Gripper Jaws for the lathe

hey welcome back to my leaf that's a piece of Delrin and that's a lot of overhang for clamping it on to mow me up that have to millimeter clamping high-tier and about sixteen millimeters of overhang normally with a normal street gel or sixty object without any precautions i would say better don't do that but these are gripper jaws this is my soft jaw chuck and i made a set of adaptor jaws here with grippers these bite into the material and deform it and create a form-fitting connection and to rip this out of the chuck that would take a lot of force even probably tip the leaf over so let's see how i make these and how they work the stock I'm using is 2 lakhs 33 which is pre hardened and tempered tool steel and it's pre ground stock so it's it's nice and parallel squarish usually this stuff is not really very square and it's usually oversized to give grind allowance I'm not going to grind this and I'm going to mill it just faster and I already have parallel device everything's clean I usually when I work with with raw stock I take a file and hit the flats of the stock with a file just to be sure to knock down every every high spot and then we put it in device and this will squared up and material is square in this direction and the vertex job device is vertical too and when I clamp it now the thickness will be standing up vertical and when I mill the top here I will get a 90 degree angle here so that's a very fast way to square this stuff up running an 8 millimeter for flute carbide end mill here we're going for 3000 rpm and 2 lakhs 33 is considered it can be machined it's 33 Rockwell which is a good amount harder or tougher than annealed steel or in normally on the old condition 33 is still more than soft enough to even be machined with high speed steel normal file will still take a very nice cut on it but it's very tough the heat treated more for strength than harness in this case and yes I have a face mill of course I have several face mills in fact but usually I don't I don't like the face mill to be used on material that narrow except if I'm in the mood to do a lot of de buri you saw me running the end mill on the edge in this direction in this direction that way I cut the burr into the material and that leaves me minimal burr - to remove later if you do that if you run a face mill in one path across the top surface here you pull up pull a quite heavy bird on one side of the material that needs to be removed and I will give you that a face Milus of course more impressive but I don't need to impress somebody I want to make parts so I'm checking my dimensions flip the part around drop it down to the parallel with the machine side clamp it down now give it a light tap I'm just sure that it's seated down problem properly take notice what feeling what's going on is the the clamping action very abrupt and very very hard torque curve and you can be pretty sure that there is no dirt somewhere in your setup if it feels like you're clamping against the spring chances chances that something is wrong or very high okay squared it up on all four sides hit my dimensions with within caliper precision cutting the the bandsaw pieces to length I have one spare part over here and device to balance out the moving jaw so we don't rock it too crazy and the second part goes in here I changed my aunt Mills to a 10 millimeter sri flute because this has enough flute length to clean up the end the 8 millimeter that I used before was barely long enough [Music] I usually take a skim pass just to establish somewhat of a clean surface and I'd take a measurement with calipers or micrometer and in this case I need to remove two point two two millimeters so zero out my dro and then I step over point five increments and just remove material [Music] and yes I did take climb and Convention and muling passes this is such light over cut 20 millimeter height 0.2 0.5 millimeter step over on a half-decent type setup mill and a cutter that actually cuts and does not just push material around that's no problem even on a manual mill and this thing has some backlash in the and the feet screw so you have to try to yourself what what you can get away with on a client milling path [Music] okay now as we squared up the blocks I can machine this interlocking key structure into them which mates up with the with the base jaws of my three jaw Chuck and you see a lot of numbers scribbled down here this these are my approach coordinates I figure details when I make the first one so the next three count came come up exactly the same the important dimensions here is the width of the central key this needs to be 12 millimeters which according to my disk Mike it is and the width of this slot here needs to be eight millimeter plus 20 microns and an 8 millimeter gauge block barely goes in here so that's good too and once you figured out those so those coordinate is just milling by numbers and for it yet proving I put on some layout lines just to just to be sure we're we're doing the right thing here three flew carbide end mill to flutter running at 3000 rpm and I'm going to take the hole three millimeter depth than one cut that should be should not be a problem and my my numbers here say that for roughing I need to go to plus K and take a path through now we go to - eat [Music] and that removed the majority of the material [Music] [Music] okay I took 8.2 cleaning out the cleaning up the outside wall 7.6 and 7.5 to bring this key in the center almost to size and when we idiot check it with calipers now we get 12.04 that's our last step moving over 20 micron from each side that will bring us to 12 - a little bit this is basically the CNC program just that I manually crank all the positions double check with the disk Mike okay that's 12 minus 10 micron very pretty good and now we rough out those two slots I start at y plus minus 1 millimeter to Rafael slot and I step over again to clean it up [Music] [Music] and there we go [Music] to double-check what I'm actually doing i mounted the jaws on onto the street jaw chuck and mounted it on the lathe and I'm checking the run out on the inside of the jaws before I bore the pockets for my gripper jaws ran out with with these kind of jaws is not su is not very critical especially as they bite into the material deform it but I wanted to be reasonably accurate anyway my might used he sup these base jaws with their pocket for something else too so icy road out here on top dead center on the inside of this jaw the chuck is preloaded I clamped on a bearing race down in there this is plus one so let's zero this out okay that's zero go to the next jaw that's plus one that's plus ten micron and this one is plus one so the way that's that's pretty okay the way I made my base jaws in the Fortis Chuck these are modified heart jaws the way I meet these and the way I made my adapted jaws here that that matches up quite nicely written within yeah within a solid 10 micron I'm pretty sure I cannot flip those jaws around I always kept my orientation the same when I machined them because they are not exactly the same length but that's that's pretty that's pretty cool [Applause] okay finished all the major machining on the jaws the remaining steps that need to be done on that are chamfering deburring some engraving needs to be done on the backside for the number of the jaw I'm using the pockets are bored and I used will help the boring head to face the floor of the bore so our gripper inserts once bolted down sit sit nice and sturdy in there this is a go/no-go gage 416 h7 that this side is 16.000 and this side is plus 18 micron and that's used to check this fit this is this is a 16 h7 fit in my in my design so that the the 16 millimeter end goes in nicely and the 16.0 1/8 and does not so that's a very good way to check your work in addition to the three point three point internal micrometer that I used earlier at the life and I have a stick of one 2363 tool steel and the lathe and in in the NZ verb that's a two it's an air hardening tool steel and that's what we're going to use to make the gripper sawed off okay draft it down to 17 millimeter final dimension is 16 I also turned a small step here which defines the gripper structure now it changed your TCM tea tool and we're reducing the speed touch off on the end zero outdoor tool move over to point one millimeter lock the carriage because we're creating a lot of sideways pressure by plunging with this tool [Music] [Music] never changed tree nine-millimeter milk holding the nth million in a collet holder for for plunging is way more rigid than holding it in a grilled Chuck [Music] I did a little bit of work off-camera i engraved parts on the CNC router and also I finally engraved the base jaws they have a factory engraving in here but you can't read this when the joist is mounted so put the same engraving here on the back rounded over all the edges and corners put a ball ball shape on the cornice and hit everything with a sanding sponge just to clean it up these a two grippers out of a two air hardening tool steel hardened them and I'm not set up to do air hardening it's quite a problem for me to do I tried it with a work with a stainless steel wrap but I couldn't get the parts quick enough out so the air quenching works so and then I redid the hardening with without the foil and that means that my D carburized layer of of steel is quite thick so they have a soft shell and a very hard core now not ideal but for a first test these should work I will make a few more sets of these and just send them out for for a proper heat treat so let's put them together they go in here screw those in and then they go on to base jaws all within their within their number and in a right orientation these jaws only pursued about two millimeters buff above the jaw and this face of the of the gripper Chell is 0.2 millimeter behind the surface of the jaw so the part should be pulled due to the angle of the gripper down on to the jaw let's see and the jaw should should bite into the material let's see and well they do and not even with a terrible amount of torque you can see the bite that the jaw took and this this could be really a good way to hold raw plastic stock with very little material on the backside with very little waste stock in the life so let's put the thing on the lathe and and play it play a little bit with it okay I have my torque wrench here and I'm going to set it to let's start at 10 Newton meters that's 8 lbfft whatever that is so part goes in and I want to try it with the with the torque wrench first so I can judge the torque needed to hold the part securely it almost feels like 8 10 Newton meters is oh there it is there it clicked and this dug in quite good that's just really yeah at this this is not there's my only my only concern is that the material behind the gripper jaw could break away if I if I give this a good whack in a crash situation but for returning yeah this is a rock-solid way to hold the stock on two millimeters of material that's I I like this this looks promising and I have a ton of plastic turning in the future to do making a lot of these couplers here and this allows me to go with very little material with very little extra stock if I cut the material half-decent square to make these parts this is a trash piece obviously by butter Chuck marks here but yeah this is this that this looks very promising I might experiment with the shape maybe I will do a Halfmoon cutout on these lips so I get two points that dig into the material and not this blade style I have to look at commercial creepers but we do not only want to do plastic we also want to do aluminium a piece of aluminium here let's see if these work here to get our torque wrench in there we go yeah those take quite a nice bite into the aluminium - let's bring the camera in a little bit closer okay that's a close-up view and as you can see just displayed disk scraping nicely into the material and obviously this is not my first try I tried it off-camera already and this takes a really good good imprint into the material and judging by the way - Chuck tightened I would not worry to machine on this quite aggressive and if I was doing something that requires a ridiculous amount of holding force I always can come in with basically an operation zero hot apart not crazy tight because we're only plunging this little tough tail groove in here just with a DC empty tool plunge into the material and then we have a form-fitting holding lip behind those grippers and before this part flies out this is what woodworkers do when they turn a bowl or something like that they may turn a dovetail she contour and they have jaws that match it that's basically the same or when you do CNC milling and you have a dovetail fixture to hold your part and you also prepare your stock worth of tail and that's not going anywhere I thought to stand use this technique on his large mazak lathe either to hold a smaller Chuck in his large portrait Chuck or even he prepared stock with dovetail like that because it's basically a dual contact you're contacting on Honda dovetail on the angled surface and either on the on this flat of the dovetail or on the backside depending on on the size of that tail your machine the dovetail how do we create it here is a DC MT tool there is the dovetail doesn't make much sense to put a dovetail on both sides of the part of course this is just for demonstration purposes there's girls in here line it up with the with the gripper jaws would be easier without a camera in the way and I I don't see any way how this could come out of the Chuck except for the material itself failing let's put on some safety glasses and give it a cut yeah I'm not running of course not a crazy feat because I'm not mad but still this is like a this is like six millimeters depth of cut with a relatively dull insert so that finishing insert for steel doesn't seem like the part wants to go flying anytime soon so that seems to work you probably wonder if this will work in steel too and yes it will I already tried it here at least way smaller marks on the steel but still being much stronger harder than aluminum and plastic a smaller a smaller engagement depth of the grippers will hold Chester just fine the only problem is the treat on my my grippers is not brilliant so they will most likely get damaged during this but well they are around and once a section of them is damaged I can just turn them a little bit let's see 10 Newton meters there we go this is yeah this is not going to be a problem I like these already let's let's show these jaws in practical use I have a chunk of Delrin that's kept a little bit oversized in length and this goes into Chuck with the gripper jaws I slightly tighten it with by hand with a normal wrench then I changed to torque wrench set at 10 Newton meters and I torque it down there we go and as you can see I put a perfect square cut on the end of this piece DC MT tool with a polished carbide insert for El minion if the tool upside down so I don't get sprayed with chips and I will close the Chuck guard so it - first of all not get chips all over me and secondly if if this lets go I don't get hit by this in the head and if you have a tool upside down you need to run the Machine in Reverse of course [Music] so I'm turning the OD with a feed of 0.2 1 millimeters per Rev that's quite an aggressive feed but does that allows me to break the chip speed is about 2,000 rpm okay roughing is done now we change to a finer feet 0.08 six millimeters per Rev now we go for a nice car d MDF inserts drill combination tool that's also acting as a boring bar [Music] next tool is a radial grooving tool next tool is a chamfering tool and the last tool is a G 1/4 inch by 19 tap and these descriptive jaws work marvelous the holding power is really really intense for relatively low torque on an opinion drive of the chuck and yes it deforms material quite a significant amount but it works it just works it's really nice setup I think I have beaten the topic to death one last thing Adam the machinist on Instagram Adam you should follow him he he does some incredible work out of his garage way more sophisticated than the things I do and the idea that this could also be used to mount very simple soft jaws take the grip result machine a plug out of aluminium 16 millimeter shank was a slightly large a head altered in and it's a very very fast and very easy way to make soft jaw maybe for even only for one time use end then recut it for another job I might try that and I'm very sure that this will work and also thanks to Robin Rand said he wants for once again he gave me he gave me the basic idea for this he showed Sherlock showed turning plastic of a large overhang with a clamping latch on the back I used that technique in the past quite a bit but it's always the extra step of turning the clamping legend with the grippers just bites right into the material Robin also showed a set of soft jaws with a gripper with a turned gripper contour and that bites into the material but I wanted to try this especially as I want to use these on a meal too I think that's it for now really thank you all for watching and I'll be back [Music]

Channel: Stefan Gotteswinter

Views: 73,610

Rating: 4.9624276 out of 5

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Id: lsSBKUMT5Ew

Length: 37min 25sec (2245 seconds)

Published: Sun May 03 2020