How to hand scrape metal for flatness

today we're going to talk about ultrafine machining using and tools hey guys welcome back to metal tips and tricks my name is dale today we're gonna talk about scraping and scraping is the skill or the art of removing little pieces of metal scraping them off to develop an incredibly flat surface now you ask why would you do that well some people think well a milling machine is great well a milling machine is accurate let's say over six inches maybe a half a thousands if your machines in good shape if your machines a bad shape well let's just say accuracy is a relative term then we talk about surface grinders surface grinders are great you can grind accuracies down to two tenths really really easy but the problem is you only have a certain amount of surface on your surface grinder you could do that works you had a piece that was too large it wouldn't fit on the magnet you have to do it a different way and that's where scraping it by hand comes into play so the other reason you scrape something by hand has actually developed what we call a bearing surface that is two metal surfaces that slide together now when we scrape this the surface well let me show you here's a beautifully scraped surface and what it has it has a series of high spots but all these high spots are exactly at the same place so that also means there's valleys or low areas where oil can go in and stay it stays very well lubricated and will last a lot longer set up this way before I get started I want to give a shout-out to Jonathan at core print castings actually supplied the cast scenes that I'm going to be working on today they supplied this 45-degree angle dovetail it's 18 inches long he also supplied the 16 by 8 inch square this is gonna be sent up for another video this video is actually about scraping for alignment this one here it's about scraping for flatness but what we do here applies here let's talk about what we need to scrape first of all we need an object to scrape we've got the block here I'm going to do some tests on we also need different types of hand scrapers we need some bluing ink we need a paintbrush to wipe off chips we also have some precision ground flat stones and we also need a granite surface plate like this here now this granite surface plan I like it because it's small it's simple I can actually pick it up and take it over to other areas that's a great one that's only a great be actually a little too short for what I'm doing but I am just doing a demonstration when I do the final work on this I'll be done on my larger surface plate other thing you want to be cognizant of is how do you hold your material and that's up to you you've got to find a great way because I've got the setup on a very sturdy table also a magnetic Chuck off an old surface grinder so when I grab it it stays into place great great way of doing it so what is scraping so scraping is when we're going scrape off little bits of material at a time in a very very controlled fashion and we also have a way of measuring that by using a granite surface plate and also spotting dyes but we'll get into that in a little bit right now I want to talk about scrapers and the different types of scrapers now scrapers don't have to be fancy you can actually here's the very first scrape or I ever made you can see that it's actually an old planer blade with a radius ground in on it I use this for quite a long time you can also just take an ordinary file so if you want to play around with it you don't need a bunch of fancy tools so the different types of scrapers I'm gonna be showing today is I've got a large medium a small and then I've got something that doesn't lift and came up with and I copied I'm looking forward to talking about that but one thing you want to be concerned with when scraping is how much material you're removing and we control that by three ways one is we control it by pressure distance we scrape them the way we grind this radius here I work with four different radiuses and I've got a little radius gage that I made here um I've got 140 set up here a 90 a 60 and this one here is 40 and what we're trying to do is control how wide the scrape mark is when we scrape here is my big heavy scraper this one here has a radius of 140 centimeters and when we're talking centimeters instead of inches I don't know why that's just kind of the industry standard so I'm just gonna stay with it and the flatter this is the wider the channel is it's gonna make so let me show you here so if I come in here it's great you can see how wide this is now if we go in with one with a medium radius this one here I think is set up to 60 now look at how wide it is and that's the the more refined radius then we can go down to something really small this one here is a 40 and even smaller now you'll also see that the length of the scrape changes how much material we're removing and the more we press down the deeper we go so let's do something interesting here let's actually measure how deep these grooves are I've already ground this in and will actually measure how deep these scrapes are go with the next one the medium and then the fine now I've got something to measure here disadvantage to using a magnetic chuck is well metal filings stick to it so let me get set up here so we make some measurements so let's bring this in another salad this indicators a temp indicator so every mark on there is a ten thousandths of an inch let's see what kind of depth we get here so that's a half a thousandth four tenths has the length on this so we're averaging about a half a thousand on each stroke let's go to the medium Willett mediums hitting about four tenths and we'll go to the small it's hitting about three tenths I find that really interesting I expect it would be a bigger discrepancy between all these so they're all within about two camps I just found this really an interesting that's to see what's going on let's talk about surface plates so here the small granite surface plate actually got it a woodworking store those guys use these to put sandpaper on them and use them for sharpening it's actually too small for this job but I'm actually just doing a demonstration I'll finish this whole thing up on my big surface plate so we've talked about three different types of scrapers and how to control how much material are scraping off by pressure distance and the radius on the end of the scraper now we want to talk about bluing and bluing people call it all sorts of things we're just going to stick to the word bluing we're going to use two different types of spotting guys are actually colors we're going to have a blue and a yellow the yellow is the highlighter but what we need to do now is cover how we put down the ink and this is to me really really critical a lot of people ignore this step and shame on them because it's so critical because if you put it down too thick you'll get a false reading and there's several different levels just like we have different types of scrapers and different radiuses well I look at putting ink down as something you have to be able to control accurately and we're gonna have three actually four different levels of it where we're gonna have a thick moat a medium coat a thin coat and then no coat at all I know it's kind of cool to think of that when we get to a certain point when we're starting to get down to 40 points the ink is actually too thick and you can't get a really a strong reading and that's where we'll put the put our object down that we're scraping and when it's really good and you're really getting refined you'll actually move this around and it'll polish up you see these little facets in here those are all high spots that when we're at this point will scrape these off but I want to show you different thicknesses and this is the way that I do it I don't say that it's the right way I say it's my way but actually let me back up let me talk about how other people put down the dye they'll have another plate over here a piece of glass they will put their dye on there squeegee it out with a roller and then bring it over to here I have never liked that system because I don't have the control that I want what I'm gonna do here is we're gonna put down a real thin coat and I'm gonna develop what I call a formula and I'm just going to go in with two dots and we're gonna spread this out get that wheel rolling because you can see it just kind of repeating and we want to make sure that we squeegee this ink out through the whole thing now what's great about this type of diet we're using actually it's a paint that's not a dye but people will call it a dye it's actually water-based but it doesn't dry out usually use an oil base you can actually go to an art supply store and get an oil you know for like paintings and the reason the oil was so popular for so long is because it doesn't dry out well they've come up with new formulas now and they've actually come up with artist paints that don't dry out better water-based and you can clean these up really easy now you can see I've got a nice thin coat here let's do a rubbing I need to put a highlighter on this and we're going to go with the yellow the yellow is of course if you remember your art classes the opposite of blue so it's going to give us some contrast and we're going to rub that in nice and deep now why do they use blue well I think blues one of those colors that has traditionally been used since the beginning of time there are other colors you can use the problem with blue is well steel is kind of a blue color and it doesn't give you enough contrast so you have to go in with the yellow highlighter to give it separation so again why blue well blue is one of these colors back in antiquity blue is a very hard color to mix to get it dark enough because the pigment in blue is so fine well if you think about it we want something that is a real real fine fine pigment so it doesn't build up any thickness in the ink and I think that's why blue is still so popular is they people think in those terms so now you see this see how that set up now look at where all these high spots are anywhere there's blue that's a high spot you know what I talked about dots per inch we put this down this one inch square and we count up the dots how many dots so we have one two three four five six seven eight nine 10 11 12 13 14 15 16 17 18 19 20 22 23 and I'm kind of cheating on that cuz some of them are a little bit larger but I see if I cut that in half cut that one in half cut that in half so this one is done pretty nice but you can see how the high spots are set up and how much better the yellow helps the separation now let's go to the next level like I said I'm trying to set up a formula here I set this up and I just use two dots let's see what happens let's add three I want you to see this build up and I think you're understanding what I'm trying to do here is develop a formula you because as I put ink on here this becomes less ink here and eventually you have to keep re inking it now you can also see right now I put on too much but I'm going to prove my point here in a second and you want to get this even if there's any thick spots you're going to get a false rub there and you can listen to this and you'll hear the roller and you'll also feel the roller and you'll kind of know when it's out of position now this is also something you have to keep very very clean if you get any dust on this well you're kind of screwed so let's go for another reading now actually this end here is really a good example of a false rub see what happens when I put down the ink thicker I'm not getting this accurate rubbing as I should and now I look at this and I try to put my gauge on here and well that's just a mess so you have to be very careful with how much ink you put down the plate without an accurate rub you're doing extra work that you don't need to do so when I got these castings from Jonathan they were rough castings I called up teeth because well my milling machine when I moved I never got it put back together and I need to mill these and I wanted to scrape in the mill so I call it Keith records ed hey Keith did I come over and use your shop for a day and he goes I sure do I'll come on down [Music] [Applause] [Music] so again Keith thank you very much for letting me use your shop I know you don't let that happen very often so I feel very honored after we've ground it now the ground surface is too smooth to actually get a proper inking on this is what happens when you press it together think just kind of smush this out and it has no place to really go so you don't get an accurate reading next up we want to take a look at our casting and we want to develop a strategy here because it's either gonna be concave or bowed so what we do is we do something called hinging and hinging is when you pivot the piece where you want it to end up is you want the pivot here and here's you're going in about a third if it pivots there its pivoting here and it's pivoting here so what that's telling me is this is not straight let's see actually how this side does so that's pivoting here it's pivoting here so you obviously get to know that hasn't been completely scraped but by pivoting it or hinging it it's gonna tell us a story right now I know I've got a high spot here so what that means if I were to do a rub on this right now it wouldn't be an accurate rub because I might push here I might push here so what I'm gonna do first I'm going to pre scrape this and I'm not gonna do a lot of heavy scraping I'm gonna go over with a medium scraper and we're just going to do a quick scrape on this and then we're gonna bring it back to the granite surface plate and study it again another key component to scraping is stability you need a way to clamp the material down I've got here in a magnetic Chuck this works great I'm also on an incredibly heavy cast iron people so when I'm scraping I am making sure most of my energy is going into the part and not into the wobbling of a bench now here's something really cool because this is a magnetic Chuck I can use magnetic vblocks and clamp this in and now I've got a flat surface to scrape on for that 45 but now we're gonna work on the backside and we're gonna just do a quick light scrape over the whole thing we're doing out of 45 and I don't have to hit a hundred percent now I'm going to go 45 degrees in the other direction and this has served me two things one is its averaging out and cutting these other scrapes in half so I'm getting more bearing surfaces trying to get again to that forty points the other thing is it prevents you from getting chatter and that's the other thing you want to worry about so let's go on this side same routine we're not trying to get a hundred percent now we've raised up thousands of little birds so I'm going to take my sharpening stones here these are actually ground flat and I'm just going to go over this get rid of any of the birds bring over my surface plate now normally I would not be moving the surface plate back and forth actually wouldn't be moving it at all but I do keep where I'm scraping and my surface plate separate because these filings have a tendency to stick to the oil paint and that's just not fun alright now let's see what happens if we pivot this again okay so we're still high in the center so before I ink this up what I'm going to do is I'm gonna Reese crepe just the center I would like to get it and the reason I want to do that is this could rock when I'm making it so I'm not going to get a good rub so I want to just clear out the center a little bit try to lower it a bit so I don't have a problem with the band's great thing now there's other techniques you could do for this I just found that works for me edges can be really hard on castings so when these cool and one of the things you got to be worried about is this edge because it's so thin will cool faster therefore it will harden up so you got to make sure when you mill and grind this that you get all the way through that and just test it with a file come over the side does it skip if you come over this side that doesn't skip you know you need a mill and grind a little bit more on it let me show you what I did to get this through so I actually went in with the bigger scraper this one just powered through it and you can just see kind of on that finish of how much I had to take down but let's look at it a little more detailed so I've got a 1,000 shim here what I'm going to do is I'm just gonna see if I can put it under there this will also give me a little bit more of the story of what I need to do I should have done this at the beginning just didn't think about it so I'm coming under here just a little bit but overall this is excellent this may not be this may not be that hard to scrape to get it lined up now I'm gonna blue this and I'll show you what it looks like after it's been blued now you can see what I've got hallo hallo hallo so we're just going to concentrate on these blue areas again this is why I went with a lot thicker rub because it really gave me some great information with having a lot of paint hit this if I would have went really thin just showed a little there a little there and wouldn't have helped me out at all we're going to stay with the big one here here with this I'm going to do pretty much a 100% straight in other words it's not going to be a lot of blue left over when I'm done and if it be very the little lighter where I was scrape it on this you can see it right there that I went a hundred percent in one direction then I pretty much just cut it in half from there I don't want to go too much I don't know how far off I am now this is when it's always good to have paint thinner around because I like to clean off the yellow because it starts to get really sticky after a while and it gums up my stone so we're going to stone this again we actually because these are precision ground we're actually getting to read a little bit of a story here what's going on see these little see that little facet right there that was a real high spot the stone knocked it down but I'm gonna take my medium scraper and I'm just going to go in there and knock that out I got a couple there that one was just really big so let's stone it again always remember always smooth out your your ink every time oh there we go now that's working as you can see I don't like to waste my time I like to get in and get it scraped I'm gonna keep going at this level I'm gonna probably stay with the big scraper get rid of this in this when I start getting ink here in the center that's why I'm gonna switch to the medium scraper I finished up my first round of scraping with the bigger scraper with the 140 centimeter radius now you see I've got my blue spots pretty well spread out fairly even so I'm actually ready to go down to the medium tool with about a ninety and what I'm gonna do is I'm gonna start cutting these in half now I may be a little premature on that we're gonna probably take the bigger ones take them out completely but as they're smaller we're just gonna kind of work around it but before we go into that I want to talk about using the bigger scraper and one of the techniques you use with it sometimes you're trying to move as much volume as possible and you're doing a hundred percent scrape that means every bit of this is going to get scrape but I caution you is it can get out of control really quick then all of a sudden you know you go over this a couple times you're out a thousands and a half remember by just going three rounds so what I've done here is you'll see there's actually a checkerboard pattern and what happens is where these lines are those are lower and where in between is actually a little bit higher and that's a great way to control how much you're erasing at one time because really you're removing a lot of material sometimes especially when let me say in relative terms you're removing a lot of material so each time I scrape this with a big scraper I'm moving a half a thousandth at its deepest point well that's a lot of material like I say it can get away from you real easy so just be careful this may be a good plan to go if things are starting to go a little wonky on you go with that and then you can see where your high spots are and then attack the high spots so let's get on to this one and another thing I haven't really talked into much detail is is going in a 45 degree angle this way and then coming this way that averages out your strokes light like to start on one side and I'm still staying with a pretty long stroke around 1/2 inch 3/4 of an inch because I'm not close enough yet and again I'm not scraping 100% I'm scraping about 80 as you can see I'm kind of hunting around and going after the blue spots but I'm still working on consistency the length of my scrapes are all the same length the angle that I'm scraping is all the same like because we need to develop that consistency because you'll find out when you measure things you need to have it predictable so you know what you're doing is right or wrong now we're getting a pretty nice rub as you can see we're starting to get within 1 2 3 4 5 6 7 8 9 10 about 10 points and that's about where I want to be using this scraper having some challenges here have a hollow spot there I'm going to continue this and I'll bring you back when we're ready for the next level of scraping [Laughter] we're now going on to going for 20 points this is looking really good that kind of a hollow area right here which is kind of frustrating just to recap we went in with the big scraper this 140 centimeter radius we've worked with this scraper with a different tip in it and it's tip was 92 centimeter radio now we're actually going to go to 60 on this and we're going to start chipping out even smaller pieces now one of the things you'll notice when you're scraping is because this radius is so much sharper that you actually end up having more control and where your habit with this one here is to just go in get big heavy strokes because you've got to get a lot of weight behind it to get it started this one here has such little resistance that you can go in and scrape much shorter and more precise so I'm gonna go through this whole thing I'm gonna be careful about this hollow spot when I say hollow spot as you can see there's no high spots making it lower I'll bring you back after we get to a really nice solid look of spots on this I'm going to take this down to 20 now I know one of the questions gonna ask well how many times you have to ink it and come back and forth back and forth until you got it to where you need it well let's talk about this so there's different levels so the first level we went with with the larger scraper with a hundred and forty centimeter radius I probably did five passes now we're at probably around 20 crudely around 20 points yeah yeah maybe 15 points some of them are a little large need to be cut in half but you get the idea is to get to where I'm at here probably took another five rounds okay but now when we start getting into really refining to the 20 it may take 1015 times going back and forth so that's a long process I think I'm a little bit faster than most I don't know but it's a long process so I'm gonna get back to scraping see if I can't get this all finished up soon so you guys get an idea of where we're at now this is looking great if I put this on here we're sitting there about 15 points the points are pretty large so now what we're going to do is actually physically start cutting the points in half now when we're inking this up this here is what I would call a medium ink so it's not thick so it was thick right now it would cover this hole in blue in medium it looks like this if I went thinner than this we'd be looking more in this area here so again look at how thick your ink or your paint your pigment is and be very careful on that because you can get a false reading like it's really thin here really thick here but my experience I know where I'm at on this so now we're going to do is physically just cut these in half you can see what we're trying to do by just cut cutting it in half really careful to show you guys I'm just not getting rhythm so now let's look at this you can see the spots are a lot smaller this is the way you start getting down to let's see how many points we have here 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 23 24 we're at around 24 points here but to me it's not a 220 because it's not consistent enough now this may be good enough for the machine you're working on right now if I was working the ways on a bridge port I'm darn close I'm probably about 2 3 scrapes away before I've got it just the way I'd want it for a bridge port but we're taking this we're now getting down to the final stretch we're getting a really consistent area of spots still a little thin here still a little thin here but overall it's looking great now now I want to talk about how to read the spots themselves and that's where it gets tricky but when you start to think of it logical you'll see what I'm talking about if we take one of these spots in this area you'll see that there's a dark rim around it and the height and in the center it's thin its thin because that's a high point so you gotta think of it as a mountain where when the blue touched sit on this surface plate it actually squeezes out and goes down to the side and that's what we're seeing here and we're getting at that point where we're scraping dots okay some people call it hunting and pecking well you'll see why here in a second we're gonna actually come in here with a scraper and we're just gonna be looking for the Centers and we're just gonna bump them and we're just after centers now I will tell you I'm a little premature I'm simply doing this part here because I've got too many low spots but I want to show you that and I want to also get this video done another way of doing it Tom Lipton came up with this basic concept and it's a bump scraper and it allows you to come in with a very controlled amount of force and you just tap tap tap tap now I built one of these the first one I made didn't work I changed the design I went around to a very flexible tip here this is actually a spring steel but I'm still having a problem I had a lot of problem with chatter so you could look at the cut and it was chattered through and so I called up Thomas and hey Tom what are the challenges you're having and what did you do to fix the chatter and what he ended up doing was he actually set up the hammer part and put a bronze Bush in there so it doesn't vibrate because you can imagine that vibration transfers through and chatters and he also put a rubber hose here and between those it absorbed the vibration and gave it a smooth cut what I did was I went in with a couple o-rings and a plastic disc and that's the way I absorbed the vibration so let's back up and talk about the three threes again we talked about how do we control how we're scraping while we do that with pressure length of stroke and also the shape of the cutter itself number two we think about the inking and there's three steps in the inking a real thick coat a thin coat and then when you really getting refined past 40 points will you get into actually new doing no inking and you just end up getting mirrored surfaces then we talk about a real coarse scraping to just remove a lot of material and we use usually a bigger more extensive radius like this which is 140 centimeters then after the course and we've got some big splotches that are consistently spread over we go to a more refined like a ninety radius and we start breaking that down and we get that within I don't know 15 points or so then we want to get to 20 points is where most machines are scraped - we end up using a 60 centimeter radius and now since this is actually going to be a reference surface I'm going to take it past 40 and it's a long process and I think it might be kind of boring to watch the whole thing but you'll get to see it in other videos so I don't know if you guys have noticed this sitting in the corner this is actually a slow speed grinder or sharpener that I built and there's actually a video gun coming out for this so look for that and in that video I'm going to cover something I didn't cover in this video and that's how to sharpen all these cutters and how I approach it using the slow speed grinder and also in that video I show you how I made this entire thing alright guys I want you to go out and shake take this on challenge it like I said you can use very simple tools you can just use it file if you like - it's not that's not that big a deal remember we're about going out in the shop and building something cool so that's the conclusion on this video I hope you guys enjoyed it there's a lot of material the best way to learn it is to just go out in your shop and do it it's not that big a deal just go for it also if you liked this video please give me a thumbs up also don't forget to subscribe and click that little bell and until next time go out in the shop build something cool thanks

Channel: Build Something Cool

Views: 361,162

Rating: 4.7189617 out of 5

Keywords: Milling machine, Metal Lathe, Lathe, Metal scraping, Scraping for alignment, Richard King, Richard King scraping class, Keith Rucker, Tom Lipton, How to scrape metal for flatness, Hand scraping, And scraping for alignment, How to use a scraper, How to scrape the milling machine, How to scrape a metal lathe, the richard king way

Id: T7w84CrBEE8

Length: 31min 31sec (1891 seconds)

Published: Fri Nov 23 2018

Reddit Comments

[u/m3ltph4ce]

This was surprisingly interesting