SNS 310: Machining a Cast Iron Prism Straight Edge

[Music] guys might remember this this is the cast-iron straightedge that my buddy Lance sent me that I'm doing some trade out work for he did some tool grinding for me and this is one that he needs to get machined so he sent it to me for me to do so we're gonna go ahead and get started on it what I want to start with first though is just kind of dressed down the high spots of the casting light like right here there's a high spot there these little raised ears I'm just gonna try to dress that down on the top of it here or maybe the back there's some high spots there so I'm just going to kind of even out the cast first with the hand grinder and then we're gonna go to the knt mill and I'm going to make this a mill project we'll probably start with will putting this in our 8-inch vise we're gonna mill the ends and the top to begin with and then once we do we'll start rotating it and getting the milled in the angle I haven't decided how I'm gonna do it but I think I think I have a game plan so anyway let's let's go get started on these are a couple wheels that I just recently bought from KB CTools just got two different brands here the CGW and then the other one is superior abrasives these are stripping wheels you can use these to shrimp paint or polish metal with and they work good for things like this where you just need to knock down some high spots or polish it or deburr or if you want to polish metal like this table right there or if you got something that you want to do some stripping you know paint stripping and that kind of stuff they're they're excellent for that so I just got a few just thought I'd show you what I'm gonna use here I think I'm gonna try the superior though and I'll see how it does I'm using my sandpaper trick here in the vise just got a coarse sandpaper taped to the jaws and this always helps it helps bite in on raw castings and it provides with the uneven surface that you're trying to clamp on there as well so I think what we're going to do is start with this side I don't know what side this would be considered on this straight edge but we're going to start we're going to cut this one since I've already got my face mill set up and I'll take that out and do the side milling and then once we get this one done and we will take it out and flip it that way and then we'll deck the top of that one right there I think that's I think that's what we'll do or maybe we'll well deck this one deck this side and then put the end mill in there and do the size I think that's makes a little bit more sense I just want to get it kind of equally spaced here five eight seven eight I do need to check level here I'll probably run an indicator across this right here just to make sure that this casting isn't out and it's kicked at an angle you know so we'll get this kind of averaged out across the surface and everything is going to be square to that one just give it a check see what it does okay we're a little low on that side it's like we're about 25,000 slow on that end right there so I might just put a jack under there so that we can slowly control how we move this thing [Applause] [Applause] all right that's indicator says -5 - ten try that right there - five [Applause] yeah I think we're averaged out pretty well right there where it's at we're ready to make our first pass across the prison here I touched the corner off and I fed down what I think is going to be a clean up I'd like to try to clean it all up at one time but if it looks like it's not going to clean up this edge here we'll come back and start over again so we're from touch off we're 155,000 steep on the on the back corner and hopefully it is clean up this front edge lock the table here [Applause] [Music] well it was our first pass across the the first side there and we got it all cleaned up and it looks really good very nice [Applause] we're ready to turn it in the vise you see we've got the first side that's been machined right there and is nice and smooth we've got everything cleaned dust free I've got a parallel sitting down there in the bottom that we're gonna use to raise it up so so we're gonna go from that side we're gonna rotate it back one I'm gonna leave the sandpaper on this side to push against that edge right there and we'll just be pushing it against the machined the machine to side so let's get it even again I think it was four and seven eighths is what it was supposed to be yeah go this way just a just a touch all right tighten it up just just seat it all right there we go and then I've got these again we're gonna put these little machinist jacks we're gonna have to raise them up now just want to put them underneath the ends just to kind of help give it a little bit more stability out here on these on these ends here looks like we're gonna have just enough yeah okay just enough I'm just gonna just finger tight it just like that and then we'll do the same on the other side there establish our touch off here see if we could get it all the way across there [Applause] alright guys here we go a touched off and we're going to take 30,000 hopefully that'll clean everything up nicely [Applause] [Music] after the first pass across this side here I went ahead and fed it back the other way taking another ten thousandths only because that that first initial pass I was feeding at ten inches a minute and I did the finish was fine but it was a little bit coarse for what this is going to be used for because this is going to be scraped in so I thought it'd be nicer to kind of match what I did on the on this side here which is five inches a minute so we did five inches minute across there and I like that it's got a lot smoother feel to the finish there so I think we're just going to continue to finish all of them at five inches a minute for at least our finish pass anyway so we're going to go ahead and I'm going to take the face mill out and we're gonna go ahead and side mill both sides of it right there with an end mill and then once we do that we're going to break all this down I'm going to have a totally different set up to machine what what is now the bottom here and this angular side there [Applause] that was a total of 1/8 to the net but you can see right there at the very top well boys in there I'd like to go ahead and clean that up and get those out of there so make another pass across there clean it up all right we got both ends of it machine now that did really well I'm really surprised but happy with the way that this iron is machining I was worried that maybe be some hard spots in there that they call chill whenever they gassed them but this has been good it's been soft and easy to machine ends look good top and bottom well the top and the back looks good so time to take it out of here and we'll change our setup so that we can finish out our last two surfaces [Music] all right we're set up and ready to machine the other two sides of the prism and what I'm using this time is my Carver machine vise so these are manufactured by a company called Carver they're out of the UK so they're a European made I had a viewer probably three four years ago at least give me this as a gift and I used them several times over on the current horizontal Bora mill when I was at motion as well as the vertical mill there was a there was a few times I was making these large brooch plugs and I had to mill a big key way in this broach plug and this was the the perfect setup to be able to hold that big brooch plug in there and milla so I've got them bolted down with two five-eighths bolts on each side right there this one is the fixed jaw so this one you just bolt it down you've got just enough room underneath this moving jaw here to I use a cont pea not a combination square machine is square to square this one up nice didn't bolt it down and get it nice and tight and then what I do is I put a toe jack behind it there because I have found that even though you've got these things bolted down real tight it still tries to push it back if there's nothing to back it up there so toe clamp back there keeps it from trying to move after you get so much torque on it the this one here the same thing you bolt it down it bolts the center block down and then you tighten up this nut which actually pushes the orange housing that way and then you can draw each one of the jaws down with this nut right there and we've got it we've got the square or the straight edge I mean bolted down you see I got my parallels nice and tight tap down we've got brass shim stocks in between there to us to protect the surface you can see these are some deep serrated jaws on there to really kind of bite it in and hold on a workpiece there so just trying to protect that Assad we should be good to go I've got everything tight and we're not taking any kind of big heavy cuts we just want to touch off here and just clean it up you know maybe 20 30 thousandths hopefully and we'll see how that does and once we get this side done we'll go ahead and flip it over and I'll you know get the angle knifes of leveled out and we'll hold it the same the same exact way to machine this angular side there as well so we're ready to roll let's go ahead and start doing our cutting [Applause] I'm here to slide him outta chatter they're in the center I think what I see a gentleman putting Machias Jack under the bottom there to support it didn't think about it till after I started making the cut I'm just going to let it finish you know we want to make another thread across there we'll see how the penis works so unfortunately my little machinist Jax is too tall to go up underneath there this is a common problem that I've had several times where the Jax was just too tall it's almost like we need 1/2 this size be a nice shop project to make a small set of a shorter set of machinist jacks so next quick solution without spending a bunch of time just to use I can adjust the parallel but in this case I'm actually using a big planar gauge that I have and I've actually got this snug underneath there okay I just adjusted it until it was snug I can kind of slide it back and forth but it is tight so maybe that'll help dampen the vibration in the center I'm gonna head might bill to see it right there see it it's also a little bit low to there's still I mean it's cleaned up but I can still tell it just barely clean the surface up so we're gonna take another ten thousand so I slowed it down to two hundred forty six rpm to kind of reduce the surface speed and help maybe it will help eliminate this little bit chatter right in the very center the rest of it did really good just started right there and went away as one across that second pass did the trick we took a total of 30,000 so it was 20 thousands the first passed and then we came back that way and I took another 10,000 off of it and it cleaned up nice there's no chatter wasn't bouncing or anything so I think our planar gauge right there work plus slowing it down one notch on the speed really helped there and it's nice to men it's just silky smooth that finish on there really happy the way it turned out so all right it's time to loosen it and I will get it rotated leveled out and then we'll cut this last side right there that angular side all right we're just lining it up with the protractor they're on 45 degrees that's what this angle is actually cast at at 45 degrees and this is not a critical dimension it doesn't need to be indicated or just dead nuts on 45 that's actually gives clearance whenever you're scraping in dovetails on on lays the dovetail is usually 60 degrees so 45 degrees gives you plenty of clearance because they take they stick this thing up inside the dovetail and then they raise it up to do their print and then pull it back down and get it out of there so we've got our lined up very very close by sight on this scale with the protractor set at 45 and what's neat about these Carver vices right here is that once you once you get it tight here once you get it squeezed you can actually crank these guys down and it actually pulls the it pulls the workpiece down onto your parallel tight so we've got it down tight on the parallels now so we're ready to go ahead and start taking a cut on this thing get it cleaned up there we go with our first cut for the 20,000 step there [Applause] [Music] [Music] as our results for the first pass there you can see we didn't touch right in this area here little bit low this side looks beautiful I could see a little bit of lower right in there as well so we'll just take I think we'll do another 20,000 and come on back all the way down that side and I think that'll probably clean that up you'll see looking good we're almost done planted up taking 30 thousands on this last cut right there and you can see we still got a little hollow there to clean up I did I did my 20 and come in it was still open there so I took another 10 didn't quite clean it up so that was 30,000 but that also helped clean up this edge over here on this side but I think I'm gonna bring the cutter back down to this side here and let it cut into the sharp edge right here to kind of help eliminate any chipping we got to take one more to clean this up plus the you know the different corner but I want to clean that up there as well so probably another twenty to thirty thousands is what we need to take off there to clean it all up and make sure that edge is cleaned up [Applause] I think we're gonna get at that time [Music] [Music] [Laughter] okay our prism straightedge is now fully machined and I have filed all of the edges so everything's rounded off nice so the millwork is now done but there's the actual work on this is far from over what's going to happen with this prism here is lances going to end up surface grinding it and get it as flat as possible using the machine and then once he does all the surface grinding on all the edges he'll didn't hand scrape this in so I did in fact confirm with him that this is a this is a scraping job or a job in general that he's doing for a customer there so this is something that he's doing for somebody else so machine it in you know get the rough casting off of it surface grind it nice and flat and then hand scraped it in fact I've got a I got a short clip there of another one that he just finished up that I'll throw in right here so you can see what it looks like whenever it's finished up so the other thing that I want to bring up before we in the video is this appears to be nice and straight and flat right well I've got my straightedge out this is my precision ground straightedge and just doing some visual checking on all the sides it is not flat it's got a slight amount of curvature to it alright that side it's pivoting in the middle all right so we got a little bit so it's sort of curved that way all right and then whenever I check it I check it this way right here this is the side that we just machined right I can see a little bit of a gap in the center so it's actually bowed in the center that way right and that's I imagine that's because of the clamping forces that I put on it on the end squeezing it like that now let's check I'll go ahead and check this side right there I'm gonna have to clean it up this way and pull it in there all right same thing you got a little bit of a bow to it in the center so he'll definitely have to get this thing ground in so that it's nice and flat there's tricks that you have to do in order to whenever you suck it down to the mag keep the bow from pulling back into it once you release the mags that's a whole you know trade in itself and tricks that you got to do to try to continue to get it as flat as possible so that's just an example right there whenever people when they're curious and they ask questions are like why can't you just mill it it's flat whenever it's milled but no it's not in flat it's not perfectly flat and you have to hand scrape it to get it there so machine it surface grind it and then hand scrape it so that you have you know anywhere from say 20 to 40 points per inch along the surface there even straight contact and in a nice even plane there so I think that I honestly think because I've been machining these cast iron pieces like this for a little while now if I do this on the shaper like the straight edges already done I typically get on something like this about 1/2 a thousands out of flatness across one one face right there when I do these things on the milling machine I always get more than that I always get a few thousands out I think that if I would have done this on the shaper it would have been a lot more flat than doing it on the KMT mill so anyway my work is done here now I'm gonna get this thing sprayed down with some rust inhibitors so don't start flash rusting and I'm gonna be actually hand-delivering it to Lance because we got us a little weekend camping trip coming up soon so I'm just going to take it with me and give it to him and then he can start his hand scraping on this prism they usually tapped the ends there as well and they have like candles put on the ends so that whenever somebody is using this to do your checking so you're gonna use this surface here you have your handles and you come in and do your print and then pull it back out and then read it so there we go all finished up hope you guys enjoyed we'll see you on the next job alright [Music] [Music] [Music] [Music] [Applause] [Music] you

Channel: Abom79

Views: 389,058

Rating: 4.8944192 out of 5

Keywords: abom79, straight edge, cast iron straight edge, prism, prism straight edge, cast iron, milling cast iron, kearney & trecker, kearney & trecker milling machine, facemill, face mill, carbide insert mill, sky hook, tmx, tmx vise, milling vise, milling machine, manual machining, manual machinist, machine shop, job shop, Carver, carver machine vise, machine vise, two piece machine vise

Id: RhTsGgRxViE

Length: 44min 19sec (2659 seconds)

Published: Sat Jun 20 2020