MACHINE SHOP TIPS

Tubalcain shows how to grind the jaws on a lathe chuck. These jaws are bell-mouthed and untrue.

[@77.88.]

Thank You Mister Pete for all your knowldge and HELP! Regarding lathe Jaws grinding fixture ?Machine shop program at Yuba College, Yuba City California Circa 1975; Use a 3/8" thick steel plate cut the outside circle maybe 8" in diameter locate the center and drill and bore the center hole slightly larger than the jaws inside edge inside diameter which would be larger than the jaws clearence depending on the size of the cutting wheel? Next you need to scribe a circle maybe 1/8 larger from the jaws clamping surface. Next you need to bore three holes at 120 degrees so they each intersect on center each jaw, when cut out each circle you can clamp the jaws down on the fixture and it is perfect you can grind all three jaws parallel and is really simple to make perfect like new jaws. If there are any questions I can make a simple drawing and send it to you, please note my dimentions might be wrong as it has been 50 years since I made the last one taught to me by the Machine shop instructor MIKE that was the states transportation machinest. Most sincerly your 81 years old apprentice, Raymond Brown

[@mrpete222]

Thank you very much. Good idea

[@ikesquirrel]

I just ground my chuck jaws last night. I used the flex shaft on my dremel and zip tied it to the tool post. It worked great! The chuck used to feel squishy when tightening and the work could wobble around. I am the 3rd owner of this lathe and the jaws were bell-mouthed but still tight in their slots. A previous owner used a pipe on the chuck key because it's s-shaped. It took a while to grind them, but the end result is a chuck that is no longer squishy and it holds stock firmly. It's good enough for the stuff a 3 jaw is used for.

[@mrpete222]

👍👍👍

[@markgrevatt4867]

Hi Pete you never cease to impress me with your experience on lathe's and how to get out of difficult problems. As well as resolving them. So glad to learn a great deal from your channel. Really am grateful to you for these wonderful teaching training videos. Thanks so much Pete hope your having a wonderful day. My friend.

[@mrpete222]

Thank you very much

[@KeithFenner]

Thanks for this video Mr Pete, I had intentions of doing a similar demo and of course my jaws on the Clausing are needing the same care once again also. Thanks for taking my self induced pressure off! You did a great job and the community of viewers of our machine trades group, needed this demo, I had been asked many times for my take and just hadn't got a round to it! LOL ;{)------

[@coollasice4175]

looking forward to seeing the chuck disassembled.

[@mrpete222]

Thanks Keith--I guess I beat u to the punch. Thanks for all your videos & the plugs you have made. pete

[@JosephLorentzen]

I think this even helps those of us with wood lathes. Thanks

[@mattwilkins1597]

Keith Fenner We still expect you to do your four jaw this year. :)

[@ypaulbrown]

great answer Keith, hope all is good on the Cape, cheers form Florida , Paul......Lyle, your video is awesome......still late for class, but better late than never......

[@edkobus9349]

Love all your instruction Mr. Pete!

[@agylub]

Thanks so much for sharing your knowledge and taking the time to make such an informative video.

[@richardkicklighter1202]

You could always do a standup comedian routine. Be sure to take the misses out to dinner to hide your guilt. She ALREADY knows everything you used with her household things: alphabetically, cronogically, and, in order of decending importance since she has let you have a shop. God Bless!

[@vajake1]

I have read about this procedure but never saw it done! Thanks so much for posting this video!

[@KingLoopie1]

'sneak the towels into the laundry'... Either she's a very understanding wife, or she already knows you're hopeless, or you just like to live dangerously... 👍

[@mrpete222]

All three of the above

[@wileecoyoti]

I've been trying to figure out a good way to do this, this is perfect. Thank you!!

[@MaturePatriot]

I think I would put my shop vac hose near the open end of the headstock spindle, and suck the dust away from my work area, and lathe surfaces. Then clean out the spindle after the process. I watched an individual machine the jaws with a boring bar on another channel. Great job. The jaw bearing surfaces looked great.

[@pierresgarage2687]

Very comprehensive video, like always. I've seen most of your videos and learned a lot from it. One thing I found out, that sometimes when run out becomes an issue, the scroll gets dirty with little grits of metal and other stuff, at this time disassembling the chuck and a good cleaning improves the run-out situation. The only thing I might suggest, is maybe to clean the whole chuck prior to the truing of the jaws, question of putting all chances on our side to start with. Because of fabrication tolerances a 3 jaws chuck never gets 0 run-out on it's full range of operation, unless you pay shitloads of cash for the ultimate chuck. Good thing I'm not your wive, You would sleep on the couch for a long time, at least until you stop snatching stuff from her, imagine drying yourself with a gritty towel after your shower... Scratch... Scratch... Scratch... Wearing out our Mr Pete. Thanks again for your commitment. Pierre

[@livinlifefishin]

Very informative and very well explained. Great work. I really enjoy your videos.

[@t.d.mich.7064]

Hey Lyle, I find that when the jaws are in bad shape, it's because the scroll gear is worn along with the jaw guides machined into the chuck. In other words, overall wear of the chuck. Grinding the jaws will be exact only in the position they are ground at. Sometimes the jaws wear at the outer ends because the slop in the chuck allows them to get cocked in the guides. The best defense is to always cover the length of the jaw with your workpiece. Gripping on the end of the jaws only causes problems in the future. Thanks for the videos, I look forward to watching them.

[@Bread996]

Excellent tutorial Mr. Pete! I need to do the same thing to my chuck jaws. You'll find that if you clamp a part with a diameter that puts the jaws in the same position they were ground, there will be no runout. But just like you said, the worn scroll will affect the runout differently in different positions. Nothing you can do about that, but the bellmouth is the main problem and you fixed it beautifully.

[@larrypeterson4945]

Thank you for the careful effort you put into these demonstrations. I am using this technique to true up a rather new 3 jaw chuck. Best wishes, LP

[@dawnconti2964]

I just spent a few days trying to ture up an old south bend 13" swing lathe. A work piece would run out about 18 thousandths. It is a Babbit box head stock. I was sure that the head stock AND the chuck were to blame. I made a girdle, much like a steady rest to fit behind the chuch. attaced by-way-of a welded bridge from the ways to the ring that was used as a steady rest.( to clamping devices, nothing welded to ways.) Screws with balled ends ran onto the back shoulder of the chuck plate. i dialed down the screws till the spindal ran true. With this arrangement in place, i re installed the screw on chuck( Cushman 6") The indicator on the work piece was all over the place. I decided to grind the jaws. i jiged a die grinder to the tool post and went very slowly and carefully. Things improved, so i believed that i was on the right track. Back to the head stock. Removed girdle adjusted headsock with shimming and tourquing. Re-ground loaded jaws( forgot to mention that) We now have the work piece running at 3,1/2 thousandths. I never thought i would see that tolerance from this old girl ( about 1935) I just want to say that ALL of you men posting throughout youtube. have been a tremendous help through your teachings . I never attempted to grind jaws in my life. I developed the confidence to try, because of watching several of the video1`s that you men created. Thank you gentlemen. You all helped this lady to a successful result.

[@millomweb]

Always worth checking everything is correctly assembled first - including the jaws being in their correct slots in the chuck.

[@piotrlenarczyk5803]

Thank you for video. 20:45 As far as I know, turning between dead centers with rests at single mounting, provides best results for many reasons. 2/3/4/6 jaw chucks are mainly convenient (cause of making proper center holes) - it is theirs main advantage.

[@kwd57]

Great video, looking forward to see how much of the chuck you can take apart and clean.

[@engtech10]

I had this bell mouth issue on the center of a 4 Jaw chuck. I used a large outer bearing race ring to load the jaws on a outer chuck step. Center Indicated the race ring and ground the bore much like you did and now both steps are true to each other.

[@TheWreckingYard]

Nice work, one tip i heard some time ago was to use tin foil to protect the bed, far far less likely to be snatched by any rotating parts and friendlier to the spouse :)

[@tansit2344]

I love those little Rayovac LED pen lights! No fancy batteries, bright enough, and they seems to run forever.

[@Patroand]

Hi Mr.Pete. Thanks for this video. It confirm my thought that I had to do that. I don't have the socket screws on the jaws. I dit tighten the jaws around a piece of aluminum set in the back of the jaws. Behind the highest point there is a flat surface on which we can place a round pièce stock. When squeeze firmly, the jaws can be grind. It really have to be done on this old chuck. Mine is a Burned 3 jaws chuck. I wanted to buy new Jaws from Burned but it is too old (1952 the says.) I am around 2-3 thousand runout at 3 inches with a 1 ¼ " round stock. I wait to see how to clean the chuck now.

[@mrpete222]

Mine is a Bernard too, from 1970. Its pretty worn

[@mikeadrover5173]

As always, thanks’ for taking the time to make this video! And I support this site. ~M~

[@TBJK07Jeep]

Hey Mr. Pete. I’d say the washer is a Machine bushing. My local hardware store has them only in 18 gauge & 14 gauge. The 10 is for 10 gauge as someone else mentioned. Getting ready to grind in our bell mouthed 3 jaw.

[@bcbloc02]

I believe the 10 on the washer is referring to its gauge thickness or about .135". This is a great video.

[@nadam35]

fantastic video, always nice to learn methods like this

[@keylargo70]

I have done the grinding and used soft jaws. I really like the soft jaws because they are much easier to true up. Just load them the same way and clean them up with a boring bar. No grinding dust and way faster, only down side is you have to have removable top jaws. Also for small thin parts you can custom fit them to the part.

[@rick6582CNCMedicalParts]

I agree .Faster & no dust inside "ways" also ." Lots of ways to skin a cat ..best

[@djpaulk]

Another fine video Lyle!

[@Etiennevisvang]

Excellent explanations. Thank you.

[@jamestregler1584]

Always knew of the problem , thanks Pete. From Old New Orleans 🤓

[@Panzerzimmerpflanze]

Great video! It wouldn't eliminate the need to clean after, but a big shopvac rigged to a scoop surrounding 1/2 or 2/3 of the headstock would help contain the dust considerably. On occasion I've even rigged one to the back of the carriage and it's helped a lot.

[@daveupndown3074]

anouther great video , I never miss one .

[@kencurtis508]

Great video, thanks.

[@happymark1805]

Nice video, when I did mine I used the washer method using a washer in the back and removed a little bit out of the back were the washer was, but this is a much better way

[@tnekkc]

There was more than ONE thing aggravating me about the Clausing 5913 that I owned for 10 years. The variable speed wanted to slow all the way down. But I love Pete's sense of humor.

[@nlo114]

I have been looking for this for a long time now. My 5" 3-jaw Bernerd definitely needs this doing. I think putting the shop-vac over the end of the spindle-hole should help stop excess grinder-grit throw-off going in the important bits. I can run a flue-brush back and forth through the hole afterwards to help dislodge any bits, and suck 'em up. Thanks for the idea!

[@mrpete222]

+nlo114 Thanks for watching

[@SuperJack1953]

Thanks for your idea

[@nedt]

Thank you mr pete for another great video. Im looking forward to your chuck dissassambly. I had a look at your shop fluids video but I couldn't find what oil you use for general use around the workshop for rust protection and lubrication, Do you use anything specific? Or can you recommend anything? Thank you again from a younger generation that isnt stuck to the TV playing mindless games.

[@PaulWattsSpringGunning]

I soak my grinding wheels with honing oil. I use Sunnen MB30 honing oil before I grind with them but I'm sure there are other grinding/honing oils that you can buy in smaller quantities that would work. It greatly cuts down on the amount of grinding dust that is thrown in the air and inside the chuck when grinding my jaws and other work in the lathe. It also grinds much nicer. Hope this helps and many thanks for the videos!

[@isoladeipirati]

A Super video about grinding Jaw chuck. Ciao grazie

[@AmateurRedneckWorkshop]

I needed a 2 cycle engine rod of a larger crankshaft diameter than was available one time and I chucked up a suitable rod and used my dremel tool fastened to the compound to resize the rod. It worked but I always worried that I got grinder dust in my lathe. Great video. I have made a few videos lately and I have great admiration for your video making ability. I did not realize it would be so hard to do.

[@mrpete222]

Thanks--you are right, its not real easy.

[@blmeflmm66]

Very interesting technique. And obviously pretty darned effective too. I wonder if you could put a piece of PVC through the spindle and connect it to a shop vac for dust reduction. I'd probably clean out the shop vac first for fear of a spark igniting lint and house dust, though. Just a thought. Keep up the great videos.

[@TheThorgoesinya]

Awesome! Thank you

[@mclarpet]

Great video. I am glad that you mentioned wear of the milled slots, the jaws and the false jaws are hardened but the chuck body is not - heck it might not even be steel.

[@rotlerin]

Of course it's steel, it's made in UK. What else? LOL. Cheers

[@TheBergy32]

Great video! I love this sort of stuff. You may want to look at reversing the rotation of the motor on the grinder.

[@TheBergy32]

Now that I think about it, reversing the motor probably wouldn't work for that application. It would probably also affect how it vents. Thanks for sharing.

[@millomweb]

@@TheBergy32 No reason not to have the grinding wheel go in the direction you prefer. It would not affect motor ventilation as the fans are bi-directional for the obvious reason the motor manufacturer doesn't know which way you want it to rotate (or both!) It's why they use simple centrifugal fans.

[@michaelidarecis]

Always like your videos there are two things to consider from my experience grinding jaws. One is that to also check diameters that are greater than what you had done the grind with think you said 1-1/2". Being that if there is some problem with the way the chuck was mounted the jaws would have a greater grind on one or two of the jaws andd when you put in smaller stock then you are on the flat of the inside center however when you have larger diameter work then the ends of the jaw hold onto the work and if one or two jaws have a deeper grind then the work can be out as much as .010. Had this happen to me on a Cushman chuck and until you look at the amount that was ground off and compare you might totally miss it. Second if scroll part of the chuck is bad then use soft jaws for an important diameter that you might be machining all the time. For me it is 2" and 3" brass. Am always turning that so one set of chuck jaws is machined to 2" and 3" and if there is something else that needs to be done either use a different set of soft jaws or the regular master jaws.

[@dogpaw775]

good simple tip what to look for when buying a used lathe.

[@clemm17]

Excellent. I need to grind the jaws on my 16" 4 jaw chuck. My biggest concern was how to center and pre-load. This gives my many ideas.

[@millomweb]

I take it that's not an independent 4-jaw chuck ?

[@CruickshankEngineeringNewick]

Just what I have to do to mine! Bell mouthed jaws are usually caused by turning things between the chuck and a slightly offset tailstock. Because the stock is slightly bent between the chuck and the center, the jaws wear as they come around to the 'inside' of the bend. A little bit of wear each revolution results in a lot of wear over 35 years!

[@gsdtdeaux7]

Keith Fenner blew my mind when he leveled a lathe in one shot with MATH lol the dude is on another level

[@mrpete222]

👍👍

[@operator41001]

Dang Good video Mr. Pete

[@michaelstorm8578]

A well thought out job.

[@mrpete222]

Thank you

[@VTX1800MC]

Good Job Sir!

[@anthonylutz8419]

mrpete thank you for thr information, correcting the jaws, one comment bread996 is that if scroll is bad you can only center so much at that position. Three things you can do buy a new chuck, or cut the back plate guide loose .010" and get a true shaft and align it, or cut a slot on schedule pipe to fit the jaw to clear the jaws needing correction. With a pipe slotted you have even load but still a maybe if chuck is really worn out scroll

[@6h471]

I've used a similar method to true chuck jaws, and it works well, however I think people get the wrong idea about the accuracy capabilities of scroll type chucks. Even a brand new 3 jaw is seldom capable of concentric accuracy inside of .003 at any given diameter, and if the scroll and jaws are worn, much worse than that, varying considerably over the scrolls adjustment range. This method works great to straighten out the jaws themselves, and it will get a 3 jaw very accurate at whatever diameter the jaws were ground at. Beyond that, break out the 4 jaw. Good informative video!

[@mrpete222]

Yes--all very true

[@guyinmorton]

Now to apply the same concept to my 4 jaw chuck!

[@garrydaniels7767]

re dust problem - why not apply shop-vac hose to rear of headstock & suck dust right through the center hole?

[@Kalkaekie]

Good video !

[@krazziee2000]

very good video, thanks

[@ValMartinIreland]

roughly what speed is the grinder spinning at? what speed is the chuck spinning at? Excellent video

[@trevorsmales9303]

You can buy adjustable rings for pre-loading chucks when cutting your own soft jaws, same method as here basically but it's a large ring and the holes for the bolts are cut outs made in a spiral, this gives the adjustability just by turning the plate. I am not sure what chucks they are available for though but maybe could make your own.

[@GraphicManInnovations]

Thanks for the video but.. I think that preloading the jaws from one side (front) is not the same as preloading with a round stock along the jaws length and perhaps thats why there was run out after the fix , before the fix the round stock was not touching in front but did you check if they are in contact at the back after the fix?, i would have used a 0.25mm paper wrapped on a test bar to check if the contact is along the entire length of the jaws or not

[@laylasuzanne29]

Very smart , love these videos

[@mrpete222]

+Layla Suzanne THANKS

[@rysammy]

Thank you very much for your educational videos. If you think about your ring setup a minute or two you will probably figure out why your jaws where out a little after grinding them. The location of preloading your ring is off. Yes, your are preloading the jaws the correct direction, but you are locating off the tapped holes on the Chuck and not the jaws themselves. The jaws locate to the chuck with the ground in step and slot, not the drilled and tapped jaw fasting holes in the chuck. You need to locate off the bolt hole counterbores on the jaws themselves by using a soft jaw boring ring. You can look this ring up on the web. I hope this makes since and is helpful. Thanks again for your very helpful videos and sharing your knowledge.

[@ken9503]

Not so. The scroll determines the position of the jaws, The bolts and ring are only proving resistance in each jaw for the scroll to tighten against.

[@jhareng]

@@ken9503 Assuming even clamping with the scroll it wont.

[@johnohara54]

I'm new at this and still learning. I get the basic idea of what you are out to accomplish and the remark by Mercmad hit the nail on the head about bell mouth . I don't see how you are progressively increasing the diameter of your boring as you go. How do you increase the diameter of the cut?

[@joemcgarry1106]

I grind lathe jaws individually. I like them ground flat, I back taper them slightly to force them to grip hard on the front. Three jaw chucks also wear in the jaw slides. That can lead the the "bell mouthing".

[@mrpete222]

+Joe McGarry Very good ideas!

[@howardtoob]

+Joe McGarry PLEASE tell me how you accomplish this. I have a nice and accurate T&C grinder and I would like to try fixing my chuck jaws using the grinder as opposed to grinding on the lathe.

[@pauljohnson7538]

I did the same thing with a boring bar on my 1929 south bend it worked well must have softer jaws

[@blondin07]

I guess if the final runout is due to different levels of wear on different points on the scroll (ie: different diameters) there's not much you can do about it. I'm wondering if the ring and bolts used to tension the jaws might also be a factor. If the ring OD was at all eccentric or one of the bolts was a wee bit bent the result might be a less than perfect contact between one or more of the jaws and the scroll surface you're trying to reference. Would a machined true and straight ring and bolts that conform to a larger, less worn section of the scroll help to make this operation more precise?

[@177BCardinal]

VERY interesting! What is the minimum diameter work you can now hold in the chuck?

[@biofall38]

is there any other way to make a homemade lathe besides the gingery lathe

[@AnotherWisenedOne]

Without going through all of the comments to see if anybody else mentioned this, I'll make a suggestion to set up a shop vac hose at the left side of the headstock tube and draw most, if not all of the grinding dust away from the lathe. Most shop vacs come with a conical tip for the hose that you can stick into the headstock tube. Randy, the gear headed technoid

[@obfuscated3090]

Dust can be blown away by a powerful fan which any shop should have for many reasons. I recommend "bounce house" fans or similar capable HIGH VELOCITY blowers. Other options could be a large shop vac nozzle very close to the wheel to catch dust. If you put the leg of a pair of panty hose over your shop vac filter it will last much longer and be easy to clean.

[@eddyde115]

+Ob Fuscated Better would be to rig a vacuum nozzle close to the chuck, that way the dust isn't blown all over the shop.

[@davidpeterson620]

That’ll REALLY make your wife mad! 😂

[@BuildSomthingCool]

Great job, I like the way you loaded the chuck. Dale d

[@djpaulk]

Will using this procedure be better for the chucks small work holding ability/repeatability if I use a smaller diameter stone? The method you used with bolted jaws would allow the jaw tips to pull out slightly, causing more grinding to be done at the rear of the jaws, guaranteeing clamping at the jaws outermost tips. Any ideas for solid jaws on a 80mm mini lathe chuck?

[@jasonreis6719]

Mr. Pete. to keep the dressing dust down simply flip your dressing point to the other side of the grinding wheel

[@toddanonymous5295]

Hi Mr Pete, I found the best time to sneak the towels past the wife is when she is brushing her teeth :).

[@mrpete222]

+Todd Anonymous I'll try that. Thanks for watching

[@millomweb]

@@mrpete222 Whizz them through the washer while she's out shopping.

[@nugterenmadalena3467]

Hi Mr.Pete, I want to grind my jaws of my (Chinese) lathe. My chuck jaws don't have the feature of your jaws, (bolts) to clamp the spacer. I have to machine a kind of a spacer where the jaws go a little bit through, and at the same time create a clamping force. I saw recently a example on u-tube of a clamping spacer. My question is, are the dimensions of this clamping spacer where the jaws go through critical? Does the three machined sleeves in the clamping spacer need to be within 1/100 of a mm? Or as long there is clamping pressure on the jaws from the chuck key, it will grind the jaws evenly?

[@secondwindmusicproductions]

At the beginning of the video you stated that you wished the grinder motor went the other direction. I think if you remove the plate that covers the terminals where the power cord goes in, you will find that you can move a couple of wires (the ones for the start windings) to get the motor to run the other direction. You may even find the diagram there to show you how. If not, there is lots of info on the web like here:www.ehow.com/how_6005849_reverse-single-phase-ac-motor.html Greg from Charlotte

[@galenpress9460]

Would the bell mouthing be caused by the front of the jaws getting the most stress during turning? The greatest force would be at the tips, constantly pushing out on them where it would decrease the further you go in.

[@scottcowen4071]

Couldn't you just do an internal cut with the ring holding tention or do you have to use a grinder?

[@ragnarmyhre8270]

I think maybe the runout you see on the indicator is not a runout on the chuck, but a little worn spindle bearing. Because when you put your hand on the chuck to turn it, the indicator moves a little to the left, but it goes back again when you let go of the chuck. But..... thank you very much for good videos. I have an old South Bend model A and I have got many good ideas from you

[@skorkmaz]

Awesome. So how do you grind independent jaws for parallelism? Edit: I don't know if independent jaws need grinding. I just got my new independent chuck. Haven't installed it yet. Sorry if it is a silly question.

[@cpasseno]

Hello Sir! My Atlas (10") 3-jaw chuck is suffering from substantial bell-mouth - and I have no tool post grinder, though I might be able to rig something up. What would you recommend?? Thank you in advance.

[@Mercmad]

I think the bell mouthing is caused by folks chucking up (thin) work in the forward part of the jaw and then leaning hard on the key to hold the work tight.

[@mrpete222]

+Mercmad Thanks for watching

[@garrydaniels7767]

FURTHER THOUGHTS Step 1 - make a baseball size funnel from a cut-down soda bottle or whatever, attach funnel to shop-vac hose and mount on headstock side of stone during sizing so grit is sucked away from tool grinder motor and lathe bed before it spreads. Step 2 - During jaw grinding part, attach shop-vac hose to outboard side of headstock and suck debris out through center hole to protect chuck parts from grit.

[@spanky5476]

I am just wondering is the Grinder motor not reversible ? it may just be wired in such a way ,.

[@jaxxbrat2634]

very nice tp grinder..the back end of the grinder shaft might have a center for the tailstock.

[@johnm9171]

Oh great... Now that my wife heard you using your wife's bath towels I can't find ours.....now they are issued as needed....:( Keep up the great lessons in domestic tranquility lol.

[@jordanrenaud-pq7rx]

Could it be that after many years of use, the groves that hold the jaws have worn from so much loosening and tightening cycles? That is if the fact that the body is truly softer cast iron. Or is the iron somehow harder than the average? Or, at the last...chuck is equipped with hard steel groove inserts?

[@oldpup4810]

The slots that hold the main jaws get worn over time and can cause the bell mouthing as well. Not the scroll but the slots the main jaws run up and down in.

[@DaddyFattyDFN]

Mr. Pete, The runout could be a result of ecentricity in the punched ring and the bolts. I am going to true the 3 jaw at work soon. When I do I will use a turned ring and shoulder bolts and see if that makes a difference in my results.

[@Bread996]

The runout is a result of a worn or otherwise imperfect scroll, nothing else. Grinding the jaws corrects bellmouth, and will create zero runout in that position on the scroll. But once you reposition the jaws all bets are off. Even new 3 jaw chucks have a few thou runout until you get into the high end brands, which cost several thousand dollars for their smallest models. And nowhere did he say his bolts bottomed out on the scroll. Perhaps the small chucks are different, but every chuck I've seen has blind holes for the jaw bolts preventing contact with the scroll. And you wouldn't want to do that even if you could.

[@TheWireEDM]

The runout of that ring or the bolts doesn't affect anything, as three contact points always make a circle and that circles center is defined by the scroll and jaws, not the object they are holding.

[@Guds777]

But is it not possible to reverse the jaws, tight them in center and turn them down (grind them) from outside in...

[@modtwentyeight]

Just saw this - Guards? we don't need no stinkin' guards! LOL

[@mrpete222]

lol

[@chemech]

1.5 mils of runout in a chuck of this style is pretty good - I just ordered a similar 8" import which is rated at 3.9 mils *new*

[@BenButler1]

Mr Pete please forgive my ignorance, but why not just bore the jaws instead of grinding?

[@jaxxbrat2634]

strong bite on the work with a hollow grind

[@jeffreyrstapler]

Did it fix your problem? Or did it spring again ?

[@mechanical1955]

There is another way to do this , use blue loctite on the chuck jaw slides, wind the jaws in and leave to set in the correct position, tighten the scroll against the locked jaws , Blue loctite will give enough to centre the jaws and pre load them ,leave to set some more and tighten again just a bit more to be sure , do your grinding and if necessary heat the chuck in an oven to get the jaws back out , don't get loctite on the scroll or chuck screws , works for 3 and 4 jaw chucks , no clamps needed

[@mrpete222]

Thats a great idea

[@Mesdriver]

No that is crap as well. There wil be no load on the jaw slides. like in the video they need pre load, this way the play in the jaw guide will be in the same position as with a work piece. Much better is to buy new jaws. Inexpensive and this will solve 80% of you problem. Chucks do wear out, like it or not.

[@mechanical1955]

Mesdriver If you at least understood the concept it would help but as you don't you resort to bad language , the whole idea surely is to help each other out in any way we can without this , My question to you is have you tried it ?

[@Mesdriver]

alan manning It is useless to try. I am an owner of a toolshop for over 30Yrs. Beeing an engineer I can tell you the methode in the video does work, since the basics are right. Yours are not, you do not understand the reason why you have "bell mouth" jaws. Two reasons" wear on the jaw guide ( both jaw and chuck) and wear on the clamping surface of the jaw. If you grind the jaws like in the vid, you will be fine for the diameter you grind, on other diameters you will have some issues, also due to wear on the spiral. The video of Mr. pete is basicly correct, he understands the true reason of the "bell mouth". I only commented on the old machines. You methode is incorrect and amateuristic. It shows you have no knowledge of the background of "bell mouth". So no need to try, it will not work. But maybe since in the US 0.025" is accurate, you may be fine. In Europe we use 0.01mm as a limit on runout in most cases. So no bad language, just plain technics. There you have it.

[@flackyoue7483]

Mesdriver"But maybe since in the US 0.025" is accurate, you may be fine." As a tool maker in California USA You have a nasty attitude and too large of an ego that shows in your comments. You know a lot but if you just want to get on youtube to talk trash on American's, I find it trashy.

[@bearsrodshop7067]

Just a good alternate to sneaking out the brides towels, is I hit local garage sales and buy up as many FR (fire rated) blue jeans you can find. The offer great protecting and besides cheap, don't have to dampen with water. I also use the leg's to sew up sleeves for welding, and fender cover, ect. Just a thought, but if one used a good shop vac (with dust trap) at rear of spindle, cut way down on contamination of the lathe & shop?? Bear in Tx

[@mrpete222]

Thank you for some good suggestions

[@paytonmac5665]

might check bearings with out turning push chuck sideways lt and rt