Just A "SIMPLE" Repair

I'm just going to show you what I made this or I mean these These are the replacement lead screw and nuts for the compound slide of my new old lathe they go in here and when I turn this handle this goes in and out simple enough now why am i showing you this doesn't that give away the surprise well no because in the case of this project the surprise isn't what I'm making I mean it's a duplicate of something that already exists the surprise was everything it took to get to this point so let the yak shaving [Music] [Music] [Music] begin there are a lot of things wrong with this lathe some may be a bit more serious than others but they all got to get fixed and I feel like tackling something straightforward so we're going to start with some issues on the compound slide this is the part of the lathe used for feeding the cutter at an angle and I'll be using it a lot when threading so we got to make sure it's in tiptop shape but what's the problem well right off the bat you can see the hand wheeel shaft is bent not a deal breaker it's more that it just makes this lathe feel janky and we certainly can't have that same goes for this bent handle but on top of that the dials aren't exactly doing their jobs this middle part shouldn't be spinning and the inner one should be synced with the outer about like how this other hand wheel is which is also bent but one problem at a time back to the compound I saved the best for last yeah it shouldn't do that this is called backlash and pretty much every machine with lead screws or gears has it but this is a bit extreme and not in the Yeehaw Cowboy kind of way now before you ask yes there is a way to adjust this inside here the lead screw threads into this body where there's a pair of bronze lead nuts normally you can adjust the spacing between these nuts to take up the excess backlash but that's not going to work here why not well that requires reassembly I've got an indicator on here and in one position you can see a few th backlash not bad but if I move this out just a bit that backlash is literally Soul crushing the only way this happens is if the lead screw is worn unevenly so there's no chance of adjusting away the backlash for the full travel of the compound which brings me to the Crux of this story I'm going to have to remake this lead screw and for good measure might as well make the lead nuts as well okay that's the full shaft in all its Glory this is the main member I'll be remaking but let's not forget about the nuts the outer is held on with a locking ring so I should be able to loosen that to get everything free but let's use less barbaric method shall we a proper spanner wrench shouldn't take long to make yes I'm aware I haven't even gotten this apart and we've already started the first side project for well there went an hour okay I'm lying it was actually two I may have gotten a little carried away making these actually look nice to be fair though I'll be using these for all future adjustments on this lathe so it was justified somewhat okay now you can really see the wear on each of the parts hardly any meat left on the threads in this section and the insides of the nuts don't look any better all three of these need to be replaced I could probably manage without making any drawings but this is the type of project that's just complicated enough that I better play it safe I want to get to the making quickly though so we're going to do this with the help of today's sponsor shaper 3D shaper 3D is an instinctive 3D modeling software and despite my somewhat masochistic drafting demonstrations on this channel I'm no stranger to 3D modeling which gives me a little bit of credibility to say that I'm Mega impressed with shaper 3D after a 10-minute tutorial to get the gist I was up in modeling from there everything came almost in distinctively it's like it knows exactly what I want to do only relevant tools show up based on what you're doing and many of them activate automatically depending on what you have selected so there's no need to go hunting through azillion tabs only to forget what you went looking for okay maybe that's just me there even a couple Easter eggs in here that just make sense like the fill and champer tools being the same command go ahead admit it you want to try this now too don't you shaper 3D behaves like a direct modeling software but is technical enough to be used for my engineering project objects and if you're really attached to your modeling tree there's actually a beta version available that lets you toggle between history based design can we just admire how clutter-free the workspace is makes working on a small laptop screen actually Pleasant which isn't surprising because shaper 3D was designed for iPad as well so you can get your ideas down in the moment in short shaper 3D just doesn't get in the way of your creative process whether you've never used CAD before or a seasoned professional I think you'll like shaper 3D especially because of how quickly you can get your ideas from in your head to on the screen plus there's a free trial so it costs nothing to add a new tool to your shop use the link in the description and when you're hooked use code inheritance 10 to get 10% off your subscription and just remember you can do this okay so I've got myself some drawings here and I've got my material so we're ready to start making parts right not so fast hot shot to cut the threads I'm going to need an Acme thread cutting tool specifically one for a 10tpi thread I could just Wing this on the bench grinder like I usually do but I kind of want this to be precise if only there was some other grinding machine in the shop that could do such a thing okay okay I'm going to make this cutter on the surface grinder but it's literally been over a year since the incident and after my recent layout change this machine isn't quite ready to go so I got a little bit of work ahead of me the whole start of this lathe restoration involves stealing the phase converter that was dedicated to this grinder I did fortunately think ahead enough to put a three-phase outlet back here but never got around to wiring the machine back in it's also usually a good idea to level a machine helps the oils and coolants flow how they need to and generally prevents the machine from walting about okay now to address the elephant in the room this busted grinding wheel other than the obvious risk of this wheel exploding this missing chunk also severely imbalances the wheel which could ruin the spindle bearings on this machine so off it comes Believe It or Not these wheels started out the same size and the same color and this one only had a handful of projects under its belt so it'll be interesting to see how long this new one lasts now this isn't just as easy as popping this back on here this wheel is likely offc Center and has some small inbalances that need to be corrected so first I'll true the outside with a few dressing passes then it's back off here and onto the balancing stand if there's a heavy spot on the wheel it will rotate to the bottom so small adjustments to the weights on the spindle Hub remove this imbalance the idea is to get the wheel to a point where it doesn't try to spin from any position I set it in perfect okay now we can get to what we came here for grinding the angles on this thread cutter which means I need a way to hold this blank at surprise surprise an angle perfect job for my beef cake sign plate I built this tool last year and while it's a bit Overkill it will work fine for setting the cutter at a precise angle Acme threads have a 29° angle so I need to set the sign plate to half that at 14.5 but I also need some side relief to clear the Helix of the threads I can do this by angling the cutter like this but this also affects the original cutting angle I tried to figure out the trig but no beans so I cheated with cat again I found that if I tilt the cutter 20° I actually have to increase the sign plate angle from 14.5 to 15. 38° this gives about 5.4 de of side clearance while maintaining the 14.5 de needed on the cutter face so so taking the sign of 15.38% I'm just taking passes about 15 th at a time until I'm about halfway so nothing too exciting but despite that it feels amazing to be back at this machine I used to use it almost every chance I got because it's such a meditative experience running back and forth back and forth slowly bringing apart to near perfect flatness it's honestly easy to lose track of hours at this machine the other side is the same deal only I flip the angle block so that the cutter relief is in the right direction last is to grind the tip square and the right width everything seems to line up with the Acme gauge so I guess I did something right and finally after all that I have the cutting tool I need to make the replacement lead screw so that's next right wrong again to make the lead screw I need to make the lead nuts first but to make the lead nuts I need an Acme tap so we're going to make the one I need now I've never made a tap before let alone an acne tap heck I've never even used an acne tap so I don't exactly know what I'm doing here but I'm going to give it the old educated guess on top of that I haven't mentioned yet that this is a bit of a weird size by my measurements everything points to this being a 14 mm x 10 TPI acne thread not a standard size whatsoever but it makes a little more sense considering this is an imperial machine made in Taiwan so the units are going to be mixed in places whatever the case I'm going to do my best to duplicate this regardless of how Oddball it is after turning the first side down for the stem I'll flip this and start on the business end this will be a progressive tap so there are two diameters here the first one about 20 th smaller than the other I don't know if this is strictly necessary but every Acme tap I can find pictures of has this sort of geometry so logic tells me it's important I'll set the compound up at a shallow angle to cut the taper at the beginning of each thread section then we can start in the actual threading which I now have the correct tool for I'm going to feed the cutter with the compound so I'll set it the 14.5 de and since I went through all the effort to make sure the angles of this cutter were dead knots I use the Acme gauge to get it perfectly straight all right here goes nothing ha it works it actually works this is awesome and it seems to be making a perfectly consistent chip I guess I did something right this is a bit of a wide cutter compared to a normal 60° point so I'm taking the cuts easy at about 5 thou per pass and using the three wire method as usual to measure the progress though I will admit I cheated once again and used CAD to figure out what the three wire measurements should be for this Oddball size of mine now I mentioned this is a progressive tap and on this diagram you can see the cutting teeth are a little narrower in the roughing section obviously I don't know the exact parameters for something like this so I'm just going to wing it and cut the first section of threads smaller to do this I'll have to set the compound to 0° so I can move the cutter left and right and because I've done this now I have to come back in and pick up on the existing threads which is basically just a matter of engaging the thread feed giving the spindle a little bit of a bump to pre-load the backlash correctly then using the compound and cross feed to align the cutter back into the existing thread Groove this gets me aligned but to make the teeth actually narrower I'll Advance the compound a couple th at a time then do the same in the other direction so that the teeth come out symmetrical if you didn't quite follow that basically I just made the threads thinner in this first section so the tap doesn't have to do all the work all at once let's go over to the middle and cut the flutes I think normal Taps use a grinder for this step but I'm not quite equipped to do that so fingers crossed this ball End Mill works I have the cutter set up slightly off center though so that I can get a proper rake angle but now I'm seeing quite a bit of deflection with this sticking out so far I'm going to need some sort of support here if only I had like a tail stock for this Mill actually hold on a second okay this is a bit janky but should do the trick oh yeah that's so much better not bad for an extra 10 minutes of work okay maybe it was 20 but I'll be keeping this around for future setups like this last step is to switch Callet blocks and cut the square drive on the end all right that turned out pretty good though I am seeing why these flutes are normally ground behind every one of these little edges is a little Burr that I now have to figure out how to remove oh wait I have just the thing actually this may seem a bit persnickity to even worry about but if you consider how a tap works one single bird on one single tooth could wreak havoc through an entire part so this extra precaution is definitely worth it now I'm cutting in the soft bronze and this 01 tool steel was probably already hard enough to work but again I want the best chance of success so we're going to heat treat this no no no ran out of propane so much for that time for Plan B now that is a torque I really should have just used this right from the Geto I wasted a whole tank of propane to do what this oxy acetylene torch did in 3 minutes a quenching canola oil puts us around 65 Rockwell which is good for cutting but also very brittle and I'd really rather this not break so I'm going to Commander the oven for 2 hours to temper this at 400° F all right now we've got some time to kill I can't make the nuts until the tap is ready and I can't make the screw until I tap the nuts but I can work on this other end of the shaft until then I got a piece of 1144 stress proof here which I'll be honest I just saw Blondie hacks use for a similar project but supposedly it's stress reliev so it won't warp as I'm Machining it and it has some additional elements in it that make it pretty hard all by itself without additional heat treatment so it should be perfect for this [Music] most of the diameters on this end aren't super critical but there is one right in the middle that slides into some bearings so I'm taking care to get this one pretty much dead nuts there's also a tricky metric thread here or at least tricky for my machine because it's Imperial which normally means I can't disengage the thread feed as I approach the end near the shoulder but with some careful timing I can actually disengage the feed at the end of the pass when I reverse the machine I just have to re-engage on the same exact thread dial Mark to get back to the start the only thing I have to be careful of is not to let the thread dial go all the way around because then I'd be screwed pun intended that's the first half of the shaft complete and just in time because the tap is finished with its tempering cycle still needs a few finishing touches though first is to remove all the mill scale from the heating process we don't need any more stuff coming up to works and something I'm not even sure is going to work in the first place second is the sharpen the tap which I can do carefully with a die grinder I mainly just want to make sure that I have a nice crisp Edge so that it cuts well on all the flutes all right I I think I've considered just about everything on this tap let's make the nuts I'm using some 932 bearing bronze here which is basically exactly what this material was made for all right moment of truth time to see if this tap is actually going to work I'm taking it easy here because one I've never actually used an Acme tap before so I don't know how hard they are to turn and two I really don't want this to break so I was pretty on edge when this thing started getting tighter but with some very small advances backing off a lot clearing the chips and generally keeping everything drenched in oil it kept making progress the torque was even enough to spin the part in the Chuck we made it past the roughing section without breaking though so I think we're good the finishing end is only clearing the remaining 10th hour or so around the thread profile and it's a lot easier going and just like that I'm all the way through and my first tap is a success this is a huge relief considering how much time I've sunk into this already I did realize something about how tight it was getting though there's one clearance I didn't consider on this tap and that's on the tapered section I think there needs to be some relief on the back of the conical cutting edges because they're actually increasing in diameter and wedging themselves in place so I'm just going to grind these down slightly and hope that the second knot will go more smoothly that actually made a huge difference this one only took about half the torque to get the tap through that was a big brain moment right there man I'll tell you what seeing these chips on this handmade tap is one beautiful sight and a not broken tap might I add I'm pretty stoked about this the tapping did bulge out the ends of the bronze nuts a little bit so I'll Chuck these up and reface the ends clean I'm not quite ready to finish them though to do that first I need to finish the lead screw this will all make sense in a minute so hold on this end gets a sort of round nipple doohickey so I'll put this on here before Center drilling the rest of the shank is turned down to the thread diameter the one difference this replacement screw will have though is the thread run out area the threads on the original screw stop abruptly so I think they were Ground rather than turned but this section of the shaft isn't used so it's no problem to do it my way now I can finish this out with the Acme thread I was a little worried at first with how long this section is even with tail stck support there's still the risk that vibrations could be a problem near the middle but keeping the cuts fairly mild seems to keep me out of trouble and once the bronze nuts fit on we're done with the shaft but it turns out this shaft is now the perfect Arbor to finish the nuts on so I'll thread both of these on here and lock them against each other with some pliers not only does this make finishing these parts easy but also more or less guarantees that these outside features are perfectly true with the threads on the inside the Final Touch is a set of threads on the outer lead nut unfortunately I thought ahead and put the locking ring on here so I can test the fit of the threads as I go all right these are almost finished I just have a few external features I'll need the mill for so once again I'll use the screw shaft as an arbor in the collet block and then tighten the nut against the collet this nut gets a set of spanner slots which are easy enough to do with the slitting saw and the other nut just gets a shallow hole for the retaining screw all right that's everything let's get this all to H almost forgot something the set screw hole on the handle okay now we're ready to get this all back together after adjusting the lead nuts the backlash is pretty much gone and that goes for the full length of travel I expect this will need a Breakin period and some Readjustment later but hey that's one problem fixed when I started this project I certainly didn't think it would be this involved though to be fair I didn't exactly make it easy on myself but that's all part of the fun for me honestly after some Inception levels of side projectory I've not only fixed one of my bigger issues with this machine but also made five other tools got another machine back in operation and even learned a few things along the way so yeah I'm going to call this a success but there's still a lot more to do on this machine so I have all my fingers and toes crossed that they'll be a lot more straightforward than this one was eh who am I kidding no I don't bring on the side projects as always thanks for watching and see you next [Music] [Music] time

Channel: Inheritance Machining

Views: 579,206

Keywords: inheritance machining, inheritance, tapping, acme, acme thread, threads, threading, thread cutting, sine bar, trigonometry, lead screw, 3d modeling, cad software, shapr3d, spanner, spanner wrench, grinder, milling machine, lathe machine, restoration, bronze, machine shop, machinist, machining, machine, machine tools, storyteller, maker, cathartic, humor, engineer, youtube, asmr, dad jokes, satisfying, do it yourself

Id: 1l2_uCyBXQ0

Length: 28min 26sec (1706 seconds)

Published: Fri Dec 22 2023