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

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Forum topic by Eric_S posted 07-23-2011 06:42 PM 1711 views 0 times favorited 30 replies Add to Favorites Watch
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Eric_S

1521 posts in 1848 days


07-23-2011 06:42 PM

I’m starting on my first bowl today. I have the outside turned using the faceplate that came with the lathe

http://www.harborfreight.com/12-inch-x-33-3-8-eighth-inch-wood-lathe-with-reversible-head-34706.html

Manual http://manuals.harborfreight.com/manuals/34000-34999/34706.pdf

The faceplate that came with it screws on just fine.
Notice the left side of image black faceplate perfectly aligning with the silver threading…

I just purchased my first chuck, a SuperNova 2. The guy at Woodcraft said I need the threading adapter for my lathe as well.

The manual for my lathe says its a 1” 8 thread right hand, which corralates to a Code D adapter for the chuck. I checked the bag of the adapter which also says 1”x8 and a D is also engraved into the adapter itself so I know the adapter is the correct one. The adapter goes into the chuck perfectly, but…. it doesn’t screw onto the lathe all the way. It stops after about 3-4 threads. Ive checked the threads on the lathe as well as the inside of the adapter for debris or any burrs or anything that would prevent it from screwing on….

But no matter what, even when using wrenches, I can’t get it on all the way. IS this safe? Is this correct? Or do I have a bad adapter?

Like I said, the faceplate that came with the lathe screws on all the way without any difficulty. I’m afraid to turn the inside of the bowl until I get some feedback from more experienced lathe and chuck owners. Please help.

Thank you.

-- - Eric Indianapolis, IN


30 replies so far

View Arch_E's profile

Arch_E

47 posts in 1175 days


#1 posted 07-23-2011 06:48 PM

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.

View CharlieM1958's profile

CharlieM1958

15696 posts in 2871 days


#2 posted 07-23-2011 06:50 PM

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"

View lew's profile

lew

10029 posts in 2408 days


#3 posted 07-23-2011 06:52 PM

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 Universe's finest custom rolling pins.

View Grandpa's profile

Grandpa

3130 posts in 1328 days


#4 posted 07-23-2011 06:59 PM

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.

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Eric_S

1521 posts in 1848 days


#5 posted 07-23-2011 07:02 PM

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

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Grandpa

3130 posts in 1328 days


#6 posted 07-23-2011 07:04 PM

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

View lew's profile

lew

10029 posts in 2408 days


#7 posted 07-23-2011 07:05 PM

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 Universe's finest custom rolling pins.

View jim C's profile

jim C

1452 posts in 1751 days


#8 posted 07-23-2011 07:05 PM

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.

-- When I was a boy, I was told "anyone can be President", now I'm beginning to believe it!

View Eric_S's profile

Eric_S

1521 posts in 1848 days


#9 posted 07-23-2011 07:13 PM

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

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Eric_S

1521 posts in 1848 days


#10 posted 07-23-2011 07:18 PM

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

View richgreer's profile

richgreer

4524 posts in 1727 days


#11 posted 07-23-2011 07:20 PM

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.

View Eric_S's profile

Eric_S

1521 posts in 1848 days


#12 posted 07-23-2011 07:28 PM

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

View jim C's profile

jim C

1452 posts in 1751 days


#13 posted 07-23-2011 07:35 PM

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.

-- When I was a boy, I was told "anyone can be President", now I'm beginning to believe it!

View CharlieM1958's profile

CharlieM1958

15696 posts in 2871 days


#14 posted 07-23-2011 07:36 PM

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"

View Eric_S's profile

Eric_S

1521 posts in 1848 days


#15 posted 07-23-2011 07:46 PM

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

-- - Eric Indianapolis, IN

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