Thanks for the video. I am not an experienced machinist, I am a mechanic with a lathe, but I have used this Chinese type equipment for 25 years, and I have a couple of these cheap 4 jaw chucks in different sizes. In my experience these Chinese 4 jaw chucks have a "master key hole" and a key hole that is really not usable. So when you get it, first thing is to test runout using each key holes, find the best one, mark it up, and always use that one. I have no logical explanation for it, but it makes a major difference in repeatability and precision, I have a runout of less than 0.01mm on these. And sorry for my English, your videos have reached as far as Denmark :-)

I think you have just about wrung that chuck out. Thanks for the video keep on keeping on.

Great video. You could have gone deeper in the backing plate by drilling three new mounting holes. Replace the standard socket head cap screws with low head height socket cap screws. These are a standard fastener from Unbrako. There is another way of restraining your chuck jaws prior to remachining a three jaw chuck. Drill a hole in the front flat face of the jaws. As the jaws are reasonably tough and hard you will have to use a carbide drill. Since your chuck is small a 6mm hole (or 1/4") should be sufficient. Fit a Grade 8.8 pin into each of the three holes. Make a restraining ring from flat 6mm plate. Drill three 10mm holes in the plate at the radius to suit the grind ID. The chuck can be preloaded before maching. The ring is self centering. I saw on a video from either TL or RR that for best accuracy always use the same tightening point. The chuck's centering accuracy changes if a different hole is use. Same hole for grinding and normal use. Hope this helps. Cheers.

Great video,Mark.Lots of surgery.It got better but I will not expect lots of precision from a 4 jaw chuck.Thank you.

The thing about scroll chucks, 3 or 4 jaws, is that the thread of the scroll is what really determines its ability to center work. You can grind/bore the jaws and make it better, if there is an issue with the jaws. However, there will always be runout and it will vary by work diameter. There might be diameters that have zero runout and diameters with .015" runout because the scroll thread is not precise. Given your intended use, I am sure it will work fine.

Thanks for the shout out. I guess that's what we get for buying budget tools, they always need a bit of finish machining. Can't be sure of this, but I think clamping round stock in a 4 jaw relies on the stock being perfectly round, if not one jaw will not be loaded as much and the runout will get worse. A 3 jaw has to load all three jaws the same by comparison. That should be a nice useable chuck now. Good job!

Hello Winky, thanks for another interesting video and for sharing your skills with us, much appreciated, cheers from me. 😃👍👍👍👍👍

At 4:10, You could install 3 more screws/bolts with thinner heads in between the current-original bolts if you really want to push that back plate deeper into the chuck, basically stop using the original holes, or, put some short studs in the original holes as alignment pins. If you truly get deeper, you could make your chuck a "Set-True" style of mounting/alignment possible. It appears that by the end of the video, you had come to my same conclusions. Thanks for making this video.

Very interesting. Nice work. Never thought of removing the dust guard.

WHAT A GOOD JOB OF ELIMINATING CLEARANCES IN THE GRINDERS EVEN THOUGH THE HEAD ALSO HAS A LOT OF FAULT. THESE CHINESE FORGET THE PRECISION

Great video winky, keep'um coming..

Very interesting thanks.

I did exactly this when I mounted my 4 jaw chuck. I have a video of the whole process on my channel. I have used the chuck quite a bit over the years. It comes in handy for square stuff. You could get around your bolt hole problem by just drilling 3 new holes in the backplate.

Good job Winky

I mount my router on my lathe tool post and grind my 3 jaws with a vitrified stone. usually get to a couple tenths. I have used the same stone for many chucks for many years. The mount took a couple days to make. It has proven useful for grinding internal bores too.

Nice work, I've only ever seen chucks ground with a tool post grinder. Interesting method I would of never thought of that due to the interrupted cut. I was waiting for the insert to break. Nice job

I, like you, have several Vevor products. I have learned to disassemble everything from them, degrease and clean them in my Vevor ultra sonic cleaner to remove all of the machining and casting grit, then debur and reassemble using a good quality grease. Some of the inaccuracy you are seeing maybe caused by a bunch of crud inside. Another great video. Thanks.

I have only purchased a couple of Vevor items & they do look to be very well-made. I did by a 3 jaw Vevor chuck only to find that one of its jaws was not a match with the other two. Got it because I had purchased another Chinese 3 jaw & left it in its box too long & the warrantee had run out, then when I went to use it the body was terrible & it was all over the place. So I had another set of jaws & with these fitted, the Vevor chuck is very good. You certainly can not machine that bad jaw & get it to fit.

Looks good . JM

Good one Mark, I just did some regrinding on an independent 4 jaw.. That's another deep rabbit hole Dust cover elimination is good idea. ATB.....

wonderful Mr Winky, Paul in Orlando

Winky, generally with quality chucks, the key hole that was used to finally tighten the jaws when the factory ground them is market with a x or number. If you always use that hole to tighten the chuck will be at its truest, due to any scrol sideways movement. When you do /did yours adopt the same procedure. Sharpie mark the last hole that you tightened the jaws to grind. Then put a permanament mark and always tighten the chuck using that hole. Good luck. Regards from Australia.

Most of the chucks I used at work had master jaws which were hardened and ground for precision work. The change out would be for soft or harden jaws depending on the job requirements. They were keyed at their bottom. Even those jaw would require grinding, to re true the jaw. I know what you're going through, because I have a 13" South Bend lathe, which I bought a 4-jaw chuck for and I to, tooled out the jaws to achieve less runout. I often see .003 " TIR. and am satisfied with that on the lathe. Unlike the precision grinding equipment which I definitely was working in .0001 - .0002 " TIR. when setting up a job.

wow, great vid! thanks

You could put new bolt holes in the back plate and use flat head Allen head screws and locktite brass plugs in the old holes. That would look good.

I've seen Mark Presling use a vernier caliper designed specifically for scribing. They're inexpensive and readily available from Amazon or AliExpress. I'd like to get one, but the inch vernier scale is in 128ths, which to me is just silly. I'm mulling over ideas for modifying an inexpensive digital caliper to have a similar configuration.

Just a thought. Before you make another chuck backing plate, first make a copy of the spindle. that way you can check the fit without taking the chuck off and trying to start the threads of the new backing plate onto the spindle. I just made one out of plastic. works well.

I would never put this much time and energy into a new product. Send the junk back. Life is too short.

We all hope for tool room precision from bargain priced chucks. A bit of time can turn that bargain priced lump into a serviceable chuck. Nicely done.

Hi, would it be a good idea to put registration marks on the chuck to backing plate? Rich

Interesting. Not an independent four jaw chuck. I don't think that I have any like that in my machines. All the four-jaws that I have are independent. Well, you made it better. That was good. 👍

Just an idea, could you have faced the existing dust cover down to fit the smaller gap and then glue it to the backing plate?

Using the little plates between the jaws was hod did my chuck too. It works perfectly fine.

Mr Winky, not sure how a self centering 4 jaw Chuck is desirable, would have preferred a standard 4 jaw especially as it is a low cost item, also surprised that those jaws are not hardened

Big improvement, well done. I am just curious, did the hardened jaws blunt the carbide insert? Dave.

At 20:44 you conclude the scroll is the problem,. I agree - it’s a cheap chuck and that’s the best it’s going to get.

i tru my jaws the same way but i machined the face of the jaws in the closed position so i can use a steel bushing took me from .004 original runout to .0005 after. best of all no grinding only slow and carefull machining

I have both a Vevor 3 and 4 jaw chucks and both are way out. They advertise as to how accurate they are when they really are not very accurate at all. My collet chucks are really accurate, well at least a lot better than the 3 and 4 jaw paper weight chucks that I have. Perhaps I should try this process on my chucks, I don't use them that often but when I do they only cause problems. Any improvements that I can make would definitely be a plus.

Thanks for the video and happy for your success to make it a better product. Many people have given their opinion on how to do things to make it more accurate. Vevor is a company for cheap products and therefore just average quality in my opinion.

Excellent 👍

have you tried lightly snugging chuck, then rotating bar until you feel resistance, then do your final tightening? I find it helps on my 13" SB...hope this helps, Paul

Robert Shaw [Quint] would love how you are taming those Jaws........you may need a bigger Lathe

one question, have you put an indicator on your spindle ??? is your lathe a 9 or 10 SB ?

Hay buddy I think you missed something ! when removing the dust cover you left the end of the scroll gears able to twist a bit... this will cause them to bind and the chuck will not be as tight as you think it is... yes it's a cheap chuck but you made it worse by removing the dust cover.... the dust cover has protrusions under it that support the end of the scroll gears so they can't twist out of alignment and bind.... you removed that so now they can twist and bind and worse move UP and allow the tightening gears to slip. so you NEED to weld in a metal piece to the chuck to do that now something to support the end of those scroll gears if you use it like that very long it will eventually ware out the scroll gears because they are forcing themselves out of the teeth when you tighten them down. maybe a drilled out nut welded onto the center column of the chuck would do it, I don't know but then you would not be able to get the spryl gear out to clean it good.... I think you worked yourself into a pickle this time.... putting the dust cover back in means making a new back plate.... but I think that is your best option in this case. sorry for the bad news but you have 3 options put it back the way it was, weld on some gear supports to the chuck, or use it like it is and hope it will last ! perhaps you can figure out another way to support those gears eh ? but they need to be supported on the far end !

Taking the dust cover out might make things a little worse. You are now going to have a gap between the mounting plate and the chuck inside the bore. As a result, you could easily end up with small chips getting into the pinions and scroll gear surfaces.

Why not drill new holes with countersink screws?

Good work Mark. But you have a habit that bothers me… you slow down the chuck using your hand as the brake. When you did that with the hose clamp flying round I could see the possibility of a badly torn hand - and that might slow your video production! Bad news for all of us.. Take care my friend, safety third, and all that👍 Les in UK 🇬🇧

Why not put 3 new boltholes in the backplate. Seems enough space to me ;-)

Excellent job. You made an accurate chuck out of a so-so chuck. Jaws are probably about 45 Rockwell C.

Or you take off as much as you would need for the plate to sit down all the way and drill three more holes to fasten the plate to the chuck.

Man I almost bought one of those crummy chucks.

The innermost faces of the external jaws are not designed to be used. This is why they were not finished machined and had so much runout. Self centering 4 jaw chucks are not meant for round parts. Round parts will only clamp properly on two opposing jaws. The jaw faces on the external jaws should be flat, not machined on an arc. Otherwise now they will leave marks on any flat faced parts that the chuck was designed for.

Have you ever put your test bars (at least the smaller one) in a collet and checked for runout in your bar? That way you know where you stand with the bar when you use it.

Why just do a new bolt circle and no counter bore this time?

As you said a self centering 4 jaw hast the same Problem like a chair, they are prett good when you want to machine square stock

Mark I am trying to understand what the advantage of having a 4 jaw scroll chuck is? I understand the advantage of a 4 jaw adjustable but not a scroll.

I am not a machinist, but I have a question: Wouldn’t the runout change based on where on the internal screws the jaw is engaged? Meaning that if you chuck a 1” bar, you get one runout reading, but if you open the jaws a little, engage a different area of the internal screws, and chuck a 1 1/4” bar, would you get a different runout?

Hi, can do you show de concentricity of this plates and put a bar to see it too?

Now unless you're clamping precision square stock, the exact dimension of when you bored it... It's completely useless.

With all due respect it's a silly chuck. A 4 jaw with a scroll? No! A four jaw that's worth having has individually adjustable jaws. The idea is for clamping on odd shape work and or being able to dial in greater precision than you can get on your 3 jaw. 6 thou runout to me would be worthless. More than 1 thou is not useful to me. 3 jaw chucks with scroll tension and even better if you can get one that allows you to adjust to fine tune the center. My 3 jaw has three possible mounting positions, the best giving me half a thou runout which is acceptable. I used a punch to mark that best position. Same with mounting my ER collect chuck to the lathe. No offense but I would scrap that chuck, or find some other poor soul to give or worse sell it to. It's really hard to believe that the manufacturer thought it was something worth building.

Why would you buy a 4 jay chuck that doesn’t have 4 jaws that are not Independently adjustable. That’s what there four😮