How to Remove and Inspect A CNC Chuck

[Music] hello everyone welcome back to northeast wisconsin technical college i'm matt schmelzer here with practical machinist uh today we're talking about lathe chucks uh on this particular machine usually once a year we like to remove the chucks do an inspection on all the components inside the chuck make sure they're safe to use for the students so that's kind of the process we're going to go through today we're going to remove the check go through the process of disassembling it inspecting all the parts and then reassembling it getting it back onto the machine so let's look at some of the tools we're going to use today over here is going to be the tools that we're using for removing this chuck of course i'm always going to start off with a good shop crane this is going to assist us with lifting the chuck on and off the machine here to save the strain on our back i also have some metric hex keys for this job a piece of tubing to help with some leverage for breaking free some of the fasteners i got an eye bolt for fastening to the chuck for the hook crested wrench to help us keep the chuck from rotating as we're removing the fasteners and then of course the draw tube nut wrench here that's going to allow us to remove the draw tube nut inside the chuck so let's get over back to the machine now before i remove the chuck from the machine what i want to do is stop the machine in the emergency stop state in the middle of the chuck strobe so what i'm going to do is i'm going to press the pedal to open the chuck and i'm going to hit the e-stop in the middle of that stroke that's going to take the pressure off from the draw tube not allow me to remove it so i'm going to go ahead and hit the pedal and when it gets to the middle of stroke i'll hit the emergency stop right at that point so now i got the pressure off from the draw tube nut i'm going to be able to uh release that nut without having any pressure on it so the next step here is i'm going to remove two of my jaws so i'm going to remove two of the jaws from the chuck the third one i'm just going to slide out of the way but still leave it on the chuck so i have access to the draw tube nut in the middle so i'll go ahead and do that now i have two of my chuck jaws removed and then again the third one just slid out of the way that gives me access to the center of the chuck i'm going to start off by removing this chip plug or this chip guard in the center of here there's three screws that hold that in i'm gonna remove those three screws and then i can pull this component out the next step uh that i'm going to do to remove this chuck before i get the crane in place to assist me with this is we have uh six socket head cap screws that fasten this chuck to the spindle nose so i'm gonna go ahead i'm gonna remove five of those and i'll loosen the sixth one but i won't remove it at this point i'll just loosen it up so of course i got a crescent wrench here i'm just going to use this third jaw that i have left on here just to just give me a point to keep the chuck from rotating i'm going to grab my leverage tube and my hex key and then i'll start breaking all of these socket head cap screws loose now i've removed five of my socket head cap screws that hold this chuck to the spindle nose i have the last one again i had that loose so before i remove that i put my eye bolt in the outside of the chuck and then i brought my crane in into place now i have just enough tension to support the weight of the chuck no more no less i don't want it to fall and damage the threads on my draw tube and i don't want it to get bound up on the draw tube either so i got just enough tension i'll go ahead and i'll remove this final cap screw and then the next step is to take our draw nut tool that's a special tool this comes with the either the machine or it comes with the chuck when you purchase one so this is going to slide through the center of the chuck and these two drive dogs are going to engage the draw tube nut and that's going to allow me to spin it off from the draw tube so right now i'll just bring this in and i'll find the dogs and then before i uh start rotating that i want to keep a reference on where that draw tube uh is in position with the nut so it goes back on the same way so what i'm going to do is i'm just going to put an indicator mark on the top of this tube and then when i go to remove it i'm going to rotate this counterclockwise and that's going to remove that draw tube nut and allow the chuck to get separated from the machine i'm going to count how many revolutions that i turn this wrench so then when i go to reassemble it i can go back the same amount of turns to get the chuck in the jaws in the right position so at this time i'll go ahead and i'll spin that nut and i'll get the chuck off of the machine so i inserted my wrench rotated the draw tube nut and again i counted how many turns it took to remove the chuck here and it was 11 and a half turns so i go ahead and i just wrote that on the tool here so when i go to reinstall it it's right there for my reference so at this point we can get this check over to the workbench and we can begin to disassemble it we're at the workbench here i got the chuck on the table here i just set it on some blocks just to get it up off the surface a little bit allow some of these components to move a little freer as we disassemble some of the tools we're going to be using today of course i got a mallet some of these parts have some pretty tight tolerance tight fits between the two so we may have to just tap those components to get them to break free again we've got our hex keys i'm gonna go to reassemble i got some gloves uh just to keep our hands a little bit cleaner a torque wrench make sure all of our fasteners get torqued back to a manufacturer's specifications and then i got some of our chuck e's grease here this is a special grease made for hydraulic chucks keeps all the internal components from seizing up goaling causing any kind of damage so over on the chuck here the first component i'm going to remove here is our adapter ring and this ring adapts the chuck to the specific machine that we have it on there are three cap screws that hold this to the body so i'm going to go ahead and remove those three cap screws and then remove this adapter ring so i removed our adapter ring here i've removed those three cap screws took a little bit of manipulation with a rubber mallet but i got that out of there now looking at the inside of the chuck here you can see even though it's clean on the outside here down inside of this tool you can see there's a lot of metal chips dirt debris and that's one thing that we pull this apart to get all that stuff cleaned out so with that ring off and removed now we have access to the wedge plunger assembly inside of this chuck and basically this slides in and out attached to the draw tube and that's what activates our chuck jaws so i'm going to go ahead and just place my fingers on the inside of this and as i remove that it's going to draw the jaws inward so i'm just going to pull nice and straight up on this to get this thing out of the tool body and then that comes out just like that so i'll place this off to the side we'll look at the next components now with the wedge plunger assembly removed from the inside of this chuck now i have access to the master jaws located into the body here the master jaws are what you're fastening your chuck jaws to on the outside surface so down inside of here to remove these i'm just going to push just two of them a little bit out of the way and then i'll grab the third one here and i'll slide it towards the center of the chuck and then i'll pull that out now as that gets removed on the bottom side there is a small ball bearing and spring that holds just a small amount of tension on that master jaw just keeps it stabilized in the body so make sure these components do not go rolling across the floor and get lost so i'll go ahead and remove the other two make sure again i don't lose my bearing in my spring here and then we'll flip the tool over and look at the opposite side so with the master jaws removed from the chuck body i flipped it over on the bench here and here you can see where these counter board holes are that is where those spring and ball bearing detents were placed and again they just hold a little bit of tension on the master jaws just to keep them stabilized inside the pocket so we've got one more component to disassemble and then we're ready for washing all of our components in a parts washer so our final component here going back to our wedge plunger assembly again this houses our draw tube nut so that nut is held in place with this plunger ring right here and there's eight i'm sorry six socket head cap screws that hold that in place so i'll go ahead and remove those socket head cap screws and then this plunger ring can be removed getting access to the draw tube nut now i went through and i removed the six socket head cap screws from the plunger ring here and this comes out kind of as an assembly the draw tube nut and ring basically just slide out of there now to remove the draw tube nut i'm just going to press that out of this ring but be aware there's a set screw on the outside of this ring and that holds a small spring and ball bearing detent for this draw tube nut also they'll see some dimples on the outside to keep it locked into position so it doesn't come loose and change your chuck uh adjustment so i'm just going to just lightly press that ring off of this draw tube nut and then again be careful that we do not lose that small ball bearing detent located right there looking at the outside of the draw tube nut you can see the dimples every 90 degrees for that detent so i'll go ahead and remove that place that off to the side i'll get the spring out of there so at this point we'll take all these components over to our parts washer we'll get them all cleaned up i'm going to check anything that may have some sharp edges or burrs and i'll go ahead and remove those with a honing stone clean up all of our fasteners make sure we don't have any damaged threads and we'll get it all laid back out on the bench here for assembly okay we're back from the parts washer we have all of our parts laid out cleaned and dried thoroughly next step is to go through and just do an inspection on all these components you know anytime a part gets tossed out of the chuck or there's any kind of a collision or accident with the machine i always recommend pulling these chucks apart and doing a thorough inspection we don't want any any of these components failing causing a safety issue so looking at the body to begin with i'm looking for just signs of damage here i don't see any marks or any you know big you know wrecks or anything on the face here some of these sharp edges here i'm going to come back through with just a honing stone and just remove some sharp edges from any of this area where the master jaws are moving in and out so i'll go ahead and address that issue we'll flip this body over we'll take a look at the opposite side again i'm looking for any signs of seizing or galling where we had some severe metal to metal contact the inside of this chuck looks very nice very good shape it's fairly new looking at this surface where our adapter ring fastens too i want to look for any nicks or chips or any kind of damage there if i have anything there i'm going to take a honing stone and hone those down so they're nice and flat so that's the body next thing coming over to our wedge plunger assembly we've got the wedge ring you know of course i'm get again i'm looking for any signs of seizing or any raised edges nicks or burrs on this component this one looks fairly good shape looking at the detent spring i want to make sure that's in good shape the ball bearing next is the draw tube nut i'm always going to be looking for any signs of damage to the threads this is what threads on to the draw tube in the machine so this one looks really good shape i don't see you know any thread damage there what would cause you know some difficulty getting this to fasten to the draw tube if there would we'd have to get in with some tools to address that issue no signs of seizing or galling on the outside of this where it would be difficult to rotate this nut inside the ring next is our wedge plunger itself uh again looking at the outside surface of this i'm looking for any signs of balling any nicks or damages i see one small little nick on the outside surface there so i'm going to take a honing stone and address that just looking at the rest of this looks fairly good shape again looking at all of our threads for our wedge ring this internal surface where the draw tube nut rotates in that all looks in good shape i also want to go ahead and grab one of my master jaws and just make sure there is no interference where that moves in and out on the wedge plunger itself so i'll go ahead and i'll check all of the jaws check all of these pockets to make sure these are going to move nice and free inside of this plunger looking at the master jaws itself i always want to make sure i address these little serrated teeth in here sometimes metal chips get pressed in between that and the jaws when they get fastened so i want to make sure i clean all those out get any kind of metal or debris out of that one area too if there's ever a collision or an accident on the machine is looking through this area here looking for signs of cracks or damage you know if any of these devices become cracked this would cause a safety concern there so any kind of cracks around that all of these precision ground surfaces i want to look for signs of galling or any kind of damage there where it runs inside the wedge plunger any of those areas these all look fairly good also i want to look at the grease manifold system there's a small grease slot here in here when the grease is introduced into the outside i want to make sure i don't have any solidified grease or any kind of dirt or anything in that area also so these are the master jaws the final component here is our adapter ring and this is what seats up against the face of the spindle nose uh the biggest concern is i'm looking at this surface here for any kind of signs of nicks or damage when this thing may have been assembled last this surface looks in really good shape i'll flip it over to this surface here i can see one area of concern here where it looks like there might have been some debris when this was fastened to it and i can feel it with my finger there's some raised edges there so i'm going to go ahead and take a honing stone to remove those the final part of this is the tapered portion of this ring here and this is what actually seats onto the spindle nose controlling our concentricity or our run out so i'll make sure there's no nicks or damage to that tapered portion there so i'll go ahead and address a few of those issues and we'll start to reassemble this chuck i went through i've addressed all of our concerns after the inspection every every one of these components is now where we need it to be clean and inspected back to reassembly now first part of reassembly i'm going to put my master jaw spring detents in place now i put a small amount of chuck ease grease down into those counter bores and that's going to help hold these springs and ball bearings in place so when i flip it upside down they don't drop out of position so i'll go ahead and i'll place these springs ball bearings in place i'll get the chuck upside down and insert the masters so i flipped the chuck over i applied a generous proportion of this chucky's grease to the inside of this body here i can't stress enough the lubrication inside of this chuck and then i've inserted the master jaws again just ensuring that the ball bearing detents did not fall out of position and i just moved them out of the way so the next part of the assembly is going over to the wedge plunger assembly i'm going to start off by getting the draw tube nut inserted into the wedge ring so i just apply just a small amount of grease to the hole that our spring and ball bearing detent are placed into so i'm going to just go ahead and insert my spring and then my ball bearing detent and just put a little bit of grease on that just to hold that into position for assembly from there i can go ahead and insert my wedge or my draw tube ring so i'll go ahead and get that together so now with the draw tube nut assembled into the wedge ring i have the ball bearing detent in place i just want to make sure that i rotate this make sure that this moves nice and free and i can feel the ball bearing detent lock in place every 90 degrees so that's all good this is going to move nice and free next step here is i'm going to insert this assembly into the wedge plunger itself drop that down into place and i'm going to add my fasteners and then with my torque wrench i'm going to torque those to the manufacturer specification so i have my wedge plunger assembly all complete uh i'm going to go ahead and now we can insert that into the body this tends to be some kind of a challenge from time to time there is a very tight fit between the two components so this thing has to be fairly straight to get this to slide down into the body the other thing is i want to make sure that my master jaws are engaging this wedge plunger as it slides down into the bore all three of them have to engage at the same time so i'll go ahead and i'll get this lined up i'm going to apply a generous amount of chucky's grease to the outside of this component and i'll get this inserted into the body so now with the wedge plunger in place engage to the master jaws one last thing is i want to make sure that this device moves nice and free and smooth there's no grabbing or going or anything going on by feel so this is moving very nice so that's good to go the last thing to do is to assemble our adapter ring to the body and from there we can go back to the machine so i'm going to get the adapter ring bolted on three socket head cap screws holding that in place and i'm going to torque those two manufacturer specifications then i'll go ahead and back to the machine i'll get this on my crane and i'll uh insert the draw tube nut onto the draw tube back my 11 and a half turns and we'll go from there we're back here at the machine before i go ahead and install this chuck i want to make sure i do a thorough inspection of the spindle nodes and draw tube also you know i want to make sure i'm looking at this flange on the spindle nose i want to check that for any nicks or burrs if i have to i'll hone take a honing stone and remove that check in the taper on the spindle nose make sure i don't have any damage to that either and then finally the draw tube itself i'm going to do an inspection on those threads once the threads are cleaned up i'm going to put a small amount of chucky's grease or anti-seize on those threads after that i'll go ahead and i'll get my chuck installed going back again our 11 and a half turns on the nut be very careful when rotating that nut onto the draw tube if you get any resistance or any cross threading you will damage the threads so at that point i would remove the chuck try again the key is getting the the chain hoist here just in the right position where it's supporting it at the right height so i'll go ahead and get this fastened back onto the draw tube now i have the chuck mounted back onto the spindle of the machine i brought my draw tube nut in my 11 and a half turns right back to where it was when i removed it and of course now i've added my six socket head cap screws that hold it to the face of the spindle and i've torqued those to the factory specification also now the one final check is to make sure our jaws are in the correct position and those are controlled by that draw tube nut so i can rotate the jaw tube nut either direction to fine tune my position of these jaws now on master jaw number one there's an indicator mark on the face of the chuck and then a small scribed line on the master itself sometimes difficult to see but what we're looking to do is have that indicator mark on the master jaw slightly above that box in the middle of the scale that is in the open position then in the closed position it needs to be at the bottom side of that box now if it is anywhere out of that position i will go ahead and make an adjustment on my draw tube nut to either move it up or down into position so once i have that set i can go ahead and put my chip guard back in place always make sure that chip guard is in place whenever you're doing any machining that's going to protect all the inside components of this chuck from getting any chips or coolant or any damage like that once once that's done i'll go ahead and put my jaws back in place and i'll go ahead and grab a grease gun with my chucky's grease and i'll give each one of these jaws a couple of pumps of grease and then we'll be ready to go so we put our chip guard back in place inserted all of our jaws torque those to what we needed to and this machine's ready to go so i just want to thank you guys for joining us rebuilding this chuck today any questions or comments leave them below otherwise we'll see you next time you

Channel: Practical Machinist

Views: 13,160

Keywords: lathe, chuck, chuck removal, removing chuck from CNC lathe, removing a chuck, machining, nwtc, northeast wisconsin college

Id: 92IOc8lD-Ic

Length: 22min 3sec (1323 seconds)

Published: Thu Oct 21 2021