Scraping basics - Scraping flat - Part 2

[Music] and you always want to fart to be very clean before you go back to the surface plate okay clean the you can use your bare hands to wipe down the blue area on the surface plate the connote paint cleaned off every unit from your hands with water and soap you don't want to do that with the bike and otherwise you look like Papa Smurf which is ridiculous when your top two metres tall okay we're up tit defer to flip it over we hinge it it seems like you can also use just a pen and drop it on the park while you hinge it and watch the motion of the pen to find the hinge point feels about here and over here okay over here we have to score not high this corner is high so flip it around take a look at it this corner is high and this corner up here is high there are just attacking this area here we're trying not to scrape too hard and to the area here which we did before and we ignore all the other blue again okay I knocked down the high area from the last pass and when you look at the hinge now it's rotating around this point pretty much and same on this side almost like here so that's pretty much 33% so now we know that the blue that we get here is the actual bearing pattern of the part because it cannot wrap erect rocking back and forth so now we attack all the blue areas really all of them okay I scraped one more pass and I got pretty much one one blue spot per square inch to take our stage this is this is almost four to five points per inch right now except for this area here this obviously is low because there is not a single high spot in there we cook on and scraped semi-rough all the blue for two or three passes down this will take forever so we can do something that's called blind scraping we will straight everything except for this area one or two times just hitting the whole surface with the scraper removing a little bit of material that's what we're going to do now [Music] now we offset 90 degrees and go a second time still ignoring this area and in this stage you still can stone pretty hard without doing any harm I went on two passes more by hand and this is what I will consider reasonable flat to proceed on when I take the gauge with the one inch by one inch window in it no matter where I move on this test piece I will always find a high spot a blue spot in the window so that means the bar is reasonable flat and I can confirm that on the surface plate the most obvious thing to check the flatness of course the bluing but as we saw earlier this can lead to misunderstanding or to fake bluing because part is rocking or tipping or something stupid like that that means we have to find a way to well edate well yes well date our bluing for example hinging the part and when I hinge the cart you see that we are rotating around these points that gives us already a very very good indication of support is is high in the middle or not then you can go by I found until you knock the part with a plastic hammer or copper wrist or something like that and you listen if it if you if it bounces you will hear it and that means there is a hollow and it's also tipping and what I like to spit slower but what I like is to use an indicator place an indicator on top of the part in different areas and I press down on it you do this preferable on the end because it's the part is hollow in the middle you cannot depending on the parts geometry it would have to bend down the part but mainly we want to see if the part is rocking and you do this for example in all corners then you have a very good idea what's going on this part is pretty darn solid flat you can also use some feeler gauge stock or a feeler gauge the SM is possible my thinnest is for hundreds of a movement that one and a half thousand of an inch so this is pretty sick so in this state we don't need this anymore but when you go around the edge of the work piece in the roughing state you can find hollows pretty easy that way just going around checking if there is something stupid going on and one last thing you can do to check if it's high in the middle in this direction we can use a 1-2-3 block for example or any other ground block place it on top make sure it's clean and stoned well and hinge the 1-2-3 block and check where its points of rotation or this looks they're doing good this was a little bit harder to identify but also a good way to do it and it helps always the problem with hinging the part is it's hard to hinge for example about Taylor prismatic wave cottage locked in one direction there's only so much degrees of freedom if you're working on a slight way is to find out a way to check for bow but as I said dial indicators can check a lot by hinging by hammering down on the part you have to find a way to verify you're moving otherwise you make a pretty blue surface you scraped it until it's very pretty blue and all you made a nice rocking chair that make sense at all so now we continue on now we can stop rocking and go a little bit finer before we go on it might be a good idea to riche or more carbide insert because we did a lot of roughing now and I feel it already getting dull and you can check it just like a just like a sharp blade when it peels off nice trip from your fingernail when it catches on your fingernail it's pretty darn sharp or when you run your fingernail along the edge you shouldn't feel any any imperfection in this curve so this is this is my striper blade sharpener it comes system an old high-speed bench grinder 3000 rpm 150 millimeter diamond wheel from eBay China they come in different grits they are 150 millimeter in that diameter this is a 1500 grit mounted on here is a 3000 grit and they are cheap I think there are about 10 to 12 bucks free shipping from China and they work really good they leave a nice crisp finish on the carbide inserts I started to use this also for a sharpening carbide tooling for the lathe for example so we take our carbides out of the straight cake and this is real just cobbled together the bench grinder is bolted to old piece of wood and I have a rest in front here that's Chet screwed on and it shimmed in the back so it's five degrees up towards the blade like this and that's all you need for scraping cast iron 5 degree negative and a surface or it can rest your blade on just like this it will turn on the grinder and just sweep the curve like this sweep it like this dumb once you have the five degree negative on the blade and you use always the same rest to rewind it with the same setting regrinding goes super fast and there is not much need to do heavy roughing anymore yeah this grinder doesn't run super smooth it wants to move away on me but that's fine let it move just using a little bit of glass cleaner for lubrication and you check your grind and surfers really ginger is really pretty darn good which displayed or with this which is Grindr that's just a piece of phenolic as a support for the same sheet metal diamond wheel and that's it took me about an hour to cobble it together while it looks really cheap and stupid it works quite well surface finish on the car by this is what you would expect from a proper car back grinder now we are at the point where we can scrape a little bit more refined than just scraping paint off until now we really were going in and removing a whole lot of material now we can start to create something that's general known as checkerboard pattern we will create individual scrape marks that do not touch each other in one direction then we come back and we place another row of those scrapes marks great marks along the surface and that will in the end create something that looks a little bit if you hold it up against the light that will resemble the classical checkerboard pattern that we see on old machines as we will not blindly go over the whole surface we will try to identify again the real area that need scraping we will leave for example this here we won't touch this because it looks a little bit low we won't touch this not this this is also not good we might leave something like this away this doesn't look too high - but apart from that maybe this here - so what a leaf the green areas the green films on harm and for the nice pattern on the remaining ones we shorten the length for her stroke now - we are not going to use a 20 minute long stroke by hand anymore would maybe reduce it to something like 10 10 millimeters 8 millimeters that way the pattern will also get more even and the surface will get nicer [Music] [Music] okay lentils first pass now we go clean it and blew it okay it was pretty hard to film or show bluing on camera so I had to turn turn off two of my overhead light and I bumped up the ISO sensitivity of my camera so my produc should show up pretty good and I used the canoed a little bit and I wrapped it heavier so I went on a few passes just using short strokes and removing the areas that were heavy blue and as you can see without having to do anything with the high spots itself I got I got already a pretty good bearing there we take our one inch square here and replace it here we can we can count the bearing points this is 24 over here one to machine 19 this is 19 out here we have maybe just one 21 and out here this is the burst area 1 2 3 16 so 16 24 1921 we're getting there even without having to do anything special about trying to hit one okay speaking of high spots it might be time to explain the meaning of the bluing let's say we have a surface plate down here and we roll down a layer of the blue paint no matter if it's like an orican owed or Prussian blue or whatever some non-drying blue then we have a piece that has a roughness to it for example this create the landscape I drew up here and when we take the workpiece against the surface plate and we rub it then it will be blue around these high spots it will collect around the top of the of the high spot and the high spot will have a very faint bluing surrounded by a very heavy ring of bluing some of the not so high high spots will get some bluing they will have a relatively dark blue on the top and depending on the height of the valleys some of the very low high spot might even get a little bit of blue and when you check out the bluing of your workpiece you have to keep those in mind you have low high spots medium high spots high highs but there is another kind of super super high spots verda the color on top gets polished off completely so that's I will I will remove this blue up this workpiece and show you what I mean here we have a good selection of the different icebox we have a light blue surrounded by very heavy blue around it this this all these these are pretty high points the bluing gets rubbed on on off the top of the high spot and gets squished around it and that creates this ring of heavy blue around then we have lighter blue point these are but medium height these here they don't have they are blue that they don't have a heavy ring around them and I cannot IO here this is a very very low high spot this one is only very faint blue and is pretty much below surface off of these ones here and you want an average be most of your points like this like the high spot surrounded with the bluing that's what we're aiming for and that will give you a good bearing the percentage of bearing is the relation between the surface area of the high spot in a certain area to the low spots like this low spot is everything that's not covered by blue after you rub it that's a low area and only the high spots are bearing and carrying the load load bearings and you want for a slide surface sliding surface like a machine weigh about 50% of bearing surface you can't you can change the percentage just bearing with stoning but you have to be careful not to knock the surface convex or concave when you do the stoning now as we have a bearing across the whole surface we can start to pick out individual points and create them we would take the scraper and just remove high spots like these this will take some time if you have to do a full pass this takes really at some time metal creates basically a complete new pattern on the bluing slightly lower and it will increase the bearing surface because points like these that are very faint might come into contact then yeah and that's what we're going to do but you still have to together a nice pattern you have to follow the rule of the individual scrape marks who want to do this and not do this with your scrape marks this will end up as a very horrible surface especially not only for vishal but also when you blew it up become official in the end effect will create a full high spot this will create a hole and at this point it gets really tedious i already did one pass knocking down all the high spots and as you can see this looks pretty darn good for just a practice piece or demo piece [Music] I change to a 40 radius blade and I will do one more pass and then the other compound the confidence just a demo piece anyway I won't don't want to put too much work into it so let's go and if you see a very large high spot you can also split it in two it just goes through the center of it like this and you have to thought to decide on the fly which you consider a high spot or not so high spot otherwise it will take forever okay that's what it looks after the last tasks I did I will leave it there you cook from now on you prove it piece by piece that's really the basics off scraping something flat you need a scraper you need a surface plate you need a way to show the scraper blade and you need some high school glue and patience and patience and seeing me hand scrape that's also the reason why they invented the power strip or the power scraper this goes so much faster so I think that's enough for a first episode on hand scraping I plan to do one or two more videos in the next one I want to show how to align surfaces to how to scrape square and parallel and also how to use a power scraper at least basics of using a power straighter I really have to say thank you to Melanie who brought the matter of scraping in and back to the mind of the hobbyist in Germany back a few years ago when he did a very good post about rebuilding when he started to rebuild a small surface grinder and when he rebuilt his my for cylindrical grinder he figured out very much after scraping by his own and he got a pretty darn good really and he has a lot of videos for he does aligning and measuring and those are worth checking out even if nick is not doing videos right now but I will put a link down in Scripture to Nick's channel also big shout out to mr. Richard King he is really a wealth of knowledge and a genuine good guy I learned the class really a lot from him Gazza had the opportunity to do some hands-on learning with him it improved my scripting quite a bit I think and it made me faster which was main reason I went there and yeah if you want to learn hands on scraping try to get into one of his classes it's it's a lot of money but if you have some interest in it that might be worth it so check out I think it's hand scraping comm I will also put the link down in description to Richard and yeah he's not going to do the class forever he's planning to retire so yeah thank you all for watching and see you next time [Music]

Channel: Stefan Gotteswinter

Views: 133,886

Rating: 4.948112 out of 5

Keywords: scraping, schaben, flachschaben, handscraping, biax, renz, richard king, richard, mueller nick, dykem, canode, high spot blue, carbide, diamond wheel, diamantschleifscheibe, flachschaber, tuschierfarbe

Id: S9N3Q8Qww2A

Length: 27min 57sec (1677 seconds)

Published: Sun Jun 11 2017