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Chuck help.

Glenn Lefley

Glenn Lefley

Joined
Jul 10, 2017
Messages
831
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689
Location
Windermere, British Columbia
i am getting tired of changing jaws on my chucks. I have one stronghold chuck, a talon chuck and a vm 100. I am thinking on getting a few more chucks so I can put dedicated jaws on each chuck.

Now when I use my Oneway stronghold on bigger pieces. ( my lathe will handle 20 inches inboard) I notice vibration and work seems to get out of Center or never seem to true back up when I start to get thinner on large platters. I am a new turner. Could this be a defect in the chuck of is this normal when things get thinner. I have never noticed this when I use the vm100.

I don’t want to get a couple of new stronghold chucks and have this same problem.

Has anyone experienced this with the stronghold chucks, and if so are the vm 120’s a good alternative. I do realize non of my present jaws would fit the new vm120’s.
 
Glenn, I have several Stronghold chucks and have never had a problem. Same with the Talons. They are excellent quality.

Here's one possible scenario to consider. If you close the jaws all the way, each jaw should meet evenly. I seem to recall taking a chuck apart once to lubricate and putting one in the wrong place so that three of the jaws met but the fourth was out a little. Putting it back together right caused them to all close evenly. It's worth a check, if you haven't already.
 
Zach LaPerriere said:
Glenn, I have several Stronghold chucks and have never had a problem. Same with the Talons. They are excellent quality.

Here's one possible scenario to consider. If you close the jaws all the way, each jaw should meet evenly. I seem to recall taking a chuck apart once to lubricate and putting one in the wrong place so that three of the jaws met but the fourth was out a little. Putting it back together right caused them to all close evenly. It's worth a check, if you haven't already.
Click to expand...
I have not checked that. The jaws are not numbered on a oneway chuck like the vicmarcs. How would I tell? I change the jaws all the time as I only have a few chucks and can’t dedicate a chuck to one set of jaws.
 
The problems you describe don't sound like they are related to the chuck. Are you talking about removing the turning from the chuck and then rechucking it at a later time? If so, it's not a problem with the chuck. The jaws are all the same so swapping them around doesn't matter. Wood is a compressible material and it never quite stops moving. For that reason removing and remounting will always result in some change in alignment.

While the top jaws are identical, the base jaws aren't so for minimum alignment error when remounting here is a suggestion that should help. Before removing the turning use a pencil to mark where the edges of each jaw grips the tenon or mortise. Next , put a dot to show the location of the #1 base jaw ... I usually mark all four positions (•, ••, •••, and ••••) so that I don't have to hunt for jaw #1.

Another hint for even greater precision: use dovetail jaws at the perfect circle diameter. The perfect circle diameter is where the gap between jaws is about ⅛". You can get dovetail jaws for both Talon and Stronghold chucks in sizes 2, 3, and 4. Oneway uses the term "smooth jaws" instead of calling them "dovetail jaws". FWIW, I think that Vicmarc gearing is a bit tighter than Oneway so when I have a piece which requires maximum repeatability when remounted I use a Vicmarc chuck and carefully size the tenon to the perfect circle diameter.
 
I have both the stronghold and Talon chucks. I found that when I turned the spigot using a parting tool, it was never quite round because of the face and end grain on the spigot. I then started cutting the spigot with a spindle gouge AND making sure that the corner where it meets the base of the bowl is "perfectly" square and flat. Since then any wobble on reseating is due to my carelessness when tightening the chuck, usually because I have seated it so not all 4 jaws touch the base.
I would definitely buy Oneway again.
 
I have several strong holds, a talon, and a vicmarc - they are all excellent.

About the only issue I have heard of with a stronghold is damaged jaws or jaws not properly seated.

1. top alignment of the jaws.
Put the chuck on the ways with the tops of the jaws on the ways.
Look for any space under the jaws.
I had a chuck that was dropped - there was light under one of the jaws it had been bent.
A new set of jaws fixed it fine.
Dirt under the jaws could also cause them to not seat.

2. Check to see if the jaws close tight against each other. When changing jaws it is good practice top open all the screws a 1/2 turn close the jaws and tighten.

99% of misalignment issues are the tenon. A tenon cut with a spindle gouge will be truer than one made with a scraper. A tenon cut with a sharp tool will be truer than one cut with a dull tool. The area where the tops of the jaws rest should be flat and square.
Also on the profile jaws the tenon should be a little longer than the last tooth. If you have made a 1/2 degree dovetail instead of a 90 degree square tenon the length of the last tooth - the closing jaws first contact is the tooth against the edge of the tenon and it may push it up when closing.
I like using dove tail jaws for most things. I can use a shorter tenon.

I also have a preference for the vicmarc chuck. I like the hex key over the toothed key.
We have 3 strong holds and the keys are not interchangeable among the chucks.

Lastly for thin work the chucks won’t always align perfectly because wood moves and the tenons are never a 1000% perfect. For thin work I true the face against the chuck after mounting in the chuck. Maybe just a shear scrape. With NE bowls I just plan for my finish cut to be trued after some hollowing to relieve tension.
 
Last edited:
Bill Boehme said:
While the top jaws are identical, the base jaws aren't so for minimum alignment error when remounting here is a suggestion that should help. Before removing the turning use a pencil to mark where the edges of each jaw grips the tenon or mortise. Next , put a dot to show the location of the #1 base jaw ... I usually mark all four positions (•, ••, •••, and ••••) so that I don't have to hunt for jaw #1.
Click to expand...
Great minds work similarly! I also have all four jaws marked 1,2,3,4......when I install a workpiece, I mark #3 jaw with pencil. ( #3 jaw, because it's convenient for key placement, when the chuck is mounted on the spindle) When removing, and re-installing a workpiece, align the mark on the workpiece with #3 jaw, and gently close the jaws. When the jaws are almost closed, you can fine tune to get a perfect re-chuck fit to where it was previously, by feeling for where the jaws fit best.....then tighten.

Glenn......I agree with others, that the problem most likely isn't with the chuck, but rather the technique you are using for a re-chuck. One thing to remember, is with any re-chuck, there is going to be an inherent error......but, things can be done to minimize it. Another thing to remember is every time you remove wood from your workpiece, you change the balance dynamics......as well as harmonics at a particular RPM. There isn't much you can do about the balance, but you can adjust RPM to best harmonics. Think about checking the vibration periodically throughout the process of turning your bowl.....and, adjust the RPM accordingly. Sometimes it doesn't change, while other times it does. Awareness of these things is the key to dealing with them. ;)

Glenn Lefley said:
i am getting tired of changing jaws on my chucks. I have one stronghold chuck, a talon chuck and a vm 100. I am thinking on getting a few more chucks so I can put dedicated jaws on each chuck.
Click to expand...
Many turners find it inconvenient to change jaws, and have bought more chucks with dedicated jaws. It's an expensive thing, but once all is said and done, it's a real convenience to not have to change the jaws right when your mind is working on something else. I have four Stronghold chucks, and purchasing extra chucks was something I've been glad I did......over and over again! :D

In the past, I've also owned a couple of Vicmarc chucks.The Vicmarcs have the best machining, but don't really work any better than the Strongholds. I sold the Vicmarcs, and went dedicated Stronghold.......mainly because I preferred the jaw selection on the Strongholds. (The Vicmarcs I had, also had the old style "tommy bars", and that made the decision a little easier, as well. :()

If I could go back about 30 years, I'd think very seriously about the Easy Wood chuck......that is, if such a thing were available back then!:rolleyes:

Good luck, in whatever you decide to do here, Glenn......making things more convenient is that which makes turning a much more pleasurable thing! :D

-----odie-----
 
Thanks guys for all your help. It’s hard when you have no one to physically help you. I found when turning a platter, say 14 inch round when I trued it up on the second side every cut I took from outside in it never would be true smooth running. I’m assuming now the wood is moving with each cut I take as I’m getting thinner ( 1/2 inch) . I only had used the stronghold with these bigger bowls as that is only big chuck I had.
 
Glenn Lefley said:
I’m assuming now the wood is moving with each cut I take as I’m getting thinner ( 1/2 inch) .
Click to expand...

Exactly, Glenn.......Some woods will warp more than others, and some won't warp at all. The diameter and profile shape are also likely determining factors. Just about every piece of wood will warp at some point......if it gets thin enough. This is just one more reason to keep checking for vibration at intervals, and continuing to adjust the RPM to minimize it. The cleanness of the cut you can achieve, is directly related to making that piece of wood revolve with as little vibration as possible. (.....among other things, of course! :D)

-----odie-----
 
I haven't read through all of the responses yet but there are 2 things often over looked. One is grain orientation. When putting the tenon in the chuck orient the grain so you have end grain and side grain on each jaw. The way to visualize this is to draw a line perpendicular to the grain and one parallel to the grain. Then mount the bowl so the lines go through the gap in the jaws. Doing it this way you have equal amounts of side grain and end grain in each jar. It's not perfect but a lot more accurate than just randomly inserting the tenon.
The other thing is making the tenon so the inside corner is actually undercut slightly. This lets.the jaws sit more accurately. Stewart Batty has an excellent video dis using this but I'm on my phone and have trouble finding it.
 
Just a thought- if jaws aren't marked, a Sharpie should stay visible for a while. This has been interesting and I have learned a lot. John Lucas' post makes sense to me. The budget doesn't allow a number of chucks. I'm not a production turner so I don't have the need for multiple chucks. Thanks to all for their replies. I find that these types of threads to be most useful.
 
Maybe Oneway chucks are different, but for other brands, the manufacturer makes the jaws as one piece, then cuts them into 4 quarters. If you don't mount them in the same sequence as when they were made, the grasping of the jaws will be off. Wouldn't this still be a possible explanation for the OP's problem?
 
I don't know how the jaws are made but the Vicmarc guy told me one time that all the jaws are made by CNC and are the same. He said they number them only because the older turners demanded it. I measured a few sets one day because I have 3 vicmarc chucks and they all come with 2" jaws. All were.as close to identical.as I could measure. Bare in mind that I'm not a skilled machinist but do own a good set of dial.calipers and micrometer.
 
Dean Center said:
Maybe Oneway chucks are different, but for other brands, the manufacturer makes the jaws as one piece, then cuts them into 4 quarters. If you don't mount them in the same sequence as when they were made, the grasping of the jaws will be off. Wouldn't this still be a possible explanation for the OP's problem?
Click to expand...

No, the Oneway premium profiled jaws are not made that way. They are identical to one another and, therefore, aren't tied to any particular base jaw.


William Rogers said:
One thing I always do (guessing all of you do) is when changing jaws I leave them snug and close the chuck completely before tightening.
Click to expand...

I've tried that to see what the difference would be compared to tightening them with the jaws open and found that closing the jaws before fully tightening the screws can cause one or both of the following problems:
  • The screws will feel tight because the screw head is binding against one side of the countersink. Then when the jaws are opened a bit the top jaws won't be solidly locked to the base jaws.
  • The slot on the bottom of the top jaws won't property engage the boss on the base jaws and while the two pieces are solidly locked together, the alignment will be crooked.
My conclusion is that the correct registration interface is determined by correctly mating the boss on the base jaw to the slot on the top jaw. There is no assurance that aligning the sides of the jaws will give satisfactory results.
 
Bill Boehme said:
I've tried that to see what the difference would be compared to tightening them with the jaws open and found that closing the jaws before fully tightening the screws can cause one or both of the following problems:
Click to expand...

I guess I disagree somewhat. I believe it does help by closing the jaws (not tight, but snug) before final tightening. I have never had the two problems you have listed.
 
William Rogers said:
I guess I disagree somewhat. I believe it does help by closing the jaws (not tight, but snug) before final tightening. I have never had the two problems you have listed.
Click to expand...

Aside from numbering the jaws, this is what I do, as well. As William says......"not tight, but snug". I haven't experienced any problems with this, and it does seem to help "true" the jaws up in a repeatable manner......

-----odie-----
 
Glenn Lefley said:
I have not checked that. The jaws are not numbered on a oneway chuck like the vicmarcs. How would I tell? I change the jaws all the time as I only have a few chucks and can’t dedicate a chuck to one set of jaws.
Click to expand...

Hi Glenn,

I should have been more clear. The top jaws are what we change out, the base jaws are what stay permanently. If you took your chuck apart and removed the base jaws, it's possibly to misalign the base jaws so that they are close but off just a little. Normally misaligned base jaws are very obvious, but to my memory I once put them together so the difference wasn't obvious. I only noticed it after attempting to close the jaws entirely, and one of the top jaws didn't meet the other three.

By now you've probably tried closing your jaws completely, and if the top jaws align properly, you're golden.

Interesting comparison Bill. I also had the opposite experience, and fall into the camp that snugs the top jaw screws, then tightens up the chuck until there is mild tension, and tightens the top jaw screws completely. This has given me the best results.

At the end of the day: what matters most in my opinion is that we check top jaw alignment by tightening the jaws until almost touching to see how close they align. It should be dang near perfect.
 
It’s amazing how there is never a clear concise answer for most things. Like everything it seems what works best for the person doing it.

I really appreciate all the answers and help every one is giving. It really helps us guys and gals when we live in areas where all our hands on information is obtained from the internet and this forum. The more input one gets the more sense it makes and one can finally find the solution that works for you. Where I live there is not even an aaw member within a 3 hour drive.

I’m going to go through everything, everyone has posted when I’m in shop and find out what is giving me this problem. I’m sure it’s not the actual stronghold chuck. But could be how it’s set up. Good point about internal jaws not being aligned. I got everything used so it’s possible the previous owner had it apart and it’s not aligned.
( thanks Zach ).

It’s only happening with the stronghold. And thanks for the multiple posts on tightening jaws before tightening screws. I would have over tightened thinking that more is better. Barely snug makes sense. And the post about jaws being made on CNC . I always thought they where made in a whole piece and then cut , therefore needed to be numbered to go back together.

Would the older jaws be made this way? Before cnc technology!
I have been deligent im putting my Vicmarc jaws in order because they are numbered and thought my Oneway ones where inferior because they where not numbered and thought I had to try all the combinations of putting them together til found perfect fit and then engraving numbers on them.
 
Not sure on the stronghold by on the SN2 the book recommends the tightening jaws then tighten the screws. You might want to find your instruction book or look it up online to find out what they say about this matter. Funny how that is always the last place people look.
 
Beginners Primer on Woodturning Scroll Chucks
Part I​

John's admonition about reading instructions notwithstanding, here is a primer on chucks in case you decide to ignore his "man rule"..

First of all, here are some pictures to explain certain terms and show various parts of the chuck jaws.

The "perfect circle diameter" shown below is the diameter which provides full contact when expanding into a mortise or gripping a woodworm screw or for holding a tenon when using dovetail jaws (Oneway calls them smooth jaws). The same is true for serrated or shark jaws. If the jaws are the Oneway premium profile type as shown then they are contoured to provide approximately equal tenon holding over the jaws operating range. I was surprised to learn that the angle on dovetail jaws isn't consistent, but is different on the inside and outside. The angle is different for jaws on different size chucks as well as different size jaws for the same chuck. I had been contemplating making or buying a tool for cutting a "perfect" dovetail angle, but now I see that might be a waste of time unless I want a whole stable full of dovetail tools.

image.jpeg


The image below shows the underside of a top jaw with its raised boss that mates with the slot milled in a base jaw. This is a precision machined interface that provides accurate registration with a very slight interference fit once the mounting screws are tightened. In my previous post I said that the raised boss was on the base jaw, but it is just the opposite ... the boss is on the top jaw.

The top jaws are rather soft steel so it is important to make sure that the top and base jaws are fully engaged before tightening the mounting screws so that the sides of the boss aren't scuffed. If the boss becomes scuffed it might cause a future problem with precise alignment.

I should also mention that the countersink angle for the screws is slightly smaller than the actual angle of the screw heads thus creating an effective friction lock. The reason is the chuck works in a potentially strong vibration environment and it's critical that the screws don't loosen during use. We are all familiar with the strong breakout torque needed to loosen the screws.

image.jpeg


In the image below I removed the base jaws to show the rack gear teeth that mesh with the scroll gear to provide an accurate "no-back" design (meaning that the chuck gear train can't be back driven from the jaws). The jaws are numbered and must be installed counterclockwise in the sequence 1, 2, 3, 4. The location of jaw #1 is marked on the chuck body. The jaws are removed in the opposite sequence.

image.jpeg


When the base jaws are installed in the correct order they will all meet together in the center as shown below. When top jaws are installed the base jaws can't be closed completely together as they are without top jaws as pictured below.

image.jpeg


On Oneway chuck models one of the jaws has a roll pin that goes in a slot either on the #2 or #4 position to limit the maximum extension from the body. Vicmarc chucks have a stop pin in one of the jaw slots of the body.

Oneway jaw sets come with screws that have been coated with copper grease. Sometimes new turners mistake this for rust because of the similar color.
 
Bill Boehme said:
Beginners Primer on Woodturning Scroll Chucks
Part I​

John's admonition about reading instructions notwithstanding, here is a primer on chucks in case you decide to ignore his "man rule"..

First of all, here are some pictures to explain certain terms and show various parts of the chuck jaws.

The "perfect circle diameter" shown below is the diameter which provides full contact when expanding into a mortise or gripping a woodworm screw or for holding a tenon when using dovetail jaws (Oneway calls them smooth jaws). The same is true for serrated or shark jaws. If the jaws are the Oneway premium profile type as shown then they are contoured to provide approximately equal tenon holding over the jaws operating range. I was surprised to learn that the angle on dovetail jaws isn't consistent, but is different on the inside and outside. The angle is different for jaws on different size chucks as well as different size jaws for the same chuck. I had been contemplating making or buying a tool for cutting a "perfect" dovetail angle, but now I see that might be a waste of time unless I want a whole stable full of dovetail tools.

View attachment 26567


The image below shows the underside of a top jaw with its raised boss that mates with the slot milled in a base jaw. This is a precision machined interface that provides accurate registration with a very slight interference fit once the mounting screws are tightened. In my previous post I said that the raised boss was on the base jaw, but it is just the opposite ... the boss is on the top jaw.

The top jaws are rather soft steel so it is important to make sure that the top and base jaws are fully engaged before tightening the mounting screws so that the sides of the boss aren't scuffed. If the boss becomes scuffed it might cause a future problem with precise alignment.

I should also mention that the countersink angle for the screws is slightly smaller than the actual angle of the screw heads thus creating an effective friction lock. The reason is the chuck works in a potentially strong vibration environment and it's critical that the screws don't loosen during use. We are all familiar with the strong breakout torque needed to loosen the screws.

View attachment 26569


In the image below I removed the base jaws to show the rack gear teeth that mesh with the scroll gear to provide an accurate "no-back" design (meaning that the chuck gear train can't be back driven from the jaws). The jaws are numbered and must be installed counterclockwise in the sequence 1, 2, 3, 4. The location of jaw #1 is marked on the chuck body. The jaws are removed in the opposite sequence.

View attachment 26570


When the base jaws are installed in the correct order they will all meet together in the center as shown below. When top jaws are installed the base jaws can't be closed completely together as they are without top jaws as pictured below.

View attachment 26572


On Oneway chuck models one of the jaws has a roll pin that goes in a slot either on the #2 or #4 position to limit the maximum extension from the body. Vicmarc chucks have a stop pin in one of the jaw slots of the body.

Oneway jaw sets come with screws that have been coated with copper grease. Sometimes new turners mistake this for rust because of the similar color.
Click to expand...
Can’t wait for part 2
 
This is why I love this site you ask a question you get the answer and also sometime you get a whole lot of other answers to questions you didn’t know you even knew you had at the time. I find woodturning is a progression learning hobby. You can’t see something or even learn it till your ready or at the step , that it makes sense.

Thanks again everybody.
 
Been using Oneway Strongholds and Talons (got four of each) for a long time without a problem. A few years ago, while at a demo (don’t remember who the turner was...but he claimed to have been a demonstrator for Oneway at one time) it was mentioned that its a good idea to check the taper-lock adapter every now and again - particularly with new chucks. He took two Strongholds - one in each hand - and tapped them together adapter to adapter. He then checked the adapter screws and found the newer took about a quarter turn on each screw.
Since then I do check the adapter screws about once or twice a year - and more often if I get a new chuck. With a new chuck it seems that the first couple of times they’re checked this way the screws will turn slightly. Once they’re seated fully they seem to stay that way...
 
I bought a new Stronghold chuck a few months ago and was wondering if something has changed. On the Talon bodies the tapered bore extends about an inch and my recollection was that it was about the same for the Stronghold body. However, on the new Stronghold body the tapered bore has been counterbored about ¾" and the tapered section is only about ¼" in depth. I was concerned that that might be problematic in getting the taper lock adapter perfectly aligned with the body. However, everything went OK, but I was wondering if anybody else has noticed a change or has my recollection gone south on me.
 
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