word but wildly appropriate to the task. Impressed, 2 thumbs way up!
Being a Cumbrian (UK) the word Fettle can be (Dialect) used in conversation such as What's your fettle, meaning how are you. Or I'm bad fettle today, meaning I'm not feeling well today, Or I'm in good fettle, meaning I'm feeling well.
A bit of useless information but there you go.

Mike.
 
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