# Ordering a 6-jaw Chinese Chuck-



## ErichKeane (Mar 2, 2020)

So I currently have 2 3 jaw chucks, a 12" that requires an engine hoist to install, and a 8 inch that has a couple of broken teeth in the tightening mechanism.  I typically use the smaller one, but it has quite a bit of runout as well.  I also find myself switching between the 4 jaw, collet chuck, and smaller 3 jaw pretty often.  I see that Abom79 has a 6 jaw that he says is better concentricity wise than a 3 jaw, so I figured I'd give it a shot!

I found a cheap backplate for my lathe that has been left unused for a while (L1 backplates are worth their weight in gold it seems!), and bought this: https://www.ebay.com/itm/6-jaw-chuc...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

My 4 jaw is the same brand and seems reasonably good, and I plan on surface grinding the face if it seems too far out.  Despite being the cheapest one on ebay, the seller seems to have shipped via UPS quite quickly (despite a month long expected delivery date, I should be getting it in roughly a week overall, this Thursday).  I'm cautiously optimistic that this 6 jaw will be good enough to just use on the lathe!


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## aliva (Mar 2, 2020)

I'd be curious of the repeatability and concentricity. Hopefully it's within an acceptable range. 
please keep us posted.


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## ErichKeane (Mar 2, 2020)

aliva said:


> I'd be curious of the repeatability and concentricity. Hopefully it's within an acceptable range.
> please keep us posted.


Will do!  I'm curious as well, I haven't decided whether I'll do a teardown before trying it out yet, but I likely will.  I figure as long as it is close-ish it can take the place of my 3 jaws.


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## mikey (Mar 2, 2020)

Abom's 6 jaw chuck is an adjust-tru type chuck. The one you ordered is not; it is just a 6 jaw scroll chuck so it will run out about as much as any scroll chuck does, about 0.002-0.003" or so.


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## ErichKeane (Mar 2, 2020)

Ah, that makes more sense an adjust tru is just an undersized recess plus some set screws in the chuck to recenter it, right? If I feel motivated that seems easy enough to change on this one.


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## mikey (Mar 2, 2020)

An adjust-tru has a set of 3 or 4 hardened dog nose set screws in the rear body plate of the chuck. Those screws bear on the nose of snout formed on the back plate to allow you to shift the chuck around. Your chuck does not have that provision. It is just a scroll chuck that happens to have 6 jaws instead of 3.

You can turn the register/nose/snout of your back plate a tad undersized and this will allow you to knock it into alignment. However, it will be aligned only for the diameter you used to adjust it. If you work with thin walled or plastic a lot then a 6 jaw makes sense. If you do production work with the same nominal diameter stock then you can adjust the chuck on the back plate to minimize run out and it will be pretty good for that diameter stock. If you change diameters then the setting will need to change if you must run tight tolerances. If you're just doing first operations work then none of this really matters; just use it.


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## ErichKeane (Mar 2, 2020)

How does the adjust tru work for multiple diameters? Or does it have the same "single diameter" issue?


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## mikey (Mar 2, 2020)

Okay, folks have the idea that an adjust-tru can be adjusted once and it will be as accurate as a 4 jaw independent and will work for any diameter you put in the chuck. This is not true, simply because it is a scroll chuck. The nature of a scroll chuck is that run out changes depending on where on the scroll you happen to be locking down on. If you are turning multiples of the same diameter then you can adjust the chuck to run that diameter accurately because you're locking down on the same spot of the scroll. However, if you change to another diameter then you have to reset the chuck. 

Thing is, if you use a 3 or 6 jaw scroll chuck for first operations work - that means the first time you turn something - then that chuck will be accurate, even if it isn't an adjust-tru chuck. It is when you do second operations work on a piece that has already been turned or is accurately ground that you must have the adjustability of an adjust-tru or 4 jaw independent chuck in order to control run out.

Bottom line is that you ordered a scroll chuck and if you use it like any 3 jaw scroll chuck it will be fine. If you need the ability to adjust run out for second operations work and you need the speed of a scroll chuck then you need an adjust-tru chuck. Return the chuck you ordered and buy what you need.

There is one other option. You can buy a Bison combination chuck, which is a standard scroll chuck but each jaw is independently adjustable. Big bucks but it is a cool configuration.


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## middle.road (Mar 2, 2020)

Not a Set-Tru? Check out this video from Joe Pie.


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## darkzero (Mar 2, 2020)

ErichKeane said:


> 6 jaw that he says is better concentricity wise than a 3 jaw



More jaws doesn't really make a difference for concentricity or accuracy. Really it's the quality of the chuck. As Mike said, it's just a plain back chuck, runout will be no better than a 3-jaw chuck. Even most quality name brands only guarantee .002" TIR for plain back chucks.



ErichKeane said:


> Will do!  I'm curious as well, I haven't decided whether I'll do a teardown before trying it out yet, but I likely will.  I figure as long as it is close-ish it can take the place of my 3 jaws.



IMO, every China chuck should be disassembled & gone through. In my experience Gator chucks are better but I still did. They get carried away with the amount of grease they put in them.

Unfortunately a 6-jaw chuck is not a replacement for a 3-jaw chuck IMO. More jaws doesn't mean more holding power on a scroll chuck. You mentioned that you have 12" chucks so you must have a decent size lathe. If you do heavy turning you may find that a 6-jaw will not hold as well as a 3-jaw & the work piece will slip, usually getting pushed back into the chuck. I don't have a big lathe & there's times where I had my 6-jaw slip. Because the scroll has to transmit force through 6 jaws instead of 3 you'd have to tighten the pinion(s) more than you would on a 3-jaw to get a really good hold of the work piece. A 6-jaw usually won't dig into a part like a 3-jaw or 4-jaw independent can, not necessarily a good or bad thing depending on your needs. Sure you can crank down on the pinion harder but if you do this repeatedly on short parts you risk bell mouthing the jaws over time.

6-jaw chucks are considered 2nd op chucks. They're more like a collet in a sense. Their main advantage is for holding thin wall parts, less chance of deformation. They don't hold parts well that aren't perfectly round. I use cold roll stock which is usually ok but if the stock is not very round a 6-jaw will have a hard time holding it. I find a 6-jaw chuck has less chance of leaving jaw marks on a machined part. So in that sense, they will hold a machined part better than a 3-jaw with less chance of damage to the part from the jaws. There's more but that's the basics.

I may make 6-jaw chucks sound like there are more disadvantages than advantages. That may be true to most. Unless you need the advantages of a 6-jaw chuck, IMO it's better to go with a good quality 3-jaw for a primary use chuck. With that said I still primarily use a 6-jaw chuck although I may not need it as much these days. They sure are sexy though. I love using my 6-jaw but I still use a 3-jaw too.



ErichKeane said:


> Ah, that makes more sense an adjust tru is just an undersized recess plus some set screws in the chuck to recenter it, right? If I feel motivated that seems easy enough to change on this one.



I'd be curious to see your method if you plan on doing this. Please share if you do. Most plain back chucks don't have room on the body for set screws to convert it into an adjust-tru. You can make it a tap-tru but without set screws to lock the chuck into place, under heavy turing they can possibly get knocked out of alignment.


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## ErichKeane (Mar 2, 2020)

Thanks for the info guys! I have a 4 jaw and a collet chuck plus a pair of 3 jaws. I might consider turning down the recess of the back plate a little tighter to see if I can get it closer to running true, but perhaps I'll just dial in my 3 jaw instead. I guess I don't really have a NEED, just a curiosity.

I guess worst case I'll have something for if I ever do thin wall stuff.


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## darkzero (Mar 2, 2020)

ErichKeane said:


> Thanks for the info guys! I have a 4 jaw and a collet chuck plus a pair of 3 jaws. I might consider turning down the recess of the back plate a little tighter to see if I can get it closer to running true, but perhaps I'll just dial in my 3 jaw instead. I guess I don't really have a NEED, just a curiosity.
> 
> I guess worst case I'll have something for if I ever do thin wall stuff.



Sounds like you are covered for chucks with this new addition. I'm curious if that 6-jaw comes with a set of OD jaws, the listing doesn't say. OD jaws come in very handy on a 6-jaw. Mine has 2 pc jaws so I can just flip the top jaws.

I would make the backplate register fit tight with the new chuck, then check runout. If the runout is not acceptable, then proceed with making it a tap-tru if you feel the need to.

The very first 6-jaw I purchased was a China chuck, it didn't come with OD jaws but at the time I had no use for them on my mini lathe. I never ended up using that chuck though, literally right after I received it I found a used Bison 6-jaw Set-Tru for cheap. I fell in love with that chuck so when I got my current lathe I bought another Bison 6-jaw Set-Tru for it.

Sanou seems to be a newish chuck manufacturer, well at least the brand name. From what I seen they seem to better than most other China chuck manufacturers. I actually bought a couple of 3-jaw chucks by Sanou & they aren't too shabby. Can still tell they are China though. That didn't matter to me though, they are micro chucks, the kind that use tommy bars. What's interesting is that they did not come with OD jaws but the jaws can be used in reverse for OD due to the way they made the scroll teeth on the jaws. I'm curious if your chuck is like that too. But I've never seen larger chucks that can do this. I'm thinking that may just be a common feature of micro chucks, I'm not sure.


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## ErichKeane (Mar 2, 2020)

I'll take pictures when I take it apart I guess   Unfortunately Set-Tru/etc stuff for an L1 taper is INCREDIBLY expensive and rarely comes up inexpensively.  I thought that $200 for an 8" 6 jaw was pretty cheap and have a spare backing plate so I am going to give it a shot.  Worst case I'll have something for when/if I ever do hollow tubing.


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## mikey (Mar 2, 2020)

Higher end chucks will have removable jaws. My Pratt and Rohm chucks have them. Cheaper chucks tend to have jaws that can be reversed. Not that that's bad; it just means if the jaws are damaged then replacing them will be harder.


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## mikey (Mar 2, 2020)

ErichKeane said:


> I'll take pictures when I take it apart I guess   Unfortunately Set-Tru/etc stuff for an L1 taper is INCREDIBLY expensive and rarely comes up inexpensively.  I thought that $200 for an 8" 6 jaw was pretty cheap and have a spare backing plate so I am going to give it a shot.  Worst case I'll have something for when/if I ever do hollow tubing.



Best thing to do is to buy a plain back adjust-tru and make a back plate to fit it.


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## ErichKeane (Mar 2, 2020)

mikey said:


> Best thing to do is to buy a plain back adjust-tru and make a back plate to fit it.


Even beat up ones in a useful 8-10" size seem to be worth more than I spent for my lathe   The backing plates are actually quite challenging to make for my lathe between a taper, a threading, and a keyway.  Perhaps I just need to buy a shaper first...


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## darkzero (Mar 2, 2020)

mikey said:


> Higher end chucks will have removable jaws. My Pratt and Rohm chucks have them. Cheaper chucks tend to have jaws that can be reversed. Not that that's bad; it just means if the jaws are damaged then replacing them will be harder.



Oh, so they do have larger pinion type scroll chucks where the one piece jaws can be reversed? All the China chucks that I've had in the past with one piece jaws couldn't, they came with a set of OD jaws. I've always wondered about this. With my limited experience I've only seen this on those micro chucks I got.


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## mikey (Mar 2, 2020)

darkzero said:


> Oh, so they do have larger pinion type scroll chucks where the one piece jaws can be reversed? All the China chucks that I've had in the past with one piece jaws couldn't, they came with a set of OD jaws. I've always wondered about this. With my limited experience I've only seen this on those micro chucks I got.



I have two Rohm chucks with reversible jaws so yeah, they make them. It takes careful machining to make it work. I sold my Samchully chuck and it also had reversible jaws.


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## mikey (Mar 2, 2020)

ErichKeane said:


> Even beat up ones in a useful 8-10" size seem to be worth more than I spent for my lathe   The backing plates are actually quite challenging to make for my lathe between a taper, a threading, and a keyway.  Perhaps I just need to buy a shaper first...



Yup, adjust-tru chucks are big bucks and the 6 jaw variety is even more so. Here is one that you could adapt a back plate to that is in nice shape but there is no denying that they're expensive.


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## darkzero (Mar 2, 2020)

mikey said:


> I have two Rohm chucks with reversible jaws so yeah, they make them. It takes careful machining to make it work. I sold my Samchully chuck and it also had reversible jaws.



Thanks Mike for fullfilling my curiosity! Ah, so is that how another Mike owns a wonderful Samchully chuck? You are the only person I have ever heard of owning one. I drooled over them for a whille.


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## mikey (Mar 2, 2020)

darkzero said:


> Thanks Mike for fullfilling my curiosity! Ah, so is that how another Mike owns a wonderful Samchully chuck? You are the only person I have ever heard of owning one. I drooled over them for a whille.



Yeah, I had too many chucks for just one lathe. After I bought the PB 6 jaw, I figured I needed to get rid of at least one of them. I wanted it to go to someone who could use and appreciate a really good chuck so I sold it to Aukai for what I paid for it. That chuck was only lightly used to hold something in the 1" OD range; it was silky smooth in that area. The outer parts of the chuck weren't even broken in yet so the jaws were tight. It was a very nice, very high-end chuck that went to a really good guy who just happens to be making a back plate for it right now!


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## NCjeeper (Mar 2, 2020)

I got my 6 jaw fro this seller. I got a D1-4 back plate for it and dialed mine in using the back plate. I have been please with it. It also has reversible jaws. 








						8" 6-JAW SELF-CENTERING  LATHE CHUCK w. top&bottom jaws, L00 adapter back plate  | eBay
					

Find many great new & used options and get the best deals for 8" 6-JAW SELF-CENTERING  LATHE CHUCK w. top&bottom jaws, L00 adapter back plate at the best online prices at eBay! Free shipping for many products!



					www.ebay.com


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## Shootymacshootface (Mar 2, 2020)

NCjeeper said:


> I got my 6 jaw fro this seller. I got a D1-4 back plate for it and dialed mine in using the back plate. I have been please with it. It also has reversible jaws.
> 
> 
> 
> ...


Yup, me too, but I got the 6". I'm very satisfied with my Sanou. That is the only company offering affordable L00 backplates that I could find. I now have bought 2 from them.


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## darkzero (Mar 2, 2020)

Me three. The 6.3" 6-jaw I use on my rotab is from them so I purchased mine without a backplate. That seller is CME Tools. Mine is not a Sanou, says CMEC on mine. I have purchased a few things from them through ebay & direct from their website. Sometimes it's cheaper to go through ebay, sometimes cheaper on their website (total with shipping).


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## Aukai (Mar 3, 2020)

I hope I can get my backing plate to be good enough for the quality of the chuck it will be mounted to. A tall order indeed. And Messy....


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## mikey (Mar 3, 2020)

If you guys want to see a nice chuck, have a look at this one, a Kitagawa 3 jaw, 7.5" plain back chuck. There are several chuck makers who make high end chucks that go on high end lathes. Samchully and Kitagawa are two of them and they make some of the finest chucks in the world, although most of them are powered chucks for CNC lathes. They do make chucks that are reachable for mortals and this is one of them. I'm guessing it saw little or at least reasonable use judging by the pics. 

RandC tends to price high but does take offers. I would guess this chuck would go for maybe $400-425, and it would be worth it. I would make sure the jaws are reversible, which they should be, but this is a really nice chuck in nice condition. If I didn't already own more chucks than any decent human should own, I would buy this thing.


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## Alcap (Mar 3, 2020)

Newbie question here:    Say you have a 6 jaw chuck and your having problems holding a piece that would have worked better in a 3  jaw , you have a 3 jaw but the thought of swapping heavy chucks around for one job , could you run the 6 jaw with 3 jaws removed ? (Take out every other jaw )


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## darkzero (Mar 3, 2020)

Alcap said:


> Newbie question here:    Say you have a 6 jaw chuck and your having problems holding a piece that would have worked better in a 3  jaw , you have a 3 jaw but the thought of swapping heavy chucks around for one job , could you run the 6 jaw with 3 jaws removed ? (Take out every other jaw )



Yes you could. I personally never needed to. Well I have on my old lathe but it was so I could have more room to measure the thickness of the part while machining without having to remove the part from the chuck. My chucks aren't heavy so I would just swap them but mainly cause I wouldn't want an open slot where chips could easily get into.

However I do this for the chuck for my RT sometimes (again for clearance). Except that I just remove the top jaw instead of removing the master jaw (quicker).


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## Alcap (Mar 3, 2020)

Didn't think about some having jaws that unbolt !   Didn't want to hijack the thread but my wife's uncle who's retired asked if I wanted a 6 jaw chuck a week ago for $200 , no back-plate  , he didn't remember what brand but said " it's a good one "   he did work in a tool and die shop , waiting for him to get back to me with the brand .  On the fence if I should buy it .


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## ErichKeane (Mar 3, 2020)

For the outside jaws, worst case I can Grind the current jaws into softjaw bases and just use bolt on reversible soft jaws.

@Alcap  unless it is chinesium or a 3" chuck, $200 is worth it. If it was big enough for my lathe, i would take it sight unseen


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## ErichKeane (Mar 3, 2020)

So, I just watched this video: 



 about the set-tru style chucks, the one thing that stuck out to me is the size of the set screws.  The chuck I bought only has a 5mm register, so that obviously wouldn't work.  However, I would think I could bolt an 'adapter' to the back to make it work.  Now that I've seen it, I think I have my 4 jaw already attached to the back of a true-adjust back plate, except with an adapter to make up the register!  

I wonder if I should just mount my new backplate (that is flat) to my 4 jaw and see if I can create something to make my 6 jaw into a homemade true-adjust.


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## mikey (Mar 3, 2020)

That might work but you'll have a fair amount of chuck overhang. Plus, with so many interfaces the chances of something moving under load are higher but it might work for light work. OR you could return the 6 jaw and get a real set-tru chuck ... $$$.


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## mksj (Mar 3, 2020)

I would check the chuck first and then decide where to go with it. If off, you would be better off taking a little off the back plate registration step and using the tap method. I have three set-true type chucks, one which I made. They tend to stay within spec. which is usually 0.0004" over most of the scroll range or collet variation. If it is slightly out, you can nudge one of the adjustment screws and compensate easily. The adjustment screws are 12mm fine thread with flat heads, you need a deep registration step for these types of chucks.

I do recall a few postings for the Shar's 6J Scroll Set-Tru version chucks with 2 piece jaws and they were satisfied with their performance.  They were less than 1/2 of the comparable Bison, Rohm and PBA types.





						6" 6 Jaw .0005" Adjustable Universal Chuck 2 Piece Jaws
					

Shars Tool




					www.shars.com


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## ErichKeane (Mar 4, 2020)

So, I remembered why I did the offset-ring on my 4 jaw   My 4 jaw has 4 bolts really close to the center that end up being in the way of the L1 taper with a normal backing plate. 

I also worked on my 3 jaw.  The jaws closed properly, but runout measured at ~.025" (yes, 25 thou!).  I tried tapping it, but as soon as I would tighten it down it went right back.  SO, I pulled it off the backing plate and realized the register was ~3 thou too big!  So I was clamping oddly on the chamfer I think!

I re-faced the contact surface (I used cutting fluid last time, which made the finish horrible), then turned the center section down a little more than 20 thou, so I would have adjustment room.  I re-mounted it, and indicated it in to a little more than 1/2 thou (touched both lines of a 1/2 thou indicator) at 3 different diameters!

I figure I'll try to do the same with the 6 jaw, but I'll have it for the situations where I've currently been abusing my flex collets, which is stuff I am afraid to clamp in the 3 or 4 jaw. I can keep the collets for when I need an accurate center   BUT, probably won't be doing a home-brew adjust-tru.


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## ErichKeane (Mar 7, 2020)

Got it yesterday so unpacked it today. It is of surprisingly good quality! I opened the back, and it seems to lack the common chinesium grit that most do. I cleaned it a bit, oiled and greased it, then put it back together. I turned down the backplate about 10 thou under so I can dial it in later.

The backplate is a cheap one (less than $100 for L1 apparently means Swiss cheese!) And I was able to find a place to drill the holes. Dinner bell rang right as I was setting it up in the mill!


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