Problems with my nova chuck

[Sarge]

I have just purchased a new second hand lathe, a Mao Shan MSL-3815, this is a stepping stone till I can afford a DVR.

Anyway I bought a new insert for the nova chuck I have been using for a few of years on my old GMC. The problem is that when I put it on tonight it is not running true, I mean it is so far out of alignment that you can see the chuck moving. If I put a 30cm length of wood into the lathe and line it up with the tail stock before I tighten the chuck there will be about 3 or 4 mm movement at the tail stock end

I guess there could be a couple of reasons for this:

1. The new insert is not drilled straight.
2. The thread is worn down on my lathe.
3. Some other reason that I don't know about

I'm not sure what the problem or the answer could be but when I was putting the chuck on there was plenty of movement in the thread until I tightened it up. Is this normal? I tried putting plumbers tape on the tread but that made not difference.

I don't know if it makes any difference but the thread is 1 x 8 tpi

Any advice would be most appreciated.

[Calm]

Screw the insert onto the lathe without the chuck. Does the insert wobble - place your thumb nail on the edge at the end to feel the smallest movement.

If there is no movement screw the chuck onto the insert and ensure it screws all the way on until the shoulder locks onto the outside shoulder of the chuck. If this doesnt happen it needs to be machined shorter.

The end of the insert that goes inside the chuck should locate/touch on the circumference not on the end.

This was also covered in a thread before christmas.

[robyn2839]

i had the same problem with an insert i bought from carb-atech ,chuck was all over the place, got one from vermec and fixed the problem.bob

[Big Shed]

Screw the insert onto the lathe without the chuck. Does the insert wobble - place your thumb nail on the edge at the end to feel the smallest movement.

If there is no movement screw the chuck onto the insert and ensure it screws all the way on until the shoulder locks onto the outside shoulder of the chuck. If this doesnt happen it needs to be machined shorter.

The end of the insert that goes inside the chuck should locate/touch on the circumference not on the end.

This was also covered in a thread before christmas.

I had the same problem, G3 chuck with 1"x8tpi insert. Took it with me to DJs Timber BBQ, DJ had a look at it and established the same problem as described above. He was kind enough to skim some off the insert, it then sat properly on the back of the chuck, runs fine now.
Seems that Teknatool still has QC problems, doesn't it ?:(

[Jim Carroll]

Is the insert you have a hex nut style or a round nut.

We sometimes have bothers with the non genuine round ones. Not very often but generally on the 1"x8 thread because of the thread angles between BSW and UNC

[Sarge]

Thats just amazing Jim, I have just ordered the Supernova 2 off your website and asked you the exact same question about the difference between the BSW and UNC:)

So the round one is non genuine ??

I bought the insert from Stan's in Preston and he said it was an original nova insert, it is the round one, I am returning it tomorrow and maybe he can give me the answers I need or he can have it back.

Maybe I don't have an original nova insert like I was lead to believe.

Big Shed, was yours a round or hex head.

Thanks for the help

[Big Shed]

So the round one is non genuine ??

Maybe I don't have an original nova insert like I was lead to believe.

Big Shed, was yours a round or hex head.



Sarge, mine was supplied with the G3 chuck by Carbatec, it is round but has 2 flat sides (if that makes sense?)

Maybe I was casting aspersions at Teknatool unjustly?:-

[Calm]

I have 2 SN2 chucks both from Jim and one has a round insert the second one a hexagon insert. They both were too long and the chuck wobbled. When machined to the correct length the chuck runs true on both of them. The hexagon one i shortened it myself by fitting the insert to the lathe and turning it at full speed (2000 rpm) and used the 4" angle grinder to start with and finished with a file. I did that until the chuck bottomed out on the shoulder of the insert and they both now run true.

[robutacion]

I'm having some wobble problems also with my Nova G3' hex nut insert. Everything was right until I had a nasty catch on a big blank while in reverse. The lock screw in the chuck has cut/strip an half turn thread in the insert, making it very hard to remove it, even with the lock screw totally out. I tried to repair the insert thread with some small files and my Dramel, but the chuck as never run dead true since. I have to order another genuine insert to replace the damaged one.

Cheers
RBTCO

[Sawdust Maker]

I was all worried after reading these posts that I had to go and check for wobble:rolleyes:
not a problem on mine:2tsup:
Though I wobble a bit on occasions

I'll have to be careful of big catches in reverse though!

The round inserts with the two flat sides for the spaniard may be vermec, I've seen them on their website

[Big Shed]

I was all worried after reading these posts that I had to go and check for wobble:rolleyes:
not a problem on mine:2tsup:
Though I wobble a bit on occasions

I'll have to be careful of big catches in reverse though!

The round inserts with the two flat sides for the spaniard may be vermec, I've seen them on their website

? spaniard ? (assume you meant spanner?)

I just had another look at my insert and the Vermec site, it certainly looks like the Vermec, including the hole (for tommy bar?) in the round side.

[Harry72]

I went and checked mine after reading this thread, put a torch behind the chuck low and behold...a gap of about 1.5mm was visible!
I have the round shaped thread adapter.
So I just marked it with a texta set the speed about 300rpm then grabbed me trusty scraper and gently removed the offending material... worked a treat:D

[Frank&Earnest]

Hi guys, as Calm said above there was a similar discussion before: here is my update. Went to the supplier (no names to be charitable, Adelaide is a very small place:wink:) and the guy very kindly removed the insert and replaced it with a genuine one. Very good customer service, but I find a bit questionable that he seems to have a policy to cut corners first and fix the complaints later.

[OGYT]

I was under the assumption that my instructions that came with the chuck said to make sure the insert bottomed out in the hole.
Somebody still have their instructions? I'd like to know if I'm full of it. I have a little bit of runout on my SN2s.

[Calm]

It needs to locate on teh circumference in the hole and bottom out on the shoulder outside the hole. This was all the "slop" in the thread is locked against the outside shoulder.

Also i dont run locking allen key grubscrews in my chucks but i dont have reverse either.

They dont seem to come undone when i change chucks at all.

[Sarge]

Just to update my adventures over the last week, I have tried everything to work out my problem, well everything I can think of.

When I run the shaft on it's own I can not see any movement, nor can I feel anything when I hold my fingernail against it.

As soon as I put the original nova chuck on I can hear a rattling noise from the head stock area only or low speed, I can hear nothing over about 1000 rpm.

If I change it for the Jacobs chuck or a 30 kg bit of wood between centres I can hear nothing.

I went back to Stans and exchanged the insert for another and nothing has changed

The insert is an original Nova 1 x 8tpi bws, it has some movement when I am threading it on, but it snugs up tightly against the shoulder now that I have ground 2 mm off the insert.

Jim Carroll suggested a leather washer between the insert and the headstock but my lathe has an indexing ring and a nut on the shaft, the insrt and chuck goes after that. I didn't have any leather so I made a Masonite shim to go between the insert and the nut but it didn't seen to make any difference.

I went and bought a nut at 1x8tpi unc tonight and it defiantly fits on more snuggly but I do think it would make that much difference to the chuck

Could it be something so simple as the bearing have gone to God

Or could the shaft be bend, I can not see this with the naked eye, I'm guessing it mast be pretty hard to bend a shaft.

Any ideas greatly appreciated.

[Big Shed]

If you have a dial gauge, run that on the shaft and it will soon tell you. Dial gauge should cost about $25 and a magnetic stand for same another $25.

I have these and have used them from time to time and at such a relatively low cost it would give you piece of mind.

[Calm]

Does the face of the nut on the spindle - where the insert tightens against have any "run out"?

if no

Does the insert have any "runout" if you fit it without the chuck?

if no

then it appears to be in the chuck itself.

On my lathe the inserts are very "loose" or "wobbly" on the thread until they lock against the shoulder on the spindle this is what makes them run true.

I don't use any "spacer" or soft material between these surfaces to allow the insert to lock true against the shoulder of the spindle - the same goes for the chuck to insert surface.

[TTIT]

This is a long shot Sarge but if you only hear the noise with the chuck mounted and at low speed, it might just be the pinions rattling - centrifugal force will keep them quiet at higher speed - it happens with my chaiwanese chuck all the time :shrug: but won't do any harm.

[Jim Carroll]

Sarge puting masonite between the insert and the headstock wont help.
The leather is flexible enough for the insert to bed in.
It also helps to get the insert of as it wont bind up on the headstock bearing.
As indicated it could just be a rattly chuck, if you dont hear anything under load then it should be ok.
When you hear strange noises under load then worry.

[artme]

I have a Nova Scroll chuck, the one operated by TWo Tommy bars. It does not run true so I'll look at some of the suggestions here again and see what I can do.
It's a pity that this chuck is that way because I like its compact design, especially for the Jet Mini - Not so much weight hanging on the bearing.

[Jim Carroll]

The runout can be caused by dodgy thread or a bearing not seated properly and sitting slightly askew.

The leather washer is to help take up some of the slack so you can tighten up the chuck and hopefully run true.

You may find a new chuck will not always fix the problem.