Lathe Tool Cutter Height Gauge

so this tool is going to seek to address a problem that everyone rates a lathe has and that is to line up your the cutting edge of your tool with the cutting axis of your lathe and if you are off the off axis you can have your part try and climb on top of your tool you can have premature tool wear and breakage so a lot of times not always depending on the tool you want to be right on center and getting there can be quite challenging one of the common solutions is to bring your Center up to your tool then attempt to line up your tool the point of your tool with the point of your Center but being a point it's a very small point in place in mathematical terms a point has no length with their height in reality obviously that's not the case but it's extremely small so getting them to line up is very hard and the closer to dead center you are for a lot of cases the better cutting action you'll get and let the fewer problems so this method is one it works ok for a rough estimate but I find it very difficult to get it right on let's look at another approach so the next approach the one I learned in school involves taking a tool that you always have close at hand or most people do which is a rule and placing the rule between the point of the cutter and the workpiece and you will notice that it's tilting significantly forward so as you adjust the height closer to center I'm just going to rough it then the rule being pressed between the work and the center will when accurate go to perpendicular so right now I've gone a little bit over and now it's pointing the other way so if I drop it a little more that's roughly centered right now because the rule is vertical there are some problems with this method one if I if I have the cross slide applying ten pounds of force on this carbide cutter and the very point of the carbide cutter is a thousandth of an inch I will effectively be plying applying ten ten times a thousand or ten thousand pounds of force on the very tip of that cutter pounds per square inch which is extremely high and makes it very easy to chip your cutter also there's a second problem with this which I'll show you now so the second problem is when the diameter of your stock is large because the window of error increases because the curvature of the side becomes closer to approximating a line so it has an approximate flat the less deflection you're going to see in your rule so I have thrown my cutter way off center and you'll notice there's only a slight shift in angle and as as I move the cutter up quite a bit it gets harder and harder to tell whether the cutter is exactly on the axis or not so Jo pies in ski in his video has given us a third way to do this and it's really straightforward and really simple I will be providing a link to his video and the only reason I am going over this is because I want to make the tool that he demonstrated so since my videos were all about making tools for the most part I thought that it would be fun for me to make one and it's a very useful tool for me to have and at the same time I might make some variations on his design so Joe's solution involves the ground part of the ways of the lathe and what he did was he created a piece of aluminum that was exactly the height of the center axis of the lathe and he cut a milled a flat into it so that you could bring your tool cutter up while leaving the aluminum on the flat of the ways and line them up and get your height right on so the next step if you want to make this is what exam you exactly find that height I have a 14-inch lathe so you might think it's exactly 7 inches but it turns out that it's not so the next step is to find the height of the center axis of the lathe copying joepie Z&C school solution I have got a gauge pin in here that's a half an inch gauge pin and look for the high spot that's pretty close to zero it's really touchy there's a half thousand syndicator so if I set that at my zero now I've built a stack of gauge blocks here that also reads zero so now all I need to do is I need to take the stack of gauge box add them up and subtract a quarter inch for the quarter inch that's above the center axis of the half-inch gauge block so you can get a better view so that's all I did so you can see it's really close within a half a thousand and there's the high spot there's the high spot on my gauge good so when we're done we should be able to get this within a thousandth or so so now that I have a height all I need to do is cut out a block that's very flat and parallel and that I can set on the flat part of my ways which is right here so the flat part of my ways and then I can set my tool height based on that all right so this is some one a quarter inch aluminum stock my first task is going to be a rough finish rough face the bottom so I can Center drill it because what I want to do is I want to extend this material out enough that so that I can dimension it across its entire length and so I'll need the live Center for that so also it's going to be very important that the bottom be really flat and parallel with the vertical surface so that's why I'm only rough facing it right now so this point I'm going to Center just a hole center drill the end of the part which will be the bottom just to hold the live Center it should be good so this first pass is going to be a really light pass and it's just to make it round essentially because what I'm interested in is having a round surface to clamp on to with the Chuck so that I can then check for taper because I don't want there to be tapered because taper would imply that it's at an angle and not square with the base those first cut I'm just taking off 5,000 - the 4144 Molly this step that's just beautiful especially with this new positive break insert sameer tennis all right so I just wanted to make sure that my part was not only round but that there wasn't taper in the shaft I did notice something on this with this one-inch indicator that being stuck out like this that as I move it'll look like it's going to be off a thousandth but it's actually not and that's me if I'm pulling back on the cross light as I move it because you can see here just loading and unloading it's causing a little flexion in it but in any case there's not any really discernible taper so that's good so we can move on to facing it and drilling for a magnet I want to put in the bottom to hold hold it more steady while I'm doing the measurement so we're going to drill for fifteen thirty seconds so next I need to bore this out to 0.499 ordinarily this would be a terrible idea with so much stick out but a very thick large diameter kind of thing a very small cut very okay so our last pal pass got it into 0.499 and I'm just going to deburr it a bit and I'm going to test fit the magnet so this feels like it's going to be a perfect pressed fit that's really tight just starts okay alright so it's part in time and I only need to stop and chamfer this because it needs to made up flush so we're just going to part away as I get closer to the middle the linear velocity actually decreases and the service fee permit decrease so I'm actually going to speed it up try and keep my cutting speed somewhere to make sure to stop periodically and break it to nearly I also left this side about 1/10 large on purpose so in case you're wondering why I left the overall length a tenth of an inch larger it's because for thumb McGrew as he's walking over to put the senior drops on the ground and Dinks the bottom which is one of the reasons why I was a little hesitant to use aluminum to begin with because it's so delicate however the ways themselves you know I didn't want to risk a harder material that would scratch the ways because if anything gets damaged I can always make another one of these and having the ways redone well that'd be expensive so I'm going to face this side again that I board the half inch hole then we're going to turn it over and cut it to length bore the half inch hole on this side that will hold the stainless steel portion of this tool so this next step is really straightforward but I just wanted to mention it because I'm going to follow the recommendations of machining book I I was reading from the 1940s and it said if you want the best whole possible a spot drill followed by drilling followed by boring because the drill roughs out the material the boring makes it you know parallel to your axis of your lathe and finally remit to size so I'm going to give that a shot see how it works and see if it does a good job I'd like a really tight fit good sign doesn't sound like it's an interrupted cut so it sounds like we're pretty much on axis all right I don't want to go a little slower hindsight a little bit of deburr and just for the hell of it I'm going to take a measurement see how close we are should be right on I measured the reamer ahead of time but Oh almost to one and a half thousand so ver so we'll need to take that into account when we're doing the stainless steel next so next I need to turn down this about 3/4 of an inch of this this is stainless steel 303 I need to turn down about 3/4 of an inch of this down to half an inch so that it will be a press fit into the aluminum part so let's rough some out of here is one 1/4 stock or try some hundred thousands passes so let's see that's not incremental so we're at about PI point five one three six so I need to take one more pass at least but it's kind of warm so we're going to let it cool off before we do that plus I think I'm also going to chamfer the end and make it feed in the other part more smoothly really tight can't won't go on which is good early 680 rpm 2004 resolution that just starts and it just starts we're really close I think I could probably fit that on you know press fit that on right now yeah I'll take it down just a tiny amount with sanding standing removed material on the order of well depending on the grid of paper of course but this fine a grid something on the order of 10 1 to 2 tenths every time yeah okay that's going to be a really tight fit as perfect leaving a film of aluminum behind it perfect so I've got a little bit of a burr here and a little bit of burr on the inside not to sit on a bird and it should do it all right so the two sides press fit together really nicely and now I am going to pin it so I'm going to spot drill it drill and then ream for 1/8 inch pin okay so we're gonna go three eights down from the top this total length of the aluminum part here is four inches 80 thousandths the top part is to will be three exactly it's actually a little long right now so that holds a bit larger than the 8th inch but that should help start the pin we're going to drill undersized hurry about this freaking cold Phil next step pin it and then finish to height once we finish the height then cut the flats way back here at the mill okay so I'm using a hardened steel pin and that went in very nicely I'm going to counter set that this is an inch and a quarter in diameter so but there you go I will set it a little lower me an eighth inch below the surface on each side okay so we're sort of our final stages here right now I am trying to get the total height of this bar to be seven point zero eight zero so I'm taking off a facing pass and then going to the surface plate measuring coming back I'm taking it slow I'm about thirty thousand plus right now so I'm gonna take a twenty thousand pass going measure come back and see the problem is every time I leave and come back since I have no way to reproduce the position of this certainly within a thousand I have to retouch off and that sort of gets you off by a thousand so I have to be really slow and meticulous about this three thousand town about 11,000 tall 7,000 in case you were wondering this was 302 stainless steel it's an easy machine forma stainless steel not quite as corrosion resistant as other versions but easier to work with in some regard finishes very nicely all right so let's take this over the surface plate and show you how we're measuring so I got my stack gauge blocks back again two seven zero eight zero and then set this to zero on that stack and then face this until we got really close all right so now we can take it to the mill and cut both sides to get some flats to have our tool measure up against all right so let's find both our zeros this is definitely not a critical full set of adjustments here surely access so absolute values are not important however I would like to take off as much material on the top as possible only because the weight of the the density of the stainless is a lot higher than the density of the aluminum so it's top-heavy so the magnet helps that but if I can get some more weight off it'll be even better all that rz0 so let's do hundred thousand we're gonna take about three or 50,000 to side so you're not going to want to see the whole thing so I'll just show you if you're doing not to mention that the large depth of cuts causing a lot of vibration in the camera so we'll skip this and I'll just show you setup so when I flip this over you have a problem if I want to get it exactly 180 over what I did was I put the flat down which actually doesn't touch the parallels and then I use an adjustable parallel and swept across to get it flat and that was pretty much it so we're going to cut the other side we have to refine zero and then we'll be done okay so putting it all together putting a tool in the tool post placing the new magnetic height setter on the ways and bringing your tool close you use the fingernail test except in this one I can use the finger test because it's way off so drop it down still a little bit a little closer still needs to be a little lower nope too much the other way beauty's your fingers are amazingly sensitive and you can get surprisingly accurate results this way and there we go and I can tighten the nut and ready just as a side note running through my tools about half of them were off like this aluminum one just off by a little bit which probably says that being off a little bit isn't super critical but why not be on as close as possible so another useful technique I discovered was that for really sharp pointed tools you can turn this to one side so you can go parallel to the edge and get a much better surface to compare against it also works for boring bars which mine is way off here so here's the new tool in my arsenal we're setting height on all of my cutters alright

Channel: Dudley Toolwright

Views: 462,279

Rating: 4.6691227 out of 5

Keywords: metalworking, mill, lathe, indicator, cutting, metrology, tool, measurment, dial, height, gauge, heat treating, lubrication, coolant, geometry, chuck, key, engineering, stainless, steel, carbide, cutter, drill, reamer, center drill, sanding, finish, caliper, micrometer, test, gage block, lathe spider, spider, set screw, bushing, spindle, tap, threading, height gauge, turning tool, boring bar

Id: iNhQYFsou1Y

Length: 31min 0sec (1860 seconds)

Published: Tue Nov 22 2016