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 .

[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.