Help needed. Is this safe or do I have a bad threading?

I’m doubtful of its use, from what I see. I’ve got Oneway chucks and adaptors, so I can’t help with the Nova equipment. However, on three lathes I’ve never seen that for the various chucks I have.

Eric, you don’t show the adapter uninstalled, so it is hard to judge how much is screwed in. However I would thing if you are getting several turns before it stops, you should be okay.

Is it possible that there are 2 sets of threads on the adapter? From the photo, it almost looks like it is screwed in as far as it is supposed to go, and that the next set of threads are for a larger size lathe opening.

-- Charlie M. "Woodworking - patience = firewood"

I’m afraid if you use this setup, you will jamb the head stock threads into the adapter so tight you may never get them apart.

-- Lew- Time traveler. Purveyor of the world's finest custom rolling pins!

I have seen people not tighten plates on a lathe. When the machine tightens them they are on to stay. You don’t want that. It there is a burr or something that you are not seeing and it does finally go past this point you are in that forever position. I think I would go back and talk to the store again. It could be a bad adapter since today most things are not 100% inspected in a manufacturing facility. It is still cheaper to toss you a new adapter that it is to inspect those parts. Some say there is now quality built into a part like this but we are still there. We followed the Japanese into this deal (no inspection). When they said this doesn’t work, we said we will make this work so we poured more into it and the entire world has followed.

Lew and Arch, I was afraid you’d say that. Its too hot to continue today anyways in the garage so I’ll return it I think later and try again tomorrow. It is a Woodcraft brand adapter, maybe that is the problem lol.

Charlie, I’ve included a few more pics of the inside of the adapter. It looks like there is only one size threading in it and a little bit of space at the end so in reality it is probably only holding on to like 2-3 threads so I’m guessing its not going to be safe.

Thanks for the help guys.

-- - Eric Indianapolis, IN

take the chuck to the store with you when you return the adapter.

Another thought, this lathe comes from the orient, could the threads be metric. I had this happen on a Bridgewood product- also oriental.

I quickly scanned the manual and did not find an actual spec on the face plate threads but may have over looked it.

-- Lew- Time traveler. Purveyor of the world's finest custom rolling pins!

It almost begs of being an incorrect pitch on either the adaptor or lathe head. (Chinese quality?)
I would take the adaptor back and have them try it on one of their lathes, just for safety sake.
From the looks of it, I wouldn’t use it. I don’t think there is enough threads making contact.

-- Government does not solve problems; it subsidizes them.

Grandpa, there are no burrs I can feel on either the headstock threading or adapter inside threading and it looks well machined.

It is Central Machinery and I’m sure from China or somewhere else in Asia. This is the first issue I’ve had with it and id suspect its the adapter since like I said the faceplate goes on smoothly.

lew, that could be it. The only place it says threading is on first page of manual it lists specs and threading as 1” 8 Thread right hand

-- - Eric Indianapolis, IN

Thanks Jim. I’ll see if it goes on the stores ok. If it was metric what is 1”x8 RH equivalent to?

-- - Eric Indianapolis, IN

I doubt that it is unsafe but I think there is another significant problem. As you use the lathe, the adaptor could tighten onto the arbor to the point that it would be extremely difficult to get it off.

The action of turning will cause the chuck to tighten onto the adaptor and the adaptor to tighten onto the arbor. They can get VERY tight, especially if you have any catches.

I actually think that they could tighten up to the point that you could not, without a propane torch, get the adaptor off.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

Yeah Rich I’m afraid to turn it on for that reason. I doubt it would fall off since it would just thread further on in use but yeah, based on how difficult it was to even attempt to tighten with a wrench I’m not going to try anymore. As soon as I find the receipt I’m heading back…

Here is one more picture with measurement of headstock threading….

-- - Eric Indianapolis, IN

The more I think about it, DON’T USE IT! It’s definitely unsafe. Its the same condition as a metric nut being screwed onto a english screw. 2 or 3 turns and it stops.
These adaptors are designed to bottom out on the shoulders, NOT on the threads. Richgreer is right.
When you put the adaptor on, the shoulders have to be clean and free of debris so as to bottom out and force parallelism. (Note the adaptor and chuck bottoming out.)
Thats why the threads stop before the shoulder with a relief undercut. To ensure the mating of both shoulders.

-- Government does not solve problems; it subsidizes them.

Yeah, after seeing that last photo, there is definitely a problem. Most likely it’s the adapter. Simples fix to try is just get another one.

-- Charlie M. "Woodworking - patience = firewood"

Thanks everyone for your input. On my way to woodcraft I’ll give an update later

-- - Eric Indianapolis, IN