Errr got my chuck stuck !

[HappyHammer]

I seem to have tightened my chuck a little too tight. I've already lost the skin from my thumb nail to my knuckle and now I'm not sure which way I should be pushing or pulling. I have a Super Nova on a reducer attached to an MC1100 any tips or assistance most welcome.

Can't seem to budge the reducer or the chuck:B:~

HH.

[DJ’s Timber]

Put the spanner on the spindle of the lathe and then rotate it towards you so that the spanner rest on the bed of the lathe and then using Allen key T-bar that came with the chuck, give it a quick sharp rap with a mallet or block of wood.

It is almost impossible to undo it by hand, it needs to be cracked using the rap method.

Next time you put the chuck on, just do it up hand tight using the spanner on the spindle and just tighten the chuck with your hand.

[DavidG]

Same direction as it normally turns.
Lock the spindle, (not sure what type lock you have) and using some thing big and solid (pipe wrench) turn the chuck in the forward direction.

[scooter]

Agree with the above, you need a bit of an impact to "break" it free, and also take precautions against it happening.

My lathe doesn't have a spindle lock, so I use a pair of vise grips locked onto a "non-critical" (read: no drama if it has a few small scars on it) area of the outboard end of the shaft that stops against a short piece of wood partly inserted in the end of the hollow bed bars. I then grab the chuck with both hands, & rotate it quickly anti-clockwise about a 1/4 turn so the vise grips rap the stop & the chuck loosens. The impetus from the rotation helps the process, rather than just grunting it off if the spindle was locked solid.

There should also be some sort of washer where the chuck insert contacts the shoulder of the spindle. This stops the steel against steel contact that can make it hard to undo. I have a piece of credit card thickness plastic cut into a washer. Some have used successfully a piece of leather or hard rubber, I tried this but found the chuck had a bit of "give" on the spindle even when tight.

I think Ern also mentioned recently being careful about subjecting a lathe's spindle lock to impact loading in case it's not up to the job & breaks. Don't know how robust that is on your lathe, but makes sense to check this aspect out.


Cheers..................Sean

[scooter]

Little bit more info, early days I found the above actually loosened the chuck on the insert. If this happens, I reckon you'd be better off loosening the grub screw, undoing the chuck off the insert, using a large spanner or similar to undo the insert off the spindle (rap it with a wooden mallet or piece of wood to break it free). Then clean the mating threads & mount the chuck back on the insert. I did this by holding the insert by the flats in a vise (superjaws, actually) and "spinning" the chuck onto it so it was nice & snug. Then do the grub screw up tight, not forgetting the fibre plug under the grub screw so it doesn't damage the insert's threads.

When mounting the chuck on the lathe, apart from having the washer mentioned above, spin the chuck on so it is positively locked up against the shoulder. Doesn't have to be ridiculously tight, but seating it snugly to start with prevents the situation of seating it softly then the first impact you encounter when turning (eg. decent dig-in) instantly tightens the chuck hard against the shoulder which can make it difficult to remove. This also happens with other machines, like blades on circular saws.


Cheers.....................Sean

[Cliff Rogers]

I have found that if I have a stuck chuck & I am finished using it so I can remove the work piece, I can grip a longish bit is timber that is small enough to go across inside the open jaws so it sticks well out one side of the jaws & then simply hold the hand wheel with my left hand & give the protruding bit of timber a good wack down toward the floor, that is enough to get it loose.

I avoid using the indexing pin as a spindle lock for this sort of work as
it may well break or bend.

I do not use any sort of a washer behind the chuck as I find that any sort of a spacer can introduce a slight wobble in a chuck.
I firmly believe that the back of the chuck should sit dead square with the shoulder of the spindle.

Instead, I apply a regular coating of rust preventative on the spindle & the chuck.
I used to use 'sheep-in-a-tin' but now just use U-beaut Trad Wax. :2tsup:

[HappyHammer]

Thanks guys I was using the black spanner in the picture below and it bent under the strain so I "modified" the second spanner in the picture on the grinder to fit the spanner slot on the spindle. It got a bit hot..:U

Anyway once cool held it easily, inserted screwdriver into hole on side of chuck, a couple of taps with a mallet and the chuck and reducer came of as one...job done.:U:B

HH.

[rsser]

Good one.

I use a thin plakky washer on the spindle cut from a 2l milk bottle.

Before that the odd jam was solved with a pipe wrench on the insert and a whack.

[Skew ChiDAMN!!]

Ahhh... this is a familiar problem. :U I do the same as Cliffy (Shock! Horror!) and for the same reasons except I use a metal bar in the chuck (one I've modified to also work with faceplates) and hit it with a rubber mallet.

(Pix are in this thread. (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=32134))

[Ross]

I use a washer made out of thin MBF, never had this problem.

Ross

[Frank&Earnest]

I do not use any sort of a washer behind the chuck as I find that any sort of a spacer can introduce a slight wobble in a chuck.
I firmly believe that the back of the chuck should sit dead square with the shoulder of the spindle.
:2tsup:

The professional turner who taught the TAFE course I attended also recommended a cardboard washer. I cut one out of vinyl floor covering. I tried with and without it but it did not make any difference to the slight wobble my chuck displays. Being soft material, I would expect it to conform to the hard surfaces on each side.

Which brings me to ask about the similar problem I have. I was trying to remove the insert of the SN2 chuck to see whether it was not sitting properly and causing the wobble (run out? I do not know the correct terminology) using the metod suggested by Al (OGYT) i.e. grasping a steel bar with the jaws and wrenching the insert out, but after a couple of fair wacks to the wrench with a heavy hammer I gave up lest I did more damage than good.

I might try again after a couple of drops of penetrating lubricant, but I am not holding my breath. Any suggestions? If after checking everything the wobble is still there, can I complain about the chuck or, say, .2 mm at the jaw edge is within expected tolerances? In this case, is there any other chuck on the market that is expected to run true?

[rsser]

F&E, check to see if there's a grub screw holding the insert to the chuck. The Vicmarc has one if memory serves; not sure about the TTool.

[Frank&Earnest]

F&E, check to see if there's a grub screw holding the insert to the chuck. The Vicmarc has one if memory serves; not sure about the TTool.

Yes there is, but I loosened it.

[Calm]

I have a 2 SN2's with a 1x 10 insert. both have wobbled and i found that the insert was bottoming out in the chuck before the sholder came against the end of the chuck. A mate machined the insert shorter so that the end of the insert fitted into the internal boss of the chuck and the shoulder bedded against the back of the chuck. This iliminated the "wobble" form both chucks.

I also use no "soft" spacer between the chuck and teh spindle.but when fitting chuck spin it up til it snaps tight by hand.

Picturtes can be attached if required.

[Skew ChiDAMN!!]

F&E, check to see if there's a grub screw holding the insert to the chuck. The Vicmarc has one if memory serves; not sure about the TTool.


Yes there is, but I loosened it.

My SN2 has two, opposite each other...

...why this is so, I've no idea. If the threads on the spindle and insert match, then there's no benefit that I can see.

[Frank&Earnest]

Thanks David. I bet that I am having the same problem. There is a thin gap between the shoulder and the back of the chuck. If I manage to unscrew it I'll try to "machine" a millimetre of thread off with a file- that end would not require absolute precision then, would it?

Skew, you must be lucky, but then, you are also younger...you can manage two, I am sure!:D

[scooter]

Thanks David. I bet that I am having the same problem. There is a thin gap between the shoulder and the back of the chuck. If I manage to unscrew it I'll try to "machine" a millimetre of thread off with a file- that end would not require absolute precision then, would it?

Frank, AFAIK the insert seats by the machined inner face meeting the inside of the chuck squarely, which is the face you're talking about filing?

Doesn't sound like a good idea IMO, I reckon you'd be best taking it to a Nova dealer to have it checked out.


Cheers...............Sean

[Frank&Earnest]

Thanks Sean, that's probably what I will do anyway, don't seem to be able to unscrew the damned thing.
If I understood David correctly, this is what he did and I was proposing to do:

[joe greiner]

Sean: Not a bad idea to have it checked by the dealer, of course. But the end of the threads might not be as square as the shoulder, and the shoulder has a larger diameter for more substantial purchase.

I'd be leery about clamping a bar in the jaws crosswise, mates. Too easy to throw things out of whack by whacking. With the jaws relaxed, it might be safer to use the chuck key or one of the tommy bars, whichever it uses. My Griz H6265 is a near clone of the SN2, except the insert has a hole for a chuck lever. With a spanner on the spindle, the lever is a few mm away, and the chuck can be disengaged by squeezing the handles together, similar to some two-wrench router collets. YMMV.

Skew posted a nifty pin spanner for faceplates in his link. Thus far, I've used a surplus Allen wrench in one of the unused holes, with the long leg wrapped across the hub for its reaction point, then whomp with something soft (except my hand).

Joe

[Skew ChiDAMN!!]

I'd be leery about clamping a bar in the jaws crosswise, mates. Too easy to throw things out of whack by whacking. With the jaws relaxed, it might be safer to use the chuck key or one of the tommy bars, whichever it uses.

Agreed. :yes:

I definitely recommend against hitting a metal bar clamped in the jaws with a metal hammer!

With my setup I can break the "seal" by hitting the bar with my fist, although by preference I use a rubber mallet; it usually only needs a light tap. If this applied enough shock value to damage my chuck I'd be wondering what damage is done every time I have a catch... :wink:

[Calm]

Thanks Sean, that's probably what I will do anyway, don't seem to be able to unscrew the damned thing.
If I understood David correctly, this is what he did and I was proposing to do:


F&E that is exactly what I meant. The threads are a loose fit and the shoulder is a machined surface as well as the end of the chuck. By machining to fit at this shoulder 99% of the wobble was eliminated. The internal end actually has a surface on the "thread" area to fit snuggly. I now have no grub screws in the chuck (adaptor to chuck) and it has not come loose at all. I would only reccomend that it is done in a lathe i'm not sure that doing by hand would be good enough.

[Frank&Earnest]

Ok guys, thanks everybody. Given the difficulty with both unscrewing and machining, taking it back to the seller seems the smartest thing to do. How un-blokey, though!:D

ETA: reading more carefully your latest posts, Joe and Andy, the problem I have with unscrewing is not spindle/insert, it is insert/chuck. I can't get any purchase on the circumference of the chuck, hence the clamping with the jaws which we all agree is dicey.

[scooter]

F&E, have you tried clamping the insert by the flats in a bench vise, then trying to undo the chuck from it with an oil filter spanner or similar?


Cheers...............Sean

[Frank&Earnest]

Thanks Sean. I thought about that possibility, but have no suitable spanner. I'll take your first advice and get MIK to have a look at it.