I Might Have Invented Something New...

is it going to work this is a perfectly reasonable question to have during a new project but it's not one I often wonder about as I'm making something for the first time usually all the engineering efforts that I put into a design had me pretty sure of the outcome whether that's out of confidence in my decisions or just plain ignorance but every once in a while I designed something that I'm not 100 sure will actually do what I want it to so I go into the build knowing I may have to make some adjustments on the fly or do a complete redesign or in an absolute worst case abandon the idea altogether this is one of those builds I have a new design that I want to try out and I don't know if it's actually going to work but if it does it'll be pretty cool and really really useful [Music] [Music] all right what is this mysterious and possibly questionable design that I want to make well I recently built this awesome Vice mountable rotary fixture plate for making rounding part Corners a breeze and so far this thing has exceeded my expectations no seriously this thing is absolutely dialed but I still need yes need a set of guides for locating parts that don't necessarily have corner holes in them there are three requirements for these guides they need to be adjustable and positioned they need to be solid when locking them down and most important of all they need to always be perfectly square and I mean perfectly if I can measure so much as a thousandth of an inch of variation across the edge I won't be pleased simple enough right well as the old adage goes the devil is in the details I can't just whip up a set of bars and Tina's to slide into this groove because even if I manage to keep the clearances as minimal as possible to allow things to slide these will still be sources of error and over time that error will only increase as everything wears unacceptable I need something that can have both adjustable clearance and wear compensation but also be self-squaring so here's what I came up with the heart of it all is the dovetail slide think of it like a t-nut only it's meant for a dovetail slot the top has a set of chamfers that will match another set of chamfers on the bottom side of the guide bar this keeps the guide Square to the slide so the guide mounts to the slide that rides in the groove you with me now things get a little tricky I also need the slide to stay Square in the groove I could try to work it out so that the top chamfer locks with the guide bar at the same time that the slide engages with the dovetail Groove but even if I manage to get this distance correct to a ten thousandth of an inch one is always going to touch before the other and nothing will get tight so I'm going to need a little bit of the secret sauce compliance by slitting the dovetail slide down the middle I can make it a flexible piece and including a v-groove creates a set of ramps that a semi-circular nut can ride along now as I tighten the screw from the top the guide bar locks and squares the dovetail slide first then as I tighten further the nut is pulled into the v-groove which expands the slide pulling it down further into the dovetail Groove while squaring it as well makes sense right yeah it does to me too but the more I look at it the less I feel that way I can already spot a few things I'm not so sure about but at some point you have to stop pondering the possibilities and just start on a functional prototype yeah that's what I'll call it then I have an excuse if it doesn't work okay let's begin I'll need the guide bars in order to make the dovetail slides so I'll start on these first and I've got an inappropriately sized block of A2 tool steel that would do the trick don't worry I have a plan I'll start on the top fly cutting it flat and square to the mill then switch to a four flute End Mill to work on the perimeter first the left side which I'll set as a reference then move over to the right cutting this down to establish the length of the bars I'll repeat this on the front and back as well making this wide enough for both the bars plus the width of an End Mill to fit between the two now to cut away the metal this is effectively a slotting operation and my preference would be to use a two fluted slot Mill these are better for slotting operations because by only having two flutes you only ever have one flute engaged at a time so tool deflection is minimized making a more accurate cut but it turns out the longest two flute or I have isn't long enough so I'll have to stick with the four flute I already have mounted this is perfectly acceptable though since I don't have to take this slot to an accurate width in a single pass I left enough room in here to come back after most of the material is removed to clean up each side independently and take the guide bars to width and pretty much just like that I have five out of six sides on two parts squared up and ready to go I ended up turning a little more metal into chips than if I had cut two individual bars and milled each side square one at a time but for the time this approach just saved me this was a no-brainer these could technically be either the tops or bottoms of the bars so I think I'll go ahead and call them the bottoms and work on the chamfered grooves not that I couldn't dial it in later but this will pretty much guarantee that the groove comes out perfectly parallel to the sides of the bars an absolute must if I want everything to be square later on I'll start by cutting away the square portion of the grooves that will give clearance for the chamfering operation Dimensions aren't critical here but it never hurts to practice Precision even when it doesn't matter now for those chamfers I've got this chamfering bit here to do the job and it has a very subtle but important feature that I have to consider the bottom is flat rather than coming to a point I have to take this into account when referencing this cut otherwise I could overshoot the width of the chamfers so after a little bit of figuring I get the cutter in position and send it on its way I'm not going to worry about measuring it though one because I can't think of a reliable way to do so in this setup and two because I'll be able to account for any small deviations when I make the next part after a little deburring these are looking great now to free these from the rest of the stock and work on the other sides since I'm already set up here I'll go ahead and just use the slitting saw for this hey wait wait wait the coolant stopped don't okay Brandon what's the number one rule of coolant it only helps if it's actually present now you're perfectly good slitting blade is toast let's try this again with a fresh blade and this time I want to see that thing drenched and there goes another blade this is the point where both past and present randoms learn the hard way with the A and A2 tool steel stands for air meaning this is air hardening tool steel meaning that flash or red we saw then it immediately air cooling basically heat treated the area around the cut to a hardness somewhere in the neighborhood of 62 Rockwell C a high speed steel blades I'm using are only about 63 Rockwell C so pretty much those blades were never getting through that hardened area learn from my mistakes people luckily I wisened up and moved over to the bandsaw to cut the parts from the stock of course avoiding that hardened area from the first attempt alright with that lesson learned let's finish out these guide bars I'll get these mounted up in the vice and start Milling them down to thickness I still have that hardened area to contend with but since I'm using a carbide face Mill with hardness around 70 Rockwell C cutting through this is not an issue after getting within a few thou the final thickness I'll switch to a fly cutter to take it the rest of the way while also achieving a better surface finish nice now to round these out with the screw slots I'll get the first bar mounted against a vice stop and use an edge finder to set my reference on that corner then bring in the drill and pop an undersized starting hole at each end of the slot and since I have a vice stop in place I can swap to the other bar and repeat the operations on here as well while I have the tool mounted for these slots I will actually use a two fluted slotting Mill starting with the wider counter board portion of the slot so I'll plunge this all the way to depth then let this thing turn its way across the part on second thought that might have been a touch too aggressive looks like the massive cutting forces on the spiral flutes of the End Mill actually pulled the End Mill down slightly overshooting the depth on top of that I also got quite a bit of cutter deflection which I wasn't expecting since I used a two flute Mill you can see a step in there from the return pass thinking on this now though the deep cut combined with the spiral geometry of the flutes meant the End Mill was cutting on both flutes at once causing the deflection I guess this is one of those nuanced things you never really think about until it happens but you can guarantee it's ingrained in my memory now fortunately for me the depth and width of This Groove is pretty arbitrary so I'll bring the mill back in to even out the bottom and might as well open up the slot a bit to clean up the sides much better I'll repeat this on the second bar taking it to the same dimensions just so everything matches then I'll also bring in a quarter inch End Mill to cut the through slot in the bottom looking sharp but not in a good way just one more thing and these are finished much better dropping some nice consistent chamfers on a part always makes such a big difference of course now that these parts are finished it occurred to me a way to check the width of these bevels so let's have a look placing a pin against the bottom and side of the groove I can bring in a depth micrometer and measure the distance from the side of the PIN to the side of the part by my math this should be an even 12 thousands but I'm reading closer to 22. not sure where I went wrong earlier maybe I forgot to offset one of the axes or something I can of course account for this one I make its mating part but now that I know this error is here it's going to bug me until I fix it so let's back to the Vise for some quick skims along those bevels to open them up closer to my target alright now these are finished it may have taken a few lapses in judgment to get here but we made it barely I can move on to making the dovetail slides next but I think I'll need to do some testing to nail the final fitment so instead I'll whip up the half round nuts next don't worry I'll make this a quickie who doesn't love a quickie am I right the nuts around so naturally I'll start on the lathe I've got a piece of A2 tool steel perfect for this it even has a center drilled end so I can move right on the turning down the length I'll need enough for two nuts plus a little extra for work holding and after nailing the diameter I'll part this off already halfway there I told you this would be fast on the mill I'll set this up in a collet block with about an inch sticking out after squaring up the end with an End Mill I'll get a touch on the top side then mow away half the rod to make the semicircular shape from here I'll use the edge finder to locate the center line and end of the rod then start the sequence adding the threaded hole after hacking this off and repeating that once more I have two nuts almost ready to go just a quick trip back to the Vise to clean up the last ends well this is a first the Vise stop is thicker than the part so nothing gets tight oh something just dawned on me my grandfather had this second buy stop here that looks like he modified it to be shorter I never pieced together why until now there we go now I can finish these parts out Milling the first to length then swapping for the second and repeating on it as well I'll also go ahead and give these a good deburring and a Little Love on the emery board noise that takes care of the top guide bars and the bottom nuts now it's time to work on the piece that goes in between the dovetail slides I've got another hunk of A2 tool steel for this as well so I'll get this mounted and quickly square up the top and sides just like the guide bars only this time once I get it dialed in I'll flip it over and repeat on the bottom as well I promise there's a reason for this just hang tight now with all six Side Square I'll actually begin sculpting the parts yes Parts with an S I'm making both of the dovetail slides at the same time I'll start by Milling down the front and back to define the width which is a nice round 16.668 millimeters or 21 30 seconds if you prefer obsolete units like me Now for Something less pedestrian let's cut the dovetail features I'll zero the cutter on the top surface bring the material off the prescribed distance get a touch on the side of the part then start taking 20 thou passes along the length let's check the progress I'll use another pin to measure this depth it took a little bit to work out but the distance from the outside of the PIN to the opposite side of the part should be 0.704 inches five thousand ago one more pass should do it perfect from here it's just rinse and repeat on the opposite side this is shaping up nicely next are the through holes for each of the clamping screws though no need to go all the way through this block only the part thickness the last thing I can do from this angle is cut the v-groove in the bottom a perfect job for the chamfering bit I'm pretty sure I'm getting my money's worth out of this tool on this project to measure the depth I'll use another gauge pin but first I need to determine a baseline distance from the top so I'll place a one two three Block in here and get this Baseline then bring in a pin and measure to the top of that I should get a difference of 0.203 and be reading 0.635 so another 32 thou to go and there we go now remember how I went through all that trouble to square up all sides of the block well I did this because now I can turn this in the Vise and be reasonably sure that it's Square to the rest of the dovetail features already cut so next I'll drop a 16 inch hole in the end this will act as a termination point for The Parting slit so I don't end up with any sharp interior Corners that would act as stress concentrations this tiny drill isn't long enough to go through the whole thing though so I've got this Vice stop in place that lets me flip this and drill the other side without having to relocate the part another change of position and it's time for that secret sauce yeah I guess I don't know where I was going with this let's cut The Parting slit lucky for me the only way I have to do this is with that slitting saw I've had some time to really reflect on what went wrong before though so I think as long as I keep this thing absolutely drenched and coolant from the start I should be all right okay that seems to be doing the trick my theory about the air hardening of the steel must be true though maybe I went slightly overboard with the coolant at any rate it worked and I also managed to get the slit perfectly centered on that hole like I wanted it doesn't get much better than that next is the mill down the width below the dovetail faces so I'll get this repositioned with a vice stop then bring in a roughing Mill to hog away the rest of the material on either side all right this is the first time I get to see if this is actually going to fit sweet I still have to nail down some dimensions on the top side but so far this seems to be perfect let's get this freed from the base block and finish up the other side and with my confidence restored I'll give the slitting saw another go all right this part just got a lot smaller and a lot harder to hold I can't just clamp this in the Vise or I would compress the slit and it would likely come loose so I guess it's time to come up with a fixture plate of some sort okay I need this fixture to do a few things and the first is to hold my part perfectly straight while I Mill the top down to thickness I've included a threaded hole on the far end giving me a spot to mount a hold down clamp so now I can bring in a Mill and skim the top surface well half of it anyway once I get the first side spot on I'll flip the part end for end and Mill the other side as well and that's as much as I can do with this as a single part so over on the bandsaw I'll cut this into two now to pretty up these faces a bit and get them on par with the rest I'll get the first remounted in the fixture plate but there's definitely no room to get a clamp in here now so I'll use a socket head screw to secure it and then bring in an End Mill to clean up the other side and also take it to length with both of these to size I can now do the final operation of chamfering the top side these chamfers are what engage with the groove on the bottom of the guide bar keeping everything perfectly Square and I can pretty much count on this being true since this fixture plate had its alignment pocket cut in situ the chamfers also need to be symmetrical side to side to keep the through hole aligned so I'll flip the part on the fixture and bring the cutter in the exact same distance okay I left a little meat on here so that I can fine tune the clearances so let's see where we're at stacking the slide on the guide the distance from the top to the bottom should be 0.969 inches but adding five phallus for mechanism clearance should put me at okay 0.976 maybe I didn't leave as much meat on here as I thought talk about cutting it close well I guess that means I'm ready for a test oh just one more thing though I'll need to shorten this screw okay now let's try this Booyah baby excuse me Booyah baby it works it actually freaking works I think I absolutely nailed the clearances too with the screw loose I can move the guide in both directions but if I snug it just a bit that locks the side to side while still letting me move up and down then snugging a bit further and that Direction gets pinned down as well and with the friction between everything this isn't going anywhere but what's probably the coolest of all is that this is all done with a single screw two directions of adjustment plus squareness alignment and it's all done with one freaking screw I think this might be one of my proudest moments I do have one small nitpicky thing to address though the screw is Wrecking the bottom of the slot but this isn't something a couple of soft brass washers couldn't rectify oh and I guess I'll need slightly longer screws now turns out that little mishap making this slot deeper was more of a happy accident now there's just enough room for the washer and screw head to hide below the surface I also went ahead and finished up the other dovetail slide so now things are truly done and man it is such a satisfying feeling to see how well this mechanism actually works if I want a guide here boom locked or if I want it here boom locked and with hardly any tightening of the screw I might add this is just awesome but I made these guides for a reason so let's get this on the middle and play with it a bit I adjusted the tram or this fixture plate in my last video with this screw so it should be interesting to see a free mounting caused any variation well I'd say that's still pretty much spot on same at the 90 degree position as well did I mention how pleased I am with this thing as a whole let's go ahead and check the guides while we're here nice only five thou variation Wait no that's awful what the [Music] okay so I think I found the problem two problems actually and one is so painfully obvious now that it's well it's stupid that I didn't see it before when I tighten the screws the chamfers that align the bar Square also cause it to expand in this case five hour more so pretty much the straight side needed for aligning Parts isn't straight at all the problem is not existent on the ends where the bar has more support structure but that defeats the purpose of this being adjustable the second problem is more subtle so let me demonstrate with the mechanism about 50 tight you can see I can still pivot the guide bar slightly One Direction or the other tightening it further and it starts to pull itself towards zero which would be square but it doesn't quite get there and the same happens from the other direction as well but once it's tight it doesn't go any further I'm 90 sure this is a result of the friction between the top plate and the guide bar and tightening the screws further only increases that friction so basically the friction I thought was playing to my advantage in this design is a big reason for its failure go figure I'm already thinking of ways to redesign this mechanism to get it to work like I want but as it stands that's beyond the scope of this build plus I'm going to have to sit on this for a while until I have an epiphany but even though it isn't exactly to my standards it's still kind of sort of works it would be a shame to make it this far and not at least try it out so let's do that the whole point of these guides was to locate parts for Corner rounding Parts with corner holes can be located with a central pin but Parts without a hole need something else after finding the center of the table with a coaxial indicator I'll offset a gauge pin or End Mill a specific distance to establish the radius of the round I want then bring the guide in bump it against the mill and lock it down after repeating this on the other guide as well I can mount my part then clamp it down and start cutting the corner around you know I guess this does actually do what I wanted it to just not as accurately as I'd hoped in fact I'm still pretty stoked that this expanding dovetail mechanism works as well as it does sure it still has some bugs to work out but this is like a 99 functional concept I think that qualifies as a win the whole purpose of this build was to see if a new idea I had would even work and even though it kind of didn't it also kind of did so it's given me a starting point that I can tweak and fine tune until I get a design that works flawlessly designing Machining and heck even life in general isn't about getting it right the first time it's about having an idea and trying it out because if we don't try how will we ever know what's possible as always thanks for watching and see you next time [Music] [Music]

Channel: Inheritance Machining

Views: 235,203

Keywords: inheritance machining, inheritance, dovetail, dovetail joint, compliant, new design, machine design, engineering, engineering design, prototyping, drafting, blueprints, side projects, machining, machine shop, machinist, engineering mechanics, chamfer, bevel, end mill, milling machine, lathe machine, slitting saw, square, mathematics, trigonometry, maths, handmade

Id: awkhVmcxgR0

Length: 25min 7sec (1507 seconds)

Published: Fri Jul 07 2023