MACHINE SHOP TIPS #148 Disassembling a 3-Jaw Scroll Chuck tubalcain

how do you this is tubal-cain and this video is a follow-up to my previous video which was a tips number 147 where I ground the jaws on this Chuck and as I mentioned this Chuck became very contaminated with grinding dust so this video will be concerned with taking this Chuck apart and cleaning it and I'll explain how to do that and what a scroll chuck is in this video if you have any interest at all in little steam engines I built this in one of my previous videos and I think it's five parts so if you enjoy that type of thing go back and look at those videos now before I start this I just wanted to mention there are three different kinds of spindles that are commonly on lathes and the most common that you're going to run into on small lathe this is just a threaded spindle where the Chuck threads onto the spread a threaded spindle on the lathe the disadvantage with these is on a larger heavy chuck it's kind of hard to line it up and get it on there and also if the chuck is relay this reverse the chuck can spin off and I have seen that happen in the school shop so often that it at one point I had to disable the reversing switch on on the lays because the chucks were flying all over the place the second kind that is quite popular enlarger lays is like this this is just a backing plate for what we call the cam lock or some people call it a short taper because the taper is right here and it's relatively short come compared to the time to the next one I'm going to show you these come in different sizes some of them had six pins on them and again that's called the cam lock and the sizes are d 1 - 2 d 1 - 3 and so on so that's how those are sized and the kind that we're concerned with right now is called teh perky drive or we often call it a long paper because the taper here at about two inches so it aligns real well and is held onto the lathes with a collar well these last two that I mentioned will not spin off and even heavy chucks can be attached fairly easily if you have some kind of saddle arrangement or a hoist or something because some of the chuck get very very very heavy this is only a six-inch Chuck so I'm going to take this Chuck apart now and show you how it's built and I'm going to clean it thoroughly and get the grinding dust out of there while I'm at it incidentally these chucks the long taper key come in different sizes as well this believe is the smallest it's an L zero zero and then they go to L 0 and L 1 and so on as they get larger so there are different sizes and that would be proportional to the size of the lathe when you take these chucks apart for the very first time they need to be marked such that you assemble them exactly the way you took on the part and this one's been apart probably many times but notice that there our Center punch marks there and they're on the body because this chuck has three pieces here this is the backing plate and then this is the main body and this is how you take it apart and I've got it marked there and I circled those so that you would be able to see them better here on the camera these are called scroll chucks because there's a scroll inside there that allows all three jaws to move in and out with one keyhole here actually the three keyholes on here they do make a four jaw scroll Chuck as well as opposed to four jaw independent chucks this is a Barnard made in England the first thing I'll do is take the jaws out and remember the jaws are numbered so here's a slot number three and then the jaw is is marked number three and also remember that the jaws are not interchangeable between different chucks and many of them have serial numbers on them and this again is two-piece jaws with that is there's the jaw and the jaw caps that are held on by this cap screws so now I'll take the jaws out which you've all seen done I'll do that off-camera just back the screw out here until the jaws come out that way I can clean them these are the jaws that were just ground in the previous video and greatly contaminated with grinding dust I wish I had a parts washer I would just put them in there and wash them but these will be cleaned thoroughly with brake cleaner outside outdoors now you can see the air and the next thing I'm going to do for taking this apart is to remove these three cap screws I've already loosened those well this was still mounted on the lathe because they were so tight it would be a struggle to try to get them loose here on the bench with nothing to hold the chuck down because I wouldn't put this in a vise even if I had a vise large enough to hold so these three cap screws will be taken out and set off to the side and then the truck will separate hearing at this point at this point using a lead hammer I don't even like to use a brass hammer I've been tapping it to getting in order to get it apart and it is starting to separate right here as you can see it was a pretty tight fit but now it's coming apart you see that was such a tight fit there isn't any swarf in there and it's there's still plenty of oil in there from the last time it was taken apart from the construction of these I think you can begin to see why these Chuck's are so expensive now from the back side here you see the bevel gears and there's a separate one for each keyhole here some cheaper chucks only have one gear here that helps them get the price down a little bit I don't believe I'm going to take these out but you can see there's a screw here that allows you to remove the gear you know what old tubal-cain just changed his mind I am going to remove the gears here and I took the screw out and be sure you'd brass when you as a punch and that will come right out you think that's what that looks like and now I'll take the other two out off-camera and these screws came out really easily they weren't tight because everything's oiled and now this is sealed pretty well because there is no no dirt or grit back in here or chips I have all three of the little gears out and now the gear scroll assembly should pop out of there or possibly has to be driven but I'm just going to bang this little bit on the wood yeah and it came right out there's the scroll now apparently on this particular truck this is a press fit here because this doesn't seem to come apart at this joint and I don't think I need to anyway because I can just clean everything real thoroughly now now looking at the scroll this is called the scroll that's why sometimes called a scroll Chuck notice that it's nothing more than a thread really that's like a spiral and the jaws of course fit into that now a lot of grit got into this but even if you're not grinding eventually chips work their way in there and that's what caused it binding when it's real difficult to move the the Chuck jaws and that's when it ought to come apart and be cleaned and that that should actually be serviced regularly but generally that's something that is a chore and and people do not do also I think this helps you understand now why the jaws are numbered because they are going to start in different positions because of the scroll so we got jaws 1 2 & 3 that go into slots 1 2 & 3 you can imagine that this is quite an expensive part to manufacture the scroll wears and that's also part of the problem sometimes and either run out of the chuck and there's nothing that can be done about that but this might also help you understand why I needed to load the Chuck jaws when I did the grinding in the previous video now I'm going to proceed to clean everything Hospital clean and I'll do that off-camera be very nice if I had a pan or something to do this in but any kind of good thinner you know whether it be brake cleaner or lacquer thinner or heavens knows you don't want to use gasoline certainly if it's any dangerous thinner that you're using do it outside but stick with safe thinners such as mineral spirits or paint thinner it's 20 minutes later and I have cleaned everything thoroughly and dried it off wiped it with clean bounty towels no other brand will do it's better than using rags because you know the condition of the clean towels and I spent particularly a large amount of time on the scroll and I cleaned the scroll thoroughly with this is some kind of fiber brush it isn't but do not use steel brass is okay or of course your wife's toothbrush will work too but clean it real well and now we're ready to start reassembly and everything will be very lightly oiled with 20 weight as you reassemble it never assemble anything dry but use a minimum amount of oil or ultimately the extra oil will spin out and end up on your left shoulder again just a little bit of oil because that will spread around and I like to put a little bit here and then I like to wipe it in with my hands same thing here I've already done that and then I will drop the scroll into place check for Brewers before you reassemble it and if anybody did any trying on this with a screwdriver or whatever get it apart you probably got some little burrs so take a nice sharp flat file and run it on all these flat surfaces so that there is absolutely no burrs also this is sharp in some places here from original manufacturer so watch it you don't cut yourself and that's all been lately oiled and the scroll and it goes this way not that way into place down she goes I've got the gears in place and I double-checked it with my Chuck key that they will turn freely and now the screws need to go in there there combination actually of a pin and a threaded screw go in there and I'm going to use just a little bit of this extreme pressure lubricant here on the gear because this side here seems to be sealed pretty well so that the oil will not get flung out at me the operator nor does the grit and swarf get inside of the body of the Chuck now a white grease or some other kind of grease could also be used in there and this is all free and lubricated and the screws are tight and this is the location marker the index mark and the corresponding one right here and I've already oiled this lately and this is actually where it's going to get located here where you see this step here like that and it's I'm lining it up with the screws which they're going to go in from the other side but before I tap that into place I want to make sure that those screws are started and I got the correct location here in this direction and then I will tap it down or pull it down with the bolts the threads are started with the three cap screws and at this point I can tap it until it starts to close and I'll pull it back up with the cap screws and I'm going to put it on the lathe and do the final tightening and install the jaws while it's on the lathe spindle because it just makes it a little bit easier to handle rather than rolling around like it is right now now I will mount it on the spindle here for the last step and now make sure that you clean everything thoroughly with a bounty towel and then two drops of oil only this is again what we call the l00 spindle or long taper or taper key and clean out the inside of the of the Chuck although that's already been done but using your bare hands you can really feel if there's any grit and protect your lathe bed with a board and the collar is can be brought up and then I tighten it with my spanner French and this is how I do with the final tightening of the cap screws because the thing can't get away on me now let's tell originally almost like it's in a vice I am now ready to install the jaws and remember there are numbers on them that's number three and number one will be the first one to go in and that's number two and we need a little oil in here but not much because again remember that that oil will get slung out at high speeds now when you go to put these in the number one is put in as this end of the scroll now that you know what the scroll is comes around right there you can put a little bit of oil here also if you want but bring that down rotate the Chuck and you will feel it advance I know that that was that one is in place and as I come around I'll watch this at the end of the scroll right here there it is I back it off and number two jaw goes into place and I can see that is engaged watch for the scroll to come around and the number three jaw is put into place and they will all move in together and at the same time and close together if you have done that all correctly and there I am and the job is done and that took over an hour so that's why people tend to not do this because it's not a pleasant job but it needs to be done from time to time because you're going to feel that the chips and the swarf in the scroll when it is difficult to move the jaws in and out when you're when you turn the Chuck key so that's something that you will want to do but try to do it ahead of time when you're doing lathe maintenance rather than in the middle of a job when it becomes most frustrating hope this was helpful this is tubal-cain saying so long for now

Channel: mrpete222

Views: 164,749

Rating: 4.9243441 out of 5

Keywords: sherline lathe, myford lathe, logan lathe, bridgeport mill, atlas lathe, hardinge, starrett tools, brown & sharpe

Id: CP6tW2ge2xs

Length: 18min 52sec (1132 seconds)

Published: Sat Mar 29 2014