Chinese lathe Half Nuts availability

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bearhunter

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I need a set of Half Nuts and a Thread Dial GEAR for my Chinese lathe.

I've tried the place I bought it from, but the fellow that was running that part of the business passed away last year.

Busy Bee seems to be a bust, unless you want to buy a new lathe.

Same goes for all of the companies that sell this particular model lathe in North America or China.

I'm up against a wall on this one.

I might have to take off the lead screw, which is fine, then take it to a local machine shop to make up a set.

Does anyone here know of an importer for these parts?

TIA
 
bearhunter said:
Thanks, I appreciate the input but that will be a last resort.

My lathe is a common type, made for at least 30+ years. Common parts should be available somewhere.
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They are not though... You would be doing pretty good if separate years of the same make and model will actually interchange. The Chinese government had sets of more or less standard blueprints available for any company that wanted to, and thought they were capable of, making these types for export, and they all seemed to make changes at random and as needed. Parts support is mostly non-existent. But they come cheap!

Check in with Grizzly tools, they sometimes have parts that can maybe be adapted.

Another option is to use a resin to cast new threads. Search out a source for small quantities of Moglice, rig up on an unused portion of the lead screw. Use the resin threads to make your own new half nuts, or a threaded tube that can be split and soldered or bonded in place to replace the worn threads.
I am guessing it's the threads....no?

If you need to make the entire half nut units, consider getting artistic and carving out some wooden patterns, and cast your own.
ZA12 alloy wears really well, and melts at a pretty low temperature. It machines well, and is cheap. Zinc, with 12%Aluminum in the mix.

One way or other, you are most likely going to be making or repairing what you have.
 
Thanx trevj, I have been suspecting that

This lathe is basically identical to the Grizzly G4003 except that it's slightly larger 14x36 with 1.5in bore spindle.

The specs say they use the same lead screw.

Also, Axminster was selling the same model lathe and still do. They, just like Grizzly, don't carry replacement parts any longer

I was just hoping to make this simpler.

Axminster also includes drawings and specs of the lead screw and half nut dimensions in their manual. So if push comes to shove and I can't get these parts made myself, I can take the specs and as you suggest casting to a local machine shop.
 
I seem to recall a write-up - maybe in HSM - about boring out worn half nuts, and installing freshly machined bushings. Saved making the whole blocks.
 
this might be a dumb question, but -
Have you e-mailed or preferably telephoned www.grizzly.com ?
They advertise that they sell parts, and they appear to offer direct shipping to Canada.
 
I came across this some time ago and squirreled it away in the cranium for future reference. It just might be a way out of your bind. Remove the space between http: and //.
http: //www.moglice.com/articles/replication_techniques/wrotethebook.html
 
Bearhunter, I'm going to recommend you go and join up with the "Canadian hobby metal workers". If replacement parts are available someone there will know where. They have a excellent pipeline of knowledge on off-shore machines and often trade parts back & forth between each other from machines that have been tore down for parts.
If your Lathe use's a common Acme thread you may do well to just try a good local fastener/bolt supply shop, they sell new feed screw type ready-rods up to 60" long with new nuts. The nuts wont be !/2 nuts but i've read of guys on that site splitting them themselves and modifying to mount into their carriage's.
 
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I had forgotten about this until fingers284's post jogged my memory. This is a source for generic ACME lead screws and nuts.
https: //www.roton.com/family/acme-left-screws-and-nuts-7159284/
 
bearhunter said:
Thanx trevj, I have been suspecting that

This lathe is basically identical to the Grizzly G4003 except that it's slightly larger 14x36 with 1.5in bore spindle.

The specs say they use the same lead screw.

Also, Axminster was selling the same model lathe and still do. They, just like Grizzly, don't carry replacement parts any longer

I was just hoping to make this simpler.

Axminster also includes drawings and specs of the lead screw and half nut dimensions in their manual. So if push comes to shove and I can't get these parts made myself, I can take the specs and as you suggest casting to a local machine shop.
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Y'know, it boils down to being in the same boat as just about every other lathe owner out there.

Buying parts off the shelf, is pretty much a minority of the stuff that can be done. Almost every decent small lathe maker out there, got plowed under, once the Chinese started competing on price rather than quality.
It kind of puts the lie to those fellas out there that insist they need a new lathe, rather than a decent condition older one, "Because parts support". There really isn't very much of it, very often.

Approach the repairs like the original makers did. ask yourself, "How can this be made, as cheaply and simply, as is possible?", and go forward from there.

Phone Grizzly, rather than emailing. I'd be really surprised if they actually bothered to read through the general inquiries that get sent their way, but a person alive on the phone may be able to point you at a possible source, or person to talk to.
 
bearhunter said:
Depends on the part that's broken or worn. In this case a worn half nut/feed nut won't allow me to cut an internal double lead thread in a block of brass.
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Double lead? You sure? Not saying it couldn't be, just that if it were, it'd be a downright rarity on par with finding a steaming pile of Rocking Horse Poo! :)

But even so (and I could see them doing so, if the space the half nuts had to fit in was really tight) you can still pretty handily make a workable thread out of metal filled epoxy, say, for a temporary and short term use. Cast it directly off a good section of oiled lead screw, clean up the parts with a file, and use them to make your part for a better fix.

Wrap your head around indexing the work piece 180 degrees, or work out the Trig needed to withdraw the compound far enough and move the carriage in far enough to accommodate the offset required for the second start. That would prevent needing to remove the work for indexing.
 
trevj said:
Double lead? You sure? Not saying it couldn't be, just that if it were, it'd be a downright rarity on par with finding a steaming pile of Rocking Horse Poo! :)

But even so (and I could see them doing so, if the space the half nuts had to fit in was really tight) you can still pretty handily make a workable thread out of metal filled epoxy, say, for a temporary and short term use. Cast it directly off a good section of oiled lead screw, clean up the parts with a file, and use them to make your part for a better fix.

Wrap your head around indexing the work piece 180 degrees, or work out the Trig needed to withdraw the compound far enough and move the carriage in far enough to accommodate the offset required for the second start. That would prevent needing to remove the work for indexing.
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No you're right, it's not a double lead thread. Brain Fart happened.

Just finished pulling the "carriage group" It's heavy and care needs to be taken not to drop it.

The lead screw nut and the half nut look fine, with very little wear. What was wrong was that the thread indicator dial gear does show a lot of wear and it looks like it may not be tracking the lead screw, which is also fine and has 8TPI, which I thought was strange, seeing as it's a Chinese made lathe.

I have a rotary table for my mill and can grind proper shaped cutters for the right form, angle and pitch.

Likely making up this small gear is going to be finicky and tedious for me, so time consuming. I have lots of time.

The follower gear is SOFT, as it should be when riding against a harder lead screw. I can either use brass or some cast iron material I have on hand.

One thing I did learn from this was that parts can be made up at a few different places, both in Canada and the US. Pricey.

Companies that actually were able to source spare parts a year ago, no longer have access to those parts. They blame Covid of course.

I have another Grizzly type lathe but it's equipped with a quick change gear box. It's fully capable of threading the material I would have used to make up new nuts.

The one good thing about my particular back gear lathe is that the blocks holding the nuts accept "round shells" which are held in place by screws.

I took some measurements and I'm going to make up a spare set next winter. If I get ambitious, I'll make up a set for the other lathe as well.

Always something new and interesting to challenge my capabilities.

Thanx again for all the information, which saved me days of searching on my own. Very much appreciated.
 
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