G3 Chuck users.....something doesnt seem correct with mine....help :)

[George Farra]

Hi All,

Along with my G3 chuck I purchased a 1x8tpi adapter, type D. I have a Rikon 70-220VSR lathe. The thread adapter fits on my lather fine, but it doesnt appear to be fitting the chuck correctly.

The chuck comes with a grub screw and the instructions state the screw should be installed if the lathe is going to be run in reverse. The thread adapter has a valley past the threads for that grub screw to hold onto without messing up the threads.

My adapter does not screw down far enough so if I did install the grub screw it would mess up the threads. I have not yet installed the grub screw.

Without the screw in place, the chuck does wiggle loose when in use. I'm making a tool handle to accept the Hosaluk inserts. I turned a 16" long blank using a spur drive center and a live center in the tailstock. I created a round tenon for the G3 jaws to hold onto. When I mounted the blank into the chuck so that I could drill out the end to accept the insert I discovered it wouldnt spin round....it was out of round.

I had originally assumed I didnt mount between centers straight, and thus my tenon was parallel to the stock?? Possible??

I slid the tailstock back up against the blank assuming this would center it, and began running the lathe to see if it would spin round and within a few seconds I could feel a vibration. I move the tailstock off the blank and sure enough the chuck was no longer fully seated on the thread adapter.

I'm convinced I did something wrong, but cant figure out what that was. I think I have 2 issues....a mismatched thread adapter, and user error.

Thoughts? Below are pictures of the thread adapter seated into the chuck. You can see threads in the grub screw hole and the flange of the threaded insert is not in contact with the chuck. I did check the inside of the chuck and the insert is indeed bottomed out and cant be threaded any further.

Thank you, George

[Patrick Morris IV]

On my G3,(used with 3 different adapters 3/4 to 1 1/4) there is a small plastic insert that you place between the grub screw and the insert threads to protect the insert. Check for a small red dot piece in the packaging that came with the grub screw. Hope that helps.

Pat

[Thom Sturgill]

First issue - is that a NOVA adapter? There have been problems with other brands such as Woodcraft.

Secondly, the adapter on Nova chucks do not seat by having the hex head touch the chuck body. The inside faces mate. As Patrickl said, there should have been a small red plastic dot that goes in the hole to protect the threads from the grub screw.

Thirdly, there will almost always be SOME run out when you move from one holding method to another. In this case it is possible that the centers are not perfectly aligned with the spindle even if they line up perfectly when they touch.

[George Farra]

ah ha! so that what those little red things are for. no where in the packaging did it indicate that. Yes its a Nova insert. I purchased them together albeit from Amazon so i became skeptical that amazon pared the wrong insert with the chuck.

Thank you for elaborating on the runout when changing holding methods. Question.....when using a chuck to hold blanks, is it wrong to hold the other end of a blank with a live center in the tail stock? Say you are turning a 16" long blank to make a tool handle.

Thanks

George

[Thom Sturgill]

Thank you for elaborating on the runout when changing holding methods. Question.....when using a chuck to hold blanks, is it wrong to hold the other end of a blank with a live center in the tail stock? Say you are turning a 16" long blank to make a tool handle.

Thanks

George

Use the tailstock ANY TIME that you can. I will also use the tail stock center to help align the blank in the chuck before tightening the chuck completely in some cases. Its better to have a firm 'seat' in most cases, but in others the run-out can be more critical. If its too far off, put it back between centers and re-cut the shoulder. You should not be able to slide a sheet of paper between the jaws and the base of the tenon (shoulder). It is better to have the shoulder slope inward so that the jaws meet the shoulder towards the outside than the other way around. Absolute flatness is essentially impossible to attain. The jaws you show want a straight tenon and a dovetail recess. The slight ridge on the inside is supposed to crush into the tenon and should NOT have a relief cut per NOVA.

[Michael Mills]

As Thom said, the adapter mates on the inside of the chuck, not at the hex. Make sure the interior of the chuck is clean of any metal shards before installing the adapter. I run a small brass brush or an old toothbrush around to make sure. Any shard can keep the two surfaces from mating properly. I also hold the hex in a vise and with light pressure seat the insert with a bar held in the jaws, some are difficult to seat fully by hand. Then put in the set screw from the chuck to the adapter.

I'm not sure how the insert could come become loose without turning in reverse. Seems it should get tighter. It should also not wiggle if the adapter and chuck mate properly.

[George Farra]

Michael,

The insert didn't wiggle loose from the lathe's spindle. The chuck wiggled loose from the adapter. This only occurs when I slide the tailstock with a live center up against the opposing end of the blank. The blank was spinning with a fair amount of runout. I'm speculating that the tailstock holdings things down on other end caused it to come loose from the vibration caused by the runout. I will recheck to ensure the adapter is fully seated in the chuck tonight.

On the flip side I milled a new blank 2x2 square and 16" long. When I mounted that blank into the chuck, again I had runout...enough so that the live center was unable to center itself. The blank was milled by jointing 2 sides square to each other and then squaring the opposing sides on the table saw. Using digital calipers both ends measured the same and all 4 sides sat flat on my tablesaw's table. Perhaps I don't have the adapter fully seated thus causing the runout.

George

[Michael Mills]

Michael,

The insert didn't wiggle loose from the lathe's spindle. The chuck wiggled loose from the adapter. This only occurs when I slide the tailstock with a live center up against the opposing end of the blank. The blank was spinning with a fair amount of runout. I'm speculating that the tailstock holdings things down on other end caused it to come loose from the vibration caused by the runout. I will recheck to ensure the adapter is fully seated in the chuck tonight.

On the flip side I milled a new blank 2x2 square and 16" long. When I mounted that blank into the chuck, again I had runout...enough so that the live center was unable to center itself. The blank was milled by jointing 2 sides square to each other and then squaring the opposing sides on the table saw. Using digital calipers both ends measured the same and all 4 sides sat flat on my tablesaw's table. Perhaps I don't have the adapter fully seated thus causing the runout.

George

I was referring to the adapter and the chuck. I had one chuck that had a shard of metal inside keeping the insert from seating correctly. I also had one where the insert fit much tighter than others and had to apply more pressure in order for it to seat.

When I mounted that blank into the chuck, again I had runout...enough so that the live center was unable to center itself.
I am probably reading this wrong. A standard live center does not center itself.
From post #4 Question.....when using a chuck to hold blanks, is it wrong to hold the other end of a blank with a live center in the tail stock? Say you are turning a 16" long blank to make a tool handle.
From my experience there is no way to hold a 16" long item (such as a tool handle) in a chuck without tailstock support unless they are deep spigot jaws and even then very iffy.

[George Farra]

Hi Michael

I am definitely explaining things wrong. After mounting a blank between centers and cutting a tenon, I mount the blank into the chuck and tighten the jaws down. My tailstock has PSI's cone shaped live center with a really sharp point. When I slide the tailstock up to the blank and rotate the blank by hand, the point cuts a circle in the end of the blank. I assumed I was experiencing runout in the blank, thus the point is not lining up to a single location at the end of the blank.

I first thought it was my inexperience in cutting the tenon, so I prepared a 2x2x16 square blank as indicated in my last post. I mounted the square blank into the chuck and tightened the jaws down. After sliding the tailstock up to the blank I have the same issue where the point cuts a circle in the end of the blank, which to me means the blank is spinning true. Im pretty certain the blank was square and true as it rested flat on all sides.

So something is causing the blank to spin with runout. If I place the tool rest at the end of the blank on the tailstock side I can see it rotating out of round as it creeps closer and then moves away from the tool rest as it rotates.

I checked to make sure all the jaws on the chuck are even and forming a circle and nothing looks wrong as they are all lining up and each jaw lines up smoothly with the next jaws all the way around.

I'm stumped. Either I am doing something wrong, or there is a problem with the equipment. Im a novice at this and am having a tough time figuring out which piece of the equation is causing the issue.

Thanks

George

[George Farra]

Also.....an FYI.....this all started because I wanted to drill a hole in the end of the blank to accept a Hosaluk insert. I noticed the blank was not spinning true, thus there would be no way to drill a clean hole. That is when I introduced the live center to see how things were lining up. The rest is above :)

Thanks,

George

[Michael Mills]

Hi Michael

I am definitely explaining things wrong. After mounting a blank between centers and cutting a tenon, I mount the blank into the chuck and tighten the jaws down. My tailstock has PSI's cone shaped live center with a really sharp point. When I slide the tailstock up to the blank and rotate the blank by hand, the point cuts a circle in the end of the blank. I assumed I was experiencing runout in the blank, thus the point is not lining up to a single location at the end of the blank.

George

I may be wrong so hopefully other will jump in. I do as Thom stated...
I will also use the tail stock center to help align the blank in the chuck before tightening the chuck completely in some cases.
I hold the wood lightly in the chuck, then bring up the tailstock and align to the center of the stock by eye (usually marked with an X), then tighten the chuck.
With the difference in grain hardness in wood I don't think you can fully tighten the chuck to start with. It will just squish the wood one way or the other just a little bit. That little bit may be a lot by the time it is amplified out 16" away.
Not necessarily run out in the blank, just wood being wood :D.

[Thom Sturgill]

Michael is right on. Use the tailstock - since you turned between centers there should be a mark from where the centers were - to recenter the blank BEFORE tightening the chuck. A few thousanths out of square at the jaws gets magnified by quite a bit 16" away, and is almost impossible to seat the blank perfectly without the tailstock. In addition there is the probability that the point of the live center is not perfectly aligned with the point of the drive center at 16" even if they were perfect at 0". This is not a precision machine lathe and you would need a specialized laser system to check it. Unlike metal lathes, there is no adjustment to offset the tailstock or correct existing offset.

[George Farra]

Michael & Thom,

Thank you for your help. I will give it another go around tonight. Much appreciated

George

[Michael Mills]

Let us know how it goes.

The reason I brought up the shard of steel is in your pics it appears there is a small "slot" cut through where the key sits. It may have been drilled a little deep (I have one like that and it has never hurt the chuck). When you put in the insert a "hanging chad" may have been broken loose and still be in the chuck keeping it from seating.
The insert/adapter backing out is still very strange to me and would like to know the reason in the event it happens to me in the future.

[Kyle Iwamoto]

One mistake I made when fist started using a chuck, is the chuck seating surface is the jaw faces, not bottoming on the chuck. In other words, the tenon has to be shorter then the depth of your jaws. You need to cut a shoulder that is nice and square. Seat the jaw faces against the shoulder.
Another trick, always mark 2 sides of your #1 jaw. That way, if/when you remount the piece in your chuck, you can put it in the same place. It will line up much better. I leaned that the hard way too.

[John K Jordan]

George, It sounds to me like the threads for your chuck or insert are either bunged up or machined incorrectly. I have 11 Teknatool chucks, some G3 and most Supernova and Supernova2. I have inserts for my lathes from several sources. (I hate to change jaws.) The runout is better on some jaws/chucks than others but it is minimal and acceptable. I don't use the locking set screws and have NEVER had a chuck or insert come loose, even with large bowls. (Perhaps this is because my lathes accelerate very gently when spinning up and down and never "jolt" the work.)

i would take a close look at the threads. If you bought this locally, perhaps take it to the store and have them test the insert and chuck with a different chuck and insert. Otherwise, you might take it to a local turner who has the same equipment. I am assuming you have the right insert for your lathe - can't imagine the wrong one even partially fitting (you can check the number stamped on the hex flat.)

Note that as you tighten the jaws on the stock it can easily be accidentally jacked to one side as the jaws bite into and crush the fibers, especially when chucking square stock without a tenon. (Incidentally, you can take advantage of misalignment when tightening the jaws to turn multi-axis pieces.)

BTW, this is how I mount long spindle stock in a chuck: If the stock is too large to mount square or quite long, I mount between centers and turn a tenon on one end, making sure to cut a sharp shoulder and making sure the tenon is not so long it bottems out in the jaws. I usually mount between steb centers, both at the headstock and tailstock. If I plan to mount a turning square without using a tenon, I mark the center of the right end and if the wood is hard, make a small hole (with a gimlet). I put the stock in the jaws and barely snug them, then bring up the tailstock (with the live steb cinter) and advance the point into the center hole. Then I tighten the jaws firmly while cranking down on the tailstock. This method keeps the work centered precisely since it can't shift as the jaws dig into and somewhat deform the gripped surface. I use roughing gouge or skew to round the length then remove the tailstock. I often turn 1" to 3" blanks 6" to 14" long.

If the stock is relatively short or I have more thichness than I need, I don't use the tailstock to center but just eyeball it from above, aligning roughly with the lathe ways while tightening the chuck, first on one axis then when rotated 90 degrees. When I have just barely enough wood thickness (i.e. want to make a 1-7/8" piece from 2" stock) I always use the tailstock to aid in centering - it lets me get very close.

In case you don't know, chuck jaws will grip the best on a round tenon a wee bit larger than the jaw's smallest diameter. This not only grips the best but deforms the wood (crushes the fibers) the least.

Also, I make a mark between jaws #1 and #4 in case I have to rechuck the work at some point. And here's a drilling tip for no extra charge: I always start a hole with a machinist's center drill. These are short and stout and get the hole started correctly even with wild end grain. Set of 5 different sizes are very inexpensive on Amazon (for wood, the high-dollar center drills are not needed.)

While on my chuck soapbox, I recommend to get and use a proper wrench to tighten and remove a chuck. I cringe when I see someone put in and whack the chuck key with their hand or piece of wood. I once bought three used chucks from a gentleman who abused them this way and worse: he used a cheater bar to get them REALLY tight. I've never seen chucks in worse shape. The steel in the bodies was actually deformed at the jaw slides to the point that I could barely adjust the jaws. It took me hours to rework them.

JKJ

[Ron Rutter]

George. It sounds to me like you are not starting out correctly. Mark the center of the tailstock end of the piece. Put the turned end in the chuck & bring up the tail stock to mark. Tighten up chuck end ( shoulder in place) with tail stock centered in piece. Ron.

[Michael Mills]

. I don't use the locking set screws and have NEVER had a chuck or insert come loose, even with large bowls.
JKJ

Interesting. I don't have as many chucks but I do always use the set screw in the body of the chuck to lock it to the insert. I really don't see a reason not to unless you are switching chucks between lathes with different spindle sizes (changing inserts). I seldom use the other set screw from the insert hex to the spindle; I just use a lighter touch while sanding in reverse but for safety I really should use it any the time in reverse.

Seems to me not using the set screw in the chuck body (as the OP did) could easily result in the chuck unthreading from the insert upon removal from the lathe leaving the insert on the lathe. There may well be greater force in the insert/spindle mating than in the insert/chuck body mating; especially if the chuck was placed on the lathe in "hero" method as described by Capt. Eddie.

[George Farra]

Hi Everyone,

Thank you all for your input. From all of the posts I am concluding that my technique was completely wrong, in that I was tightening the jaws without having the tailstock in place. Also on a square blank I was bottoming out the blank in the chuck. I never made it back into the shop last night and looks like my next go around will be this weekend.

I will change my technique and see if my problems go away. I will also post a follow up regarding the chuck wiggling off the adapter because I am still stumped as to how that happened considering the lathe is spinning the chuck in the opposite direction of the threads.

Regards, George

[Kyle Iwamoto]

Your chuck loosening. No offense intended, but are you turning in the right direction? I do know from experience that a skew CAN cut with the lathe running in reverse. I remember thinking, why is my skew bouncing up and down. I don't recall that before. I should put MORE pressure on it so it won't bounce. I also know that a band saw can cut with the teeth in the wrong direction (up). And I checked it 3 times. I remember thinking this is a NEW blade. Why is it such a POS. Don't be embarrased about making misteeks we all do it.

[George Farra]

Evening all,

I checked to ensure there is nothing preventing the adapter from fully seating in the chuck. The internal threads on the chuck are all clean and the the adapter bottoms out in the chuck body. I also made sure the lathe was running in the correct direction :)

I prepared a new 2x2 square blank and marked the center on 1 end. Used an awl to mark the center. Slid the blank into the chuck jaws without bottoming the blank out in the chuck. Brought the tail stock up and got the point set in the awl mark, held the stock and tightened the jaws. Spinning it by hand I could not detect any visable runout. I started up the lathe and let it come up to 950rpm, then i cranked it up to 1100 rpm. Ran smoothly for about 10-15 seconds and then I started to notice a vibration. Shut it down and sure enough the chuck came loose from the adapter.

I took everything apart and this time I inserted the grub screw to hold the adapter in place. i used the little red plastic dots to protect the threads. Used the same set up procedure and this time it ran okay although i still noticed a vibration develop after about 10-15 seconds of run time.

At this point I'm thinking its best for me to return both the chuck and the adapter and try it again with fresh equipment. I sent Teknatool an e-mail yesterday about this issue and I have not yet heard from them.....what a difference from Rikon customer service. The guys at Rikon are super responsive.

Not sure what to do/try differently at this point

George

[John K Jordan]

Very strange. Was the vibration with the set screw in place also accompanied by a loosened insert or was it still tight? If the insert is still tight (when you remove the set screw) I would want to try that chuck on a different lathe and/or try a different chuck on that lathe. Do you know someone who has a chuck and/or insert you can try? I can't imagine the vibration being due to an imbalance in the chuck since it should vibrate immediately and not wait 10 seconds.

But if it still loosens wirh the set screw in place, and assuming both threads are in good shape and you have tightened securely with a wrench, perhaps some blue loctight would help.

I also assume you have tested to be sure the vibration is not coming from the lathe itself, with no chuck installed but with a blank held between centers or faceplate or jam chuck. And I don't temember if you said, but be sure the tailstock is aligned perfectly with the headstock - not only do the points need to touch exactly but the axis of the headstock spindle should be parallel to the ways and the axis of the tailstock.

JKJ

[Jack Mincey]

At what RPM are you turning your spindle? The vibration could be due to turning with your chuck at high rpm's. Just a thought.
Jack

[George Farra]

Hi Guys,

The lathe comes up to speed at 950rpm and I turned it up to 1100rpm. The vibration occurs 10-15 seconds in at 1100rpm. I will try running the same blank between centers at the same rpms tonight and see what happens.

I didn't remove the set screw prior to removing the chuck from the lathe to see if it was indeed loose after releasing the set screw. I can also try that tonight as well.

I will keep you all posted, thank you for all your help

George

[John K Jordan]

Any lathe I've used would easily turn 2000-3000 RPM with no vibration. I typically turn all my spindles at over 3000 for a cleaner cut.

Check the drive belt too. I have never had this happen but I've heard of other cases where a vibration was caused by a bad belt. Dust buildup in the motor can also cause vibration. Bad bearings too, but this is usually pretty obvious even turning by hand.

JKJ

[Joe Bradshaw]

George, your location would help. I'm sure that there are some "Creekers" near you and would be glad to help you sort this out. Check and see if both ends of your lathe are level. Solving your problem is going to involve a lot of trial and error. As someone has mentioned, try another chuck on your lathe. Try your chuck on someone else's lathe. If all else fails, sell your G3 and get a Oneway Talon with the proper insert. Good luck.
Joe

[George Farra]

Hi Guys

I spun tool handles between centers at 3,000rpm just last weekend without any vibration which is why I am focusing on the chuck or the insert adapter. I was looking at the Oneway Talon chuck this morning and have to admit their tapered insert intrigues me. I think I am going to order one with the 1x8TPI adapter. I can always return the Nova chuck as I bought it 2 weeks ago.

I am in NJ, Bergen county.

Thanks

George

[George Farra]

Hi All,

took another go around at it tonight. took a brass brush to the threads on the chuck, mounted the adapter into the chuck and tightened it with a spanner wrench. I did not use the set screw.

Prep'd a new 2x2x16 blank, marked the center on 1 end, made a detent with an awl. Got the live center point set in the awl mark and tightened up the jaws making sure the blank was not bottomed out in the chuck.

Started up the lathe and got her running up to 2800rpm....ran smoothly, no vibration. Shut it down pulled the tailstock and the chuck was still tight on the spindle. Suddenly I was happy.

Next I ran the lathe up to 3000rpm with the blank in the chuck without the live center...just spinning freely. All was okay.

Lastly, I put a jacobs chuck in the tailstock and drilled out a hole in the center of the blank. At this point I did notice that drill bit wasnt lining up perfectly with the awl mark....not off by much, just a hair off center. I drilled out a hole and as I was backing the drill out, I noticed it started vibrating. Lathe was running at 950rpm. Shut everything down and sure enough the chuck was loose on the adapter. the adapter was always rock solid on the lathe spindle.

Thoughts.......improperly machined adapter? chuck? or is this a situation where I would always need to use the set screw??

I am leaning towards purchasing a Oneway Talon...15% off at Rockler. If that chuck doesnt give me any problems....the Nova gets returned

Thanks

George

[Thom Sturgill]

Sympathetic vibrations tend to peak at specific speeds. It is not uncommon in spindle work to have to turn the speed up until a vibration dampens down. So the questions are:

Did you check the spindle (between centers) at 1100 rpm where you had noticed vibration or did you just turn the speed all the way up and not see vibration?

Did you try checking the chuck alone at different speeds?

Are you using one of those plastic washers under the chuck? They have been known to create vibration, and to cause the insert to stick while the chuck spins off when the motor stops too quickly if the grub screws were not in place.

I have one chuck (out of seven) that always requires a wrench to remove. Before I tightened the grub screw the insert would unscrew when I tried to simply unscrew the chuck by grabbing the chuck body and locking the spindle. So not all inserts are created equal either.

[George Farra]

Hi Thom,

#1, yes. I started at 950rpm and let the lathe come up to speed. Moved it up to 1100rpm and let it run, and after that I ran it up to 3000rpm. This was done with the tailstock in place.

#2, yup, after being satisfied that it was running smoothly with the tailstock in place, I removed the tailstock and ran the blank just with the chuck for the same 3 intervals as above.

It ran smoothly again at all 3 rpms, each interval ran for about a minute. In each of the runs above the red washer was in the grub screw hole, however the screw was not installed.

It came loose as I was drilling a hole in the center of the blank, which would have been the third time spinning the blank in this session. I had a Jacobs chuck in the tailstock and drilled a hole about an inch and a half deep, running the lathe at 950rpm. As the drill bit was exiting I started to notice the vibration.

On shut down the lathe slows down gradually so I cant see how that is the cause. I do believe its the adapter since in all instances the chuck was loose on the adapter but the adapter was rock solid on the lathe spindle. In fact, unless the set screw is in place, the chuck will come off the adapter when I remove it from the lathe and I need a wrench with the spindle lock on to get the adapter off the lathe.

I was thinking about it more last night and it seems the solution is to put the set screw in and leave it in, rather than buy the Oneway Talon. The chuck operates smoothly and I like the fact that Nova jaws are interchangeable across all their chucks so upgrading later is an easier investment.

Thanks for all your help,

George

[Thom Sturgill]

I think maybe you misunderstood the question about the washer. I am NOT talking about the red dot. Some users place a plastic washer between the chuck and the shoulder of the spindle. These are known to sometimes cause runout and vibration. Since the presence or absence was not mentioned the assumption was that it was not there since most turners do not use them. But, if a salesman sold you the washers and made you think their use was normal, you may not have mentioned it.

By all means, keep the grub screw in place.

[George Farra]

Hi Thom,

Yes I did misunderstand your question. No plastic washer between the chuck and the shoulder of the spindle in my set up. So funny, I was actually thinking about your comment and was scratching my head as to how that little red dot could be the culprit. Too funny!!

George

[James Combs]

I think maybe you misunderstood the question about the washer. I am NOT talking about the red dot. Some users place a plastic washer between the chuck and the shoulder of the spindle. These are known to sometimes cause runout and vibration. Since the presence or absence was not mentioned the assumption was that it was not there since most turners do not use them. But, if a salesman sold you the washers and made you think their use was normal, you may not have mentioned it.

By all means, keep the grub screw in place.
DITTO, DITTO, DITTO
I have reread this thread a couple of times and get the distinct impression that you do not want to use the "insert retaining grub screw". I do not understand why the chuck would ever be used without the insert retainer in place. That is it's purpose and it should be installed as soon as the insert is seated in the chuck and before it is ever mounted on a lathe. I have 3 Nova chucks and the grub screw was installed in each at the same time as the insert and has never been removed except possibly to clean the chuck or change to a different insert. I can understand the initial concern about damaged insert threads from the screw but with finding and installation of the red fiber washer the screw should be left in place. I wouldn't think it even safe to spin the chuck without it especially at the speeds I am seeing mentioned here. I am pretty sure that Nova's suggested max RPM for their chucks is well below the 3000 or even the 1200 RPM mentioned above. I am not saying that they can't be run at higher RPMs, I typically hit 2000 with mine, I am just saying that above factory suggested speeds we are taking risks and if I am going to take a risk I certainly won't do it with some retention device missing on my chuck.

There is another grub screw associated with an insert, it is usually found in the hex portion of the insert and is typically found on inserts intended for use on reversible lathes. As far as I know it does not come with the fiber washer as it normally seats in a thread vacant area on the spindle. The two screws should not be confused with each other. I am not saying that's what is happening here, this is just a heads up for those that are new to chuck usage.

[John K Jordan]

"insert retaining grub screw". ... should be installed as soon as the insert is seated in the chuck and before it is ever mounted on a lathe.

...There is another grub screw associated with an insert, it is usually found in the hex portion of the insert and is typically found on inserts intended for use on reversible lathes.


James, you are absolutely right - I think it is a good idea to use the screw that locks the insert to the chuck body. Tecknatool instructs this, and strongly for left-hand threaded inserts. From the Supernova2 manual under fitting the insert to the chuck:
"The Insert can now be locked to chuck body by means of the M6 x 6 grubscrew provided. Make sure that the fibre washer is inserted first to act as a buffer between the grubscrew and insert thread. DO NOT SCREW IN GRUBSCREW BEFORE INSERT IS SCREWED HOME IN CHUCK. IMPORTANT: LH THREAD INSERTS MUST BE LOCKED TO CHUCK BODY OR CHUCK BODY COULD UNWIND FROM INSERT."

I checked my chucks and all have the insert retaining set screws installed since my primary lathes have the same spindle threads. I installed the set screws when the chucks were new and have never removed them or even thought about them since. I bought separate chucks for a small lathe I sometimes take to demos so I never have to remove an insert.

It is the other set screw on the 1-1/2" hex flats on the insert that I was thinking about and never use or found necessary. Some of the inserts are not even threaded for this. I find them unnecessary since the chucks stay so tight they always need a wrench to remove, even when mounted by hand. (Years ago I got into the habit of mounting a chuck in this way: thread on the spindle up to the last 1/2 turn or so, then while keeping the spindle from turning with the left hand, spin the chuck quickly so it seats with a clunk. This obviously requires clean mating surfaces. This works well for me.)

As for speed, Technatool makes some generic safety warnings such as "WARNING: EXCESSIVE SPEED IS A SERIOUS LATHE HAZARD. ALWAYS TURN AT THE SLOWEST SPEED POSSIBLE. Speed will vary with wood blank size. The larger the blank the slower the speed. Consult your lathe manual or lathe information plate for speed guidelines." They make specific speed recommendations for specific jaw sets.

The "speed will vary with wood blank size" is the key. It would be insane to turn a big chunk at high speed. It is reasonable and desirable to turn a small spindle at high speed. The type of jaws and the depth of the spigot or tenon makes a huge difference in save turning speed. I would not try to grip a very narrow spigot on a substantial piece with a long unsupported overhang at high speed. But a long tenon or square of strong wood gripped securely in the right jaws is a different case. I personally use the jaws that grip a long tenon about an inch or so (I think they are the 35mm, 45mm, and 25mm pin jaw set for very small things. Even long unsupported spindles are not going to be levered out of these jaws even with a big catch.

Another thing about speed: if a magic wand or a finger top breaks or otherwise comes off, no one gets hurt (except perhaps the moron without safety glasses but he needs to take up knitting or TV watching instead anyway.) A heavy hollow form or vase or lamp stand can store a LOT of energy at speed due to it's mass. A similar issue is turning a chunk of light-weight dry cedar vs the same size chunk of wet hickory.

Regardless, one should never turn at higher speeds than comfortable based on experience level. With experience, higher speeds become more comfortable and desirable. I've heard Jimmy Clewes several times start a demo with "won't this thing turn up any faster?!" Of course, Jimmy is known for turning things of size and imbalance at speeds that scare even me. Some people front and center have been known to move.


As for the point of this thread, if I had a chuck that even ONCE came off the insert but was otherwise ok, I would dress the metal as needed (as per Tecknatool instructions), apply removable (blue) Locktight thread locking compound, put the chuck in a vise and tighten the insert securely with a wrench (as per Tecknatool instructions), and tighten the grub screw (perhaps also with Locktight.)

JKJ

[George Farra]

Hi James,

Well perhaps my confusion all began because of the users manual that accompanied the chuck. The manual stated to use the retaining grub screw if the lathe is to be run in reverse which made me believe that it was not needed in normal operation. In addition, the threaded insert (type D) has a void after the threads which I would have normally assumed is where the grub screw should engage the area behind the threads on the adapter which is not the case for my adapter which maybe why the red nylon button is supplied.....to protect the threads in the adapter.

Also my adapter does not have a second grub screw in the hex section AND my lathe can be in reverse....so perhaps I simply have the wrong adapter.

Lastly, given the threads are cut in the opposite direction of the normal rotation of the lathe I believed the instructions as they are stated.....rotation in an opposite direction of the threads would cause the chuck to tighten not loosen. Seems like my reading of the instructions lead to all this confusion on my part

George

[Thom Sturgill]

Lastly, given the threads are cut in the opposite direction of the normal rotation of the lathe I believed the instructions as they are stated.....rotation in an opposite direction of the threads would cause the chuck to tighten not loosen. Seems like my reading of the instructions lead to all this confusion on my part

George

My take on this - when the lathe slows down, even if slowly, the chuck's inertia wants to keep it turning at the same speed. If the adapter's threads are tight on the spindle but loose in the chuck, the chuck can 'unwind' from the adapter. The grub screw prevents this by increasing the friction between the insert and the chuck body.

[Michael Mills]

Also my adapter does not have a second grub screw in the hex section AND my lathe can be in reverse....so perhaps I simply have the wrong adapter.



I'm not sure why Teknatool does it but they have two inserts in some sizes. One with the set screw in the hex and one without. They sell for the same price so :confused:.

In the 1X8, with the screw in the hex is Insert X, without the hex screw Insert D.
In the 1.25X8 with the screw in the hex is Insert L, without the hex screw Insert Y.

If you have a real hardware store you should be able to get a tap and appropriate drill for about $6. Only takes a couple of minutes to add the screw yourself.

This show the Insert X.
http://www.tools-plus.com/nova-lathes-ixns.html

[George Farra]

Thanks everyone. Grub screw is in place and adapter is firmly secure to the chuck. I may as a backup use blue locktite as suggested. If I get to the point in my turning where running in reverse becomes a possibility I will drill out the adapter and tap for the second grub screw to lock to the lathe spindle

Enjoy the weekend and thank you all for your help. Much appreciated.

George

[Thom Sturgill]

Reverse is used by most of us just for sanding. Alternating rotation between grits presents a cleaner surface. As face grain rotates past a point, one section will be against the grain - then with the grain laying down - then side grain and then back to against the grain. When the grain is lying down, you cannot cut it clean so reversing the rotation reverses which sections are laying down and which are against the grain. If a light touch is used, a grub screw is not an absolute requirement.

Wetting also helps to stand up the grain for cutting.

A few cut while in reverse by cutting on the back side of the lathe rather than the near side. THAT is an advanced technique that most do not attempt.

Reverse is also used on some machines where the work can be mounted on the back side of a fixed headstock to allow cutting large items off the end of the lathe. Since you are cutting on the other side of the headstock the motor is running in reverse, but the work is not. Sliding headstocks eliminate this need as you just move the headstock down the bed for better access, or to the end for turning large diameter pieces.